Study on the stability of roof beam consisted of cracked rock

裂隙岩体顶梁稳定性研究

• 批准号: 07651151
• 负责人: OBARA Yuzo
• 金额: $ 1.34万
• 依托单位: Kumamoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07651151/
• 关键词: Roof beam; Cracked rock; No-tension model; Buckling; Stability; Coal mine; 岩盤梁; 節理; たわみ解析

This research is one of the fundamental study to clarify the failure mechanism of tunnel roof, which is a problem in coal mine in the world.Recently, the system rock bolt becomes a main support member of the tunnel. However, a large scale fracture of the roof occurred in a coal mine in United Kingdom a few years ago. A cause of this accident is considered to be too much confidence in the ability of the system rock bolt. Therefore, it is necessary to develop the procedure to predict the fracture of roof beam. There are many theoretical and experimental researches until now. However, the theory of rock beam has hot been constructed. This cause is considered to be the difficulty to introduce the complex problem, which is opening and closing of the preexist joints in a rock beam, initiation and propagation of the cracks, in the theory of rock beam.In this research, the behavior of roof beam of cracked rock is analyzed, based on the rock mechanics. The obtained results are as follows :1) The cause of fracture of the roof beam is classified into the following three classes. First is the lack of the frictional force on the support plane of the roof beam. Second is the buckling of the roof beam. Third is the compressive fracture of rock near the support plane of the roof beam.2) It is made clear that the criterion on the buckling of the roof beam is represented by the maximum displacement and its location induced.3) To analysis behavior of the roof beam due to the compressive fracture of rock near the support plane, the no-tension model is suggested. Using the model which is assumed that the tensile strength of rock parallel to the beam axis is zero, the results of the analysis are good agreement with those of the experiment.4) It is concluded that the ratio of the Young's modulus to the uniaxial compressive strength is an important parameter to estimate the stability on the roof beam consisted of cracked rock.

巷道顶板破坏机理是世界煤矿界普遍关注的问题，系统锚杆支护是近年来巷道支护的主要手段之一。然而，几年前，英国的一个煤矿发生了大规模的顶板断裂。该事故的原因被认为是对系统岩石锚杆的能力过于自信。因此，有必要开发一套预测顶梁断裂的程序。迄今为止，已有许多理论和实验研究。然而，岩梁理论尚未建立。本文从岩石力学的角度出发，对裂隙岩体顶板梁的力学行为进行了分析，并对裂隙岩体顶板梁的力学行为进行了研究。结果表明：1）屋面梁断裂的原因可分为三类。首先是屋面梁支承面上的摩擦力不足。二是屋面梁的屈曲。提出了以最大位移及其位置为判据的稳定性判据; 3）提出了无拉力模型，用于分析支承面附近岩石发生压缩断裂时的稳定性。采用平行于梁轴方向的抗拉强度为零的模型，分析结果与试验结果吻合较好。4）得出了岩石弹性模量与单轴抗压强度之比是评价裂隙岩梁稳定性的重要参数的结论。