• r----------------------------------------------- 1 AD Accession No I I U . S . Army Snow Ice and Permafrost Research l. Establishment, Corps of Engineers, Wilmette , Ill. I. EXCAVATIONS IN FROZEN GROUND. PT. II: II. EXPLOSION TESTS IN FROZEN GLACIAL TILL, III . FT. CHURCHILL-C. W . Livingston and IV. Glenn Murphy SIPRE Report 30 , pt. II, July 1959, 19 pp-illus v. tables. DA Proj 8-66-02-400, Contract DA-11190-ENG-17, SIPRE Proj 22.4-5 Unclassified Report Explosion tests were conducted in frozen ground near Fort Churchill {Man.) as an extension of previous tests in Keweenaw silt. Atlas 60 Per cent Straight Gelatin Dynamite, Demolition Block M5 Composition C-3, and Atlas Coalite 7S Ammonia-Base P e rmissible Dynamite were used as the explosives i n amounts ranging from 0. 5 to 20 lb. Approximately 150 craters were produced. The charges were cylindrical with height-diam ratios from 0. 12 to 9. 12, with the majority {over) r-----------------------------·----------------- 1 AD Accession No I I U. S. Army Snow Ice and Permafrost Research l. I I Establishment, Corps of Engineers, Wilmette, Ill. I. I EXCAVATIONS IN FROZEN GROUND. PT. II: II . I EXPLOSION TESTS IN FROZEN GLACIAL TILL, III . I FT. CHURCHILL -C. W . Livingston and IV . I I Glenn Murphy I I SIPRE Report 30, pt. II, July 1959, 19 pp-illus I v. tables. DA Proj 8-66-02-400, Contract DA-11190-ENG-17, SIPRE Proj 22.4-5 Unclassified Report Explosion tests were conducted in frozen ground near Fort Churchill {Man.) as ap extension of I previous test·s in Keweenaw silt. Atlas 60 PerI I cent Straight Gelatin Dynamite, Demolition Block I M5 Composition C-3, and Atlas Coalite 7S I I Ammonia -Base Permissible Dynamite were used I as the explosives in amounts ranging from 0. 5 to I 20 lb. Approximately 150 craters were produced.I The charges were cylindrical with height-diam I I ratios from 0. 12 to 9. 12, with the majority I {over) I I I L---------------· ----""'-----------~----------- -------------------------r------------------------------------------------ UNCLASSIFIED 1 AD Accession No . I Explosives--Applications I U. S . Army Snow Ice and Permafrost Research 1. Livingston, Clifton Establishment, Corps of Engineers , Wilmette , Ill. I. Murphy, Glenn EXCAVATIONS IN FROZEN GROUND. PT. II: II. Barodynamics, Inc. EXPLOSION TESTS IN FROZEN GLACIAL TILL, III . U. S. Army Snow Ice and FT. CHURCHILL-C. W. Livingston and IV. Permafrost Research Glenn Murphy Establishment SIPRE Report 30, pt. II, July 1959, 19 pp-illus Contract DA-11-1 90- v. tables. DA Proj 8-66-02-400, Contract DA-11 ENG-17 190-ENG-17, SIPRE Proj 22.4-5 Unclassified Report Explosion tests were conducted in frozen ground near Fort Churchill {Man. ) as an extension of previous tests in Keweenaw silt. Atlas 60 Percent Straight Gelatin Dynamite, Demolition Block M5 Composition C-3, and Atlas Coalite 7S Ammonia-Base Permissible Dynamite were used as the explosives in amounts ranging from 0. 5 to 20 lb. Approximately 150 craters were produced. The charges were cylindrical with height-diam ratios from 0.12 to 9. 12, with the majority {over) ------------------------·r------------------------------------------------ UNCLASSIFIED AD Accession No Explosives--Applications U. S. Army Snow Ice and Permafrost Research 1. Livingston, Clifton Establishment, Corps of Engineers, Wilmette, Ill. I. Murphy, Glenn EXCAVATIONS IN FROZEN GROUND. PT. II: II. Barodynamics, Inc. EXPLOSION TESTS IN FROZEN GLACIAL TILL, III. U. S. Army Snow Ice and FT. CHURCHILL-C. W . Livingston and IV . Permafrost Research Glenn Murphy Establishment SIPRE Report 30, pt. II, July 1959, 19 pp-illus Contract DA-11-190- v. tab1es . DA Proj 8-66-02-400, Contract DA-11 ENG-17 190-ENG-17, SIPRE 'Proj 2.2.4-5 Unclassified Report Explosion tests were conducted in frozeq ground near Fort Churchill {Man.) as an extension of previous tests in Keweenaw silt. Atlas 60 Per I cent Straight Gelatin Dynamite, Demolition Block I I M5 Composition C-3, and Atlas Coalite 7S I Ammonia-Base Permissible Dynamite were used I I as the explosives in amounts ranging from 0. 5 to I 20 lb. Approximately 150 craters were produced. I I The charges were cylindrical with height-diam I ratios from 0. 12 to 9. 12, with the majotity I I (over) I I I I -----------------------· L---•------~----------~--------a--------------- · ------------------------, UNCLASSIFIED : I Explosive s--Applications I Livingston, Clifton I I Murphy, Glenn I Barodynamics, Inc . .I I U. S. Army Snow Ice and IPermafrost Research I Establishment I I Contract DA-11-190- I ENG-17 I I I I ------------------------, UNCLASSIFIED : Explosives--Applications Livingston, Clifton Murphy, Glenn Barodynamics, Inc. U . S . Army Snow Ice and Permafrost Research Establishment Contract DA-11-190 ENG-17 I I I I I I I I I I I I I I I I I I I I I t -----------------------..1I .----------------------------------------------------------------------------r----------~,--------------T' --------.-,. -----------~-r-------------------.-..----.--, between 2. 5 and 4. 0. The depths of c h arges varied from quite shallow to sufficiently deep that no surface effect was observed. In general the r.esults vet;ify scaling law.s and show that the critical depth varies a s the cube root 'bf the weight of the charge. Cons i s tent d iffer ences in performance of the explosives were observed. The s hape of the charge also influenced the results , but scatter of the data preclude establishing conclusive trends of the influence. Detailed data on the shapes and sizes of the individual craters are reported. between 2. 5 and 4. 0. The depths of charges varied from quite shallow to suffic iently deep that no surface e ffect was observed. In general the results verify scaling laws and show that the critical depth varies as the cube root of the weight of the charge. Consistent differences in performance of the explosives were observed. The shape of the charge also influenced the results, but scatter of the data preclude establishing conclusive trends of the influence. Detailed data on the shapes and sizes of the individual craters are reported. I I I I I I I I I I I I I I between 2. 5 and 4. 0. The depths of charges varied from quite shallow to sufficiently deep that no surface effect was observed. In general the results verify scaling laws and show that the critical depth varies as the cube root of the • weight of t h e charge. Consis tent differences .in •performance of the explosives were observed. The shape~of the charge also influenced the res ults, but scatter of•the data preclude establishing conclusive trends of the influence. Detailed data on the shapes and sizes of. ~he individual craters are reported. between 2. 5 and 4. 0. The depths of charges varied from quite shallow to sufficiently deep that no surface effect was observed. In general the results verify scaling laws and show that the critical depth varies as the cube root of the weight of ~he charge. Gonsistent difference s in performance of the explosives were observed. The shape of the charge also influenced the results, but scatter of the data preclude establishing conclusive trends of the influence. Detailed data on the shapes and sizes of the individual craters are reported. -------------------------, L-----------:-.----~---------:-;---------------------------------------------------------~---------------~ ------------~-----~---~ Stp~te !!< The surface of the esker was cover ed in places with a thin layer of frozen gravel. B e low the gravel was a layer of unstratified till, which consisted of silt interspersed at random with rocks that had been carried long distances b y the glacier and with irregularly shaped blocks and boulders of dolomite that had been plucked by glacial action from the underl ying dolomite beds and carried along with the load of glacial debris. Details of the subsurface stratigraphy at the test site are shown in the graphic log of well no. 3 , (Fig . 2). As might be expected, the material varied from place to place within the test area, depending upon the extent to which the unstratified till had been reworked b y stream action. Instrumentation and temperature records Weather data during the test p eriod, a s recorded daily at the Fort Churchill Meteoro logical Office, are plotted in Figure 3 . '~ R e port by Cornell University states that this is not an esker but an old beach. EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL 3 N DESkiNO PT . tf C\l•l}Do a no g " ~ 0::: w > 0 A C)C' 0::: ..J 0 0 G 0 {1 ..J ......... u a: :::::> 0 0 {J ~~ oo 11<3 :::c u Figure l. Site location map. EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL IRELATIVE GEOLOGIC WEL~I 0 £SCRIPTION RELATIVE GEOLOGIC WELL DESCRIPTION DEPTH COLUMN DEPTH I EPTH COLUMN DEPTH •• 0 0 GRAVEL D 0 0 .::v..