锚杆围岩力学作用研究

发布时间：2018-02-10 10:02

本文关键词： 锚杆变形协调高预紧力锚杆支护支护优化　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：在煤矿巷道支护中,锚杆支护的普及率几乎接近100%,针对如今锚杆支护理论远远滞后于实践,且在工程应用中仍然主要依靠经验法和工程类比法的现状。对锚杆支护作用的本质进行了总结分析,对锚杆预应力的作用机理进行了说明。对现有锚杆的悬吊理论和组合梁理论进行实例计算,并对其在工程设计中的实用性进行评价。取锚杆体与其所接触的岩体作为锚固单元体并对其进行研究,当岩体发生受拉破坏时,由于杆体与围岩体力学参数的差异,锚杆上荷载很小,为了使围岩破坏时锚杆能发挥最大约束作用而假设围岩破坏时锚杆达到屈服状态,发现锚杆施加的预应力需接近杆体屈服强度。根据锚杆与围岩之间的变形协调关系推导得到锚杆的最大预紧力计算公式;进一步的研究针对不同强度锚杆作用,发现当锚杆上不施加预紧力时,不同强度的锚杆对岩石破坏前的加固作用是相同的,高强度锚杆没有优势,高强度锚杆的优势在于可以施加高预紧力及在岩体破碎后提供更高的约束力。为了研究锚固体与围岩之间的力学作用,对岩体与锚固体的弹性模量比进行了分析。通过对锚固体进行力学分析得到了锚固长度与锚固力之间的关系。运用数值模拟软FLAC3D以巷道顶板下沉量、两帮收敛量和塑性区体积为指标对巷道不同支护工况下的支护效果进行比较,验证高预紧力有利于控制围岩变形。将研究结果应用于董东煤矿支护优化设计中,经过现场监测表明,围岩控制效果良好。
[Abstract]:In coal mine roadway support, the popularization rate of bolt support is almost close to 100. The theory of bolt support lags far behind practice. And in engineering application, it still mainly depends on the present situation of experience method and engineering analogy method. The essence of bolting action is summarized and analyzed. The mechanism of prestressing force of anchor rod is explained. The suspension theory of anchor rod and the theory of composite beam are calculated by examples. The practicability of the rock mass in the engineering design is evaluated. The rock mass in contact with the bolt body is taken as the anchoring unit body and studied. When the rock mass is subjected to tensile failure, the mechanical parameters of the rod body and the surrounding rock are different. The load on the anchor rod is very small. In order to make the anchor rod exert the maximum restraint function during the surrounding rock failure, it is assumed that the anchor rod reaches the yield state when the surrounding rock is destroyed. It is found that the prestressing force applied by the anchor rod must be close to the yield strength of the bolt body. According to the deformation coordination relation between the anchor rod and the surrounding rock, the formula for calculating the maximum pre-tightening force of the anchor rod is derived, and the further research is aimed at the action of the anchor rod with different strength. It is found that the reinforcement effect of different strength anchors on the rock before failure is the same when the pre-tightening force is not applied on the bolt, and the high strength anchor has no advantage. The advantage of high strength anchor is that it can apply high pretightening force and provide higher binding force after rock mass is broken. In order to study the mechanical action between anchor body and surrounding rock, The ratio of elastic modulus of rock mass to anchor body is analyzed. The relationship between anchoring length and anchoring force is obtained through mechanical analysis of anchor body. Numerical simulation of soft FLAC3D is used to calculate the settlement of roadway roof. By comparing the support effect under different supporting conditions of roadway with the index of convergence and volume of plastic zone, it is proved that high pretightening force is beneficial to control the deformation of surrounding rock. The research results are applied to the optimum design of support in Dong Dong Coal Mine. Field monitoring shows that the control effect of surrounding rock is good.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD353.6

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