含地下采空区岩质边坡的施工过程数值分析

为研究含地下采空区的岩质边坡在施工过程中的各种响应与稳定性,采用SURPAC建立某磷矿的三维地质模型。在边坡坡顶、坡角与采空区四周布置应力与位移监测点。利用接口程序将三维模型导入FLAC3D,计算露天边坡开挖过程中监测点的应力与位移。计算结果表明:坡顶与坡角水平位移与竖向反弹位移随着边坡开挖的进行越来越大,但每步开挖完成后新增的反弹位移越来越小,这与每步开挖的卸载量大小有关。坡顶监测点处于拉应力状态,坡角监测点处于压剪应力状态,在监测点所在位置开挖时,压应力显著变大。地下空区的开挖过程对空区的竖向位移与应力有极大影响,最大主应力在每步开挖完成时突然增加,且增幅很大。建议在施工过程中,加强对采空区与边坡坡顶及坡脚的位移与应力的量测,以确保施工安全。

Numerical Analysis of Construction Process for Rock Slope with Goaf

In order to study the response and stability of rock slope with underground goaf in a construction process,a 3D geological model for a certain phosphate mine was built with SURPAC software.Monitoring points of the slope and the goaf were set in order to monitor the stress and displacement.Stresses and displacement of key points were calculated by FLAC3D through the interface program between SURPAC and FLAC3D.The calculation results show the horizontal displacement and rebound displacement of the slope's top and foot increase with the stage excavation,but the increment of rebound grows down because of excavation unloading.The slope top is in a tensile state and the slope foot is in a compression-shear stress state and the stress markedly increases at its' own step.The goafs remarkably change the displacement and stress distribution and the maximum principal stresses abruptly increase at the every step.It was recommended to the management of the mine that the measuration of displacement and stress of the slope and the underground goaf in construction process should be strengthened.