=:a: 3: 5.0' +50 FEET +40 +30 +20-+...!.Q_ 00 -· =.-;,?~ CLAY a GRAVEL -.D-_o_ :i=o~o= 20.0 ' _o:=-c~ CLAY, GRAVEL a -A--o-Q.. ORGANIC MATTER , -c•-:: 31.0' _O:..J_fL. CLAY a GRAVEL ~J.:::!'.:=. 41.0 ' ----CLAY ---51.0' ;,-"--"-•-o--o=0-=~~f--__gA_ LEVEL +50 + 40 + 30 +~ +~ 00 FEET {~.:~:. 20.0' 23.0' :l'~ -o-o-.o:1=A.J:: -4-D-.Ly.=c 40.0' ' D , D • ' 0 /J ' .' IJ ' , 0 • 13 SANOY GRAVEL SAND a CLAY CLAY a GRAVEL GLACIAL MORAINE SEA LEVEL -...!Q. -20 - ~""""!:::. --v -o -o"JZ~~-= 0 no ,0 .' ;:.·.· .· 72.7',73.5,77.6 CLAY, GRAVEL 8 ORGANIC MATTER GRAVEL -...!.Q.. -20 CLAY, SAND a GRAVEL 2Q. ·0 -o-- ~ LL a: 0 UJ a.. 0 ::IE UJ .... MARCH APRIL MAY 60 WIND VELOCITY > !:: u 0 40 -I UJ X > a.. ::IE 20 0 z i 0 13 MARCH APR I L MAY Figure 3. Weather data. 3) Atlas Coalite 7S Ammonia-Base P ermissible Dynamite were detonated in frozen glacial till, using the schedule of tests shown in Tabl e I. P ercussion drilling P rincipl es of similarity required several different diameters of blast holes for the tests. At the beginning, the effect of charge shape upon the results of blasting was unknown. Moreover, the Keweenaw explosion test data indicated that considerable variation in charge shape was possible for critical depth blasts without influencing greatly the results. Blasts in rock (Livingston, 1949, p. 38-39) show that the shape of the charge materially affects the volume of the resulting crate:-. However, a means of measuring the effect had not been devised prior to the Churchill explosion tests. In practice, a blast hole with as small a diameter as possible will be used because of the greater speed of drilling and because of the increased size, weight, and cost of EXPLOSION TESTS IN FROZEN GRO UND, F T . CHURCHILL Table I. Schedule of tests for each explosive. w d c Charge weight Distance from ground surface to (lb) center of gravity of charge (ft) 0.5 0.5 l.O 1. 5 2 .0 l.O 0.5 l.O 1.5 2 . 0 2.0 l.O 1.5 2 .0 2.5 3. 0 5.0 1.5 2.0 2.5 3 .0 4 . 0 20 .0 3 .0 4 .0 5.0 6 .0 7.0 From 2 to 4 additional shots were made with each expl osive . machines capable of drilling large-diameter holes. P reliminary tests at Fort Churchill showed that auger drilling and rotary drilling with a t ri-cone roller type rock b it using the same equipment that had been used successfully in frozen Keweenaw silt (Livingston, 1956, p. 19-21) could not b e done in froz en gravelly silt b elow a mantle of frozen gravel. A heavier Failing drill, using a tri-cone roller b i t and operating at greater bearing pressures, was able to drill the frozen ground. The range in hole diameters selected after consideration of the several factors was from l 13/ 16 to 5 in. The drill holes, in addition to penetrating a thi n mantle of frozen gra vel, were apt to penetrate almost any kind of boulder embedded in the till. The boulders range in l east dimencion from 4 to 14 in. and are flat, angular, or rounded (Fig . 6). Boulders en countered were metamorphic, sedimentary, and igneous. Roc k type ranged from acid~c such as granite to ultrabasic such as peridotite . Cuttings removal becomes exceedingly difficult if ground temperatures closely ap proach 32F, regardless of the design of the b it. Bits for the Churchill tests were designed specially by Barodynamics, Inc ., u s ing exp erience gained in drilling frozen Keweenaw silt. In order to supply sufficient air to the bottom of the hole to remove the cuttings, the air passage through the center of the drill rod should be as large as possible. As the diameter of the hole is increased beyond 2 l /2 in. , the normal blow air must be supplemented (Fig. 8). It would be desirable when drilling large-diameter holes in frozen ground with a rock drill to use two compressors --one for air to operate the drill and one for blow air . The compressor used to supply blow air should perhaps be equipped with an aftercooler. The arrangement of e quipment used for percussion drilling of blast hole s for the Fort Churchill blast tests and details of operation are illustrated in Figures 7 and 8. Blasting The procedure used for blasting with commercial explosives at Fort Churchill was the same as that used at Keweenaw (Livingston, 1956, p. 21) except that the wrapper s were removed from the cartridges at the time of charging the hole to eliminate variations in loading density with variations in hole size and to maintain as high a loading density as possible. Military explosives were not used in the Keweenaw tests. Demol ition Block Figure 4. Measuring blast M5 (Composition C-3 ) used in the Churchill hole ground temperature. tests, was the most difficult to detonate. EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL 7 30 20 10 3'b 3 FT DEPT H 20 LL. 0 10 0 30 5 FT DEPTH w a: :::;) 1eX a: LLI D.. :IE LLI 1 10 0 30 7 FT DEPTH 23 2!1 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 2 4 . 6 8 MARCH APRIL MAY Figure 5 . Ground temperatures It is so insensitive to shock that the detonation wave initiated at the top of the charge with a strong booster may die out before reaching the bottom of the charge . Consequently , a special p riming and charging technique was used that resulted in two simultaneous detonation waves advancing in Primacord extending the full length of the charge . Plan of th e tests The schedule for each of the three types of explosives was the same (Table I) . Since each of the three types of explosives had a different density, the volume of each explo sive required for a given weight differed. 8 EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL Figure 6. Drill hole through an angularFigure 7. Drill rig used for shaped granite boulder that was embedpercussion drilling. ded in frozen till. With the range of hole diameters estab lished as 1 13/1 6 -5 in., the ratio of the height to diameter of charge (H/D ratio) was determined in order to apply principles of similarity in conducting the blast tests . The first blasts (blasts 1-21, App. A ) were designed to provide information useful in answering the following questions: 1. Is the volume of crater produced by blasts in frozen ground influenced by the shape of the charge? 2 . What charge shape should be used in the Churchill tests? 3. What spacing between blast holes should be used? Figure 8. Supplementing normal blow 4. Can the Keweenaw tests results be air with air from a blow pipe when drillused to predict performance of the test ing large-diameter holes . explosives in frozen unstratified till and stratified glacial drift? From field analysis of the first 21 blasts, it was concluded that: 1. The shape of the charge influences the volume of craters. 2 . As wide a range of charge shape s as possible should be explored if time per mitted, but a charge shape of H/D = 4 might b e the only shape that could be explored completely. 3 . A spacing between blast holes of 7 times the depth of center of gravity of the charge should be maintained. 4. Optimum weight and critical weight in frozen till could be predicted from the Keweenaw tests data much more closely than one might assume, considering the difference in physical properties of frozen Keweenaw silt and Churchill glacial moraine . The general plan of tests was to complete all of the blasts with one type of explosive before beginning with the next type. The tests were started with Atlas 60 P ercent Straight Gelatin Dynamite (Atlas 60), which had been used in the Keweenaw tests, to show up any difference in behavior that might require modification of test procedure . ~ ., . EXPLOSION TESTS I N FROZEN GROUND, FT. CHURCHILL Table II. P rop erties of the F ort Churchill test explosives . P roperties Military C -3 Atlas 60 Coalite 7S V e locity , ft/ sec open - 16, 000 8,000 V e locity, ft/ sec confined 26,000 20,000 10,000 Fume classification toxic good good Cold resistance good good good Cartridge strength - 60 44 Weight strength - 52 . 3 61. 9 Absolute weight strength - 70. 6 76.6 Density, in3/lb 16.90 17. 35 20.49 Specific gravity l. 49 l. 45 l. 1 6 Stick count - 97 123 In general, a ll of the 0. 5-lb blasts were fired first, then all the l. 0-lb blasts, e tc. Order of firing is indicated by the crater number. If, after field inspection, it appeared that any feature of a re s ulting crater was inconsistent with other shots of the same s eries , repeat bla s t s were fired. All pertinent data for any blast are recorded on the data sheets in Appendix A. Characte r i stics of the test explosives Cttaracteristics of Atlas 60 P ercent Straight Gelatin Dynamite and Atla s Coalite 7S Ammonia-Bas e P ermissible Dynamite are discussed in detail in the report of the Keweenaw tests (Livingston, 1956, p. 7-10) . Composition C-3 R70WA (Demolition Block M5) has a higher velocity than Atlas 60. The three test explosives exhibit an extreme range of velocity . Characte r i stics of the m edium All of the blasts of C-3 and Atlas 60 and the 2. 