考虑初始孔压非均布及起始坡降的黏土流变固结解

doi:10.13722/j.cnki.jrme.2018.1242

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摘要外荷载引起的土中初始超静孔压往往沿深度非均匀分布。软黏土的流变特性以及黏性土中渗流存在起始坡降的现象也已被认识。但能同时考虑起始坡降及初始孔压非均布的软黏土流变固结解还鲜见报道。采用Merchant三元件模型描述黏土的流变特性，在初始孔压沿深度非均布条件下建立考虑起始坡降的软黏土一维流变固结控制方程及求解条件，采用拉普拉斯变换方法获得其解析解答。在验证解可靠性的基础上，开展大量的分析计算。结果表明：起始坡降越大，渗流移动边界移动速度越慢，土层平均固结度和最终沉降量越小。土层顶面处初始超静孔压和底面处初始超静孔压的比值(?)越大，移动边界下移速度越慢，土层固结速率越快，平均固结度最终稳定值越小，土层最终沉降量越大。流变模型中Kelvin体弹簧的弹性模量(E1)和独立弹簧弹性模量的比值(a)在固结前期对固结性状影响很小；固结后期，a值越大，土层固结速率越快，最终沉降量也越大。固结前期，黏滞系数( )的变化对固结性状影响不大；固结后期，值越大，土层固结速率和沉降速率越快，但值的变化并不影响土层的最终沉降量。

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	李传勋1
	马浩天1
	周恩全1
	谢康和2

关键词 ：土力学, 软黏土, 初始孔压非均布, 起始坡降, 移动边界, Merchant流变模型

Abstract：The distribution of initial excess pore water pressure in clays caused by external load is usually non-uniform with depth，and the rheological characteristics of soft clays and the threshold hydraulic gradient in clays have also been recognized. However，an analytical solution for rheological consolidation of soft clays with consideration of threshold hydraulic gradient in clays and non-uniform distribution of initial excess pore water pressure has been rarely reported in the literature. In this study，the rheological characteristic of soft clays are described by Merchant three-element rheological model，and the governing equation for one-dimensional consolidation with consideration of threshold gradients and non-uniform distribution of initial excess pore water pressure with depth is developed，and analytical solutions for this consolidation model are derived by Laplace transform method. Based on the verification of analytical solutions，a large number of calculations are investigated by analytical method. The results show that：the larger the threshold hydraulic gradient is，the slower the speed of moving boundary is，and the smaller the average consolidation degree and the final settlement are. With an increase in the ratio(?) of the initial excess pore water pressure at the top surface( ) to that at the bottom surface( )，the speed of moving boundary and the final average degree of consolidation decrease，and the consolidation rate and the final settlement of clay layer increase. The ratio(a) of the elastic modulus of spring( ) in Kelvin body to the elastic modulus( ) of independent spring has little influences on the consolidation behavior in the early stage of consolidation. However，in the late consolidation stage，the greater the ratio a is，the larger the average degree of consolidation and the final settlement of the layer are. In the early stage of consolidation，the viscosity coefficient( ) has little influence on the consolidation characteristics of the soil. In the late stage of consolidation，the larger the value of ，the faster the consolidation rate and the settlement rate of the soil. But the viscosity coefficient has no influence on the final settlement of clay layer.

Key words： soil mechanics soft clay non-uniform distribution of initial excess pore water pressure threshold gradient moving boundary Merchant rheological model

引用本文:

李传勋1，马浩天1，周恩全1，谢康和2. 考虑初始孔压非均布及起始坡降的黏土流变固结解[J]. 岩石力学与工程学报, 2019, 38(S2): 3859-3869.
LI Chuanxun1，MA Haotian1，ZHOU Enquan1，XIE Kanghe2. Analytical solutions for rheological consolidation of soft clays with consideration of threshold hydraulic gradients and nonuniform distribution of initial excess pore water pressure. , 2019, 38(S2): 3859-3869.

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http://rockmech.whrsm.ac.cn/CN/10.13722/j.cnki.jrme.2018.1242 或 http://rockmech.whrsm.ac.cn/CN/Y2019/V38/IS2/3859

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