断层带深埋小净距隧道稳定性及施工方案优化分析

发布时间：2018-08-31 16:00

【摘要】：断层是岩层中大量应变能积聚到一定程度而产生的一种不连续构造痕迹,断层带岩体整体性差、承载力低,在隧道施工过程中极易引起塌方。目前对小净距隧道穿越断层破碎带的研究较少,相关的施工经验并不丰富。因此,开展断层带小净距隧道稳定性研究有重要的工程意义。本文依托温州市苍南县大坪尾隧道工程,结合已有研究成果,对这一课题进行了深入系统的研究。(1)阐述了断层的形成机制,采用数值模拟的方法分析了不同位置斜交时断层对隧道开挖稳定性的影响,结果表明断层的存在会使隧道围岩位移出现显著增大的趋势,且使隧道周边位移分布不对称,隧道开挖断面中断层带的分布对围岩位移的影响有着决定性作用;(2)对含断层带深埋小净距隧道进行了施工方案的优化,模拟分析了采用全断面法、台阶法和单侧壁导坑法开挖时隧道进入断层前后的力学特征,结果显示在进入断层前的Ⅳ级围岩段施工时,最合适采用台阶法开挖,在含断层围岩中应采用单侧壁导坑法开挖。同时还模拟分析了左右洞不同顺序开挖对断层带深埋小净距隧道稳定性的影响,结果表明左右洞不同顺序开挖对隧道稳定性的影响较小;(3)对大坪尾隧道F6断层处监控量测数据进行了分析,并与理论分析的结果进行了对比,详细阐述了两者异同的原因。本文立足于学科前沿,采用了先进的数值计算方法与分析手段,对深埋小净距隧道稳定性影响进行了深入研究,研究成果具有较高的工程应用价值,对同类工程的设计和施工有一定的借鉴意义。
[Abstract]:Fault is a kind of discontinuous structural trace produced by a large amount of strain energy accumulated in rock stratum to a certain extent. The rock mass integrity of fault zone is poor and the bearing capacity is low. It is easy to cause collapse during tunnel construction. Based on the Dapingwei tunnel project in Cangnan County of Wenzhou City and the existing research results, this paper makes a thorough and systematic study on this subject. (1) The formation mechanism of faults is expounded, and the stability of faults to tunnel excavation at different oblique positions is analyzed by numerical simulation. The results show that the existence of faults will make the displacement of surrounding rock increase significantly, and make the displacement distribution around the tunnel asymmetric, the distribution of the interruption zone of tunnel excavation section has a decisive effect on the displacement of surrounding rock; (2) The construction scheme of deep buried small clearance tunnel with fault zone is optimized, and the mining is simulated and analyzed. The mechanical characteristics of the tunnel before and after entering the fault are analyzed by using the full section method, the step method and the single-sidewall heading method. The results show that the step method is the most suitable method for excavating the grade IV surrounding rock section before entering the fault, and the single-sidewall heading method should be used for excavating the surrounding rock containing the fault. The results show that the influence of excavation sequence on the stability of the tunnel is small. (3) The monitoring data of the fault F6 of the Dapingwei tunnel are analyzed and compared with the results of theoretical analysis. Advanced numerical methods and analysis methods have been used to study the stability of deep-buried tunnels with small clearance. The research results have high engineering application value and can be used for reference in the design and construction of similar projects.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4

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