0-lb and 5. 0-lb blasts of Coalite 7S were made at blast site A (Fig . 1). The 20-lb charges of Coalite 7S were fired at blast site B, since space at site A was insufficient .::':or them. Blast sites A and B, both in the same esker, represent d ifferent types of froz en ground. There has b een less reworking of the glacial till by stream action at site A than at site B. A layer of gravel ranging from 6 t o 10 in. thick was usually encountered at blast site A (Fig. 9). Below the gravel layer, igneous and sedimentary boulders are dispersed at random in a matrix of unstratified frozen silt. The unstratified frozen ground probably represents glacial moraine not reworked by stream action and is referre d to in this report as "unstratified till". The gravel layer is a result of stream action. The layers so reworked and stratified are referred to here as "stratified drift". It is difficult to obtain a representative sample of the unstratified till for unit weight determinations b ecause of the variation in size and composition of the boulders and their random dispersal throughout the silt matrix. The weight and volume of five large frozen chunks of unstratified till which contained small boulders and p e bbles in the silt matrix were determined in the field. Unit wet weights ranged from 147.2 to 149. 6lb/ft 3, a veraging 148. 7 lb/ft 3 . At blast site B, a layer of frozen vegetable matter containing ice lenses up to 3 in. thick (Fig. 10) was present in some places. The thickness of the vegetable layer varied from place to place. The maximum thickness observed was 12 in. Below the vegetable layer a layer of frozen gravel ranging from 12 to 3t in. thick had been deposited on top of the unstratified till. Field weights and volume measurements of chunks produced b y near optimum weight blasts at site B were taken. The a v erage unit wet weight of the frozen vegetable layer was found to be 74. 6lb/ft3. The average unit wet weight of the frozen gra vel was found to be 143.3 lb/ft3 . EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL .. Figure 9. "0" cracks in unstratified glacial till below a layer of stratified drift stripped by blast action, blast site A. MEASUREMENTS Flyrock travel The relation between energy utilization and flyrock travel had been observed in the Keweenaw tests. It was concluded that motion pictures would supplement visual observation and possibly increase the accuracy with which the critical depth Figure 10. Surface layer of frozen vegetable matter stratified parallel to ground surface, blast site B. could be determined. Flyrock-travel investigations were directed, therefore, towards a study of the crater rather than of venting phenomena . Blast holes were laid out in rows. Individual holes were spaced to avoid the possibility of one crater breaking into another. A hole spacing equal to 7 times the depthof center of gravity of the charge was maintained. A 10-ft high target, graduatedvertically in 1-ft intervals, was placed at the end of each line of holes to be blasted at one time. Motion pictures of shots were taken from the firing position at right angles to the line of hole s and at a distance approximately equal to the range of horizontal flyrock travel. Blasts we re fired when ready, regardless of visibility. A Bell and Howell 16-mm Corps of E nginee rs movie camera, operating at a nominal speed of 64 frames persecond was used. Pictures were taken in black and white, using Super XX film . Because of the extreme cold weather , the camera operated at less than the nominal speed.The arctic landscape in an atmosphere of blowing or drifting snow does not provide a good background, particularly for small blasts taken from 300 to 500 ft away . B etter results were obtained for larger blasts from the same distances, and excellent r e sults were obtained for near-critical-depth shots using a telephoto lens from 150 to 200 ft a way. V ertical flyrock travel-height was determined from measurements on a calibrated screen using a 16-mm projector. It was found by experience that the linear scale could be obtained more accurately using the known distance between blast holes at the two ends of the blast line than using the 10-ft vertical target. EXPLOSION TESTS IN FROZEN GROU:-.JD, FT. CHURCHILL 11 Field analysis and crater surveys P rocedures followed in field analysis and in taking measurements of craters were the same at F ort Churchill as those described in the Keweenaw report (Livingston, 1956, p . 21-22) . B ecause blasts were larger than those at Houghton, Michigan, crater cross sectioning ey_uipment was modified and a special p l atform was constructed by the Field Test Team Arctic for taking crater photographs. The platform was mounted on a forklift so that the camera could be raised or lowered, depending upon the diameter of the crater being photographed. Data sheet computations The details of each blast and the characteristics of the resulting crater are summarized in the data sheets (App. A). Calculating crater volume C alculation of the volume of a crater produce d by a blast was made from two cross sections and a plan map of each crater. Two mutually perpendicular cross sections through the center of the drill hole were made to scale using a crater profiling rig. These cros s sections were designated as cross section A a::J.d cross section B. The plan view was mapped to scale using an alidade and a plane table. Crater volumes were calculated in two ways. The cone-formula method used in the Keweenaw report is less accurate than the centroid volume method introduced in this report. If the crater is trumpet-shaped, the cone-formula volume is larger than the centroid volume. If the crater is spherical, the cone-formula volume is smaller than the centroid volume. The shape of the crater is influenced not only by the depth ratio but also by the type of explosive, the material blasted, and the charge shape ratio. The coneformula volume method is as follows: 1. The areas of cross section A and cross section Bare measured w i th a planimeter. The two cros s-sectional areas are then averaged to minimize error due to irregularity in the crater s h ape . 2 . The plan area of the crater is determined by planimetering the plan map. 3 . The radius for each crater is calculated assu=ing the planimetered plan area to be a circle . 4. The crater volume is then computed using the formula V = iT Ar 3 where V = the crater volume A the average area of the two cross sections A and B r = the radius of a circle of area equal to the crater area. The centroid volume method is as follows: 1. Areas of cross section A and cross section Bare measured with a planimeter. 2 . The cross sections are traced upon a piece of stiff cardboard. The tracings are then cut out of the cardboard and exact working models obtained. 3 . The model of each cross section is then cut into two pieces along the center line of the drill hole . 4. The centroid of the right side and of the left side of cross section A was located. 5 . The perpendicular distance (centroidal radius) from the center line of the drill h o l e to the centroid of the right and left side of cross section A was measured. An average value was obtained from the two measurements. 