基于大型高围压界面环剪仪的钢管桩-砂土界面剪切试验研究

摘要

To study the mechanical behavior of different steel-sand interface shear, a new torsional shear device for pile-soil interface shear testing is developed. Some interface torsional shear tests between steel pipe pile and uniform fine sand, Fujian sand, and American Davis sand are performed based on this new device.The test pressures are between 200 kPa and 800 kPa.The mechanical behavior of different pile-soil interfaces can be studied by testing and analyzing the torsion properties of the interface shear. The results show that with the increase of the shear displacement, the interface shear strength increases and remains unchanged finally. But when the shear displacement becomes bigger, the interface shear strength will change slightly. Moreover, both the shear displacement and interface frictional angle of the inflection point of pile-soil interface shear curve increase linearly as the normal stress increases.%为研究不同钢管桩基础与砂土界面剪切特性,研制一种新型桩土界面环剪仪,并基于此设备开展不同围压下钢管桩与均质细砂、 福建砂、 美国戴维斯砂的界面剪切试验.试验设计压力为200～800 kPa,通过测试分析桩土界面环形剪切时的扭力特征,探究不同桩土界面条件下的剪切应力应变关系.研究结果表明:界面剪切应力随剪切位移增大而增大并趋向稳定,但是在大应变的情况下,界面剪切应力有一定的波动.桩土界面剪切应力拐点对应的剪切位移及界面摩擦角随着法向应力的增加而增加,呈近似线性关系.