京广铁路K1219路基土质边坡深层滑移失稳机制与整治对策

为研究土质边坡深层滑移失稳机制, 以京广铁路下行线K1219+000处路基边坡失稳为例, 通过现场调查测绘、工程地质钻探、原位试验和室内试验、深部位移监测和数值模拟等手段, 详细研究了该土质边坡变形破坏特征、地质力学过程和失稳模式。结果表明: 路基边坡表面裂缝宽度及深度呈坡顶至坡脚逐渐变浅变窄, 变形具有一定的旋转性, 牵引式特征明显, 属于深层滑移拉裂式失稳; 土质边坡经历了因坡脚开挖、抽水引起的应力场和渗流场重新分布阶段、雨水入渗软化导致下滑力不断增大而滑面逐渐迁移扩大加深阶段以及支挡结构抗力失效阶段3个地质力学过程, 其失稳模式包括浅层滑移、浅层滑面向深层迁移、动荷载触发深层滑移失稳3个阶段。在此基础上, 综合确定了滑面位置, 并通过反演方法确定了滑面力学参数。研究采用了刚架式双排抗滑桩的整治方案, 通过理论计算和数值分析, 边坡变形与抗滑桩变形基本一致, 且与监测结果整体吻合, 这表明土质边坡深层失稳理论分析准确且计算的力学参数科学, 整治对策稳妥、可靠。 

Deep sliding instability mechanism and remediation measures: The subgrade soil slope along the Jingguang Railway at K1219

To explore the deep sliding instability mechanism of a soil slope, taking the subgrade slope instability at K1219+000 of the downward line of the Beijing-Guangzhou railway as an example, the deformation and failure characteristics, geomechanical process and instability causes of the soil slope are detailedly studied. The results show that the width and depth of cracks on the surface of the subgrade slope gradually become shallow and narrow from the top of the slope to the toe of the slope, and the deformation has a certain rotation, with obvious traction characteristics, which belongs to deep sliding and splitting instability. The soil slope has experienced three geomechanical processes: the redistribution of the stress field and seepage field caused by slope toe excavation and pumping, the increasing sliding force caused by rainwater infiltration softening and the deepening of the sliding surface, and the failure of retaining structure resistance. The mechanism of slope instability includes the stage of shallow sliding, the stage of shallow sliding surface moving to the deep layer, and the stage of deep sliding instability triggered by the dynamic load.On this basis, the position of the sliding surface is comprehensively determined and the mechanical parameters of the slip surface are determined by the inversion method. The regulation scheme of rigid frame double row anti-slide piles is adopted. Through theoretical calculation and numerical analysis, the deformation of slope and anti-slide piles are consistent with the deformation monitoring results, which indicates that the theoretical analysis of deep instability of soil slope is accurate and the calculation of mechanical parameters is scientific, and the measures are proven stable and reliable.