竖井地基热排水固结本构模型及试验验证

考虑饱和土体先期固结压力随温度变化情况,对非等温条件下土体e–lgp曲线上点的移动规律进行研究,建立了饱和黏土的非线性热弹性本构模型,并开发编制了TSDSS有限元程序。同时,开展了竖井地基热排水固结模型试验,将试验结果与模型试验的TSDSS模拟结果进行对比,两者较为吻合,从而验证了该本构模型的正确性,且能从机理上反映热排水固结过程,数值模拟结果进一步表明:土体导热系数越大或渗透系数越小,热排水固结过程中产生的孔隙水压力峰值越大;渗透系数越小,热排水固结越慢;导热系数越大,热排水固结越快。

A constitutive model for thermal consolidation with vertical drains and its experimental verification

The rule of the point, which represents the relation between effective stress and void ratio of fluid-saturated soils, moving in the e–lgp space under non-isothermal condition is studied according to the effect of temperature on preconsolidation pressure of soils. On the basis of this rule, a nonlinear-elastic constitutive model for thermal consolidation is established. Meanwhile, a FEM program named TSDSS implementing the algorithm of this constitutive model is developed. In order to verify the constitutive model, the relevant model tests are carried out. By comparing the model test results with the numerical simulation ones, it is verified that the constitutive model can simulate the development of thermal consolidation with vertical drains from the mechanism to a certain extent. The results of numerical simulation show that the maximum of excess pore pressure produced during the thermal consolidation process will increase with the increase of thermal conductivity and the decrease of hydraulic conductivity. The thermal consolidation rate will be slower with the increment of the value of hydraulic conductivity and the decrement of the value of thermal conductivity.