高速公路改扩建工程路堑高边坡支护机理与效果

发布时间：2018-05-16 06:50

本文选题：道路工程 + 支护方案　；参考：《长安大学学报(自然科学版)》2017年03期

【摘要】：为对公路改扩建工程中路堑高边坡支护机理进行分析并对支护方案进行优选,以柳南(柳州—南宁)高速公路改扩建工程K1415+200左侧高边坡为例进行分析。首先采用FLAC3D数值分析方法研究改扩建边坡开挖对边坡稳定性的影响,然后设计正交试验分析采用锚杆支护时锚杆倾角、长度和间距变化对边坡安全系数的影响规律;研究了原坡面施工抗滑桩及桩前土体挖除2个工况下边坡安全系数的变化情况,并沿边坡高度方向设置监测点分析抗滑桩中锚索施工前后边坡土体水平和竖向位移变化规律,且通过应变增量云图研究边坡土体内部受力情况,最后从支护效果、施工难度及经济性等方面对2种支护方案进行了比选。研究结果表明:按既定改扩建方案开挖后,边坡安全系数小于规范限值,需采取适当措施进行支护;采用锚杆支护时,适当设置锚杆倾角和在有效锚固深度范围内增加锚杆长度均能提高边坡安全系数,而增大锚杆间距则使边坡安全系数降低,且当其间距大于4m后对锚杆间距的敏感性增强;边坡安全系数对锚杆长度的敏感性显著大于锚杆倾角和锚杆间距;采用抗滑桩支护能较好地对边坡土体提供侧向支撑作用,此时边坡安全系数得到有效提高,而加入锚索能进一步减小边坡土体位移,且对边坡土体内部受力影响较小;本工程选用锚杆支护时在支护效果、施工难度和经济性上更为合理。
[Abstract]:In order to analyze the support mechanism of cutting high slope in highway reconstruction and extension project and to optimize the support scheme, this paper takes the K1415 200 high slope on the left side of Liunan (Liuzhou-Nanning) highway reconstruction and extension project as an example. FLAC3D numerical analysis method is used to study the influence of slope excavation on slope stability, and then orthogonal test is designed to analyze the influence of slope safety factor, such as slope inclination angle, length and spacing change. This paper studies the variation of slope safety factor under the two working conditions of anti-slide pile and soil excavation in front of the original slope, and sets monitoring points along the direction of slope height to analyze the variation law of horizontal and vertical displacement of slope soil before and after the construction of anchor cable in anti-slide pile. And through the strain increment cloud diagram to study the slope soil internal force situation, finally from the support effect, the construction difficulty and the economical and so on aspect has carried on the comparison choice to two kinds of support schemes. The research results show that the slope safety factor is less than the standard limit value after excavation according to the planned reconstruction and extension scheme, and appropriate measures should be taken to support the slope. The slope safety coefficient can be improved by properly setting the anchor angle and increasing the length of anchor rod in the range of effective anchoring depth, but the slope safety factor will be decreased by increasing the bolt spacing, and the sensitivity to the anchor spacing will be enhanced when the spacing is more than 4 m. The sensitivity of slope safety factor to the length of anchor rod is significantly greater than that of anchor angle and bolt spacing, and the slope safety factor can be effectively improved by using anti-slide pile support to provide lateral support to the soil mass of the slope. The addition of anchor cable can further reduce the displacement of the slope soil, and the influence on the internal force of the slope soil is small. In this project, the effect of bolting support is more reasonable, the construction difficulty and economy are more reasonable.
【作者单位】：长安大学特殊地区公路工程教育部重点实验室;广西桂海高速公路有限公司;中交第一公路勘察设计研究院有限公司;
【基金】：国家自然科学基金项目(51608053)
【分类号】：U416.14

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