基于API规范的液化土层桩基p-y曲线修正计算公式
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摘要
基于小型振动台拟静力试验和往返动荷载试验,将得到的静力p-y曲线及滞回曲线与基于静力方法提出的API规范方法进行对比研究,指出了采用目前API规范中的折减系数方法进行液化土层中桩基横向承载力计算时与实际不符并导致工程设计无法接受的原因。进行四种不同相对密度可液化土中大型振动台桩?土?承台动力相互作用大型振动台试验,考虑到API规范方法在工程中的广泛应用性和可接受性,在不改变其基本模式前提下,提出其中土体初始模量和极限土阻力两个修正参数,以地震波输入下的振动台试验对构建的公式进行验证,结果较为吻合。
On the basis of the shaking table pseudo-static and cyclic ground motion input tests, the post-calculating p-y curves based on the shaking table tests and API code are compared. As a result, the unacceptable reason of the current coefficients for calculating the dynamic p-y curves by the API code in engineering practice is pointed out. Using four different densities of liquefiable sand layers in the shaking table tests by incident sinusoidal waves and taking the sand density as a major factor, the initial modulus and ultimate soil resistance parameters in the API code are modified. Using the shaking table tests on pile-soil liquefaction interaction by incident irregular seismic waves, the modified method and the revised computational formula are verified. It is indicated that the modified method and the revised formula are agreeable with the test results. The expression of the revised formula is as simple as that in the API code and is convenient for practical engineering application.
On the basis of the shaking table pseudo-static and cyclic ground motion input tests, the post-calculating p-y curves based on the shaking table tests and API code are compared. As a result, the unacceptable reason of the current coefficients for calculating the dynamic p-y curves by the API code in engineering practice is pointed out. Using four different densities of liquefiable sand layers in the shaking table tests by incident sinusoidal waves and taking the sand density as a major factor, the initial modulus and ultimate soil resistance parameters in the API code are modified. Using the shaking table tests on pile-soil liquefaction interaction by incident irregular seismic waves, the modified method and the revised computational formula are verified. It is indicated that the modified method and the revised formula are agreeable with the test results. The expression of the revised formula is as simple as that in the API code and is convenient for practical engineering application.
引文
[1]Wilson D W.Observed seismic lateral resistance of liquefying sand[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(10):898-906.
[2]American Petroleum Inst.Recommended practice for planning,designing,and constructing fixed offshore platforms[M].Working Stress Design,Rpt.RP2A-WSD.Washington:American Petroleum Inst.1976.
[3]冯士伦,王建华,郭金童.液化土层中桩基抗震性能研究[J].岩石力学与工程学报,2005,24(8):1402-1406.
[4]李雨润.液化土层中桩基横向动力响应研究[D].哈尔滨:中国地震局工程力学研究所,2006.
[5]李雨润.桩-液化土相互作用p-y曲线修正计算方法研究[J].地震工程与工程震动,2008,28(3):165-171.
[2]American Petroleum Inst.Recommended practice for planning,designing,and constructing fixed offshore platforms[M].Working Stress Design,Rpt.RP2A-WSD.Washington:American Petroleum Inst.1976.
[3]冯士伦,王建华,郭金童.液化土层中桩基抗震性能研究[J].岩石力学与工程学报,2005,24(8):1402-1406.
[4]李雨润.液化土层中桩基横向动力响应研究[D].哈尔滨:中国地震局工程力学研究所,2006.
[5]李雨润.桩-液化土相互作用p-y曲线修正计算方法研究[J].地震工程与工程震动,2008,28(3):165-171.
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