盾构管片接缝传力垫层的接触特性试验研究

为了研究盾构管片接缝的接触特性,采用带有橡胶垫层的混凝土试件来模拟盾构管片和橡胶垫层,通过加卸载条件下的直剪试验和单轴压缩试验,探究盾构管片接缝和接头处的切向和法向接触特性。由试验结果可知:1)接触面剪切应力随剪切位移的变化过程可以分为弹性变形、弹塑性变形和应变软化3个阶段,剪切峰值应力的残余百分比为55%~65%;2)橡胶垫层在混凝土之间起到了良好的缓冲作用,对管片的失稳破坏过程有一定的延缓作用;3)根据试验结果得出管片混凝土强度等级为C50、传力垫层厚度为2 mm时接触面的切向和法向接触刚度,为盾构管片接缝传力垫层接触摩擦特性的分析计算提供参考。

Experimental Study of Contact Characteristics of Rubber Cushion Used in Shield Segment Joints

The shield segment and rubber cushion are simulated by concrete specimens with rubber cushion to study the contact characteristics of shield segment joints. The contact characteristics of the joints of shield segment are investigated by direct shear test and uniaxial compression test under cyclic loading and unloading conditions. The test results show that: 1) The shearing process can be divided into elastic deformation, elastoplastic deformation and strain softening stage; and the residual percentage of the peak shear stress is about 55%- 65%. 2) The rubber cushion plays a good buffer role between the concretes, which may delay the buckling failure of the tunnel segments. 3）The normal and tangential contact stiffness of the contact surface is obtained when the concrete strength of the tunnel segments is C50 and the thickness of the cushion is 2 mm, so as to provide reference for analyzing and calculating the contact friction of the cushion.