黏土黏附力试验研究  

Experimental study of adhesion of clay

作　　者：邱长林[1] 张庆建[2] 闫澍旺[1] 纪玉诚[1] 

机构地区：[1]天津大学建工学院岩土工程研究所,天津300072 [2]中水北方勘测设计研究有限责任公司,天津300222

出　　处：《岩土力学》2017年第5期1267-1272,共6页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.41272323);国家优秀青年科学基金项目(No.51322904)~~

摘　　要：座落于黏土地基上的结构物在起浮或上拔过程中将受到地基对其的抗拉阻力。黏土对结构的黏附力是地基抗拉阻力的组成部分,其值的选取对地基抗拔承载力的确定有重要的影响。为了研究黏附力的发展规律和影响因素,改进了组合测盘,将内测盘底部和外界空气相通,从而消除孔隙水压力对黏附力的影响,并采用该测盘测量黏土在不同含水率、不同拉拔速率下的黏附力。试验结果表明,黏土对基础的拉拔应力随着基础拉拔位移的增加而线性增加,达到黏附力后将迅速消失。黏附力在含水率较小时为0,当土体的含水率超过塑限后黏附力开始增加,增加到峰值后下降,最后衰减到一个稳定值。相同拉拔速率下含水率变化时黏附力的峰值随拉拔速率的增加而增加,其对应的含水率随拉拔速率的增加而降低。相同含水率下,黏附力随拉拔速率的对数呈S型曲线变化。黏附力和土体不排水抗剪强度之间的比值随含水率的增加而增加。以上研究结果为深入理解黏附力变化规律并指导工程实践提供了依据。Foundation will be subjected to resistance during the process of uplift or pullout. Adhesion is a contributing component of the resistance and a key factor in determining the pullout capacity of soils. In order to study the laws and factors of adhesion, the compound adhesion-measuring disc is modified to eliminate the effect of the pore water pressure of soils on adhesion during its pullout by venting the bottom of the inner disc. Adhesions of soil are measured with different water contents and pullout velocities. Test results show that the drawing stress of soil on structure increases linearly with the increase of the displacement of pullout until it reaches adhesion limit. The adhesion of soil is zero when the water content is low and increases when the water content exceeds plastic limit. It decreases to a constant value after it reaches its maximum. The maximal cohesion under constant pullout velocity increases and the corresponding water content decreases as the pullout velocity increases. When the water content of soil is the same, the relationship between adhesion and the logarithm of pullout velocity is in an S shape. The ratio of adhesion to undrained shear strength increases with the increase of water content. The test results provide a sound basis for understanding the laws of adhesion and can be used in practical engineering.

关 键 词：黏土 组合吸盘 黏附力 拉拔速率 含水率 

分 类 号：TU411[建筑科学—岩土工程]