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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。
Structures located on clay foundations will experience tensile resistance to the foundation during their ascent or ascent. The adhesion of clay to the structure is an integral part of the tensile resistance of the foundation. The selection of its value has an important influence on the determination of the bearing capacity of the foundation. In order to study the development rules and influencing factors of adhesion, the combination measuring disc was improved and the bottom of the inner disc was connected with the outside air to eliminate the influence of pore water pressure on the adhesion force. The measuring disc was used to measure the viscosity of clay in different moisture content, Adhesion at different drawing rates. The test results show that the drawing stress of clay on the foundation increases linearly with the increase of the foundation drawing displacement, and disappears rapidly after reaching the adhesion. When the moisture content of the soil is more than the plastic limit, the adhesion begins to increase, increases to the peak and then decreases, finally decays to a stable value. With the same drawing rate, the peak value of the adhesion increased with the increase of the drawing rate, and the corresponding water content decreased with the increase of drawing rate. The same moisture content, adhesion with the pull rate of the logarithmic showed S-curve changes. The ratio between the adhesion and undrained shear strength of soil increases with the increase of water content. The above results provide a basis for in-depth understanding of changes in adhesion and guide engineering practice.