砾砂与混凝土管界面剪切力学特性试验

Experiment of Shear Properties on the Interface Between Gravelly Sand and Concrete Pipe

基于数字图像相关技术,通过自主研制的可视化直剪容器,对砾砂与混凝土管接触面在常法向应力作用下的剪切力学特性进行较系统的试验研究.试验结果表明:砾砂-混凝土管界面初始剪切模量随法向应力的增大而增大;Dr=0.8的砾砂土样与混凝土接触面的摩擦系数较Dr=0.4时增大约17.5%,相对密实度每增大0.2,摩擦角平均增大2°;砾砂-混凝土接触面的剪应力-剪切位移曲线软化程度随法向应力增大逐渐减小,硬化程度逐渐明显;土体剪切位移随着与接触面距离的增加而增大,剪切变形主要发生在剪切错动带内,剪切错动带厚度约为3D50.

Based on the digital image correlation(DIC)technology,the mechanical properties on the interface between garvelly sand and concrete pipe were studied systematically under a constant normal stress condition by using a self-developed visual direct shear container.The experimental results showed that the initial shear modulus of the interface between gravelly sand and concrete pipe increases with the increase of normal stress.When Dr=0.8,the friction coefficient of the interface increases about 17.5%compared with that when Dr=0.4,and when the relative density increases by 0.2,the friction angle increases by 2°on average.The softening degree of the shear stress vs.shear displacement curve of the interface is gradually reduced with the increase of normal stress,and the hardening degree is gradually obvious.In addition,the shear displacement of the soil increases with the increase of the distance away from the interface.The shear deformation mainly occurs in the shear zone,and the thickness of shear band is 3 D50.