锚杆对围岩力学性质参数及受力状态的影响

发布时间：2018-02-27 19:10

本文关键词： 围岩控制锚杆支护力学参数预应力支护参数　出处：《中国矿业大学》2016年硕士论文　论文类型：学位论文

【摘要】：巷道锚杆对围岩的支护作用机理大致分为两个方面:锚杆对围岩力学性质参数的影响和对围岩受力状态的改变。不同的巷道围岩条件和围岩支护参数相互作用,共同影响着锚杆对围岩的锚固支护效果。因此,研究锚杆支护参数对围岩的力学参数和受力状态的改变具有重要的理论意义和工程实用价值。本论文以红一煤矿采区上部车场顶板为研究对象,现场调研了巷道工程地质特征,实验室测试了巷道围岩物理力学性质。根据实际工程地质条件,首先选取巷道顶板锚杆锚固范围内的原型尺寸为2.4 m×2.4 m×2.4 m的锚固分离体,分别研究锚杆不同的间排距、预应力、锚杆直径对锚固范围内的弹性模量E、泊松比μ、内聚力c以及内摩擦角φ值等力学参数的改变以及对含有节理的锚固分离体的抗剪强度的影响。发现泊松比随着锚杆间排距的减小、锚杆预应力的增大和锚杆直径的增加而减小;弹性模量、内摩擦角和内聚力随着锚杆间排距的减小、锚杆预应力的增大和锚杆直径的增加而增大。通过剪切实验发现随着锚杆预应力的增大、锚杆直径的增大和间排距的减小有利于提高试件中节理面的抗剪强度。其中在设计的实验方案里:锚杆直径对泊松比的影响较小;锚杆直径和锚杆预应力对弹性模量的增加范围在0.2 MPa左右;锚杆间排距、锚杆直径和预应力的大小对试件的内聚力影响最大差为0.065~0.15 MPa,对内摩擦角的影响达到2~3°,节理面的抗剪性能在设计因素的影响下,抗剪峰值均能提高0.3 MPa左右。其次,在实验室测试的巷道围岩的力学参数的基础上建立数值计算模型,通过数值计算研究发现锚杆间距的减小、锚杆长度的增加、锚固长度的减小、预应力的增大、锚杆安装角的减小有利于锚杆间的预应力的扩散从彼此独立到彼此重叠,连续均匀的状态发展;也有利于应力扩散形成的应力场的厚度增加;形成的应力场中最大垂直应力也随着增加。通过研究锚杆对围岩的力学参数及受力状态的改变有助于进一步研究锚杆支护作用机理,具有重要的理论和现实意义。现场的工程实践也表明锚杆预应力的增加对巷道表面变形具有一定的控制作用,验证了前文的结论。
[Abstract]:The supporting mechanism of roadway bolt on surrounding rock can be divided into two aspects: the influence of bolt on the mechanical property parameter of surrounding rock and the change of stress state of surrounding rock, and the interaction between different surrounding rock condition and supporting parameter of surrounding rock. Together, it affects the anchor support effect of surrounding rock. It is of great theoretical significance and practical engineering value to study the change of mechanical parameters and mechanical state of surrounding rock. In this paper, the roof of the upper car yard in Hongyi Coal Mine is taken as the research object, and the engineering geological characteristics of roadway are investigated on the spot. The physical and mechanical properties of surrounding rock of roadway have been tested in laboratory. According to the actual engineering geological conditions, first of all, the Anchorage separators with the size of 2.4 m 脳 2.4 m 脳 2.4 m are selected to study the different spacing and prestress of the anchors in the range of Anchorage of roof Anchorage of roadway. The influence of bolt diameter on the mechanical parameters such as elastic modulus E, Poisson's ratio 渭, cohesive force c and friction angle 蠁 in the Anchorage range and the shear strength of anchoring separators with joints are found. It is found that Poisson's ratio varies with the anchor. The reduction of the distance between poles, The increase of anchor prestress and the increase of anchor diameter decrease the elastic modulus, the angle of internal friction and cohesion with the decrease of the row distance between anchors. With the increase of prestressing force and diameter of anchor rod, it is found that with the increase of prestressing force of anchor rod, The increase of bolt diameter and the decrease of interrow distance are helpful to improve the shear strength of joints in the specimen. In the experimental scheme, the influence of anchor diameter on Poisson's ratio is small; The increase range of anchor diameter and anchor prestress on elastic modulus is about 0. 2 MPa. The maximum difference between the diameter of anchor rod and the size of prestress on the cohesion of the specimen is 0.065 ~ 0.15 MPA, and the influence on the angle of internal friction is 2 ~ 3 掳. Under the influence of the design factors, the shear peak value of the joint surface can be increased by about 0.3 MPa. On the basis of the mechanical parameters of surrounding rock of roadway tested in laboratory, the numerical calculation model is established. Through the numerical calculation, it is found that the distance of anchor rod decreases, the length of anchor rod increases, the length of anchor decreases and the prestress increases. The decrease of anchor installation angle is conducive to the continuous and uniform development of the prestress diffusion between anchors from each other to overlap, and also to the increase of the thickness of stress field formed by stress diffusion. The maximum vertical stress in the formed stress field also increases with the increase. It is helpful to further study the mechanism of bolt support by studying the mechanical parameters and mechanical state of surrounding rock. It has important theoretical and practical significance. The field engineering practice also shows that the increase of anchor bolt prestress can control the surface deformation of roadway to a certain extent, which verifies the previous conclusion.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD353.6

【相似文献】