• The Journal of Engineering Geology
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• v.30 no.1
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• pp.59-69
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• 2020

Pull-out load tests were performed on a CPR (Compaction grouting compound Pile with Reinforce) test pile, with skin friction being evaluated by the yield load and allowable bearing capacity after analyzing load-displacement curves and load-settlement curves. Results of the CPR test piles analyzed from the load-displacement curves show that the yield load and allowable bearing capacity of the large-diameter CPR test pile were about 1.4 times larger than that of the small-diameter pile. Results of the load-settlement curves reveal that the allowable bearing capacity of the CPR test pile with diameter of D500 was 1.2~2.1 times greater than that of the pile with diameter of D400. However, the allowable bearing capacity calculated using Fuller's analysis differed substantially from that determined using the P (Pull-out load) - S (Settlement) and log P - log S curves. Therefore, calculation of the allowable bearing capacity using Fuller's analysis is shown to be inappropriate.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.211-222
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• 2019

This study evaluates the yield load and allowable bearing capacity of ground in compressive loading tests to confirm the effect of CPR foundation reinforcement. The average compressive strength of the injection materials was higher than the planned compressive strength. Standard penetration tests for each stratum showed that foundation reinforcement improved the average N values, thereby increasing the bearing capacity of the ground. Compressive loading tests on two CPR piles revealed that the total and net settlement due to the maximum load exceed that permissible for the CPR pile diameter. The yield load and allowable bearing capacity calculated by the settlement criterion and the load-settlement curves varied greatly with the method applied. Therefore, it seems to be necessary to determine the optimum value through comprehensive analysis after applying various yield load calculation methods.