页岩边坡滑坡机理分析及治理措施研究

Mechanism Analysis of Shale Slope Landslide and Study on Relative Prevention Measures

南方某页岩路堑边坡在施工过程中因连续降雨发生滑塌,对铁路工程建设、后期运营维护及人民生命财产安全造成重大威胁.通过现场勘查,该路堑边坡已开挖成形.地层岩性主要为黄褐色粉质黏土和页岩夹砂岩,降雨下渗导致岩土体自重和孔隙水压力增加,岩体软化、抗剪强度降低,致使坡脚形成小规模滑塌,并层层牵引,最终形成3处牵引式中深层工程滑坡.通过工程地质调绘、测绘、钻探、挖探、原位测试和土工试验等综合勘察方法,查明了滑坡体的地层岩性、地质构造、水文地质条件、物质组成、结构特征及成因.结果表明,临时排水措施不完善、坡脚积水致页岩软化、边坡支挡防护不及时是滑坡形成的主要原因.结合区域内的工程地质、水文地质及气象特征,采用桩板墙、挡土墙、放缓边坡、边坡框架锚杆和截排水相结合的综合治理措施,效果良好.工程方案既安全可靠又经济合理,可为类似边坡治理提供参考.

A shale cutting slope in the south of China has collapsed owing to continuous rainfall during construction,which causes a major threat to railway construction,post-operation maintenance,and the safety of people's lives and property.Through on-site investigation,the cutting slope has been excavated and formed,and the formation lithology is mainly composed of yellowish-brown silty clay and sandstone interbedded with shale.The rainfall infiltration leads to the increase of self-weight of rock mass and pore water pressure,rock softening and shear strength lowering,resulting in a small-scale collapse at the foot of slope and traction layer by layer,and finally forming three traction-type engineering landslides in mid-deep.Through comprehensive survey methods such as engineering geological mapping,surveying,drilling,digging,in-situ testing and geotechnical testing,it is identified in the sapects of the stratigraphic lithology,geological structure,hydrogeological conditions,material composition,structural characteristics and genesis of the landslide body.The results show that the main reasons for the formation of landslide are imperfect drainage measures,softening of shale caused by water from the foot of the slope and the failure to protect the slope support.Combined with the engineering geological,hydrogeological and meteorological characteristics in the area,the comprehensive prevention and control measures integrating pile-pile wall,retaining wall,slowing slope,slope frame bolt and intercepting and drainage are adopted to achieve good effects of prevention and control.The engineering scheme is safe,reliable and economical,whieh could provide reference for similar slope treatment.