含砂垫层地基二维固结自由应变解  

Free-strain solutions for two-dimensional consolidation with sand blankets

作　　者：雷国辉[1,2] 李赞[1,2] 徐梨丹 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]河海大学岩土工程科学研究所,江苏南京210098

出　　处：《岩土工程学报》2016年第2期193-201,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51278171;51578213);中央高校基本科研业务费专项资金项目(2015B06014)

摘　　要：为分析含水平向排水砂垫层地基的固结问题,针对平面应变条件下的二维自由应变固结微分方程,分别考虑待固结土体顶底双面和顶面单面含有砂垫层的工况,采用分离变量法,推求得到了超静孔压和整体平均固结度的显式解析解答,并与有限元法的计算结果对比,验证了其正确性。同时,分析了待固结土体不同渗透系数、土层宽度和厚度条件下,砂垫层渗透系数和厚度对其固结的影响。结果表明：砂垫层渗透系数与待固结土层渗透系数的比值是砂垫层设计中的关键参数。要使砂垫层接近或达到完全透水边界条件,该比值应介于104~105之间,待固结土层越宽、渗透系数越小,所要求的比值越大。To analyze the consolidation with horizontal sand drainage blankets, the partial differential equation for two-dimensional free-strain consolidation under plane strain conditions is solved. Two cases are considered. One is with sand blankets on both the top and the bottom surfaces of the consolidating soil, and the other is with a single sand blanket on the top surface of the consolidating soil. By using the method of separation of variables, explicitly expressed analytical solutions are obtained for calculating the excess pore-water pressure and the overall average degree of consolidation. Their validity is verified by comparing the calculated results obtained from the proposed solutions with those from finite element analyses. The effects of the hydraulic conductivity and thickness of sand blanket on consolidation are investigated for the consolidating soil with various hydraulic conductivities, widths and thicknesses. It is shown that the key parameter for the design of sand blanket is the ratio of the hydraulic conductivity of sand blanket to that of consolidating soil. For the sand blanket close to or reaching a fully drained boundary condition, this ratio is required to be within 104~105, with higher values for the consolidating soil with larger width or lower hydraulic conductivity.

关 键 词：砂垫层 水平向排水体 自由应变 不完全透水边界 渗透系数 

分 类 号：TU472.33[建筑科学—结构工程]