6 . The measurements were repeated for cross section B. 7. The crater volume was computed as follows: 12 EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL where VA = the crater volume as calculated from cross section A RA the average centroid radius of cross section A, AA = the area of cross section A; where = the crater volume as calculated from cross section B , VB = the average centroid radius of cross section B, RB = the area of eros s section B; hence AB VA+ VB v = 2 where V = the crater volume averaged from the two cross sections. For meaning of other symbols and definitions of terminL~ogy, see Appendix B. RESULTS The general results of the series of tests using the three expwsives Military C -3, Atlas 60, _and Coalite 7S are shown in Figures 11-13. Each figure is designed to give a two-dimensional representation of a three-dimensional plot. If each of the series of vertical bars is imagined to be rotated about the right-hand bar (labeled zero) the figure will show values of depth to the center of gravity of charge d along the vertical (Y ) axis, c weight of charge W along the horizontal (X ) axis, and values of v I W (volume of crater I weight of charge) along an axis perpendicular to the plane of the paper (Z -axis). V a l ues of V I W, to a natural scale, are indicated along the top of the figur e. Depths and weights are plotted to logarithmic scales, and blast numbers are indica ted. It wL: be noted on each figure that, as the depth of a given weight of charge increases, the effectiveness VIW of the blast increases up to a point beyond which the volume of crater per unit weight of charge falls off rapidly. A series of lines are drawn in the de-W plane to denote approximate values of VIW. These lines have a slope of one-third, indicating that VI W is approximately constant when d varies as ~orwhen d 3 IW is constant. The lines are only approximate c c because of the variation in HI D from point to point. If the values of HID were c o nstant, the lines would be expected to be accurate in accordance with scaling laws . The top dashed line on each of the figures is of particular intes _,t in representing the minimum depth at which zero open-crater volume results . The depth corresponding to this condition is the critical depth N. The fact that it does not correspond i n all cases to the p:otted points is attributed to the effect of HID , or the charge shape, a s well as to scatter of data. The general equation for this straight line is (1) N = E~ in which the strain energy factor E is a function of (a ) the medium, (b ) the character of the explosive, and (c ) the geometry. A line of maximum volume of open crater per unit weight of charge , optimum VIW, is also indicated approximately. The equation of this line may be written as d =tlE:rvf (2) co 0 13 EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL in which c, = d IN is the depth factor for optimum conditions, 0 co dco = optimum depth of charge. The quantity c, is obviously a function of the same three variables as is E. Further 0 consideration of the figures indicate s that eq 2 may be generalized to represent any of the straight sloping lines at approximately constant VIW. Hence, in general, d = tlE;?f"W (3) c in which d the depth of charge c t::,. the depth ratio = d IN. c For any depth of placement, tl is an index of position of the charge relative to the critical depth, or minimum depth at which there is no visible surface damage or no open crater. This condition corresponds to one in which the entire energy developed by the charge is absorbed by the medium. If tl equals or is greater than unity, no open crater is produced. Negative values of tl correspond to charges exploded above the surface of the medium. The depth ratio c, may be useful in predicting b.e crater volume by comparison with the volume produced by another charge only when the explosive, the medium, and the shape of the charge is identical in the two. The influence of the charge shape upon crater volume may be shown qualitativ.ely by considering a charge for which HID is approxi mately unity exploded at a depth such that tl = 1. 2 . No open crater will result. Now if the same weight of explosive constitutes a charge for which HID is slightly less than 2. 0 and if d is unchanged, the top of the charge would be near the surface . Explosion of this c would result in an open crater. Hence the critical depth is not a function of the charge and the medium alone, but is also dependent upon the shape of the charge. Data in these tests were insufficient to show conclusively the effect of the shape of the charge upon the size and shape of the resultant crater. Comparisons of crater cross sections for three values of D. for each of the three explosives are given in Figure 14. The crater shape factor K 2 = VI rrr2h, so a value of Kz of one-third corresponds to a crater that is conical on the average . - When a charge is exploded, several observable results, such as size and shape of crater and flyrock travel height, are dependent upon (a ) the nature and quantity of the explosive, which determines the amount and rate of release of energy, (b) the medium in which the charge is exploded, which determines the capacity of the system for absorbing energy and (c) the geometry of the system. In the interpretation of the detailed results, consideration of the sequence of events occurring in an explosion of a buried charge is pertinent. As the charge is detonate"d,· a compressive shock wave front moves out radially from the center of disturbance. Near the charge, the amplitude of the accompanying strain pulse may be sufficiently high to crush the material. As the pulse progresses outward from a point source, its peak amplitude decreases rapidly but the pulse continues until it is no longer discernible be cause of dissipation or until it reaches a free surface. The initial compressive pulse is reflected from a free surface as a tensile pulse, and if the amplitude of the reflected ten sile pulse is sufficiently great it will cause tensile failure in the material, resulting in dished or approximately horizontal slabs. The number and spacing of the slabs have been analyzed and reported. The duration of the shock wave is of the order of milliseconds for blasts initiated near the surface . D uring this time interval, combustion products are forming and if the charge This results in plastic deforma is confined, an appreciable gas pressure is developed. tion of the surrounding material with the result that the bubble expands . If the pressure is sufficiently high the material may fail in shear . If the continuity.of the material is destroyed along any path leading to a free surface, the pressure of the gas bubble may be EXPLOSION TESTS IN FROZEN GROUND, FT. CHURCHILL sufficiently great to force the loosened material out into the air, forming a crater. Thus, the size and shape of the crater depend upon the location of the zone of fractured material. The energy released by the explosive is expended in several ways: (a) Production of a shock wave which may result in local crushing near the charge and in slabbing near a surface (b) Production of a relatively long pressure pulse which may deform the material plastically and cause shearing failure (c) Conversion of the initial potential energy of the compressed gas bubble to kinetic energy of loosened material I (d) Expansion of gas bubble in the free atmosphere (e) Production of heat and sound. The relative amounts of energy involved in the several processes are directly related to the size and shape of the crater. CONCLUSIONS On the basis of the tests reported, the following conclusions may be stated: l. The tests verify the general scaling laws as is evidenced by the constant V /W lines in Figures 11-13 having a slope of one-third. Scatter of data and deviations in H/ D for the charge may account for the small vari 131: >131: >131: >131: 00011 .., Il l v N =2.70W 3 I H~---· I I 11. 1 1 .1 I 44 3.0 Y ll ~ w I I I II l!) a:: 4 rJ ;;o 0 N tz::l z () ::0 0 c z t:J >rJ 1-j Cl :r:: c ::0 Cl :r:: ...... t"' t"' ..... Figure ll. Correlation diagram, Atlas 60. U1 ,__. 0' MILITARY C3 >I~ 5 cr---·-- >I~ ..............- ~ ............. - >!~ >I~ 4 3 I N =2 .65W 3 M X 'l:J t"' 0 en 0 z LLJ (!) 0:: ~ de ci 0 104 u "'CI >--3 M en >--3 en H z trj ::0 0 N M z 0 I:I: Ia.. LLJ 0 D . 103 0 ::0 0 c z tJ trj >--3 0 s 0.40 0 .50 1.0 --2.0 w 5.0 20.0 0:r: c ::0 0 :r: F t"' WEIGHT OF CHARGE Figure 12. Corr elation diagram, Military C-3 . COALITE 7 S >13: >13: >13: 010010010() 0100100100 0100100100 8 N =2.70 W* 7. 6 5. N= 2.sow! w 4. (!) a: <:"'dt"' 0 [f) 0z >-lM [f) >-l z [f) fTj :::00NM z Cl:::0 0cz t:J fTj >-l () ::r:: c :::0 () ::r:: ...... t"' t"' -.J 18 EXPLOSION T E STS I N FROZEN GROUND, F T . C H URCHILL CRATER N0.43 A•0.78 CRATER NO. 23 A• 0 .&3 CRATER N0. 46 6=0.34 _Q,__ _ K1 = 0 .33 Ka= 0 .31 K2= 0 .32 !. :1.24 .!. : 1.40 .!.: 1.67 h h h ATLAS 60 CRATE R NO.II 2 6 • 0 .77 CRATER N0. 88R 6 =0 .&& CRATER N0.74 A•0.34 LEVEL ----_jc Ka=0 . 3 3 Ka • 0 . 27 Ka: 0 .36 L • 1.40 .!. : 1.3& .!. =1.70 h h MILITARY C3 CRATER NO. I21 A•0.75 CRATER N0.118 A•O.!!I CRATER NO. II6R 6 • 0 .36 ----~- Ka = 0 . 41 K. =0 . 3!! Ka =0 .39 I i =0 . 