基于收敛-约束法的隧洞纵向变形演化规律研究与支护时机估算

发布时间：2018-05-28 02:21

本文选题：隧洞 + 开挖　；参考：《岩土力学》2017年S1期

【摘要】：依托某供水工程输水隧洞建立三维数值模型,采用有限差分法和Mohr-Coulomb屈服准则进行施工开挖过程的数值模拟,研究不同围岩条件下隧洞支护时机的估算。首先,基于收敛-约束法进行隧洞开挖推进过程中的变形规律研究,分析监测断面的围岩变形特征,研究发现围岩位移的收敛规律与围岩质量相关,提出隧洞纵向变形曲线的修正公式。然后,采用一步挖穿分期释放的模拟方法,研究监测断面位移随开挖荷载释放的变化规律,以相同的位移释放系数为出发点,构建,开挖面推进距离与荷载释放率之间的关系,并将对应的围岩位移陡增点作为施加支护的推荐时机,得出不同围岩条件下施加支护与开挖面之间的控制距离。研究结果表明,提出的纵向变形公式相关参数确定过程简单,拟合效果良好,推荐的支护与开挖面之间的控制距离符合工程实际规律。
[Abstract]:Based on the three-dimensional numerical model of a water conveyance tunnel in a water supply project, finite difference method and Mohr-Coulomb yield criterion are used to simulate the excavation process in order to estimate the time of tunnel support under different surrounding rock conditions. Firstly, based on the convergence-constraint method, the deformation law during tunnel excavation is studied, and the deformation characteristics of surrounding rock of monitoring section are analyzed. It is found that the convergence law of surrounding rock displacement is related to the quality of surrounding rock. The correction formula of tunnel longitudinal deformation curve is put forward. Then, the simulation method of one-step excavating and releasing by stages is used to study the law of monitoring the variation of cross-section displacement with excavation load release. Taking the same displacement release coefficient as the starting point, the relationship between the advancing distance of excavated face and the load release rate is constructed. The corresponding displacement increase point of surrounding rock is taken as the recommended time to apply support, and the control distance between supporting and excavating surface under different surrounding rock conditions is obtained. The research results show that the proposed longitudinal deformation formula is simple to determine the parameters and the fitting effect is good. The recommended control distance between support and excavating surface accords with the actual engineering law.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;
【基金】：国家自然科学基金项目(No.51579194) 国家重点研发计划(No.2016YFC0401803)~~
【分类号】：TV554

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