某断层破碎带致灾滑坡的变形机理分析与治理探讨

随着越来越多的高速公路在山区的建设,不可避免遇到大量的不良地质,尤其在受区域性的褶断带改造的岩体中开挖边坡,极易诱发工程滑坡,滑坡产生的速度快、规模大。以在某高速公路建设的边坡施工中修建便道及清表时,触发某边坡产生较大规模的滑坡为例,通过地质调查、钻探、物探等工作,查明滑坡区的地质构造、岩土特征等。对较易通过室内剪切试验获得抗剪强度指标的岩土层采用Mohr-Coulomb破坏准则;对不易通过剪切试验获得其抗剪强度指标的岩土层,则采用Hoek-Brown破坏准则对滑坡体开展数值分析。并与现场监测数据、地表滑移特征进行对比,分析滑坡产生破坏变形的机理及主要诱发因素,验证岩土层采用Hoek-Brown破坏准则进行判别的可靠性。并利用反分析的结果,结合路基开挖,通过数据模拟分别采用放坡、排水或加固进行滑坡处治方案的评估,以达到最优的处治目的。

Deformation Mechanism Analysis and Treatment of Landslide Caused by a Fault Fracture Zone

There are more and more highways being constructed in mountainous areas,it is inevitable to encounter unfavorable geological conditions,especially in the area reformed by fold zone,where landslides will easily occur while excavating slope,which could be quick and big.Being based on a case of large-scale landslide of a highway being built,which is caused during the construction of access road and surface cleaning,the geological structure and geotechnical characteristics of this landslide have been analyzed by researches on geological survey,drilling,and geophysical exploration and so on.Mohr-Coulomb failure criterion has been adopted for the soil layers whose shear strength index could be obtained easily by indoor shear test,while Hoek-Brown failure criterion has been adopted for the soil layers whose shear strength index could not be obtained by indoor shear test.Being compared with the surface monitoring data and the surface slip characteristics,the mechanism of the landslide deformation and the main causing factors have been obtained,which could verify the reliability of the geotechnical layer by means of Hoek-Brown failure criterion.Being based on the results of back analysis,being combined with subgrade excavation,the landslide treatment scheme has been evaluated respectively by grading,drainage and reinforcement,to achieve the optimal treatment purpose.