9!! h -»1.24 * •1.30 COALITE 7 S F igure 14 . Representative crater s . REFERENCES Benert, Robert (1957) Penetration of shaped charges into frozen ground, U. S. ArmySnow Ice and Permafrost Research Establishment, Corps of Engineers, Technical Report 45. Boyd, W. K. (1953) Minutes, Consultant's Conference, SIPRE Project on Excavations in frozen ground, 10 November 1953. Cole, R. H. (1948) Underwater explosions. Princeton, N. J.: Princeton University Press, p. 392-395. Department of the Army (1951) Military improvisation during the Russian campaign, D . A. Pamphlet 20-201, Historical Study, p. 23. Lathrop, W. C.; and Handrick, G. R. (1949) The relation between performance and constitution of pure organic explosive compounds, Chemical Reviews, vol. 44, no. 2. Livingston, C. W. (1956) Excavations in frozen ground. Part I. Explosion tests in Keweenaw silt. Snow Ice and Permafrost Research Establishment, Report 30, P t. I, July, 97p. Livingston, C. W. (1949) Series I and II experiments, underground explosion test program, Report of the Colorado School of Mines, p. 148. Livingston, C. W.; and Smith, F. L. (1951) Bomb penetration project, Colorado School of Mines Research Foundation Inc. , 245 p, CONFIDENTIAL. APPENDIX A: DATA SHEETS List of Symbols (for definitions, see App. B) Blast hole and charge data W = charge weight H = charge height D hole diameter H/ D = shape ratio d depth of center of gravity of charge c Energy utilization N = critical depth D. = depth ratio T £1 yrock travel height v v = flyrock velocity Crater data RA' RB = centroid radius V z = average centroid volume vl = cone-formula volume h crater depth Kz = crater shape factor rl = crater radius (plan) r cracking radius c ~ N Explosive: Atlas 60 Energy utilization Blast hole and charge data Hole no. Date Rock temp w Hole H D H/D d c bottom of (lb) depth (ft) (in.) (ft) 2 hole (F ) (ft) 1 3-23 14 1. 86 2.25 0.67 3 2.68 1. 92 11 1. 96 2.25 0.98 3 3.92 1. 76 11 3 1. 95 2.25 0 . 75 3 3.00 1. 88 11 4 l. 93 2 . 17 0.59 2 3/8 1. 32 1. 88 11 5 1. 92 2.38 0.86 2 3/8 4.34 1. 95 6 1. 92 2.33 1. 08 2 3/8 2.42 1. 79 7 11 1. 92 2.37 1. 16 2 6.96 1. 79 8 1. 91 2.50 1. 21 2 7.26 1. 90 11 11 9 11 1. 92 2.50 1. 33 2 7.98 1. 84 10 II 1. 93 2.62 1. 35 2 8.10 1. 95 11 II 1. 92 2.60 1. 52 2 9. 12 1. 84 12 11 1. 94 2.54 1.48 2 8.88 1. 80 13 3-28 1. 89 2.25 0.40 3 1. 60 2.05 II 14 1. 93 2.25 0.38 3 1. 52 2.06 15 1. 91 2.35 0.35 3 1. 40 2.18 11 16 II 1. 93 2.05 0.15 5 1/8 0.35 1. 98 II 17 1. 92 2. 15 0.05 5 1/8 0. 12 2.13 18 1. 99 2. 15 0.15 5 1/8 0.35 2.08 19 3-29 1. 98 2.88 0.45 2 1/2 2.16 2.66 20 II 1. 92 3.34 0.44 2 1/2 2. 11 3.12 II II 21 1. 93 3.86 0. 51 2 1/2 2.45 3 .61 N (ft) 3.32 3.40 3.40 3.38 3.38 3.38 3.38 3.38 3.38 3.38 3.38 3.38 3.35 3.38 3.38 3.38 3.38 3.43 3.43 3.38 3.38 .6 0.58 0.52 0.55 0 . 56 0.58 0.53 0.53 0.56 0.54 0.58 0.54 0.53 0. 61 0.61 0.64 0.59 0.63 0.61 0.78 0.92 1. 07 T v (ft) 96 35 74 11 11 v (ft/ sec) ~ '"d '"d txl z tJ H ~ 78.9 47.6 69.2 26.7 26.7 Crater Data Hole Area RA Plan Area RB Vz vt h no. X-Section A (ftZ) (ft) area (ft2) X-Section B (ftZ) (ft) (ft3) (ft3) (ft) l 6.38 0. 77 18.83 5.38 0.66 13.29 15.08 2.67 2 S. 63 0.7S 22.34 S.40 0.79 13.32 15.41 2.48 3 6.04 0.81 19.7S s.os 0.74 13.S4 14.S7 2.41 4 6.98 0.97 2S.70 S.84 0.89 18.76 19. 19 2.31 s 6.SO 0.84 20.74 7. OS 0.92 18.72 18.22 7.7S 6 6.41 l. 00 26.12 S.62 0.83 17.41 18. 13 2.46 7 4.37 0.67 20.17 S.2S 0.78 11. 03 12.74 2 . 6S 8 S.61 0.85 27 . 43 s.so 0.88 1S.02 17.21 2.S2 9 4.68 0.91 26. 14 S.46 0.90 14.36 15.28 2.SS 10 S. 30 0.78 2S.40 S.01 o. 72 12. 13 lS.32 2.7S 11 S.75 0.88 30.97 s.os 0.90 1S. 05 l7.7S 2.67 12 s.ss 0.90 28.38 s. 18 0.90 1S.80 16.8S 2.62 13 9.70 32. 14 8.60 l. 08 30.85 2.71 14 8.06 0.98 26.8S 8.SO l. OS 26.42 2S.31 2.66 1S 10.66 l. 26 33 .73 10.33 l. 19 40.43 26.03 2.74 16 7.6S 0.99 28.87 9.19 1. 16 28.6S 26.70 2.34 17 10.44 1. 20 43.07 11. 9S 1. 36 4S.21 43 . 36 2.66 18 9.3S 1. 14 37.21 10.61 1. 19 36 . 44 3S .93 2.S9 19 3.60 69. 6 7 2.S1 1S. 06 20 0.48 30. 0S 0.80 2.07 0.76 21 Kz 0.29 0.29 0.31 0.33 0.34 0.32 0.29 0.29 0 . 31 0.26 0.28 0.31 0.3S O.S2 0.3S 0.3S 0.34 rl (ft) 2 . 4S 2.67 2.51 2.86 2.S7 2.88 2.S3 2.96 2.88 2.84 3 . 14 3.00 3.20 2.92 3.28 3.03 3.70 3.44 4.71 3 .09 r c (ft) 3.SO 3.10 2.S1 2.86 2.S7 2.88 3.SO 2.96 2 . 88 3.SO 3 . 14 3.SO 3.20 2.92 3.90 3.03 3. 70 3.44 4 .71 4 .60 4.80 ~ VJ ~ 'U 'U M z t::J ...... :><: Explosive: Atlas 60 (cont1d) :» >!>- Blast hole and charge data Energy utilization Hole no. Date Rock temp bottom of hole (F) w ( lb) Hole depth ( ft) H ( ft) D (in.) H/D d c (ft) N (ft) ~ T v ( ft) v (ft/ s ec) 22 3-30 0.48 0.96 0.38 1 11/16 2.70 0. 77 2. 11 0.36 79 71. 6 23 II 0.48 l. 24 0.26 l 11/16 l. 85 1.11 2. 11 0.53 79 71. 6 24 11 0.48 l. 45 0.26 1 11/16 l. 85 l. 32 2.11 0.63 66 65.4 25 II 0.46 l. 70 0.25 1 11/16 l. 78 l. 58 2.08 0.76 31 44.8 26 II 0.46 l. 95 0.28 1 7/8 l. 79 l. 81 2.08 0.87 18 34. 2 '2-7 II 0.48 2.23 0.28 1 7 I 8 l. 79 2.09 2. 11 0.99 7 21. 3 28 3-31 0.95 l. 16 0.41 2 2.46 0.96 2.65 0.36 78 71. 1 :» 29 II 0.95 1. 38 0.38 2 2.28 1. 19 2.65 0.45 87 75.1 '"d '"d 30 II 0.92 1. 60 0.40 2 2.40 1. 40 2.62 0.53 86 74.5 trl z 31 II 0.94 l. 89 0.45 2 2.70 1. 67 2.65 0.63 86 74.5 tJ ~ 32 II 0.95 2.10 0.40 2 2.40 l. 90 2.65 0. 72 34 46.9 33 II 0.98 2.37 0.38 2 2.2 8 2.18 2.68 0.81 34 46.9 34 II 0.94 2.60 0.44 2 2.64 2.38 2.65 0.90 17 33.2 35 II 0.94 2.85 0.44 2 2.64 2.63 2.65 0.99 36 4 -1 1. 90 l. 44 0.84 2 3/16 4.56 l. 02 3.35 0.30 37 II l. 90 1. 61 0.78 2 3/16 4.27 l. 22 3.35 0.36 38 II l. 89 l. 80 0.81 2 3/16 4.42 l. 40 3.35 0.42 39 II l. 90 2. 12 0.76 2 3/16 4.16 l. 74 3 . 35 0.52 40 4-3 19 l. 88 2.30 0.69 2 3/16 3.66 l. 96 3 . 35 0.58 79 71. 6 41 4-1 l. 91 2.40 0.84 2 3/16 4.56 l. 98 3 . 35 0.59 42 II l. 92 2.73 0.83 2 3/1 6 4.54 2.32 3 . 35 0.69 Crater Data (cont 'd) Hole no. Area X-Section A (ft2) RA (ft) Plan area (ft2) Ar ea X-Section B (ft2) RB (ft) Vz (ft 3 ) 22 l. 92 0.64 11. 33 2.01 0. 58 3 .74 23 2.76 0.66 14.21 2.79 0.67 5.75 24 3 .53 0.76 20.72 3 . 32 0.67 7.70 25 4 .06 0.86 17.78 4.73 0.88 ll. 9 7 26 0.44 2 . 41 0.61 27 28 2.84 0.68 12.75 2.45 0.57 5.22 29 3 . 72 0.81 13.45 3 . 89 0.78 9.46 30 3.94 0. 72 16.60 3.79 0.70 8 . 6 1 3 1 6.58 l. 04 22.7.5 5 . 32 0.87 17.97 32 6.41 l. 01 32.98 6.36 0.89 19.01 33 5.88 l. 19 32 .83 6 .1 2 l. 08 21.33 34 8.51 l. 18 60. 7 3 8.42 l. 21 31. 70 35 0.45 36 3 . 45 0.87 17.03 3.98 0.87 10.09 3 7 3 . 1 3 0.68 30 .98 5 . 35 l. 11 12 .63 38 5 . 64 0.99 35 .00 5 . 6 7 0. 98 17. 44 39 6 .78 l. 18 38. 69 6 . 36 0.98 22.31 40 6.86 0.92 33 .05 5.48 0.90 17. 63 41 8 . 34 l. 16 34.98 7.20 0.98 26 .26 42 12.25 l. 52 56.65 12. 15 l. 3 1 54. 10 VI (ft3) 3 .91 6.16 9.08 10.95 0.48 5.56 8.24 9.30 16.75 21. 65 20.28 38. 90 9 .06 13 . 94 20 . 92 20.00 24.90 27. 16 54.30 h (ft) l. 15 l. 51 l. 70 l. 21 2.04 l. 45 l. 6 7 l. 86 2. 15 l. 33 2 . 56 2. 72 l. 58 l. 69 2 . 17 2.37 2.56 2.54 3 .03 Kz 0.32 0.31 0.28 0.36 0.31 0.38 0.31 0.36 0.29 0.35 0.27 0. 3 7 0.30 0.29 0.30 0.28 0. 32 0. 33 rl (ft) l. 90 2. 12 2.57 2.38 0.88 2.45 2.01 2.07 2.30 2.69 3 .24 3 .23 4.39 0.38 2.33 3 . 14 3 . 38 3 . 51 3 . 24 3 . 34 4 . 25 r c (ft) l. 90 2.37 2. 57 2.38 3 . 30 3 .00 2 .01 4 . 16 2 . 30 2.69 3.24 3.23 4.47 2. 70 2. 33 3. 14 3 . 68 3 . 72 3.24 3 . 34 4. 59 > '""d '""d trl z tJ ~ >- U1 ;p 0' Explosive: Atlas 60 (cont'd) Blast hole and charge data Energy utilization Hole no. Date Rock temp bottom of hole (F) w (lb) Hole depth (ft) H (ft) D (in.) H/D d c (ft) N (ft) ~ T v (ft) v (ft / sec) 43 4-3 19 1. 89 3.01 0.82 2 3/1 6 4.48 2.60 3.35 0.78 44 II 17 1. 92 3.37 0.73 2 3/16 3.98 3.01 3.35 0.90 5 18.0 45 II 13 1. 92 3.62 0.67 2 3/16 3.67 3.29 3.35 0.98 10 25.5 46 4-4 4.82 2.02 0.90 3 3/16 2.71 1. 57 4.56 0. 34 47 II 4.81 2.35 0.90 3 1/8 3.20 1. 90 4.56 0.42 48 4-5 19 4.69 2.50 0.88 3 I 18 3 . 38 2. 06 4.52 0.46 ~ 49 50 51 II 4-6 II 22 18 19 4.70 4.78 4.74 2.97 3.54 4. 05 0.97 1. 07 1. 22 3 3 3 /18 3. 72 4.28 4.88 2. 49 3.01 3 . 44 4 . 52 4 .54 4 . 54 0.55 0.66 0.76 12.6 25 90.4 40.3 '"d '"d M z tJ ....... 52 II 19 4.77 4.48 l. 03 3 1/16 4. 04 3.97 4 . 54 0.87 12 27.9 :X: 53 II 22 4.80 5.02 1. 01 3 1/16 3.96 4 .52 4 .56 0.99 54 4-7 17 19.04 3.20 1. 49 5 3.58 2.46 7.24 0.34 105 82.5 55 II 15 19.03 3.71 l. 50 5 3.60 2.96 7. 24 0.41 58 61. 3 56 II 16 19. 13 4.20 l. 52 4 15/16 3. 70 3.44 7. 24 0.47 146 97.3 57 II 18.99 4.17 l. 48 5 3.55 3. 97 7.24 0.55 192 111. 6 58 4-13 17. 18 19.21 5.24 1. 52 4 15/16 3.70 4.48 7.24 0.62 13 29.0 59 II 15.15 19.26 5.76 1. 56 4 15/16 3.79 4.98 7.24 0.69 42 52.2 60 II 16. 16 19.08 6.63 l. 38 4 15/16 3.36 5.94 7.24 0.81 74 69.2 61 II 16. 17 19.09 7.73 l. 4 7 4 3 / 4 3 . 72 7.00 7.24 0.97 19 35 . 1 7 3 4 -15 4.90 4.27 0 .80 3 1/4 2.95 3.87 4 .54 0.85 3 27.9 Crater Data (cont'd) Hole no. Area X-Section A (ftZ) RA (ft) Plan area (ftZ) Area X-Section B (ftZ) RB (ft) Vz (ftl) 43 11.35 1. 21 54.90 12.58 1. 43 49.64 44 4.88 1. 77 78.59 5.58 1. 90 30. 19 45 1. 23 0.37 12.89 1. 37 0.50 1. 80 46 7.84 1. 20 47.85 8.79 1. 24 31. 77 47 9.74 1. 26 53.81 9.21 1. 12 35. 72 48 8.98 1. 18 58.74 9.66 1. 19 34.56 49 10.56 1. 25 65.33 13.26 1. 34 48 . 63 50 11.44 1. 28 69.21 17.29 1. 64 67.45 51 18.26 1. 62 74.60 19. 63 1. 73 99.65 52 1. 85 0.27 8.85 1. 70 0. 35 1. 70 53 54 23.62 2.03 104.61 22.21 1. 90 121. 2'1 55 25.39 1. 95 121.78 25.61 2.09 161. 64 56 28.68 1. 85 97.98 26.99 1. 85 161.79 57 34. 64 2.03 130. 13 36.56 2.13 232.51 58 41.41 2. 13 156.56 45.54 2. 39 308.85 59 45 .10 2.35 141.64 39 .57 2.06 294.18 60 61 73 1. 20 - vl (ft 3) 50. 16 27.32 2.76 33.21 41. 