基于谱方法的层状竖井地基非线性固结计算模型
Nonlinear consolidation model for stratified soils with vertical drains based on spectral method
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摘要: 针对实际工程中很多竖井地基呈现层状,且在固结过程中渗透系数和压缩模量呈非线性变化等特性,基于对数模型(e-lgσ'和e-lgk)的非线性压缩渗透本构关系,建立了能同时考虑竖向和径向排水的非线性固结模型,并采用谱方法得到了层状竖井地基的非线性固结计算模型。通过退化研究与已有的非线性固结解析解和室内试验进行对比计算分析,结果显示本模型计算值与解析解和实测值的平均相对误差分别低于0.7%和2.0%,验证了本模型的合理性。最后对某一实际工程案例进行了应用计算分析,结果显示不同深度处的沉降和孔压计算值与实测数据吻合程度较好,能够反映在固结过程中不同土层中沉降和孔压的发展变化过程,进一步说明了本模型在层状竖井地基固结计算的可行性和工程适用性。Abstract: Many soft soil foundations with vertical drains are stratified, and the permeability and compressibility of soils change nonlinearly during the consolidation process. A nonlinear consolidation model that can consider both vertical and radial drainage is proposed based on the void-ratio dependent compressibility and permeability (e-lgσ' and e-lgk), and a nonlinear consolidation model for the stratified soils with vertical drains is obtained based on the spectral method. The validation of the solution is verified by the degradation study and the comparative analysis with the existing nonlinear consolidation analytical solutions and laboratory tests. The results show that the average relative error between the calculated value and the analytical solution and the measured value is lower than 0.7% and 2.0%, respectively. A field case is also studied and analyzed. The results show that the calculated values of settlement and pore pressure at different depths are in good agreement with the measured data, which can predict the development of settlement and the dissipation of pore pressure in different soil layers during the consolidation process. The case study further illustrates the feasibility and applicability of the proposed model in the consolidation calculation of stratified soils with vertical drains.