基于CPTU的土-膨润土隔离墙墙体材料抗剪强度评估方法  

Shear strength evaluation method for soil-bentonite cutoff wall backfill based on CPTU test

作　　者：童星[1,2] 柯瀚[1,2] 李育超[1,2] 蔡国军[3] 文一多 

机构地区：[1]浙江大学软弱土与环境土工教育部重点实验室,杭州310058 [2]浙江大学岩土工程研究所,杭州310058 [3]东南大学岩土工程研究所,南京210096

出　　处：《东南大学学报（自然科学版）》2016年第A01期36-39,共4页Journal of Southeast University：Natural Science Edition

基　　金：国家高技术研究发展计划(863计划)资助项目(2012AA062601)

摘　　要：针对传统基于CPTU测试计算土体不排水抗剪强度su的方法在土-膨润土竖向隔离墙中难以适用,以及圆锥系数的取值存在较大经验性的问题,通过引入圆锥系数Nke与孔压参数比Bq的关系,以及三轴试验中不排水抗剪强度su与有效固结压力p'的比值,提出了改进的计算方法,并且通过对文献案例的计算比较验证了该方法的可靠性.通过对国内首个土-膨润土隔离墙试验段的现场CPTU测试,采用该方法计算不排水抗剪强度su,得到了墙体中su随深度的分布规律,即su随深度增长到一定程度后便不再继续增加,甚至会随深度增长而略有减小;通过比较工后8个月和15个月的测试结果,发现整个墙体深度范围内的不排水抗剪强度随时间推移而增长,但总体上仍较小.The traditional methods for evaluating undrained shear strength su of soil based on CPTU tests were difficult to be applied in soil-bentonite cutoff walls and the value of cone factor depended on experiences. Aimed at the problems, an improved calculation method was proposed by introdu- cing the relationship between cone factor Nke and pore pressure ratio Bq, as well as the ratio of undrained shear strength su and effective consolidation stress p＇ in triaxial compression test. The reliability of the method was verified compared with the calculation results of a case in literature. Based on in-situ CPTU tests on the first test section of soil-bentonite cutoff wall in China, the undrained shear strength su was calculated with the proposed method. The distribution of su in the wall was obtained, that is, the su increased with the increasing depth till a certain extent, and then slightly decreased with the increasing depth. Comparing with test results of 8 months and 15 months after the construction of the cutoff wall, the su in the entire depth is found to increase with time, but it is still very low in general.

关 键 词：土一膨润土 隔离墙 CPTU 不排水抗剪强度 

分 类 号：TU413[建筑科学—岩土工程]