断裂力学在边坡稳定分析中的应用研究
发布时间：2018-11-22 13:17
【摘要】：边坡工程的稳定性是土木行业一直以来比较关注的问题，目前常用连续介质力学的方法对边坡稳定性进行分析，但这些方法都无法考虑边坡内部缺陷对边坡稳定性的影响。断裂力学的研究对象是带有宏观裂缝的结构体，而实际的边坡正是这种结构体，因此可以用断裂力学原理分析边坡的稳定性。本文主要针对两种不同的破坏模式对边坡的稳定性进行分析。 对于普通均质粘土边坡，假设其破坏是由坡顶开裂引起的，边坡稳定性的判据是坡顶裂缝长度是否达到临界缝长。主要研究内容及结论为： ①运用有限元软件，根据边坡坡顶不同位置的应力强度因子分布确定边坡最易开裂位置；再确定临界缝长；在最易开裂位置设置大于临界缝长的裂缝，按计算的裂缝扩展角依次往下扩展，直至裂缝贯通，所得破裂面即为基于断裂力学的边坡最危险滑动面。根据裂缝扩展时Ⅰ、Ⅱ型应力强度因子的比值判断边坡破坏类型为Ⅰ-Ⅱ复合型，但是更加趋近于Ⅰ型破坏。 ②将基于断裂力学和传统极限平衡法求得的最危险滑动面对比，，表明运用断裂力学原理研究粘土边坡稳定性是可行的。 ③运用有限元软件，研究边坡高度及倾角对边坡断裂破坏的影响。得到坡顶最易开裂位置与坡缘距离随着边坡高度或倾角的增加而增加；临界缝长随着边坡高度或倾角的增加而减小；随着边坡高度或倾角增加，边坡更加趋近于Ⅰ型破坏。 对于内部含有共线缺陷裂缝或由层状岩体构成的边坡，将其缺陷简化为内部的一组共线裂缝，假设边坡破坏是由这组共线裂缝扩展导致的。边坡稳定性的判据是裂缝尖端等效应力强度因子是否小于断裂韧度。主要研究内容及结论为： ①当边坡内部存在缺陷裂缝时，裂缝部位岩土体的抗滑力不计。运用有限元软件，假设不同长度及间距的共线裂缝，求解其应力强度因子，研究裂缝条数、长度及间距不同时，裂缝尖端应力强度因子的变化规律。 ②将基于断裂力学求得的边坡等效安全系数和极限平衡法求得的安全系数对比，表明基于断裂力学求解边坡等效安全系数的可行性。 ③将两种边坡破坏模式进行对比，研究其区别与联系。
[Abstract]:The stability of slope engineering is always concerned by civil engineering. At present, the method of continuum mechanics is used to analyze the stability of slope, but none of these methods can take into account the influence of internal defects of slope on slope stability. The research object of fracture mechanics is the structural body with macroscopic cracks, and the actual slope is this kind of structure, so the stability of slope can be analyzed by the principle of fracture mechanics. In this paper, the stability of slope is analyzed according to two different failure modes. For the common homogeneous clay slope, it is assumed that the failure is caused by the crack at the top of the slope, and the criterion of slope stability is whether the crack length of the slope top reaches the critical crack length. The main research contents and conclusions are as follows: 1 using finite element software, according to the distribution of stress intensity factor at different positions of slope top to determine the most easily cracked position of slope, and then determine the critical joint length; At the most easily cracked position, the fracture larger than the critical fracture length is arranged, and the crack propagation angle is calculated to extend down in turn until the crack is through. The resulting fracture surface is the most dangerous sliding surface of the slope based on fracture mechanics. According to the ratio of stress intensity factors of type 鈪
本文编号：2349479
[Abstract]:The stability of slope engineering is always concerned by civil engineering. At present, the method of continuum mechanics is used to analyze the stability of slope, but none of these methods can take into account the influence of internal defects of slope on slope stability. The research object of fracture mechanics is the structural body with macroscopic cracks, and the actual slope is this kind of structure, so the stability of slope can be analyzed by the principle of fracture mechanics. In this paper, the stability of slope is analyzed according to two different failure modes. For the common homogeneous clay slope, it is assumed that the failure is caused by the crack at the top of the slope, and the criterion of slope stability is whether the crack length of the slope top reaches the critical crack length. The main research contents and conclusions are as follows: 1 using finite element software, according to the distribution of stress intensity factor at different positions of slope top to determine the most easily cracked position of slope, and then determine the critical joint length; At the most easily cracked position, the fracture larger than the critical fracture length is arranged, and the crack propagation angle is calculated to extend down in turn until the crack is through. The resulting fracture surface is the most dangerous sliding surface of the slope based on fracture mechanics. According to the ratio of stress intensity factors of type 鈪
本文编号：2349479
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