Document Details


Title:
OPERATION HARDTACK, PROJECT 1.9, LOADING ON BURIED SIMULATED STRUCTURES IN HIGH-OVERPRESSURE REGIONS, APRIL - OCTOBER 1958 ( HARDTACK-I OPERATION ) (DELETED)
Author(s):
BULTMANN, E H [AIR FORCE SPECIAL WEAPONS CENTER]; MCDONOUGH, G F [AIR FORCE SPECIAL WEAPONS CENTER]; SINNAMON, G K [AIR FORCE SPECIAL WEAPONS CENTER]
Subject Terms:
HARDTACK I OPERATION; BLAST EFFECTS; SHOCK WAVES; MEASURING METHODS; RESEARCH PROGRAMS; SURFACE PROPERTIES; CACTUS EVENT; KOA EVENT; EQUIPMENT
Document Location:
Location - NNSA/NSO Nuclear Testing Archive Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - CIC@NV.DOE.GOV
Document Type:
REPORT
Publication Date:
1961 May 03
Declassification Status:
Sanitized
Document Pages:
0062
Accession Number:
NV0051382
Document Number(s):
WT1614
OpenNet Entry Date:
1994 Aug 26
Description/Abstract:
THE OBJECTIVE WAS TO STUDY SOME OF THE FACTORS AFFECTING THE TRANSMISS ION OF AIR-BLAST-INDUCED PRESSURE THROUGH SOIL AND THE LOADING PRODUCE D ON BURIED STRUCTURES BY SUCH PRESSURES IN THE HIGH-PRESSURE REGION ( APPROXIMATELY 250 PSI ). FACTORS STUDIED BY THIS PROJECT WERE: (1) TH E ATTENUATION OF PRESSURE IN A SAND DEPOSIT WHEN THE WATER TABLE IS A FEW FEET BELOW THE GROUND SURFACE; (2) THE EFFECT OF DURATION OF POSIT IVE PHASE OF BLAST ON THE PRESSURE TRANSMITTED THROUGH SUCH A SOIL; (3 ) THE EFFECT OF STRUCTURE FLEXIBILITY ON THE PRESSURE ACTING ON STRUCT URES BURIED IN SUCH A SOIL; AND (4) THE RELATIONSHIP BETWEEN HORIZONTA L AND VERTICAL PRESSURES IN SUCH A SOIL. THE PROJECT EMPLOYED 43 DEVIC ES, EACH A RIGID CYLINDER HAVING ONE RIGID END AND ONE DEFORMABLE-DIAP HRAGM END. THREE THICKNESSES OF DIAPHRAGM WERE USED TO SIMULATE STRUCT URES OF DIFFERENT FLEXIBILITIES. THE DEVICES WERE BURIED AT DEPTHS RAN GING FROM 0 TO 20 FEET AT EACH OF TWO LOCATIONS AT THE ENIWETOK PROVIN G GROUND. THE LOCATIONS WERE CHOSEN TO GIVE A PREDICTED GROUND SURFACE OVERPRESSURE OF ABOUT 250 PSI FROM EACH OF TWO SHOTS, CACTUS AND KOA. THE PREDICTED PRESSURES WERE BASED ON PREDICTED YIELDS OF 16 KT FOR SH OT CACTUS AND 1.4 MT FOR SHOT KOA. THE ACTUAL YIELD FOR SHOT CACTUS WA S 18 KT AND FOR SHOT KOA 1.3 MT. THE AVERAGE MEASURED PEAK SURFACE OVE RPRESSURES AT THE LOCATIONS OF THE DRUMS WERE 304 PSI FOR SHOT CACTUS AND 240 PSI FOR SHOT KOA. STATIC STRAIN-GAGE READINGS AND PERMANENT DE FLECTION MEASUREMENTS WERE MADE ON THE DIAPHRAGMS BEFORE AND AFTER THE TEST. TRANSIENT-STRAIN AND MAXIMUM-DEFLECTION MEASUREMENTS WERE MADE ON THE DEVICES HAVING THE STIFFEST DIAPHRAGMS. ADDITIONAL MEASUREMENTS WERE MADE BY SURFACE-PRESSURE AND WATER-LEVEL GAGES. A LABORATORY PRO GRAM WAS CONDUCTED TO CALIBRATE THE FIELD TEST DEVICES. THE ATTENUATIO N OF AIR-INDUCED PRESSURE WITH DEPTH WAS OBSCURED BY THE APPARENT EXIS TENCE OF A LARGE-MAGNITUDE HORIZONTAL WATER-TRANSMITTED SHOCK; HOWEVER , THE FOLLOWING RESULTS WERE OBSERVED: THE ATTENUATION OF THE AIR-INDU CED PRESSURE WAS ABOUT 20 PERCENT IN THE FIRST 5 FEET; THIS ATTENUATIO N APPARENTLY CEASED WITHIN 5 FEET BELOW THE WATER TABLE. IN THIS PARTI CULAR SOIL DEPOSIT, THERE WAS NO APPRECIABLE EFFECT OF THE DIFFERENCE BETWEEN THE POSITIVE-PHASE DURATIONS OF THE PRESSURE PULSES FROM SHOTS CACTUS AND KOA. ABOVE THE WATER TABLE, THE HORIZONTAL PRESSURE WAS AB OUT 50 PERCENT OF THE VERTICAL PRESSURE, WHEREAS, A FEW FEET BELOW THE WATER TABLE THE HORIZONTAL PRESSURE BECAME APPROXIMATELY EQUAL TO THE VERTICAL PRESSURE. THE FLEXIBILITY OF THE DIAPHRAGMS HAD A LARGE EFFE CT ON THE PRESSURES ACTING ON THEM WHETHER ABOVE OR BELOW THE WATER TA BLE. THE SIMPLIFIED THEORY DEVELOPED IN REFERENCE 1 GAVE REASONABLE PR EDICTIONS OF THE PRESSURES ON THE DIAPHRAGMS.


<< Return to Search Results