弱化饱和砂土中桩的p–y曲线与极限抗力研究  

p–y curves and lateral resistances of piles in saturated degradation sand

作　　者：王建华[1] 戚春香[1] 余正春[1] 冯士伦[1] 

机构地区：[1]天津大学岩土工程研究所,天津300072

出　　处：《岩土工程学报》2008年第3期309-315,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金资助项目(50579050)

摘　　要：利用给土层施加反压的方法控制饱和砂土中的超孔隙水压力,以此模拟饱和土层液化过程中具有一定残余孔压时的弱化状态。进而对不同弱化状态饱和砂土与桩的相互作用进行模型试验,研究p–y关系与水平极限抗力随饱和砂土中残余孔压增加时的变化规律。结果表明:对于相对密度为30%的饱和砂土,随土层中残余孔压增加,同一水平位移下桩受到的土层抗力逐渐降低;如果土层中无残余孔压,桩的水平极限抗力实测结果与理论计算结果接近;当土层中的残余孔压分别达到土层上覆有效压力的0.25,0.5,0.75倍时,桩的水平极限抗力分别降低30%,55%与80%;土层液化后,桩的水平极限抗力大约降低90%,这点与已有的振动台及离心模型试验结果基本一致。The excess pore water pressure in the saturated sand was controlled by applying the back pressure to the stratum,so that the degraded saturated stratum with the residual pore water pressure was simulated.Model tests of the soil-pile interaction were conducted to study variations of p-y curves and ultimate lateral resistances of single pile in degraded saturated sand with the increase of the residual pore water pressure.The following results were obtained based on model tests corresponding to the saturated sand with the relative density of 30%.The lateral resistance of the pile gradually decreased with increase of the residual pore water pressure under the same lateral displacements of piles.If there was no residual pore water pressure in the saturated sand,the ultimate lateral resistance of the stratum determined based on model tests was close to the academic value.The ultimate lateral resistances of piles degraded about 30%,55% and 80% respectively if the residual pore water pressure was 0.25,0.5 and 0.75 times the effective overburden pressure of the stratum.The ultimate lateral resistances of the stratum degraded about 90% for liquefied sand,which was consistent with shaking table and centrifugal model test results.

关 键 词：桩土相互作用 液化土中桩 桩的水平承载力 砂土液化 p–y曲线 

分 类 号：TU435[建筑科学—岩土工程]