液化场地倾斜桩动力p-y曲线研究

Study on the dynamic p-y curves of inclined pile in liquefied ground

为了研究动力荷载作用下倾斜桩的动力p-y曲线规律,采用数值模拟的方法,构建了液化场地倾斜桩-土数值分析模型,通过输入幅值为0.20 g的正弦波,对倾斜桩的动力p-y曲线数值计算结果进行了分析,并与已有成果进行了对比分析。研究结果表明:(1)距倾斜桩较远的土体受到倾斜桩的影响较小,近场土体受到倾斜桩的影响较为明显;砂土层土体孔压反应受埋深和桩距两方面因素影响;(2)倾斜桩-土相对位移呈现有正有负,交替出现桩推土和土推桩的特性;倾斜桩动力p-y滞回曲线关于原点不对称,而是在偏于原点靠右方一点处具有一定的对称性;(3)随埋深的增加,倾斜桩动力p-y滞回曲线整体呈左旋趋势,斜率变缓,桩周土侧向刚度逐渐降低,侧向力逐渐减小,而位移逐渐增大;倾斜桩下部耗能较小,吸收的能量少,抵抗变形能力相对较弱,上部则相反;(4)与已有试验成果对比分析可得,采用数值模拟得到的倾斜桩动力p-y曲线的规律是合理、可靠的。

In order to study the law of p-y curves of inclined pile under dynamic loads,using the method of numerical simulation,the numerical analysis model of the inclined pile-soil in liquefied ground was constructed.Through the input sine wave with a amplitude of 0.20 g,the numerical calculation results of the dynamic p-y curves of the inclined pile were analyzed and compared with the existing results.The results show that:(1)the soil with a long distance from the inclined pile is less affected by the structure,and the influence of the near-field soil is more obvious,and the pore pressure reaction of sand soil is influenced by two factors:depth of burial and pile distance;(2)the relative displacement of the inclined pile is positive and negative,and the characteristics of pile driving and soil pushing pile are changed alternately.The p-y hysteresis curves of the inclined pile are asymmetrical at the origin,but it has a certain symmetry at the point of the origin;(3)with the increase of the buried depth,the overall trend of the p-y hysteresis curves of the inclined pile is left,the slope is slow,the lateral stiffness of the soil is gradually reduced,the lateral force is gradually decreased,and the displacement gradually increases.The lower part of the inclined pile has less energy,less energy absorption,relatively weak resistance to deformation,and vice versa;(4)compared with the existing test results,the law of the p-y curves obtained by the inclined pile is reasonable and reliable.