• The Journal of Engineering Geology
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• v.17 no.4
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• pp.525-534
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• 2007

The peculiarity of end-expanded soil nailing method(EESNM) is in fixing the wedge-type steel body spreaded by collars and grouting its surroundings by cement milk within soils, after extending hole bottom over drilling hole diameter with top drill bit. The present study was done to establish the effect of this method. Laboratory model test were carried out to investigate the behavior characteristics with the performance of the pull-out test and failure experiment, after preparing soil test box having 1,300mm length, width 1,000mm, and height 1,100mm, and the same experimental condition was set up to compare with the general soil nailing method(GSNM). The pull-out force of about 23 percentage was increased, and the horizontal displacements 1.2 from 9.1 percentage in soil-nailed wall decreased in EESNM compare with GSNM. The axial force acting on nail increased considerably at load level over 7 ton in EESNM and 5 ton in GSNM. The predicted failure line from the maxima analyzed by axial tensile strain located at long distance from soil-nailed wall in EESNM. The EESNM demonstrated the superiority of reinforcement effect in comparison with GSNM from the results above mentioned.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.64-73
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• 2000

The joint parts was composed of inner AL(aluminum) ring, FRP wedge and motor case which was manufactured by filament wound method. Where the motor case consists of helical and hoop layer. The finite element analysis was performed for the design variable of joint parts to improve the performance of motor case. Where the adhesive layer was modeled to elasto-perfect plastic material and the contact condition of AL ring and wedge was modeled by using the contact surface element of ABAQUS. And the sliding distance of AL ring and the hoop strain of composite case were compared to hydro-static test results to verify the accuracy of analysis results. When wedge and AL ring was perfect bonding, though the hoop strain of joint part was reduced, the maximum shear stress was occurred at the adhesive layer. Thus the adhesive layer had failed due to the high shear stress before the failure was occurred at the case. And as another design method, when wedge and AL ring was contact condition, the shear stress on adhesive layer was decreased. But the hoop stress of joint part increased due to the sliding behavior of AL ring. Finally, the fail was occurred at the composite case of joint part. The improved joint method reinforced by hoop layer to the joint parts under contact condition for wedge and Al. ring reduced the joint part's hoop strain by constraint the sliding behavior of AL ring.