路堑边坡扩建开挖过程中的变形分析

Deformation Analysis of Cutting Slope During Expansion Excavation

为研究路堑边坡开挖过程中岩体边坡和变形稳定性,确保路堑边坡施工及运营期的安全,以路堑边坡扩建工程为依托,采用地表变形及岩体内部位移监测数据分析边坡开挖过程中的变形规律。边坡表面变形通过布设监测点进行监测,边坡深部位移通过钻孔安装多点变位计和测斜管进行监测,得到边坡开挖和变形关系。分析结果表明:在开挖前边坡整体较稳定,随着边坡开挖量的逐渐增多,边坡岩体位移量逐渐增大,边坡深层位移先增加后收敛,最后趋于稳定;边坡发育的断层、拉裂缝、开挖临空面等对边坡在施工期的稳定性产生较大影响;开挖结束后边坡各方向的位移均趋于收敛,地表监测点中水平最大累计位移量为12.30 mm,其方向平行道路走向,而垂直最大累计位移量为10.60 mm,发生在第三级台阶;边坡内部岩层最大水平位移为11.02 mm,主要发生在岩层分界处的断层软弱结构面位置;在边坡的软弱岩层开挖期间,边坡岩体易出现相对较大的位移变形,开挖结束后短期内边坡地表位移趋于收敛,深层岩体的位移基本稳定;在边坡开挖过程中,边坡地表位移及深层水平位移在第二级边坡开挖时均变化较大,第二级台阶岩体的合理开挖是控制整个边坡稳定的关键。

In order to study the deformation stability of rock slope during the excavation of cutting slope, and ensure the safety of cutting slope construction and operation period, based on the development of cutting slope, the deformation law of slope excavation was analyzed by surface deformation and internal displacement monitoring data of rock mass. The surface deformation of the slope was monitored by setting observation points, and the deep displacement of the slope was monitored by installing multi-point deflection gauges and inclinometer tubes. Therefore, the relationship between slope excavation and deformation was obtained. The analysis results show that the slope is stable before excavation, and the displacement along the slope is gradually increased with the increase of the slope excavation. After the excavation, the displacement of each slope tends to converge, and the maximum cumulative displacement in the surface monitoring point is 12.30 mm, which is along the parallel road direction, and the vertical maximum cumulative displacement is 10.60 mm, which occurs in the third step. The maximum horizontal displacement of the rock in the slope is 11.02 mm, which mainly occurs in the weak structural plane of the rock boundary. During the excavation of the weak rock slope, the slope rock mass is prone to relatively large displacement deformation. After the excavation, the slope surface displacement tends to converge in a short time, and the displacement of the deep rock mass is basically stable. In the process of slope excavation, the surface displacement and deep horizontal displacement of the slope vary greatly during the excavation of the second stage slope. The reasonable excavation of the rock mass of the second stage slope is the key to control the stability of the whole slope.