时变载荷作用下饱和黏土地基的流变固结特性研究  

STUDY ON THE CONSOLIDATION CHARACTERISTICS OF RHEOLOGICAL SATURATED CLAY GROUND UNDER TIME-VARYING LOADS

作　　者：王立安 余云燕[2] 孙建忠[2] 陈辉 Wang Li’an;Yu Yunyan;Sun Jianzhong;Chen Hui(School of Railway Technology,Lanzhou Jiaotong University,Lanzhou 730070,China;School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学铁道技术学院,兰州730070 [2]兰州交通大学土木工程学院,兰州730070

出　　处：《力学学报》2024年第3期682-690,共9页Chinese Journal of Theoretical and Applied Mechanics

基　　金：甘肃省科技计划(22JR11RA155);兰州交通大学青年科学基金(1200061136)资助项目。

摘　　要：基于Biot多孔介质理论,利用分数阶Kelvin模型描述土骨架流变效应,引入斜坡、三角形和梯形载荷的时空域解析函数,构建时变载荷作用下饱和黏土地基的三维轴对称固结模型.采用Hankel–Laplace联合变换和张量运算推导控制方程的变换域解析解,利用数值反演得出时空域解.通过算例分析,对模型和计算方法的有效性进行验证,并研究了3种时变载荷作用下饱和黏土地基的流变固结行为和参数影响规律.结果表明,饱和黏土的次固结沉降更为显著.土骨架流变性对孔隙水渗透具有抑制作用,使土体在主固结阶段沉降速率减缓,次固结阶段沉降速率加快,而且长期沉降量增大.加载速率越大,孔隙压力峰值越大.卸载阶段土体发生变形恢复,土骨架弹性扩张产生负孔压,卸载速率越大,产生的负孔压越大.土骨架流变性越强,变形恢复量越小,产生的负孔压也越小.载荷类型和加载路径主要影响固结过程中位移和孔压随时间的变化形态,而土骨架流变性影响土体的长期沉降量.Based on Biot's porous medium theory,a fractional order Kelvin model is used to describe the rheological effect of soil skeleton.The spatiotemporal analytical functions of slope,triangular,and trapezoidal loads are introduced to construct a three-dimensional axisymmetric consolidation model of saturated clay foundation under time-varying loads.The Hankel–Laplace coupled transform and tensor operation are used to derive the analytical solution of the control equation in the transformation domain,and then numerical inversion is used to obtain the spatiotemporal domain solution.Through numerical analysis,the rheological consolidation behavior and parameter influence law of saturated clay foundation under time-varying load were studied.The results indicate that the rheological properties of the soil skeleton have an inhibitory effect on pore water permeability,slowing down the settlement rate of the soil during the primary consolidation stage,accelerating the settlement rate during the secondary consolidation stage,and increasing the long-term settlement amount.During the unloading stage,the soil undergoes deformation and recovery,and the elastic expansion of the soil skeleton generates negative pore pressure.The stronger the rheological properties of the soil skeleton,the smaller the amount of deformation recovery,and the smaller the negative pore pressure generated.The type of load and loading path mainly affect the changes in displacement and pore pressure over time during the consolidation process,while the rheological properties of the soil skeleton affect the long-term settlement of the soil.

关 键 词：时变载荷 流变性 饱和黏土 固结 Hankel–Laplace联合变换 

分 类 号：TU470[建筑科学—结构工程]