巷道锚索破断机理及弹射防护措施研究

发布时间：2018-04-30 14:23

本文选题：回采巷道 + 锚索破断　；参考：《太原理工大学》2015年硕士论文

【摘要】：由于煤矿井下地质条件变化无常，同一巷道中的围岩会产生不同的岩性变化，同一个支护理论、同一种支护设计不能解决千变万化的地质条件所对应的巷道支护。对于不同地质条件下的巷道，对支护技术的要求是各不相同的。就回采顺槽而言，在回采时，围岩会产生较大的变形，大变形压力作用下的锚索在支护时，超过其所能承受的极限强度而发生破断现象。大变形致使巷道发生严重的变形，造成巷道支护困难、成本高、锚杆锚索返修率高等不良后果，不能正常的安全生产。同时在锚索发生断裂时，若果其断裂外部的索体没有被周围的煤体或者岩体所充分夹持住，并且在极大大的轴向拉力作用下，会以非常大的速度弹射出来，使人员设备受到了极大的威胁。我国煤矿井下出现锚索拉断弹射现象屡见不鲜，其中工人受伤事件也不在少数，也造成严重的社会影响。出于对井下工作人员生命安全的负责，有必要对此缺陷进行充分的分析研究，找出问题发生的原因，寻求科学的、有效的解决方案。从力学的角度来看，锚索破断大致有两种情况：一、剪切破坏；二、轴向破坏。具体阐述为锚索的剪切破坏是由于锚索周围锚固体沿锚索切向的变形引起了剪切力，若其切向所受应力超过所能承受的极限抗剪强度时，锚索破断。锚索的轴向破断是由于在锚索轴向受力大于其抗拉强度所致，锚索安装时的轴向力可视为施加在锚索上的预紧力，在工作面在受到采动的影响，采场围岩常常发生剧烈的松动和破碎，一般情况下变形量都相当大，尤其是横向变形，这势必将导致锚索所承受的轴向力在短时间内快速增加，当达到其临界抗拉强度，即会发生轴向受拉破断。其破坏的机理可以从三个因素考虑：第一，巷道的地质构造；第二，对锚索施加的预紧力；第三，锚索自身的结构。锚索在发生破断时，如果未被煤岩体充分夹持，会以非常大的速度弹射出来，使人员设备受到了极大的威胁，很有可能会发生人伤事件，会产生很严重的后果。对锚索破断的研究以及如何防止破断后弹射有很大社会意义的。本文以长治三元南耀小常煤业有限公司30211工作面为工程背景，对该工作面3号煤巷道锚索破断弹射问题进行分析研究并提出了可行的防护措施。通过实地考察巷道变形情况，现场观测锚索破断情况，通过理论分析锚索破断机理，并用FLAC3D数值模拟巷道回采时产生的变形与锚索的受力情况，分析了锚索在回采时断裂的过程，最终研究得出了30211工作面顺槽问题的原因。对锚索破断后弹射现象的机理做出了解释，结合目前一些行之有效的技术路径，，给出锚索破断弹射的防护措施，形成了一套较完整有效的锚索破断弹射防护体系，并针对30211工作面的情况提出了相应的解决方法。本文的研究成果将为其它相似条件下工作面锚索破断修复提供一定的理论基础和参考价值。
[Abstract]:Because the underground geological conditions of coal mine are changeable, the surrounding rock in the same roadway will produce different lithologic changes, the same supporting theory and the same support design can not solve the roadway support corresponding to the ever-changing geological conditions. For the roadway under different geological conditions, the requirements of supporting technology are different. As far as trench is concerned, when mining, the surrounding rock will produce large deformation, and when the anchor cable under the action of large deformation pressure exceeds the limit strength it can bear, the phenomenon of breakage will occur. Large deformation leads to serious deformation of roadway, which results in difficult support of roadway, high cost, high repair rate of anchor cable and so on, and can not be used in normal safe production. At the same time, when the anchor cable breaks, if the cable body outside the fracture is not fully clamped by the surrounding coal body or rock mass, and under the action of extremely large axial tension, it will eject out at a very large speed. There is a great threat to personnel and equipment. The phenomenon of anchor cable breaking and ejection is common in coal mine of our country, and the injury of workers is not few, which also causes serious social impact. In order to be responsible for the life safety of underground workers, it is necessary to make a full analysis and study of the defects, find out the causes of the problems, and seek scientific and effective solutions. From the point of view of mechanics, there are two kinds of failure of anchor cable: one is shear failure, the other is axial failure. The shear failure of the anchor cable is caused by the shear force caused by the deformation of the anchoring body around the anchor cable along the tangential direction of the anchor cable. If the shear stress in the tangential direction exceeds the ultimate shear strength of the anchor cable, the cable breaks. The axial breaking of anchor cable is due to the fact that the axial force of anchor cable is greater than its tensile strength, and the axial force of anchor cable installation can be regarded as the pre-tightening force applied on anchor cable, which is affected by mining in working face. The surrounding rock of stope often occurs violent loosening and breaking, generally the amount of deformation is quite large, especially the transverse deformation, which will inevitably cause the axial force of anchor cable to increase rapidly in a short period of time, when the critical tensile strength is reached, An axial tensile fracture will occur. The failure mechanism can be considered from three factors: first, the geological structure of the roadway; secondly, the pretightening force applied to the anchor cable; thirdly, the structure of the anchor cable itself. When the anchor cable is broken, if it is not fully clamped by coal and rock mass, it will be ejected out at a very high speed, which will make the personnel and equipment receive a great threat, and it is very likely that there will be human injury, which will have very serious consequences. It is of great social significance to study the breakage of anchor cable and how to prevent the ejection after breaking. Based on the engineering background of 30211 face of Changzhi Sanyao Xiaochang Coal Industry Co., Ltd., this paper analyzes and studies the catapult problem of Anchorage cable in No. 3 coal roadway and puts forward some feasible protection measures. Based on the field investigation of roadway deformation, the field observation of anchor cable breakage, the theoretical analysis of the mechanism of anchor cable breaking, and the numerical simulation of the deformation of roadway and the stress of anchor cable by FLAC3D numerical simulation, The fracture process of anchor cable during mining is analyzed, and the reasons for the problem of trench in 30211 face are finally studied. In this paper, the mechanism of catapult phenomenon after cable break is explained, combined with some effective technical paths, the protective measures of anchor cable breaking and ejection are given, and a set of relatively complete and effective protection system of anchor cable breaking and ejection is formed. And put forward the corresponding solution to the situation of 30211 working face. The research results of this paper will provide a certain theoretical basis and reference value for the repair of working face anchor cable breaking under other similar conditions.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353

【参考文献】