考虑岩溶管道影响的山体滑坡稳定性研究

STUDY ON THE STABILITY OF LANDSLIDE CONSIDERING THE EFFECTS OF KARST PIPELINE

西南地区近年来多次发生管道发育的岩溶山体滑坡灾害,造成了较严重的人员财产损失,明确岩溶管道在滑坡稳定性分析中的影响至关重要。本文首先根据现场调研和关键力的解析建立了发育岩溶管道的山体滑坡二维地质与力学模型,并提出了考虑岩溶管道作用影响的山体滑坡稳定性系数计算方法,认为岩溶管道对山体滑坡稳定性的影响主要体现在岩溶管道流的力学作用以及岩溶管道对岩体结构的劣化作用;根据Navier-stokes、Brinkman-extended Darcy方程推导出了岩溶地下水对管道的拖曳力和水锤作用力;通过大型数值直剪试验和流变试验分别得到水和岩溶管道发育率对岩体强度参数的弱化作用规律。最后结合重庆武隆鸡尾山滑坡实例,对本文提出的模型和计算方法进行了验证,结果表明,当岩溶管道未贯通时FOS=1.204,滑坡稳定;当岩溶管道贯通时FOS=1.053,滑坡处于欠稳定状态;岩溶管道贯通且降雨时,FOS=0.965,滑坡失稳,计算结果与滑坡实际情况基本一致。

Karst landslides have occurred many times in southwestern mountainous areas in recent years,resulting in the loss of lives and property.Aiming at the karst pipeline action of karst mountain bodies,this paper analyzes its influence on the stability of karst landslides.Firstly,according to field investigations and mechanical analyses,a geological and mechanical model of karst landslides with karst pipelines is established,and a calculation method for the stability coefficient of karst landslides under the action of karst pipelines is proposed.To improve the accuracy of the calculation method,it is considered that the influence of karst pipelines on the stability of karst landslides is reflected in the mechanical effect of karst pipeline flow on rock masses and the deterioration of karst pipelines on rock mass structure.According to Navier-Stokes and Brinkman-extended Darcy equations,the drag force of karst pipelines is deduced,and combined with the water hammer effect,the water hammer force is proposed.Through large-scale numerical direct shear tests and rheological tests,the weakening law of water and karst pipeline development rate on rock mass strength parameters is obtained.Combined with the example of Jiwei Mountain landslide,using the calculation method in this paper,it is concluded that when the karst pipeline is not connected,the Factor of Safety(FOS)=1.204,indicating stability;when the karst pipeline is connected,FOS=1.053,indicating an unstable state;when the karst pipeline is connected and rainfall occurs,FOS=0.965,indicating instability.The conclusion obtained using the calculation method in this paper is consistent with the situation at the landslide site.