围岩-衬砌接触面剪切力学性质及破坏机制的试验研究

基于巴西劈裂试验和三维扫描、3D打印技术,制作了围岩–衬砌接触面模型,结合围岩、衬砌的混凝土模拟材料,制备围岩–衬砌接触试样,通过模拟围岩–衬砌接触试样的剪切试验,研究围岩–衬砌接触面的剪切力学性质和破坏机制,分析影响其力学性质的主要因素,探究了围岩–衬砌接触面的抗剪强度公式,研究结果表明:围岩–衬砌接触试样的剪切曲线呈现出延性和脆性2种破坏类型;法向应力、接触面粗糙度和两侧材料力学性质对围岩–衬砌接触面的剪切变形、强度和破坏形态均有影响,对比发现接触面两侧材料属性的影响大于接触面粗糙度;接触面的剪切力学性质和破坏形态不仅取决于各因素的大小,还取决于其组合作用;依据接触面的破坏特征,将黏着摩擦理论引入Barton经验公式,提出适用于围岩–衬砌接触试样的剪切强度公式,实现了强度特征与影响因素的结合,为地震作用下的围岩–衬砌相互作用研究提供了试验参考。

Experimental study on shear properties and failure mechanisms of surrounding rock-lining contact surfaces

Based on the Brazilian splitting test,three-dimensional scanning and 3D printing technology,a surrounding rock-lining contact surface model is produced,and surrounding rock-lining contact samples were prepared using simulation materials.By shear test of the surrounding rock-lining contact samples,the shear properties and failure mechanisms of the surrounding rock-lining contact surface were studied,the main affecting factors were analyzed,and the formula of the shear strength of the surrounding rock-lining contact surface was explored.The results show that the shear curves of the surrounding rock-lining contact samples have two types of failure including ductility and brittleness.The normal stress,the roughness of the contact surface and the mechanical properties of the materials on both sides affect the shear deformation,shear strength and the failure mode of the surrounding rock-lining contact surface.By comparison,the material properties on both sides of the contact surface effect more than the roughness of the contact surface.The shear properties and failure modes of the contact surface depend not only on the magnitudes of the affecting parameters but on the combinations of the parameters.Introducing adhesion theory into Barton empirical formula according to the damage characteristics of the contact surface,a shear strength formula which is suitable for surrounding rock-lining contact samples was proposed,which embodies the unity of strength characteristics and influencing factors.The research results provide a test reference for the study of surrounding rock-lining interaction under earthquake action.