隧道围岩松动压力评估及稳定性分析

发布时间：2018-01-08 11:45

本文关键词：隧道围岩松动压力评估及稳定性分析　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国地形地貌多样,地质情况复杂,使得隧道成为道路的重要组成部分。松动压力是隧道围岩开挖后支护体系上作用的主要压力形式之一,对隧道支护体系设计、施工及后期运营有重要影响。因此,为更好地对隧道稳定性进行分析,本文将以该类型压力为研究对象,总结分析并比较现有松动压力分析方法。本文主要进行以下几方面的工作:首先,对现有常用的隧道松动压力计算方法进行详细介绍,按照其提出背景进行分类。简单分析计算方法适用条件的影响因素,为后续的计算方法研究、改进做准备。其次,对基于RMR系统的隧道围岩松动压力计算方法进行研究。对比原始RMR方法与其他岩体分类方法,明确RMR系统在考虑因素方面的缺失或不足。根据对比结果合理引入应考虑因素,并对RMR方法本身的不足进行弥补,从而实现对RMR分类方法的合理改进。以湖南湘西某山岭隧道为研究对象,根据设计参数确定支护体系极限承载力,并与基于改进前后RMR评估值确定的支护体系上荷载相结合,对隧道稳定性进行分析,参考工程运营过程中的实际稳定性状况对改进效果进行检验。然后,采用数值模拟软件FLAC3D建立隧道分析模型,分别赋予其依据改进前、后RMR值所得岩体参数,进行计算、验证。根据改进前后洞周监测点位移与允许极限位移的关系,以及隧道模型塑性区范围的变化情况对改进效果进行再次验证;调整隧道模型高跨比,研究高跨比对隧道稳定性的影响。最后,收集实际工程中发生拱形塌方隧道数据,分析松动压力计算高度与实际塌方高度的关系,并从隧道跨度、高跨比以及围岩质量等多方面对计算高度或塌方高度的分布形态进行归纳;通过试验对隧道开挖过程中软弱层的影响进行模拟分析,根据试验隧道的塌方高度对其影响程度进行比较。
[Abstract]:Because of the diversity of topography and geomorphology and the complex geological conditions, the tunnel becomes an important part of the road. The loosening pressure is one of the main forms of pressure acting on the supporting system after the excavation of the surrounding rock of the tunnel. Therefore, in order to better analyze the stability of the tunnel, this paper will take this type of pressure as the research object. Summary and analysis of the existing loose pressure analysis methods. This paper mainly do the following work: first of all, the existing tunnel loosening pressure calculation methods are introduced in detail. According to its background classification. Simple analysis of the factors affecting the applicable conditions of the calculation method, for the subsequent study of the calculation method, to improve the preparation. Secondly. This paper studies the calculation method of loosening pressure of tunnel surrounding rock based on RMR system, and compares the original RMR method with other rock mass classification methods. It is clear that the RMR system in the consideration of the lack of factors or deficiencies. According to the results of the reasonable introduction of factors should be considered, and to make up for the shortcomings of the RMR method itself. In order to achieve the reasonable improvement of RMR classification method. Take a mountain tunnel in Xiangxi Hunan Province as the research object and determine the ultimate bearing capacity of the support system according to the design parameters. Combined with the load on the supporting system determined by the RMR evaluation value before and after the improvement, the tunnel stability is analyzed, and the improvement effect is tested by referring to the actual stability condition in the engineering operation process. The tunnel analysis model was established by numerical simulation software FLAC3D, and the rock mass parameters were calculated according to the RMR value before and after the improvement. Validation. According to the relationship between the displacement of the monitoring point around the hole and the allowable limit displacement before and after the improvement, and the variation of the plastic zone range of the tunnel model, the improved effect is verified again. Adjust the height to span ratio of tunnel model, study the influence of height to span ratio on tunnel stability. Finally, collect the data of arch collapse tunnel in actual engineering, analyze the relationship between the calculated height of loosening pressure and the actual collapse height. The distribution patterns of calculated height or collapse height are summarized from many aspects such as tunnel span, ratio of height to span and mass of surrounding rock. The influence of soft layer during tunnel excavation is simulated and analyzed by test, and the influence degree is compared according to the collapse height of test tunnel.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U451.2

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