让压锚杆在深埋软岩隧洞中的作用机理及支护效应研究

发布时间：2018-05-22 09:43

本文选题：让压锚杆 + 深埋软岩隧洞　；参考：《山东科技大学》2017年硕士论文

【摘要】：煤矿巷道、引水隧洞等大埋深的地下洞室经常穿过软弱岩体,锚杆支护作为岩土、矿山领域最为常用的技术手段,能够有效地提高软岩稳定性。传统锚杆变形量小,不能适应隧洞软弱围岩的大变形,让压锚杆的出现有效地解决了这一问题。本文基于前人研发的新型让压锚杆,运用FLAC3D模拟了让压锚杆与普通锚杆的拉拔试验,锚杆受到拉拔作用时,锚杆端头位置轴力最大,沿着杆体向里端逐渐减小,让压锚杆减小的幅度比普通锚杆大;随着拉拔力的增加,锚杆的轴力相应增大,让压锚杆增大的速度比普通锚杆小。对比前人进行的室内与现场拉拔试验,证明了采用FLAC3D模拟让压锚杆拉拔试验与实际相符,并且验证了模拟锚杆杆体抗剪性能的可行性。对比分析了普通锚杆和让压锚杆在软岩隧洞中的支护效应,相比于普通锚杆,让压锚杆达到屈服强度的速度更慢,达到屈服强度后维持的时间更长。普通锚杆最大承力的中间位置容易被拉断,轴力呈“沙漏状”分布,让压锚杆在达到屈服强度后,能维持较长时间,轴力呈“纺锤状”分布。并且得出6 m让压锚杆的弹性让压距离为70.54 mm,塑性让压距离为130.65 mm。以“引汉济渭”工程秦岭深埋软岩隧洞为工程背景,以完成TBM掘进机卡停后的脱困工作为工程目标,基于室内岩石力学试验对现场工程岩体的参数进行了估算,根据现场实测结果,通过反分析法确定了围岩参数;采用FLAC3D对秦岭深埋隧洞脱困段的支护进行模拟,发现普通锚杆容易发生破断失效,而由于让压组件的大延伸率,让压锚杆能够适应围岩的变形,不容易发生破断,较长时间起到支护作用,从而达到控制围岩变形的效果。针对秦岭深埋隧洞TBM卡机段的脱困工作,在脱困段的支护采用让压锚杆,脱困之后的正常段支护采用普通锚杆,该方案的数值模拟结果与实测结果基本一致。后期工程实践证明,这一方案的实施能够有效辅助解决TBM卡机问题,顺利完成脱困。
[Abstract]:Underground caverns with large buried depth, such as coal roadway and diversion tunnel, often pass through weak rock mass. As rock and soil, bolt support is the most commonly used technical means in mining field, which can effectively improve the stability of soft rock. Because of the small deformation of the traditional bolt, it can not adapt to the large deformation of the weak surrounding rock of the tunnel, so the emergence of the pressure-bolt can effectively solve this problem. In this paper, based on the new type of pressure-release anchor developed by predecessors, FLAC3D is used to simulate the pull-out test. When the anchor rod is pulled out, the axial force at the end of the bolt is the largest, and gradually decreases along the inside end of the bolt body. With the increase of drawing force, the axial force of the bolt increases and the speed of the increase of the compression bolt is smaller than that of the common anchor. Compared with the indoor and field drawing tests carried out by the predecessors, it is proved that the FLAC3D simulation is in accordance with the actual conditions, and the feasibility of simulating the shearing performance of the bolt body is verified. The supporting effect of common bolt and concession bolt in soft rock tunnel is analyzed. Compared with common bolt, the speed of reaching yield strength is slower and the time of maintaining after reaching yield strength is longer. The middle position of the maximum bearing force of common anchor is easily broken, and the axial force is "hourglass" distribution. The axial force can be maintained for a long time and the axial force is "spindle-shaped" distribution after reaching yield strength. The results show that the elastic pressure distance is 70.54 mm and the plastic pressure distance is 130.65 mm. Based on the engineering background of Qinling deep buried soft rock tunnel in the project of "diversion from Han to Jiwei", and taking the work of extricating the TBM roadheader after stopping as the engineering objective, the parameters of the field engineering rock mass are estimated based on the indoor rock mechanics test. According to the field measured results, the parameters of surrounding rock are determined by inverse analysis, and the support of deep buried tunnel in Qinling is simulated by FLAC3D. It is found that the common bolt is prone to break and failure, and because of the large elongation of the compressing module, So that the pressure bolt can adapt to the deformation of surrounding rock, it is not easy to break, and play a supporting role for a long time, thus the effect of controlling the deformation of surrounding rock can be achieved. In view of the relief work of the TBM clamping section of the deep buried tunnel in the Qinling Mountains, the abutment bolt is used in the support of the relief section, and the ordinary anchor rod is used in the normal section after the release. The numerical simulation results of the scheme are basically consistent with the measured results. Later engineering practice shows that the implementation of this scheme can effectively solve the problem of TBM card machine and successfully finish the problem of getting rid of difficulties.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.71

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