06 42.14 56.85 70.59 96.57 3.12 138. 39 166.01 162.57 239.97 319.20 297.32 h (ft) 3.37 3.31 1. 89 2.34 2.89 2.84 3.53 3. 13 4.15 3.36 4.00 4.35 4.94 5.54 6. 46 6, 32 8.60 Kz 0.33 0.37 0.22 0.32 0.29 0.27 0.29 0. 32 0.34 0.18 0.29 0. 33 0. 33 0.32 0.32 0.33 rl (ft) 4.18 4.99 2.03 3.90 4 .14 4 . 32 4.56 4 . 69 4.87 1. 68 5. 77 6.22 5.58 6.44 7.04 6.71 0. 62 r c (ft) 4.18 4.99 4.50 3.90 4. 14 4. 32 4.56 5.00 4.87 5.90 3.24 5. 77 6.22 5.58 6.44 7.04 6. 71 11.00 5.80 6.80 ~ "d "d t':l z tl >< ~ ...... ;t> Explosive: Military C-3 Blast hole and charge data Energy utilization I Hole no . Date Rock temp w Hole H D HID d c N f:, T v v bottom of (lb) depth (ft) (in.) (ft) (ftl s ec) (ft) (ft) hole (F) (ft) 62 4-14 20 1. 99 1. 33 0 . 6 1 2 11 4 3 . 25 1. 02 3.34 0. 3 1 63 19 1. 99 l. 65 0 .74 2 1I 8 4 .17 1. 28 3.34 0.38 II II 64 19 1. 99 l. 86 0.76 2 1I 8 4.28 1. 48 3 . 34 0.44 64R 4-20 2.00 1. 87 0.84 2 114 4 . 45 1. 45 3 . 34 0.43 65 4 -1 4 18 1. 99 2. 12 0 .71 2 118 4 . 00 1.77 3 . 34 0.53 66 18 l. 99 2 . 3 7 0.82 2 118 4 . 52 1. 96 3 . 34 0. 5 9 II II 67 17 1. 99 2 . 62 0 . 67 2 11 8 3 .78 2 . 29 3 . 34 0.69 35 47 . 6 ;t> '""d 67R 4 -20 '""d 2.00 2. 6 1 0 .81 2 114 4 . 3 1 2 . 21 3 . 34 0.66 M 68 4 -1 4 16 l. 99 2 . 93 0.88 2 11 8 4 . 96 2.49 3 . 34 0.75 35 4 7.6 z tJ ..... 68R 4 -20 2.00 2 . 85 0.80 2 311 6 4 . 38 2.45 3 . 34 0.73 >< 69 4 -15 18 1. 99 3 . 15 0.76 2 1I 8 4.28 2 . 77 3 . 34 0.83 33 45 . 2 70 1 8 l. 99 3 . 3 7 0.85 2 118 4 . 80 2.95 3 . 34 0 .88 33 45 . 2 II II 71 18 l. 99 3 . 58 0.86 2 1116 4 . 92 3 . 15 3.34 0.94 39 50 . 3 72 II 16 l. 99 3 . 93 0.81 2 11 8 4 . 57 3 . 53 3 . 34 l. 06 74 18 4 .90 l. 98 0.92 3 1I 4 3. 40 1. 52 4 . 51 0.34 109 84.0 II II 75 17 4.94 2.47 0.85 3 114 3 .1 4 2 .05 4 . 53 0.45 80 72.0 II 76 18 4 . 92 2.96 0.74 3 114 2.73 2.59 4.51 0.57 23 39 .0 II 77 19 4 . 0 5 3.44 0 .76 3 511 6 2.75 3 .0 6 4 . 2 1 0.73 23 39 . 0 Crater Data Hole no . Ar ea X-Section A (ft2) RA (ft) Plan area (ft2) Area X -Section B (ft2) RB (ft) 62 3 . 81 0. 77 26.80 5.17 l. 16 63 5.43 0.86 12.63 5 . 22 0.92 64 5 . 10 0.86 16.04 3 . 88 0. 68 64R 7.33 l. 14 34.96 7.01 l. 20 65 7. 68 l. 06 22 . 82 6.70 0 .95 66 8.33 l. 05 34. 16 8 . 36 l. 05 67 9.29 l. 30 44. 68 7.70 l. 12 67R 11. 17 l. 44 45.17 10.45 0.69 68 9.85 0.93 29 . 89 8.12 l. 07 68 R 11. 13 l. 23 48 . 71 10.65 l. 29 69 12. 89 l. 37 63 .21 14 .71 l. 83 70 2.88 0.86 16.96 2.03 0.50 71 l. 58 59.71 l. 33 72 2.03 74 10.19 l. 48 50 .56 9 . 42 l. 42 75 10.44 l. 28 45 .0 6 9.84 l. 24 76 13 . 36 l. 24 5 1. 55 14 . 82 l. 68 77 17. 13 l. 28 74 . 64 17.28 l. 51 Vz (ft3) 14.03 14.88 10.96 26.34 22.73 27 . 63 32 .96 36 . 51 43 .00 27.90 70. 10 5 . 45 48 .99 44. 70 40 . 00 65 . 13 75.35 v l (ft3 ) 13 . 72 11.20 10. 62 25.07 20 . 32 33 . 52 42 . 88 44 . 91 5 . 96 48 . 78 28.82 29.06 65.00 41. 15 40 . 22 59 .73 87 .70 h (ft) l. 57 2.13 2.10 2 . 11 2.48 2.79 2.73 2 . 88 3 . 04 3 . 14 3 . 11 3 . 41 3.26 2.36 2.89 3.47 3. 72 Kz . 341 . 443 .344 . 350 . 3 73 . 320 . 328 . 284 . 320 . 3 19 . 359 . 304 . 33 5 . 362 . 33 1 . 363 . 286 rl (ft) 2.92 2.01 2.26 3 . 34 2. 70 3 . 30 3.77 3. 79 3.09 3.94 4.49 2.32 4 . 36 4 .01 0.81 3.79 4 .05 4 . 87 r c (ft) 2.92 2.01 3. 34 2.70 3 . 30 3. 79 3 . 94 4. 49 2. 32 4 . 36 4 .01 2.20 3. 79 4 .0 5 4.87 ~ 'l:J 'l:J M z tJ ...... :>< ~ ~ > ...... Explosive: Military C-3 (cont'd} Blast hole and charge data Energy ut;lization Hole no. Date Rock temp bottom of hole (F) w (lb) Hole depth (ft) H (ft) D (in.) HID d c (ft) N (ft) !::. T v (ft) v (ft/ sec) 78 4-15 4.81 4.00 0.88 3 l/8 3.38 3.56 4.48 0.80 79 II 4.85 4.44 l. 04 3 l/8 3.99 3.92 4.48 0.87 80 II 4.92 5. 00 0.92 3 l/16 3.60 4.54 4.51 0.99 81 82 4-20 0.50 0. 72 0.30 l ll/16 2.13 0.57 2. 12 0.27 83 84 85 86 II II / II 4-18 0.50 0.50 0.50 0.50 0. 77 0.90 0.95 l. 05 0.29 0.38 0.39 0.27 l l l l ll/16 ll/16 ll/16 ll/16 2.06 2.70 2. 77 l. 92 0.63 0.71 0.76 0.92 2. 12 2. 12 2. 12 2.12 0.30 0.34 0.36 0.43 > "d "d txl z tJ ...... 87 II 0.50 l. 18 0.40 l ll/16 2.84 0.98 2.12 0.46 22 38.0 ~ 88 II 0.50 2.12 88R 4-20 0.50 l. 37 0.42 l 11/16 2.98 l. 16 2. 12, 0.55 16 32.0 89 4-18 0.50 l. 62 0.17 l 13/16 l.ll l. 54 2. 12 0.73 90 II 0.50 l. 70 0.18 l 13/16 l. 19 l. 61 2.12 0.76 91 II 0.50 l. 96 0.20 l 3/4 l. 37 l. 86 2.12 0.88 92 II 0.50 2.20 0.39 l 13/16 2.58 2.01 2. 12 0.95 93 II 0.50 2.35 0.22 l 13/16 l. 46 2.24 2.12 l. 06 94 4-19 17 l. 00 l. 05 0.65 l 13/16 4.30 0.73 2.65 0.28 95 " 18 l. 00 l. 41 0.54 l 13/16 3.58 l. 14 2.65 0.30 57 61. 0 ' Crater Data (cont'd) Hole no. 78 79 80 81 82 83 84 85 86 87 88 88R 89 90 91 92 93 94 95 Area X-Section A (ft2) 8.94 4.02 3.33 l. 92 l. 93 l. 76 2.20 2.06 2.78 2.75 4.93 3.86 l. 21 0.83 0.86 2.70 3.55 RA (ft) 2.67 l. 59 0.54 0.60 0.62 0.60 0.62 0.63 0.68 0.60 0.89 0.74 0.44 0.27 0. 16 0.73 0.80 Plan area (ft2) 129.97 27.35 28.84 6.28 9.01 10.48 10.51 8.84 16.26 17.70 23.79 23.40 9.88 2.35 2.02 13.55 19.68 Area RB Vz VI h Kz rl X-Section B (ft 2) (ft) (ft 3) (ft 3) (ft) (ft) 7.58 2.67 69.22 54. 73 2. 72 . 423 6.33 3.03 l. 23 13 .91 10.88 l. 55 . 426 2.95 4.42 l. 15 10.78 12.29 l. 28 .292 3.03 l. 67 0.56 3 .28 2.65 0.95 . 413 l. 41 2.42 0. 71 4.83 4 .09 l. 06 . 393 l. 69 l. 87 0.63 3 .67 3 .66 0.99 .334 l. 83 l. 82 0.65 3.54 3.43 0.96 . 344 l. 83 l. 74 0.47 3.31 3 . 34 l. 20 .331 l. 68 2.61 0.68 5. 72 6.43 l. 31 .296 2.28 3. 16 0.66 5.87 7.33 l. 53 .267 2.37 6.03 l. 12 17.50 15.77 l. 99 . 370 2.75 3.99 0.81 9.53 11.22 l. 97 . 282 2. 73 1. 32 0.42 l. 70 2.34 2. 18 .242 l. 77 0.96 0.45 1. 02 0. 81 2.45 .421 0.86 0.88 0.20 0.47 0.73 2.50 .216 0.80 2.66 0. 77 6.24 5.83 l. 28 . 357 2.08 4.63 0.97 11.52 10.70 l. 66 . 359 2.50 r c (ft) 6.33 2.95 3. 03 2.40 2. 15 l. 83 l. 83 l. 68 2.28 2.37 2.75 2.73 3.00 l. 90 0.82 2.08 2.50 ~ '""d '""d txJ z I::) ...... ~ ~ ...... ...... > ,_. N Explosive : Military C -3 (cont' d } Blast hole and charge data E nergy utilization Hole no . Date Rock temp bottom of hole (F) w (lb} Hole depth (ft) H (ft) D (in.) H/D d c (ft) N (ft) ~ T v (ft) v (ft /sec) 96 4-19 17 1. 00 1. 60 0.50 1 13/1 6 3.31 1. 35 2.65 0.51 9 7 II 19 1. 00 2.07 0.52 1 13 /1 6 3. 44 1. 81 2.65 0.68 98 II 18 1. 00 2.58 0.58 1 13/16 3.84 2.29 2.65 0.86 99 II 18 1. 00 2.80 0.52 1 13/16 3 . 44 2.54 2 . 65 0.96 100 II 17 1. 00 3.07 0.56 1 13 /1 6 3.71 2 .79 2.65 l. 05 > 101 II 17 1. 00 3.24 0.79 1 13/16 5.23 2.85 2.65 1. 07 7 6 70.2 '""d '""d 102 II 1. 00 3.58 0.48 1 13/16 3. 18 3. 34 2.65 l. 26 60 62.3 t'l z 103 4-20 19. 61 l. 80 1. 49 5 3/16 3 . 44 l. 06 7.1 6 0. 15 54 59 .2 t:l ~ 104 II 19. 51 2.23 1. 40 5 1/ 8 3.28 1. 53 7. 16 0 .21 105 II 19. 39 2.73 1. 35 5 1/8 3 . 16 2.06 7. 10 0.29 10 6 4-21 19.52 3 . 27 l. 39 5 1/ 8 3. 25 2 . 58 7.1 6 0.36 148 97.2 107 II 19.96 3. 68 l. 42 5 1/8 3 . 33 2.97 7.21 0.41 42 57 90.4 104.6 108 II 19. 59 4.29 1. 33 5 1/8 3. 11 3.63 7.1 6 0.51 35 47 90.4 104.6 109 II 19.68 4.77 1. 45 5 1/8 3 . 39 4 .05 7.1 6 0.57 31 42 90.4 104. 6 110 4-25 19. 84 5. 18 1. 40 5 3.36 4.48 7 . 18 0.62 102 81. 3 111 II 19.87 5.76 l. 50 5 1/1 6 3.56 5.01 7.1 8 0.70 70 67.4 112 II 19.95 6.24 l. 39 5 3. 34 5 . 55 7. 21 0 . 77 28 42 . 6 11 3 5-3 19.92 6.63 1. 20 5 3/ 4 2.51 6.03 7. 18 0 . 84 24 39.0 11 4 4-28 19.98 7.82 1. 25 5 1/ 8 2. 93 7.20 7.21 l. 00 10 26.0 C rater Data ( cont 1 d ) H o l e Area R A P lan Area RB v z no . X -Section A (ft2) ( ft ) area ( ftZ) X -Section B ( ftZ) ( ft) (ft 3) 9 6 3.58 0. 71 19. 24 3 .78 0 .79 8 . 66 97 6.20 0. 9 1 26.54 6 .07 0 . 93 17.73 9 8 0 . 96 0 . 2 1 12.56 l. 08 0 . 26 0. 7 6 99 l. 20 0 . 33 7. 8 5 l. 43 0 . 35 l. 40 100 0.85 0. 14 l. 32 0. 90 0.09 0 . 3 1 10 1 2 . 20 0 . 57 9 .76 l. 82 0 . 38 3 . 06 102 l. 6 5 103 13 . 09 l. 8 1 88 . 84 11. 1 1 l. 82 68 .79 104 16. 7 8 l. 88 100 . 45 1 6 . 4 7 1.72 94 .05 10 5 1 8 . 60 l. 87 87. 44 1 8 .98 1.72 10 5 .77 10 6 2 8 . 26 2. 30 108. 0 3 2 3 .97 l. 9 5 175 .11 107 29. 9 5 2 . 19 13 1.12 29.78 2 . 25 20 8 . 28 108 39.1 4 2. 64 146. 09 34.1 8 2 . 34 2 8 7.1 4 109 37.76 2 . 2 9 129. 58 38 . 3 7 2. 32 27 5 . 36 110 4 1. 52 2. 3 7 1 57.58 47. 9 7 2 . 65 353 . 8 7 111 53 . 28 2. 60 1 50 . 0 4 55 . 39 2 .78 459 .0 5 11 2 65 . 3 2 3.04 2 73 . 04 65 . 26 3 . 33 647. 4 9 11 3 15 .73 11 4 VI (ft3) 9. 55 18 . 69 2 .1 4 2 . 17 3 .70 0.60 67. 25 98 . 3 1 103 .77 1 60. 18 2 0 l. 62 261. 6 9 254. 98 33 1. 58 392 .98 633 . 38 h (ft) l. 70 2.34 2. 81 3 . 08 3 . 38 2 . 24 3 .1 4 3 . 35 4 . 19 5 . 45 5 . 90 3.43 4.53 5.09 6. 39 6 . 68 Kz . 302 . 3 16 . 11 8 . 2 15 . 171 . 257 . 344 . 3 19 . 340 . 364 . 344 . 366 . 360 . 356 . 389 . 341 r l (ft) 2 . 48 2. 91 2 . 00 l. 58 0 . 65 l. 7 6 0 . 72 5 . 31 5 . 65 5 . 28 5 . 86 6 . 45 6 . 8 2 6 . 4 0 7.08 6. 91 9 . 34 2 . 24 r c (ft) 2.48 2. 91 4 . 1 5 2 . 65 2 .70 l. 7 6 l. 70 5.3 1 5.65 5 . 28 5 . 86 6. 45 6 . 82 6 . 4 0 7.08 6. 91 9 . 