浅埋松散围岩隧道破坏模式研究及其工程应用

发布时间：2018-06-20 06:12

  本文选题：浅埋松散围岩 + 破坏模式　； 参考：《西安理工大学》2017年硕士论文

【摘要】：随着公路隧道工程的增多,浅埋松散围岩隧道的坍塌事故越来越多,而常规有限元方法(未考虑松散岩体结构面及塌落体的作用)和结构荷载法在计算围岩压力和支护设计中均存在一定的弊端。本文基于Peck公式理论和有限元方法提出了浅埋松散围岩破裂面特征的计算模型,对比验证了本文方法的合理性,并对其影响因素进行了敏感性数值分析,提出了一种考虑支护时机的围岩压力计算方法。最后基于本文提出的隧道围岩破裂面模型,建议了一种改进型拟塌落拱离散化有限元方法,并对其适用性进行了数值分析和工程实际验证。通过本文研究,得到的主要结论如下:1.经过隧道塌方案例调研分析,大多数围岩破坏的破坏模式与规范方法和传统的破坏模式中假定的破坏位置及破裂角存在较大差异。鉴于此,本文提出了基于peck曲线确定滑裂面的计算模型和方法,并与文献中的模型实验、数值实验和工程实例进行对比分析,验证了本方法的合理性。2.基于本文提出的破裂面计算模型,研究了破裂角β及地表破裂点i0与隧道的覆跨比w,弹性模量E,泊松比μ,内摩擦角φ,粘聚力c及围岩类别(Ⅳ、Ⅴ、Ⅵ)的关系,并对其进行了敏感性分析。3.本文根据隧道的破坏模式提出了可以考虑支护时机的围岩压力计算方法,分析了支护时机对围岩压力的影响,并与经典围岩压力计算方法对比,揭示了规范方法在围岩压力计算和支护结构设计中存在的问题。4.基于本文的破裂面模型,提出了改进的拟塌落拱离散化有限元方法,分析了支护时机,滑裂面位置、结构面间距、结构面强度、结构面夹角、岩块参数等对围岩变形和支护受力的影响,并通过工程案例验证了本方法的适用性。
[Abstract]:With the increase of highway tunnel engineering, there are more and more accidents of shallow buried loose surrounding rock tunnel collapse. But the conventional finite element method (not considering the action of loose rock mass structure plane and collapse body) and the structural load method have some disadvantages in the calculation of surrounding rock pressure and support design. Based on Peck formula theory and finite element method, a calculation model of fracture surface characteristics of shallow loose surrounding rock is proposed in this paper. The rationality of this method is verified by comparison, and the sensitivity numerical analysis of its influencing factors is made. A calculation method of surrounding rock pressure considering the time of supporting is put forward. Finally, based on the fracture surface model of tunnel surrounding rock proposed in this paper, a modified finite element method for quasi-collapse arch discretization is proposed, and its applicability is analyzed numerically and verified in engineering practice. In this paper, the main conclusions are as follows: 1. Through investigation and analysis of tunnel collapse cases, the failure modes of most of the surrounding rocks are different from those of the standard method and the traditional failure modes, such as the assumed failure location and the fracture angle. In view of this, this paper presents a calculation model and method for determining the slip surface based on the peck curve, and compares it with the model experiments, numerical experiments and engineering examples in the literature, and verifies the rationality of the method. Based on the fracture surface calculation model proposed in this paper, the relationship between the fracture angle 尾 and the surface rupture point i0 and the overburden span ratio (w), elastic modulus (E), Poisson's ratio 渭, the angle of internal friction (蠁), the cohesive force (c) and the types of surrounding rock (鈪，

本文编号：2043266