饱和软土固结的Mandel-Cryer效应及影响因素研究

摘要

采用Biot固结理论分析饱和软土的渗流固结问题时，在固结“初期”，会出现隙水压力升高，且大于初始孔压的现象，即Mandel-Cryer效应。基于Biot固结理论，采用有限元计算方法，分析了深度、模量、泊松比和渗透系数对Mandel-Cryer的影响。研究结果显示：随着深度的增加，归一化孔压值增大3~17 m，归一化值为1.01~1.07，曼德尔效应开始时间与深度呈指数关系；模量越大，曼德尔效应的时间越提前，模量对归一化孔压值影响较小，最大归一化孔压值为1.06~1.07；泊松比对曼德尔效应的影响最大，泊松比越小，曼德尔效应越明显，孔压归一化值越大，时间越推迟；渗透系数对Mandel-Cryer效应的影响主要体现在对发生的时间方面，渗透系数越小，Mandel-Cryer越推迟。%Mandel-Cryer effects may appear in the early stage of saturated clay consolidation when the pore pressure exceeds the initial pore pressure. Based on the Biot theory and the finite element method,this paper an-alyzes how the parameters of the depth,modulus,Poisson ratio and permeability coefficient affect the Mandel-Cryer effects. The results showed that the deeper the distance the clearer the Mandel-Cryer effect,and the lon-ger its time duration was. When the depth was 3~17m,the normalized value of pore pressure was 1.01~1.07 with the exponential relation between the initial time and depth;while the modulus increased,the time of Man-del-Cryer effect delayed,and the maximum normalized value was 1.06~1.07;the Poisson ratio affected the val-ue of normalized pore pressure in that the maximum value of normalized pore pressure increased as the Poisson ratio decreased;the permeability coefficient mainly influenced occurrence time. When the permeability coeffi-cient decreased,the Mandel-Cryer effect occurrence would be delayed.