34 10 .40 7.00 > 1::1 1::1 M z tJ ~ > ....... w E xplosive: Coalite 7S > ....... ,j>. Blast h ol e and c h a r ge data E nergy utilizatio n Hole no. Date Roc k temp bottom of hole (F) w (lb) Ho l e de pth (ft) H (f t) D (in.) H/D d c (ft ) N (ft) .6 T v (ft ) v (ft/ s ec) 11 5 4 -27 l. 98 3 . 15 7 5 69.7 ll5R 4 -28 l. 98 l. 23 0 . 56 l. 34 0 . 95 3 . 15 0.30 2 7 4 1. 8 116 4 -27 28 l. 9 6 3. 13 7 5 69.7 11 6R 4 -28 l. 98 l. 4 5 0. 72 l. 7 3 l. 0 9 3 .1 5 0. 3 5 3 1 44. 8 117 4 -27 l. 98 l. 70 0 .67 2 1I 2 3 . 2 1 l. 3 7 3. 15 0 . 43 60 62 . 4 11 8 11 2 6 l. 9 6 l. 95 0 . 68 2 9/16 3 . 18 l. 6 1 3. 13 0. 5 1 90 7 6 . 4 119 11 2 5 l. 9 8 2 . 11 0 .70 2 7/1 6 3 . 44 l. 7 6 3. 1 5 0.56 57 60. 8 120 11 2 5 l. 97 2 . 45 0 .75 2 7/1 6 3 . 69 2 . 08 3 . 15 0 . 66 79 71. 5 > 't1 121 11 24 l. 96 2 . 65 0 . 65 2 7/1 6 3 . 20 2 . 33 3. 13 0.75 3 1 44 . 8 't1 trl 122 4 -28 l. 9 7 2 . 94 0.57 2 5/ 8 2 . 60 2 . 66 3. 15 0 . 85 18 34. 2 z t:l 123 11 l. 98 3.05 l. 25 2 1/ 4 6.66 2.43 3 . 15 0 . 77 x 124 11 l. 98 3 . 32 0 . 8 7 2 l/ 4 4 . 64 2 . 89 3 . 15 0 . 92 125 126 4 -29 4 . 93 3 . 57 l. 11 3 l/4 4 . 10 3 . 02 4 . 28 0 .70 127 11 5 . 0 0 3.79 1.11 3 3/1 6 3 . 14 3 . 24 4 . 28 0 . 76 128 11 4.96 4 . 10 l. 15 3 3/1 6 4 . 33 3 . 53 4.28 0. 82 13 29.0 129 11 4.96 4 . 34 l. 12 3 3/1 6 4 . 22 3.78 4 . 28 0. 88 130 1 3 1 1 32 - Crater Data Hole no. Area X-Section A (ft 2) RA (ft) Plan area (ftZ) Area X-Section B (ft2) RB (ft) vz (ft 3) vl (ft 3) h (ft) 115 115R 6.29 l. ll 20.66 4.96 0.97 18.48 15.07 l. 82 116 lll6R 5.41 l. 02 20. 15 5.83 0.98 17.60 14.88 l. 83 117 4.14 0.47 18.55 5.37 l. 17 12.88 12.09 l. 88 118 6.62 0.96 25.84 7.41 l. 03 21.87 21. 07 2.30 119 6.55 0.97 25.40 8.28 l. 07 23.78 22.04 2.56 120 9.52 l. 21 34.26 8.20 l. 12 32.46 30.60 2.75 121 11. 60 l. 21 29.37 12.97 l. 29 48.24 39 .35 3.23 122 12.00 l. 27 32.77 10.93 l. 10 42.64 38.76 3.25 123 2.58 0.56 2.07 2.59 0.50 4.26 2. 19 3.27 124 2.33 0.56 12.63 2.26 0.48 3.74 4.83 3.69 125 126 49.82 127 17.46 l. 44 62.50 16.65 l. 43 76.76 79.61 4.15 128 5.14 l. 34 41.78 4.75 l. 25 20.11 18.89 4.47 129 0.97 0.40 14.60 0.65 0.24 0.85 l. 83 4.57 130 131 132 Kz 0.41 0.39 0.36 0.35 0.36 0.35 0.41 0.37 0.65 0.26 0.32 0 .. 35 0.31 r l (ft) 2.56 2.53 2.43 2.87 2.84 3.30 3.06 3.23 0.81 2.01 3.98 4.46 3.65 2. 16 r c (ft) 2.56 2.53 2.43 2.87 2.84 3.30 3.06 3.23 0.81 3.70 3.98 4.46 4.60 3.90 ~ 'U 'U t':J z tJ ...... :>< ~ ..... lJl ~ ...... 0' Explosive: Coalite 7S (cont'd} Blast hole and charge data Energy utilization Hole no. Date Rock temp bottom of hole (F) w (lb} Hole depth (ft} H (ft} D (in.} H/D d c (ft} N (ft} /::;. T v (ft) v (ft/ sec} 133 5-2 4.93 2.20 l. 04 3 3/16 3 . 92 l. 68 4.28 0.39 134 " 4.92 2.35 l. 05 3 1I 8 4 .04 l. 83 4.28 0.43 135 " 4.94 2 . 60 l. 13 3 l/8 4.33 2.04 4. 28 0.48 136 " 4.92 2.89 l. ll 3 l/8 4.26 2.34 4.28 0.55 137 138 139 5-4 20.03 2.32 l. 40 5 ll/1 6 2.96 l. 62 7.34 0.22 102 81.0 ~ 'l:l 140 " 20.04 2.45 l. 3 1 5 3/4 2.73 l. 80 7.34 0.25 'l:l M 141 " 20.05 3 . 13 l. 24 5 7/ 8 2.53 2. 51 7.34 0.34 z tJ 142 " 20.06 3.59 l. 23 5 3/4 2.57 2.98 7.34 0.40 ...... X 143 " 20. 10 4. 18 l. 40 6 2.80 3 .48 7.37 0.47 144 5-5 30 20. 16 4.75 l. 29 5 5/8 2.80 4. 11 7.37 0.56 134 93.0 145 II 29 20. 10 5. 13 l. 38 6 2.76 4 . 44 7.37 0.60 100 80.8 146 " 29 20 ,14 4.89 l. 44 4.17 7. 3 7 0.57 96 79.0 147 " 27 20. 15 5.80 l. 17 6 3/8 2.20 5.22 7.37 0.71 70 67 . 0 148 " 26 20. 12 6.37 l. 59 5 7/8 3.24 5.58 7.37 0.76 103 82 . 0 149 20.09 7.47 0.95 5 7/8 2.03 7.00 7. 34 0.95 150 20. 11 6.89 l. 05 6 7/ 8 2.15 6.37 7. 34 0.87 17 34.0 151 20.20 7.80 l. 28 6 2.56 7. 16 7. 37 0.97 152 20. 11 8.65 l. 33 5 3 / 4 2.78 7.99 7.34 l. 09 Crater Data (cont'd) Hole no. Area X-Section A (ft2) RA (ft) Plan area (ft2) Area X-Section B (ft2) RB (ft) Vz (ft 3) vi (ft3) h (ft) Kz 133 10.27 l. 24 31. 38 ll. 21 l. 32 43.25 35.52 2.47 0.41 134 9.62 l.ll 30 .22 10.33 l. 19 36.00 32.37 2.77 0.37 135 l. 17 l. 21 27.45 10.71 l. 21 41. 12 33.89 2.96 0.40 136 10.80 l. 21 46. 14 13.77 l. 36 49.86 49.25 3.31 0.34 137 138 139 140 14'. 87 l. 38 54.28 19.49 l. 80 87.07 74.80 3.39 0.39 141 24.06 2. 12 82.84 20.61 l. 88 140.83 119.93 3.94 0.39 142 32.95 2.22 105.39 36.57 2.42 253.92 210.65 4.65 0.40 143 34.43 2.35 109. 16 30.08 2. 18 229.86 198.85 4.40 0.39 144 30.53 l. 17 90.08 31. 61 2.24 167.33 173.98 4.57 0.32 145 37.77 2.30 107. 13 41.45 2.42 293.40 241. 70 5. 17 0.40 146 38.02 2.05 84.45 2.03 240.01 203.62 5.56 0.39 147 40.60 2.37 122.34 48.85 2.69 355.33 291. 64 5.87 0.41 148 53.09 2, 61 120. 10 50.52 2.55 419.62 334.55 6.93 0.42 149 150 60.90 l. 19 188.24 64.71 1.11 241. 62 541.90 7.27 0. 15 151 152 rl (ft) 3. 16 3 . 10 2.96 3.83 4.16 5. 13 5.79 5.89 5.35 5.83 5. 18 6. 17 6.23 3.46 7.75 r c (ft) 3. 16 3. 10 2.96 3.83 4.16 5. 13 7.50 7.00 5.35 5.83 5.18 6.23 6.17 6.00 7.75 7.00 ;:t> 'D 'D M z tJ >< ;:t> ,_. APPENDIX B: GLOSSARY The terminology used in this report is an outgrowth of. that used in mining, quarrying, and rock excavation, but has been modified·and clarified where necessary to describe more accurately the factors involved. Some of the terms used in this report were evolved during the Series I and II experiments (Livingston, 1949) and the Keweenaw tests (Livings ton, 1956), others have been defined since. Several of the terms are illustrated in Figure Bl. Air Blast The pressure effects, air velocity, and noise associated with an explosion in air, with venting of a crater blast, or with an underwater explosion. Charge· depth (d ) c Distance from surface to center of gravity of charge. Charge diameter (D) Diameter of cylindrical charge. Same as diameter of drilled hole in these tests. Charge height (H) Height of cylindrical charge as placed in hole. Charge weight (W) Net weight of explosive in charge. Cracks "0", "R", and "I" Three sets of mutually perpendicular fractures parallel to the three directions of principal stress are produced by the detonation of an explosive or by impact and penetration of a projectile into a semi-infinite solid. These fractures determine the limits of the crater and are referred to respectively as "0" (onion) cracks, "R'' (radial) cracks, 11 0 11 and "I" (inward) cracks. The cracks form as horizontal planes parallel to the ground surface, but, as a result of uplift and gas bubble expansion, assume the form of successive concentric layers like the layers of an onion. The "R" cracks are vertical planes which radiate outwardly from the borehole. The "I" cracks are curved surfaces which form vertically at right angles to the "R" cracks and cause the circular outline of the crater. As a result of uplift, the "I" cracks dip in toward the center of the crater. Cracking radius (r ) c Blasts in frozen ground using a weight of explosive less than the optimum weight but greater than the critical weight, dome the surface above the charge and cause radial (R) cracks, which mark the uplift. The "cracking radius" is the radial distance from the center of the borehole to the horizontal projection of the tip of the longest "R" crack. The ends of the "R" cracks appear to coincide with the limits of uplift. Crater area (A) Area of crater opening in plane of surface. Crater shape factor (Kz) The crater shape factor is the variable Kz in the equation for crater volume where V = volume r = crater radius ·h = crater depth. If K 2 equals 1/3, V is the volume of a cone. Thus a shape factor of 1/3 indicates a conical-shaped crater. A shape factor of less than 1/3 indicates a convex or trumpet shaped crater. A shape factor of more than 1/3 indicates a concave sh,ape or indicated conversion of the crater shape to parabolic or sp~erical form. Crater volume (V) Volume of crater resulting from an explosion. B2 APPENDIX Critical depth (N) The minimum depth (measured vertically from the surface to the center of gravity of the explosive charge) at which the energy of the explosion is dissipated into a mass of earth or rock without materially damaging the surface above the charge. C ritical weight (W ) c That weight of a particular explosive of given shape which satisfies the critical-depth requirement for a particular medium and for a given depth. Depth ratio (.6.) Ratio of the depth of center of gravity of the charge to the critical depth. Flyrock travel height (T ) v The maximum vertical height above the ground surface to which particles from a blast are thrown. Gas bubble The gas bubble contains the products of an explosion resulting from the detonation of an explosive in a solid, a liquid, or a gas. Optimum depth (d ) co The depth at which a given weight and shape of explosive produce the greatest volume of excavation per unit weight of explosive. Optimum weight (W0 ) That weight of a particular explosive for which the quantity of a given type of material loosened by an explosive charge of a given shape detonated at a given depth