加宽高速公路既有高边坡二次开挖稳定性分析及工程技术研究

发布时间：2018-11-25 15:02

【摘要】：上世纪90年代我国高速公路修建进入了飞速发展的时期,近年来随着经济的发展与交通量的持续增加,早期修建的高速公路已无法满足通行要求,因此,必须对高速公路进行改建或扩建。改扩建工程中,既有高边坡的二次开挖需破除原边坡支护结构,引起原边坡应力场的变化,易导致边坡失稳破坏的特点。本文以惠深高速公路惠州段改扩建工程为依托,采用现场调研、理论分析、数值模拟等方法展开研究,主要研究成果如下:(1)对惠深高速公路沿线边坡的区域环境进行了调查分析,初步掌握了既有高边坡与二次开挖高边坡的分布情况及其基本信息,分析了高边坡的几何尺寸、地质条件与防护形式的统计特征,并调查了沿线高边坡在施工过程中发生的病害。(2)结合现场调查与分析边坡基本资料的基础上,选取K22+220~K22+460(左侧)高边坡作为典型高边坡,分析了既有高边坡二次开挖稳定性影响因素,确定了该边坡的破坏模式为“滑移-拉裂”破坏,计算了两种破裂面下该边坡稳定性。(3)针对高速公路加宽改扩建过程中高边坡二次扰动的问题,采用数值模拟的方法,在分析典型边坡初始应力场的基础上,研究不同开挖阶段的安全系数、变形特征和应力场的变化规律。研究成果表明:此类高边坡在二次开挖过程中,坡脚剪应力集中,出现剪出破坏,坡顶存在拉应力,坡顶后一定距离会出现张拉裂缝。在一级坡脚和三级坡脚出现塑形区,塑性区依附于坡角顺倾结构面,形成呈中下部为平面与上部似圆弧面组合形态的最危险滑裂面。(4)在分析二次开挖特殊性的基础上,提出了适用于既有高边坡二次开挖施工的原则与工艺,并从信息化施工和排水系统两个角度减少安全隐患。
[Abstract]:The expressway construction in China entered a period of rapid development in the 1990s. With the development of economy and the continuous increase of traffic volume in recent years, the expressway built in the early period could not meet the traffic requirements. The highway must be rebuilt or expanded. In the reconstruction and extension project, the secondary excavation of the existing high slope needs to break down the original slope support structure, which causes the change of the original slope stress field and easily leads to the instability and failure of the slope. Based on the reconstruction and extension project of Huizhou section of Hui-Shen Expressway, this paper adopts field investigation, theoretical analysis, numerical simulation and other methods to carry out the research. The main research results are as follows: (1) the regional environment of the slope along the Hui-Shen expressway is investigated and analyzed, and the distribution and basic information of the existing high slope and the secondary excavated high slope are preliminarily grasped. The geometric dimensions, geological conditions and the statistical characteristics of the protection form of the high slope are analyzed, and the diseases occurring in the construction process of the high slope along the line are investigated. (2) based on the field investigation and analysis of the basic data of the slope, The K22 220~K22 460 (left side) high slope is selected as a typical high slope. The factors affecting the stability of the existing high slope are analyzed, and the failure mode of the slope is determined to be "slip-tension crack" failure. The stability of the slope under two kinds of fracture surfaces is calculated. (3) aiming at the secondary disturbance of high slope during the widening and extension of expressway, the numerical simulation method is used to analyze the initial stress field of typical slope. The safety factor, deformation characteristics and stress field of different excavation stages are studied. The research results show that during the second excavation of this kind of high slope, shear stress concentration at the foot of the slope, shearing failure, tensile stress at the top of the slope and tension cracks will occur at a certain distance after the slope top. The plastic zone appears at the first and third slope feet, and the plastic zone is attached to the inclined structural surface of the slope angle, forming the most dangerous sliding crack surface in the form of the combination of the middle and lower part of the slope and the upper arc surface. (4) based on the analysis of the particularity of the secondary excavation, The principle and technology suitable for secondary excavation of existing high slope are put forward, and the hidden danger of safety is reduced from two aspects of information construction and drainage system.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U416.14

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