中文摘要：

钢-土界面时效性对研究钢护筒嵌岩桩的承载力具有重要意义。在总结前人研究成果的基础上,通过改进室内直剪试验,研究预压时间对钢-土接触界面剪切特性的影响。试验设计预压时间分别为0,1,2,4,6,17,24和48 h,探索不同预压条件下得到的钢-土界面在不同法向应力条件下受剪时的应力应变关系。通过引入摩尔-库伦准则,分析了剪应力与水平位移的关系、抗剪强度等随界面预压时间的变化,发现剪应力随水平位移的增加而增大并趋于稳定;随着预压时间的增加,摩擦角、黏聚力呈增大趋势,并在一定时间后趋于稳定;钢-土界面剪切的极限强度不仅与界面上的法向应力有关,还与界面预压的时间有关,极限剪应力随预压时间的增加有较明显的增长,当法向应力较小时界面极限剪应力的时效性越明显。

英文摘要：

The time effect of the steel and soil interface is significant for study of the bearing capacity of the rock- socketed filling pile with steel tube. On the basis of summarizing the research findings of predecessors and by improving the indoor direct shear tests, a study is made of the shear properties of steel and soil interface which are influenced by preloading time. The preloading time is designed as 0, 1, 2, 4, 6, 17, 24 and 48 h in the tests and different preloading time is explored under the conditions of the steel-soil interface with relationships of the shear stress-strain which is affected by different normal stresses. Relationships between the shear stress and horizontal displacement, and the shear strength along with the change of interface preloading time are analyzed by the introduction of Mohr-Coulomb Failure Criterion. The shear stress is increased to a stable value with the increasing horizontal displacement; with the preloading time increasing, the friction angle and cohesive force increase, and after a certain period of time, tend to be stable. The limit of the steel-soil interface shear strength is not only related to the normal stress on the interface, but also related to the interface of the preloading time. Limiting shear stress increases with the increase of preloading time obviously ; when the normal stress is lesser, the interface timing of the ultimate shear stress is more obvious.