Umfang:
97 Seiten
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Illustrationen
Serie:
SIPRE report 30
Inhalt:
Mining Research Corporation, Inc., under contract with Snow Ice, and Permafrost Research Establishment, Corps of Engineers, U.S. Army, conducted explosion tests in frozen Keweenaw silt, to determine; (1) the most efficient type of explosive for blasts in frozen ground, (2) the fundamental relation between weight of explosive and depth of charge, (3) the proper position of the charge relative to the frozen-ground interface, (4) the feasibility of fracturing the frozen layer by placing a charge in the underlying unfrozen material, and (5) the effect of the diameter of the borehole and of the shape of the charge upon the resultsof blasting.
Information obtained from the tests applies to the specific problem of excavating in frozen ground and to fundamental explosives research. Conclusions and recommendations based on this information are presented here concerning the feasibility of using explosives for fox-holes in frozen ground; methods of placing the charge; mechanics of crater formation; the crater equation; future instrumentation; classification of explosives; and correlation of blast data.
Anmerkung:
MAB0014.001: ZSP-201-30
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CONTENTS
Preface
Abstract
Chapter I. Introduction to problem
1. Previous attempts at blasting frozen ground
2. Necessity for fundamental approach
3. Terminology
4. Description, objectives, and scope of the Keweenaw Tests
5. Selection of explosives
6. Classification and properties of commercial explosives
7. Characteristics of explosives in the Keweenaw Tests
8. Comparison of Atlas, Hercules, and Du Pont nitroglycerine-base explosives
Chapter II. Test program
Section I. Field tests
1. General
2. Test site
3. Field test procedure
a. Site preparation
b. Instrumentation
c. Snow removal
d. Determining depth of frozen ground
e. Soil sampling and coring
f. Layout of the test site
g. Spacing of blast holes
h. Blast-hole drilling
i. Blasting procedure
j. Field analysis and crater surveys
k. Data-sheet computations
l. Photography
Section II. Laboratory tests
1. Soil handling and storage
2. Soil classification tests
a. Specimen preparation
b. Test procedure
c. Test results
3. Tests to determine stress-strain relationship
a. General
b. Specimen preparation for unconfined compression tests
c. Test procedure
d. Results
e. Observations
Chapter III. Analysis of blast tests
Section I. Mechanics of crater formation in frozen Keweenaw silt
1. Introduction
2. Shock phenomena
3. Expansion of the gas bubble
4. Rupture of surface and conversion of pressure head to velocity head
Section II. Blast Test A - Relationships of explosive, radius of crater, volume of crater, and depth of crater
1. Introduction
2. Description
3. Results and analysis
4. Summary of observations
Section Ill. Blast Test B - Energy utilization in blasting
1. Introduction
2. Description
3. Results and analysis
4. Summary of observation
Section IV. Blast Test C - The frozen-ground interface
1. Introduction
2. Relation of frozen-ground interface to scaling laws
3. Relation between the ratio of chamber volume to crater volume and the volume-utilization factor
4. Increase in volum.e-utilization factor for charges placed below the frozen layer
5. Position of the gas bubble relative to the frozen-ground interface
6. Igloo-type foxhole construction
Section V. Blast Test D - Foxhole construction
1. Introduction
2. Application of shaped charges to foxhole construction
3. Application of hand-auget drilling to foxhole construction
4. Conclusions
Section VI. Blast Test E - Temperature effect
1. Introduction
2. Description
3. Results and analysis
4. Summary of observations
Section VII. Blast Test F - Effect of charge shape
1. Introduction
2. Description
3. Conclusions
Chapter IV. Summary of objectives; conclusions and recommendations
Section I. Summary of objectives
1. Introduction
2. Objective 1: Most efficientt type of explosive for blasts in frozen ground
3. Objective 2: Fundamental relation between weight of explosive and depth of charge
4. Objective 3: Proper position of charge relative to the frozen-ground interface
5. Objective 4: Feasibility of fracturing the frozen layer by placing a charge in the underlying unfrozen material
6. Objective 5: Effect of diameter of the borehole and shape of charge on results of blasting
Section II. Conclusions and recommendations
1. Feasibility of using explosives for constructing foxholes in frozen ground
2. Methods of placing the charge
3. Mechanics of crater formation
4. The crater equation
5. Future instrumentation
6. Classification of explosives
7. Correlation of blast data
Appendix: Data sheets, Experiments 1-13
In:
SIPRE report, 30
Sprache:
Englisch
Schlagwort(e):
Forschungsbericht
URL:
https://apps.dtic.mil/sti/citations/AD0115156
