高速公路改扩建工程高边坡施工过程稳定性研究

发布时间：2018-03-23 17:02

本文选题：高速公路改扩建　切入点：高边坡　出处：《长沙理工大学》2014年硕士论文

【摘要】：随着我国经济的飞速发展,很多既有道路已不能满足交通量飞速增长的需求,因此,亟需对一些既有道路进行修复与改扩建。在道路改扩建路堑高边坡施工时,不可避免要对原有边坡进行二次开挖,而二次开挖会对原坡体造成进一步扰动,若处理不当,则很有可能造成坡体失稳,影响高速公路运营安全。因此,如何避免边坡在二次开挖过程中发生失稳就成为高速公路改扩建工程高边坡施工中的关键问题之一。本文以广西桂柳南高速公路改扩建工程K1431+380左侧高边坡为工程实例,首先采用灵敏度及正交试验分析方法对影响该边坡稳定性的各因素进行敏感性分析；然后采用FLAC 3D软件建立相应数值分析模型,优化该边坡的开挖施工工艺,并对该边坡二次开挖施工的过程稳定性进行深入系统研究,提出合理可靠的边坡加固方案,为工程实践提供参考。本文主要的研究内容及成果如下：(1)基于正交试验设计,对K1431+380高边坡稳定性影响因素灵敏度进行相应计算,得到影响向该边坡稳定性各因素敏感性大小关系为：边坡平均倾角边坡坡高岩土体礼平均内摩擦角岩土体平均重度边坡开挖分级数岩土体平均粘聚力。(2)通过对K1431+380高边坡按不同比例及不同开挖深度开挖进行数值模拟,认为边坡的稳定性对开挖坡比较敏感。当固定开挖坡比时,边坡的安全系数Fs在每级开挖深度为10m时达到最大,说明每级开挖10m对边坡的稳定性最好；最后认为边坡的安全系数与每级开挖深度的大小并不是单纯的呈线性关系,而是存在一个最佳的开挖深度使得边坡稳定性达到最好。(3)通过对K1431+380高边坡开挖过程进行数值模拟,认为当边坡开挖完第三步后及时支护能使其稳定性达到最佳。由此得出结论：边坡施工期存在一个最佳支护时机,即最关键的防护时步,在该最佳时机对边坡及时进行支护会使边坡在施工期的稳定性达到最佳。
[Abstract]:With the rapid development of China's economy, many existing roads can no longer meet the demand of rapid growth of traffic volume. Therefore, it is urgent to repair and rebuild some existing roads. It is inevitable to carry on the second excavation to the original slope, and the second excavation will cause further disturbance to the original slope body. If the treatment is not proper, it will probably cause the slope body to lose stability and affect the highway operation safety. How to avoid the instability of the slope during the second excavation is one of the key problems in the construction of the high slope in the expressway reconstruction and extension project. This paper takes the K1431 380 high slope on the left side of Guangxi Gui-Liunan Expressway Reconstruction and extension Project as an engineering example. The sensitivity analysis and orthogonal test method are used to analyze the factors that affect the stability of the slope, and the corresponding numerical analysis model is established by using FLAC 3D software to optimize the excavation construction technology of the slope. The stability of the slope during the secondary excavation construction is studied systematically, and a reasonable and reliable slope reinforcement scheme is put forward, which provides a reference for engineering practice. The main research contents and results of this paper are as follows: 1) based on orthogonal test design, The sensitivity of the factors affecting the stability of the K1431 380 high slope is calculated. The sensitivity of the factors affecting the stability of the slope is obtained as follows: average slope slope slope high rock soil, average internal friction rock soil mass, average serious slope excavation grade, average cohesive force of rock and soil mass, average cohesion of rock and soil through K1431. The excavation of 380 high slope is simulated according to different proportion and different excavation depth. It is considered that the slope stability is more sensitive to the excavation slope. When the excavation slope ratio is fixed, the slope safety factor Fs reaches the maximum when the excavation depth of each stage is 10 m, which indicates that the slope stability is best when the excavation depth is 10 m per stage. Finally, it is concluded that the safety factor of the slope is not only linearly related to the excavation depth of each stage, but that there is an optimal excavation depth to make the slope stability reach the best.) the excavation process of the K1431,380 high slope is simulated numerically. It is considered that the stability of the slope can be optimized by timely supporting after the third step of excavation, and it is concluded that there is an optimal time to support the slope during the construction period, that is, the most critical time step of protection. The stability of the slope during the construction period can be optimized by supporting the slope in time.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.14

【参考文献】