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。
In order to analyze the support mechanism of cutting high slope in road reconstruction and expansion projects and to optimize support scheme, high slope of K1415 ＋200 on the left side of Liunan （Liuzhou to Nanning） Expressway was taken as an example. Firstly, the influence of slope excavation on slope stability was studied by FLAC3D numerical method, then orthogonalexperiment was designed to analyze the influence rules of anchor angle, anchor length and anchor space on slope safety factor when using anchor support. Changes of slope safety factor were studied under the working conditions of original slope construction anti-slide pile and excavation of two anterior soil of piles. Monitoring points along height of the slope were set to analyze horizontal and vertical displacement of soil slope in anti-slide pile before and after the construction of anchor cable, and stress of the slope soil was studied by strain increment nephogram. Finally, two support schemes were compared in the aspects of supporting effect, construction difficulty and economy. The results show that the safety factor is less than the code limit value by using the existing reconstruction and expansion project to excavate, so appropriate support measures should be taken. Both setting appropriate anchor angle and increasing anchor length within the effective anchorage depth can improve safety factor of the slope. However, increasing anchor spacing will reduce the safety factor of the slope, and when the spacing is more than 4 m, the sensitivity will be enhanced. Sensitivity of the slope safety factor to the length of anchor is obviously greater than that of angle and spacing of anchor. Slope soil can get better lateral support when using anti-slide pile retaining. At this time, slope safety factor can be improved, and the slope displacement can be reduced further when adding anchor cable, which has less influence on internal force of slope soil. In this project, the support effect, the construction difficulty and the cost are more reasonable when using anchor to reinforce slope. 3 tabs, 7 figs, 25 refs.
出处
《长安大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2017年第3期39-46,共8页
Journal of Chang’an University(Natural Science Edition)
基金
国家自然科学基金项目(51608053)
