大断面小净距隧道设计与施工技术研究

发布时间：2018-02-07 10:16

  本文关键词： 大断面小净距隧道 监控量测 参数反演 数值模拟 围岩稳定性　出处：《西安科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文通过对隧道施工过程监测项目进行监测,然后对监测所得数据进行整理和线性回归分析,找出围岩在开挖支护后变形的内在规律,反演出隧道洞室围岩的综合物理力学参数,以此来进行隧道施工方案等方面的研究,主要内容如下:⑴本文结合岩石力学理论计算方法和现场监控量测的特点,立足于隧道典型断面观测点模拟所得数据,从隧道围岩的稳定性定量评价方法着手,进行隧道围岩稳定方面的探讨。隧道在不同的断面形式情况下,围岩应力分布不尽相同。隧道断面形式为五心圆时,其围岩应力状态更接近实际工程中对隧道结构受力均匀性方面的要求。⑵基于现场监控量测数据,及时运用围岩参数反演程序进行分析,可以比较准确的反演隧道围岩等效力学参数,以此能够快速、准确地对隧道施工中围岩稳定性做出合理的评价,及预测未开挖段隧道在开挖支护后围岩的稳定性。然后利用参数反演得出的岩体物理力学参数建立三维数值模型,通过计算对比得出,大断面小净距隧道使用三台阶七步开挖法进行施工时相对于CD工法的施工组织设计复杂,施工速度缓慢等缺点,施工成本降低,具有广泛地推广价值以及应用前景,在国内同类大断面小净距隧道施工方面提供一定的参考依据。⑶通过数值模拟研究了净距在10m、12m、15m、18m、20m等5种工况下,隧道围岩典型观测点处应力应变特征等,得出大断面小净距隧道在使用三台阶七步开挖法,埋深为30m、围岩等级为Ⅴ级的情况下,和本文地形及地质等限制条件相似地段,隧道双洞净距选用12~15m的范围较为合适。⑷通过数值模拟研究了掌子面间距为3m、6m、9m、12m、15m共五种工况进行数值模拟,得出当施工间距为12m时,隧道围岩稳定性相对较差,但在安全可控范围,另外也有利于缩短施工工期。
[Abstract]:In this paper, the monitoring project of tunnel construction process is monitored, and then the monitoring data are sorted out and linear regression analysis is made to find out the inherent law of the deformation of surrounding rock after excavation and support. The comprehensive physical and mechanical parameters of surrounding rock of tunnel chamber are inversely performed to study the tunnel construction scheme. The main contents are as follows: 1 this paper combines the calculation method of rock mechanics theory and the characteristics of on-site monitoring measurement. Based on the simulation data obtained from the observation points of typical section of tunnel, the stability of surrounding rock of tunnel is discussed from the quantitative evaluation method of the stability of surrounding rock of tunnel. The stress distribution of surrounding rock is different. When the cross section of tunnel is five-center circle, the stress state of surrounding rock is closer to the requirement of uniform stress of tunnel structure in actual engineering based on field monitoring data. By using the inversion program of surrounding rock parameters in time, the equivalent mechanical parameters of surrounding rock can be retrieved accurately, so that the stability of surrounding rock in tunnel construction can be evaluated quickly and accurately. And to predict the stability of surrounding rock after excavation and support of unexcavated tunnel. Then the three-dimensional numerical model of rock mass physical and mechanical parameters obtained by parameter inversion is established, and the results are obtained by calculation and comparison. Compared with CD method, the construction organization design is complex, the construction speed is slow and the construction cost is reduced when the three-step and seven-step excavation method is used in large section and small clear distance tunnel, so it has extensive popularization value and application prospect. By numerical simulation, the stress and strain characteristics of tunnel surrounding rock at typical observation point of surrounding rock are studied under 5 conditions, such as 10m ~ 12m ~ 15m ~ 15m ~ 18m ~ 20m, etc., which provide some reference basis for the construction of similar large section and small net distance tunnel in our country, and through numerical simulation, the stress and strain characteristics of tunnel surrounding rock at typical observation points are studied. It is concluded that in the case of large section and small clear distance tunnel excavation with three steps and seven steps, the buried depth is 30m and the surrounding rock grade is grade 鈪，

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