| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Bearing capacity tests were performed by the use of small box ( 30cmphi X 20cm ), medium box ( 150cmphi X 165cm) and centrifuge apparatus under the accelerations of 30, 60, 90G. Circular and rectangular plates ( ratios of length L over width B are from 1 to 7 ) were placed over lnagi Sand whose relative density was about 80%. Main results are that, 1) sliape factor ( Sgamma ) of ( 1+0.4 B/L )is obtained. 2) the bearing capacity becomes nearly constant when L is greater than 5B. 3) the bearing capacity factor Ngamma decreases following the increase in B, and when L/B is smaller, the decrease in Ngamma is more prominent, 4) the analysis by Kotter equation considering the stress dependency and anisotropy existing in the angle of shearing resistance phi' can interpret the test results in 3).
Bearing capacity tests were performed by the use of small boxes ( 60cmXlOcmX25cm; 30cmX30cmX35cm ). Circular and rectangular plates were buried in Toyoura Sand ( rations of depth D over B are from 0 to 14 ). Main results are that, 5) Sgamma 1-0.5 B/L and Sq=1.5( for B=L ) are obtained, 6) depth factor dq of ( 1+0.25 tan^<-1>( D/B )) is concluded theoretically and this analysis is confirmed by the test on strip foundation, where as the tests on circular and square plates show that dq is ( 1+0.16 ・ tan-1(D/B )) where phi' = 42ﾟ.
Slice method for bearing capacity calculation is developed. Main results are. 7) by a series of calculation, the relation of q_3 =( 1+0.8 B/L )q_2 wtiere q_2 and q_3 are bearing capacity of strip and rectangular plate is induced, 8) the predicted fail loads of plates on the slopes are compared with the test load performed on Takaragi loam, and fair agreement were found.
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