连续排水边界下考虑变荷载的软土一维非线性固结分析  

Analysis of one-dimensional nonlinear consolidation of soft soil considering time-dependent loading with continuous drainage boundary

作　　者：吴思思 罗文强[1] 李寅灿 崔伟健 王硕 WU Si-si;LUO Wen-qiang;LI Yin-can;CUI Wei-jian;WANG Shuo(School of Mathematics and Physics,China University of Geosciences,Wuhan,Hubei 430074,China)

机构地区：[1]中国地质大学数学与物理学院,湖北武汉430074

出　　处：《岩土力学》2022年第6期1503-1512,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42090055,No.41972289)。

摘　　要：土体往往具有非线性压缩特性,不同压缩特性下土体的固结规律存在差异。综合考虑土体非线性特性、变荷载作用以及连续排水边界条件建立了一维固结方程。采用无条件稳定的有限差分法和半解析法对固结方程进行了求解,两种解答方法的可靠性通过连续排水边界条件退化以及两种解答结果对比得到验证。在有限差分法解答的基础上,详细分析了界面参数、荷载参数以及非线性参数对土体固结的影响。结果表明:连续排水边界的界面参数取值越大,则超静孔隙水消散速率及土体沉降速率越大,但界面参数取值对最终沉降量没有影响;超静孔隙水压力在加载阶段逐渐增大,在恒载阶段逐渐消散;加载速率越大,则超静孔隙水压力峰值越大,并且土体固结速率越快,说明延长施工周期有利于降低超静孔隙水压力的影响;工程中要准确预测土体固结速率绝非易事,采用固结理论预测时需保证土体模型、边界条件以及土体计算参数等因素的准确性。Soil tends to have nonlinear compression characteristics,and the consolidation laws of soil are different under different compression characteristics.Considering the nonlinear characteristics of soil,variable load and continuous drainage boundary conditions,a one-dimensional consolidation equation is established.Its solutions are obtained by using the unconditionally stable finite difference method and semi-analytical method,and the reliability of the two methods is verified by the degradation of continuous drainage boundary condition and the comparison of the two solutions.Based on the solution of finite difference method,the influences of interface parameter,load parameters and nonlinear parameter on soil consolidation are analyzed in detail.The results show that,the larger the interface parameter of continuous drainage boundary,the greater the dissipation rate of excess pore water and the settlement rate of soil,while the interface parameter has no effect on the final settlement.The excess pore water pressure gradually increases at the loading stage and dissipates at the constant loading stage.With the increase of loading rate,both the peak value of excess pore water pressure and soil consolidation rate increase,indicating that extending the construction period is conducive to reducing the influence of excess pore water pressure.It is difficult to accurately predict the consolidation rate of soil in engineering.The accuracy of soil model,boundary conditions and soil calculation parameters should be ensured when the consolidation theory is used.

关 键 词：一维固结 非线性特性 连续排水边界 变荷载 界面参数 

分 类 号：TU433[建筑科学—岩土工程]