南水北调中线南阳段加筋膨胀土三轴试验研究  

Triaxial Test for Expansive Soil Reinforced with Geogrids of Nanyang Section in the Midline of South to North Water Transfer Project

作　　者：张健[1] 王新征[1] 李志清[2] 

机构地区：[1]南阳师范学院土木建筑工程学院,河南南阳473061 [2]中国科学院地质与地球物理研究所工程地质力学重点实验室,北京100029

出　　处：《人民黄河》2013年第8期129-131,共3页Yellow River

基　　金：河南省科技攻关计划项目(122102310397);南阳师范学院高层次人才项目(2006)

摘　　要：以南水北调中线工程南阳段膨胀土为研究对象,选取高密度聚乙烯土工格栅为加筋材料,对不同围压下未加筋及不同加筋层数的膨胀土进行了三轴排水剪切试验。结果表明:无论素膨胀土还是加筋的膨胀土,其应力—应变曲线均呈应变硬化特征,整体形态符合双曲线关系;随着围压的增大,初始屈服应力、应变及破坏时的主应力差随之增大,但是加筋土破坏时的主应力差提高的幅度减小;加筋使膨胀土的峰值应力、内摩擦角和黏聚力都有较为明显的提高;加筋效果系数评价表明,加筋比不加筋效果要好,其中低围压下的加筋效果较明显,随着围压的增大,加筋效果越来越不明显;加筋后土体的固结排水量增大,其原因是土工格栅在一定程度上具有排水通道作用。High density polyethylene geogrid was adopted to reinforce the weathered expansive soil in the Nanyang section of the Midline of South to North Water Transfer Project in China. The saturated samples of reinforced expansive soil were adopted to carry out a series of consolidation and triaxial drain shear test in different confining pressure. The results show that the unreinforced and reinforced expansive soil are strain hardening, curves of stress vs strain are in accord with ttyperbolic relationship. Biaxial geogrid embedded constraints the development of the shear zone and causes different failure mode. The strength of reinforced soil, the adhesion and friction angle of reinforced soils are both heightened with more layers of reinforced geogrid. Reinforcing effect coefficient evaluation shows that the reinforced better than non reinforced effect. Reinforcing effect is obvi- ous under low confining pressure. With the confining pressure increased, the reinforcing effect coefficient gradually decreased. Drainage volumes under different reinforcing patterns are more than the unreinforced soil samples. Drainage channel to be formed to a certain extent because of the presence of the geogrid.

关 键 词：土工格栅 膨胀土 强度指标 加筋效果系数 南水北调中线 

分 类 号：TV223.2[水利工程—水工结构工程]