深埋洞室围岩破裂区时空分布特征研究

发布时间：2018-03-29 23:27

本文选题：分区破裂化　切入点：时空分布　出处：《重庆大学》2015年硕士论文

【摘要】：深部岩体赋存环境复杂,高地应力以及裂隙使其表现出与浅层岩体大为不同的变形破坏机理,分区破裂化现象就是其中之一。洞室开挖形成过程中,每个施工步围岩变形都会发生变化,因此围岩分区破裂是与时间和空间都相关的过程。由于分区破裂化时空演化特征尚未明确,可能导致洞室开挖后支护设计不合理以及支护时机选择不合理等诸多问题。目前对洞室开挖过程中分区破裂的时空分布研究较少,因此迫切需要开展深埋洞室围岩分区破裂时空特征的研究。本文针对分区破裂化的两个主要影响因素,即深部岩体峰后力学特性以及洞室开挖过程开挖面周围主应力旋转进行研究,做了以下工作:①考虑深部岩体峰后力学特性,引入内变量梯度理论,在分析材料本构关系时加入梯度项以考虑周围点对材料变形的影响。通过平面应变分析,获得静水和非静水压力条件下洞室围岩中等效非弹性应变解,得到洞室围岩内部各点等效非弹性应变的分布规律。②考虑地下洞室是一个逐步开挖的过程,洞室开挖卸荷后造成开挖面周围主应力发生旋转,围岩的应力和变形将随着开挖面的前进不断变化。通过数值模拟计算,分析不同初始地应力以及不同空间位置处,洞室围岩纵剖面上距开挖面不同距离应力的变化规律。并将洞室未开挖部分假设为半空间问题,利用Hankel积分变换获得未开挖部分各点的解。通过对洞室已开挖部分和未开挖部分的分析,建立深埋洞室开挖过程分区破裂化三维模型,获得分区破裂的时空分布特征。③基于开挖过程分区破裂化三维模型,对分区破裂时空分布特征影响因素进行参数敏感性分析。通过对不同初始地应力、内变量参数以及开挖速度进行分析,得到分区破裂化围岩中破裂区的数量、宽度和延伸长度的变化规律以及开挖中破裂区的演化过程。④将深埋洞室开挖过程分区破裂化三维模型运用于实际工程,模拟新汶矿区孙村矿巷道围岩中破裂区分布特征,并与现场探测结果进行对比分析,验证该模型的可行性与可靠性,揭示现场实际情况下分区破裂化的产生机制以及影响因素。
[Abstract]:Because of the complex environment of deep rock mass, the deformation and failure mechanism of deep rock mass is different from that of shallow rock mass due to its high in-situ stress and fissure. The phenomenon of zonal fracture is one of them, and in the course of excavation, the deformation and failure mechanism of deep rock mass is different from that of shallow rock mass. The deformation of surrounding rock changes in every construction step, so the zonal fracture of surrounding rock is a process related to both time and space. It may lead to many problems such as unreasonable design of support after excavation and unreasonable choice of supporting timing, etc. At present, there are few researches on the spatial and temporal distribution of zone rupture during excavation of cavern. Therefore, there is an urgent need to study the space-time characteristics of the zonal rupture of the surrounding rock of the deep buried cavern. This paper aims at two main influencing factors of the zonal rupture. That is, the post-peak mechanical properties of deep rock mass and the rotation of principal stress around the excavation face during excavation process of deep rock mass are studied. The following work is done: 1. Considering the post-peak mechanical characteristics of deep rock mass, the internal variable gradient theory is introduced. In order to consider the influence of surrounding points on the deformation of materials, the equivalent inelastic strain solutions in the surrounding rock of caverns under hydrostatic and non-hydrostatic pressure conditions are obtained by plane strain analysis. The distribution law of equivalent inelastic strain at each point in surrounding rock of the cavern is obtained. 2 considering that underground cavern is a gradual excavation process, the main stress around the excavating surface is rotated after excavation and unloading. The stress and deformation of surrounding rock will change with the advance of excavation surface. The variation law of stress in different distance from excavation surface on longitudinal section of surrounding rock of cavern is assumed to be a half-space problem, and the unexcavated part of cavern is assumed to be a half-space problem. The Hankel integral transformation is used to obtain the solutions of each point of the unexcavated part. Through the analysis of the excavated part and the unexcavated part of the tunnel, a three-dimensional model of the subdivision rupture of the deep buried cavern is established. Based on the three dimensional model of zonal rupture during excavation, the parameter sensitivity analysis of the factors affecting the spatial and temporal distribution of zonal rupture is carried out. 3. Through the analysis of different initial in-situ stresses, the characteristics of spatiotemporal distribution of zonal rupture are obtained. By analyzing the parameters of internal variables and the speed of excavation, the number of fracturing areas in partitioned fractured surrounding rock is obtained. The variation law of width and extension length and the evolution process of fracture zone during excavation. 4. The three-dimensional model of subdivision rupture in the excavation process of deep buried cavern is applied to actual engineering to simulate the distribution characteristics of fracture zone in the surrounding rock of the roadway of Suncun mine in Xinwen mining area. The feasibility and reliability of the model are verified by comparing with the field detection results, and the mechanism and influencing factors of the zonal rupture are revealed in the actual situation of the field.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

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