is maximum per unit weight of explosive. ' Strain-energy factor (E) A measure of the energy absorption capacity of the medium in crater blasting. N=EJlfVT where N = critical depth (ft) W = weight of explosive (lb). E is a constant which is a function of both the properties of the medium and the prop erties of the explosive. Venting The phenomenon of surface break-through of the gas bubble. Flyrock travel height,horizontal flyrock travel-distance, and airblast are venting phenomena, related math emat~cally to crater phenomena for blasts in frozen ground, Weight strength Explosive s manufacturers rate explosives both on weight strength and on cartridgestrength. These terms relate to weight and to volume re spectively. The strength of an explosive is relative, but refers to the power or force developed and to the work the explosive is capable of doing. Straight dynamites are rated according to the p er centage of nitroglycerin present. Other types of dynamites have the same weight strength if they develop the same strength, weight for weight, or produce the same deflection of a ballistic pendulum. APPENDIX B3 Figure Bl. Crater cross section illustrating symbols. D = charge diameter; H = charge height; = depth of drilled hole; h = height of stemming; dh s d =depth to center of gravity h = crater depth. c of charge; GPCS 825284-3 r-----------------------------------------------------------------------':"" .------------- ------------------~~--. ~----------- -----------"-------~----~ 1 AD . Accession No . UNCLASSIFIED l AD Accession No UNCLASSIFIED i I I U. S. Army Snow Ice and Permafrost Research 1. I Establishment, Corps of Engineers , Wilmette, Ill. I . I I EXCAVATIONS IN FROZEN GROUND. PT. II: II. I EXPLOSION TESTS IN FROZEN GLACIAL TILL, III. I I FT. CHURCHILL -C. W. Livingston and IV . I Glenn Murphy I I SIPRE Report 30, pt. II, July 1959, 19 pp-illus v . tables. DA Proj 8-66-02-400 , Contract DA-11190-ENG-17, SIPRE Proj 22.4-5 Unclassified Report Explosion tests were conducted in frozen ground near Fort Churchill (Man. ) as an extension of previous tests in Keweenaw silt. Atlas 60 Per cent Straight Gelatin Dynamite, Demolition Block M5 Composition C-3 , and Atlas Coalite 7S. Ammonia-Base Permissible Dynamite were used as the explosives in amounts ranging from 0. 5 to 20 lb. Approximate l y 150 craters were produced. The charges were cylindrical with height-diam ratios from 0 . 12 to 9. 12, w ith the majority (over) ·----------------------------------------------- ; AD Accession No I 1 U. S. Army Snow Ice and Permafrost Research 1. Establishment, Corps of Engineers, Wilmette, Ill. I . EXCAVATIONS IN FROZEN GROUND. PT. II: II. EXP LOSION TESTS IN FROZEN GLACIAL TILL, III. FT. CHURCHILL-C. W. Liviag,.Lunand IV. Glenn Murphy SIP RE Report 30, pt. II, July 1959, 19 pp-illus v. tables. DA Proj 8-66-02-400, Contract DA-ll190-ENG-17, SIPRE Proj 22.4-5 Unclas s ified Report Explo s ion tests were conducted in frozen ground near Fort Churchill (Man.) as ap extension of previous tests in Keweenaw silt. Atlas 60 Per cent Straight Gelatin Dynamite, Demolition Block M5 Composition C-3, and Atlas Coalite 7S Ammonia-Base Permissible Dynamite were used as the explosives in amounts ranging from 0 . 5 to I 20 lb. Approximately 150 craters were produced. I The charges were cylindrical with height-diam I ratios from 0.12 to 9. 12, with th e major ity I I (over) I I I I L-----------------------------------------------------------------------.------------------------------------------------ Explosives--Application s U . S . Army Snow Ice and Permafrost Research 1. Livingston, Clifton Establishment, Corps of Engineers, Wilmette, Ill. I . Murphy, Glenn EXCAVATIONS IN FROZEN GROUND. PT. II: II. Barodynamics, Inc . EXPLOSION TESTS IN FROZEN GLACIAL TILL, III. U. S . Army Snow Ice and FT. CHURCHILL-C. W. Livingston and IV . Permafrost Research Glenn Murphy Establishment Contract DA-11-190ENG-17 SIPRE Report 30, pt. II, July 1959, 19 pp-illustables. DA Proj 8-66-02-400, Contract DA-11190-ENG-17, SIPRE Proj 22.4-5 v. Unclass ified Report Explosion tests were conducted in frozen ground near For t Churchill (Man . ) as an extension of previous tests in Keweenaw silt. Atlas 60 Per cent Straight Gelatin Dynamite , Demolition Block M5 Composition C-3, and Atlas Coalite 7S Ammonia-Base Permi ss ible D ynamite were used as the explosives in amounts ranging from 0 . ·5 to 20 lb. Approximately 150 craters were produced. The charge s were cylindrical w ith height-diam ratios from 0 . 12 to 9. 12 , w i th the majority (over) UNCLASSIFIED l AD Acce ssio n No I Explosives--Applications I U. S . Army Snow Ice and Permafrost Research 1. Livingston, Clifton I I Establishment, Corps of Engineers, Wilmette, Ill. I. Murphy, Glenn I EXCAVATIONS IN FROZEN GROUND. PT. II: II. Barodynamics, Inc . I EXPLOSION TESTS IN FROZEN GLACIAL TILL, III . U. S. Army Snow Ice and FT. CHURCHILL-C. W. Livingston and IV. Permafrost Research Glenn Murphy Establishment SIPRE Report 30, pt. II, July 1959, 19 pp-illusContract DA-11-190 v. tables. DA Proj 8-66-02-400, Contract DA-11 ENG-17 190-ENG-17, SIPRE ?roj 22.4-5 Unclassified Report Explosion tests were conducted in frozel\ ground near Fort Churchill (Man.) as an extension of previous tests in Keweenaw silt. Atlas 60 Percent Straight Gelatin Dynamite, Demolition Block M5 Composition C -3, and Atlas Coalite 7S Ammonia-Base Permissible Dynamite were used as the explosives in amounts ranging from 0. 5 to 20 lb. Approximately 150 craters were produced. The charges were cylindrical with height-diam ratios from 0. 12 to 9. 12, with the majority I (over) I I I I L----------------------------------------------- I Explosives--Applications I Livingston, Clifton I Murphy, Glenn I I Barodynamics, Inc. .I U. S . Army Snow Ice and I I Permafrost Research I Establishment Contract DA-11-190ENG-17 I I I I I I I I I I I ------------------------, I UNCLASSIFIED Explosives--Applications Livingston, Clifton Murphy, Glenn Barodynamics , Inc . U. S. Army Snow Ice and Permafrost Research Establishment Contract DA-11-190ENG-17 I I I I I I I I I I _ _______ _ ______ _________J -------------------------r------------------------------------------------ -------------------------, between 2. 5 and 4 . 0. The depths of charges I 1 between 2. 5 and 4. 0 . The depths of charges I varied from quite shallow to sufficiently deep I varied from quite shallow to sufficiently deep that no surface effect was observed. In general that no surface effect was observed. In general the results verify scaling laws and show that the the results verify scaling laws and show that the critical depth varies a s the cube root of the critical depth varies as the c ube root of the weigh t of the charge . Consistent d ifferences in weight of the charge . Cons istent d ifferences in performance of the explosives were ob served. performance of th e explosives wer e ob served. The s hape of the charge also influenced th e The shape of the charge also influenced the res ults , but scatter of the data preclude estabr esults, but scatter of the data preclude establishing conclusive trends of the influence. lishing conclusive trends of the influence. Detailed data on the shapes and sizes of the Detailed data on the shapes and sizes of the individual craters are reported. individual craters are reported. -------------------------r----------------------------------------------- --------------------------, between 2. 5 and 4. 0. The depths of charges . I b etween 2. 5 and 4. 0. The depths of charges varied from quite shallow to sufficiently deep 1 varied from quite shallow to s ufficie ntly deep that no surface effect was observed. In general that no surface effect was obs erved. . In general the results verify scaling laws and show that the the results verify s caling laws and s how that th e c r it i c a l depth varies as the cube root of the critical depth var ies as the cub e r oot of the weigh t of the charge. Consistent differences in weight of the charge . Consis tent differ ences in performance of the explosives were observed. performance of the explosives were obs erved. The s hape of the charge also influenced the The shape of the charge als o influenced th e results, but scatte r of the data preclude estabresults , but scatter of the data preclude estab lis hing conclusive trends of the influence. lishing conclusive trends of th e influence. Detailed data on the shapes and sizes of the Detailed data on the shapes and s izes of the individual craters are reported. individual craters are report e d . I I I I I I I I I I I L------------------------------------------------------------~ L------------------------~------------- GPO 825284-2