桩-土界面剪切机理试验研究进展及新型界面剪切仪的研制

Research progress of pile-soil interface shear mechanism and manufacture of new interface shear apparatus

桩-土界面的剪切行为是影响桩基承载性能的关键因素.从试验仪器、试验方案、试验结果 3个方面阐述了国内外的研究现状,归纳总结了桩-土界面剪切机理的最新试验研究成果.针对目前界面剪切机理研究中存在的问题,研制了可用于不同剪切幅值、剪切速率、循环剪切路径下的"大型可视化恒刚度桩-土界面剪切仪".该仪器不仅解决了传统直剪试验中存在的荷载加载方式以及尺寸效应的问题,而且可从宏、细观两个角度研究桩-土界面剪应力的循环弱化以及土颗粒位移和破碎的演化过程,试验机理更接近真实的桩-土体系.

The mechanical properties of pile-soil interface is a key factor affecting the bearing capacity of the pile.This paper expounds the current research from the respects of the test equipments,test programs,test results,and summarizes the latest test results of the shear mechanism of pile-soil interface.Aiming at the problems existed in the shear mechanism research of the pile-soil interface,it produces the large visual constant stiffness shear apparatus of pile-soil interface which can provide different shear amplitudes,different shear rates,different circulation clipping paths.This apparatus solves the loading way and size effect that exists in the traditional direct shear test.It can be used in the study of the pile-soil interface from macro and mesoscopic points of view,including the shear stress weakening after different cycles,the displacement of soil particles and the evolution of the soil broken process.Test mechanism is closer to the real pile-soil system.