层状板裂组合结构岩体力学特性试验研究

Experimental study on mechanical properties of layered slab-crack composite structure rock mass

层状结构是自然界中常见的岩体结构类型,在我国分布广泛,然而在西部构造应力的作用下,易形成一种较为特殊的岩体组合结构,即层状板裂结构。以西部地区层状板裂结构较为普遍的板岩为例,开展力学特性试验研究,结果显示板岩岩石内部构造结构面对岩石破坏模式与力学特性影响较大,各向异性特征明显。为消除岩石构造结构面的干扰,采用完整性较高、均质性较好的花岗岩预制层间薄夹层来研究层状板裂结构的力学特性,研究结果显示,岩体的峰值强度与弹性模量随着层间板裂化结构面密度的增大呈线性下降趋势,板裂化结构面密度越大,岩体在压缩变形过程中所吸收的应变能越小,破坏程度也有所减弱,破坏时板裂化结构面处率先产生裂纹,之后裂纹拓展贯通至破坏。在此基础上,引入结构面密度参数λ,对现有的弹性均质断续结构和碎裂结构岩体变形本构方程进行优化,优化后的本构方程能够更好地描述层状板裂组合结构岩体的本构关系。

The layered structure is a common type of rock mass structure in nature,which is widely distributed in China.However,under the action of tectonic stress in the west,it is easy to form a special rock mass combination structure,namely,a layered slab-rent structure.In this paper,the mechanical properties of slate with layered slabrent structures in the western region are studied.The results show that the internal structure of slate rock has a great influence on the failure mode and mechanical properties of rock,and the anisotropy is obvious.In order to eliminate the interference of the rock structural plane,the mechanical properties of the layered slab-rent structure are studied by using the prefabricated interlayer thin interlayer of granite with high integrity and good homogeneity.The research results show that the peak strength and elastic modulus of rock mass decrease linearly with the increase of interlayer plate-cracking structural plane density.The larger the interlayer plate-cracking structural plane density is,the smaller the strain energy absorbed by the rock mass in the compression deformation process is,and the degree of damage is also weakened.When the failure occurs,cracks first appear at the plate-cracking structural plane,and then the cracks expand and penetrate into the failure.On this basis,the density parameterλof the structural plane is introduced to optimize the deformation constitutive equations of the existing elastic homogeneous discontinuous structure and fractured structure rock mass.The optimized constitutive equation can better describe the constitutive relationship of the layered slab-rent composite structure rock mass.