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以静压沉桩后桩周土体的应力状态为初始条件,根据桩周土体孔隙比、渗透系数和有效应力之间的相关性,在考虑固结系数随固结时间变化的条件下改进了轴对称条件下的太沙基固结控制方程。随后,采用分离变量法和离散化分析推导得出了桩周超孔隙水压力消散的半解析半数值解,并将解答与实测数据进行对比验证。在此基础上,采用空间滑动面理论改进的修正剑桥模型(SMP-MCC)定义土体三维不排水抗剪强度,研究了静压桩周土体强度、剪切模量随固结时间的变化规律。研究结果表明:由于解答考虑了固结系数随固结时间的变化,因而与实测结果吻合良好;土体压缩指数与渗透指数之比对土体固结系数和孔压消散速率影响较大;当土体压缩指数与渗透指数之比为1时,土体固结系数保持不变,解答退化为经典的太沙基轴对称固结方程;土体强度和剪切模量随固结时间的增长而逐步增加,固结完成后其值超越了土体原位强度和原位剪切模量。
Taking the stress state of pile around the pile after static pressure piling as the initial condition, according to the correlation between the void ratio, permeability coefficient and effective stress of the soil around the pile, taking into account the variation of the consolidation coefficient with the consolidation time Axisymmetric Taesha solidification equation. Subsequently, the semi-analytic semi-numerical solution to the dissipation of excess pore-water pressure over the pile circumference was deduced using the method of separation of variables and discretization analysis. The comparison between the solution and the measured data was carried out. On this basis, the modified three-dimensional undrained shear strength of soils is defined by modified modified Cambridge model (SMP-MCC) of space sliding surface theory. The changes of soil strength and shear modulus with the consolidation time are studied. law. The results show that the ratio of soil compressibility index and infiltration index has a great influence on soil consolidation coefficient and pore water pressure dissipation rate as the solution considers the change of consolidation coefficient with the consolidation time. When the ratio of soil compressibility index to infiltration index is 1, the soil consolidation coefficient remains unchanged, and the solution degenerates into the classical symmetry of the Basis axis. The soil strength and shear modulus increase with the consolidation time And gradually increased, the value of consolidation beyond its strength in situ and in situ shear modulus.