隧洞围岩的等效弹性抗力系数及其影响因素研究

发布时间：2018-05-16 01:31

本文选题：圆形隧洞 + 围岩　；参考：《长江科学院院报》2017年09期

【摘要】：基于无限体中圆形隧洞的弹性解,结合卸荷扰动区与深部未扰动区的位移公式,推导洞室开挖卸荷区围岩的等效弹性抗力系数表达式,并通过算例对比分析,验证其合理性。研究结果表明:围岩的等效弹性抗力系数与扰动区岩体弹性模量呈非线性关系,扰动区岩体质量弱化,弹性模量降低,泊松比增大,扰动区围岩的刚度和侧向约束能力降低,围岩的等效弹性抗力系数随之减小;相同开挖半径下,扰动区范围的扩大直接降低围岩承载能力,围岩的弹性抗力系数减小;在扰动区厚度一定的情况下,开挖半径越大,等效弹性抗力系数越小。说明隧洞围岩稳定是扰动区与深部未扰动围岩共同作用的结果,仅采用扰动区岩体参数计算围岩弹性抗力系数会过高地估算围岩的分载能力,采用围岩等效弹性抗力系数评价围岩承载能力更加合理。
[Abstract]:Based on the elastic solution of circular tunnel in infinite body and the displacement formula of undisturbed zone and undisturbed zone in depth, the expression of equivalent elastic resistance coefficient of surrounding rock in unloading zone of excavation of cavern is derived, and its rationality is verified by comparison and analysis of numerical examples. The results show that the equivalent elastic resistance coefficient of the surrounding rock is nonlinear to the elastic modulus of the rock mass in the disturbed area, the mass of the rock mass in the disturbed area is weakened, the elastic modulus is decreased, the Poisson's ratio is increased, and the stiffness and lateral restraint ability of the surrounding rock in the disturbed area are decreased. Under the same excavation radius, the expansion of disturbance area directly reduces the bearing capacity of surrounding rock, and the elastic resistance coefficient of surrounding rock decreases. When the thickness of disturbance zone is constant, the excavation radius is larger. The equivalent elastic resistance coefficient is smaller. It shows that the stability of the surrounding rock is the result of the interaction between the disturbed zone and the deep undisturbed surrounding rock, and the calculation of the elastic resistance coefficient of surrounding rock mass by using the rock mass parameters in the disturbed area will be too high to estimate the load-splitting capacity of the surrounding rock. It is more reasonable to use the equivalent elastic resistance coefficient of surrounding rock to evaluate the bearing capacity of surrounding rock.
【作者单位】：四川水利职业技术学院;四川大学水力学与山区河流开发保护国家重点实验室;四川大学水利水电学院;
【基金】：国家重点基础研究发展计划(973计划)项目(2015CB057903) 国家自然科学基金项目(51079092)
【分类号】：U451.2

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