考虑涂抹作用的砂井地基大应变非线性固结分析  

Large strain nonlinear consolidation analysis of sand drain foundation considering smearing effect

作　　者：陈铭 曹文贵[1,2] 崔鹏陆 CHEN Ming;CAO Wengui;CUI Penglu(College of Civil Engineering,Hunan University,Changsha 410082,Hunan,China;Key Laboratory of Building Safety and Energy Efficiency,Ministry of Education,Hunan University,Changsha 410082,Hunan,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]湖南大学建筑安全与节能教育部重点实验室,湖南长沙410082

出　　处：《建筑科学与工程学报》2024年第6期182-190,共9页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(51879104,52078206)。

摘　　要：假定土体中渗流符合非达西渗流,通过引入有效应力及渗透系数与孔隙比间的双对数模型描述软土非线性压缩特性,建立能同时考虑涂抹作用的砂井地基大变形固结模型,并用有限差分法对该模型求解。通过退化数值解与等应变条件下的解析解及现有试验的对比,验证了该解答的可靠性,并对影响砂井地基非线性固结的参数进行了分析。结果表明:在考虑涂抹作用的3种模式中,涂抹区渗透系数呈抛物线变化时固结最快,为常数时最慢;相较于渗透系数为常数,涂抹区渗透系数线性变化时固结度最大相对偏差达到35.7%,沉降量最大相对偏差达到26.7%;涂抹区渗透系数呈抛物线变化时固结度最大相对偏差达到36.9%,沉降量最大相对偏差达到28.4%;双对数坐标系下的压缩指数和渗透指数增大,砂井地基固结速率减慢,压缩指数增大时最终沉降量增加,而渗透指数不影响最终沉降量,相较于压缩指数I_(c)=0.08,I_(c)=0.1时固结度最大相对偏差达到21.7%,最终沉降量偏差0.030 m;I_(c)=0.12时固结度最大相对偏差达到37.9%,沉降最大偏差达到0.059 m;相较于渗透指数α=6,α=10时固结度最大相对偏差达到39.3%,α=14时高达61.9%;考虑非达西渗流砂井地基固结速率更慢,固结度最大相对偏差可达16.5%。Assuming that the seepage in the soil conformed to non-Darcy seepage,the nonlinear compression characteristics of soft soil were described by introducing a double logarithmic model between effective stress,permeability coefficient,and void ratio.A large deformation consolidation model for sand drain foundation that could simultaneously consider the smearing effect was established,and the model was solved using finite difference method.The reliability of the solution was verified by comparing the degenerate numerical solution with the analytical solution under equal strain conditions and existing experiments.The parameters that affect the nonlinear consolidation of sand drain foundation were analyzed.The results show that among the three modes of considering the smearing effect,the fastest consolidation occurs when the permeability coefficient of the smearing zone changes parabolically,and the slowest consolidation occurs when it is a constant.Compared to a constant permeability coefficient,when the permeability coefficient of the smearing zone changes linearly,the maximum relative deviation of consolidation degree reaches 35.7%,and the maximum relative deviation of settlement amount reaches 26.7%.When the permeability coefficient of the smearing zone changes in a parabolic pattern,the maximum relative deviation of consolidation degree reaches 36.9%,and the maximum relative deviation of settlement amount reaches 28.4%.As the compression index and permeability index in the double logarithmic coordinate system increase,the consolidation rate of the sand drain foundation slows down.When the compression index increases,the final settlement increases,while the permeability index does not affect the final settlement.Compared to the compression index I_(c)=0.08,the maximum relative deviation of consolidation degree reaches 21.7%when I_(c)=0.1,and the final settlement deviation is 0.030 m.When I_(c)=0.12,the maximum relative deviation of the consolidation degree reaches 37.9%,and the maximum deviation of settlement reache

关 键 词：砂井地基 涂抹作用 非线性压缩 非达西渗流 大应变 固结度 

分 类 号：TU470[建筑科学—结构工程]