红层泥岩大型深层滑坡形成机制及稳定性分析

Formation Mechanism and Stability Analysis of Large Deep Layer Landslidein Red Beds Mudstone

青海东部地区红层泥岩广泛分布。由于红层泥岩工程地质性质较差,该区容易产生变形破坏现象,但大多为崩塌与浅层滑动变形破坏。供水干线16#隧洞的进口边坡,山体主要由西宁组上段泥岩组成,在隆国村一带发现大型红层软岩深层滑动破坏滑坡体,初步设计的进口位置在滑坡体前缘。根据滑坡体特征及周围地形地质条件,建立了隆国村滑坡体破坏前的斜坡地质模型,对斜坡地质模型的稳定性进行计算,分析了滑坡体的形成机制。根据工程地质条件,对隆国村滑坡体建立了三维计算模型,分析了天然、降雨及地震工况下的滑坡体稳定性。研究表明,隆国村大型深层滑坡天然工况下稳定性较好,地震工况下处于基本稳定状态,暴雨条件下可能处于失稳状态。研究成果可以为该区施工设计阶段引水线路供水工程干线16#隧洞的进口位置选择提供依据,也为红层泥岩区类似工程的分析评价提供借鉴。

Red beds mudstone is widely distributed in the eastern Qinghai.Owing to poor engineering geological properties will be easy to produce deformation failure phenomena,but mostly are collapse and shallow sliding deformation failures.The entrance slope massif of the water supply trunk line tunnel No.16 belongs to upper member mudstoneof the Xining Formation.A large red beds soft rock sliding destructive landslide mass has been found in the Longguo Village district,preliminary designed entrance position at the landslide mass front.According to landslide mass features and periphery topographic and geological conditions have established Longguo Village landslide mass before destruction slope geological model.According to stability computation based on the slope geological model has analyzed landslide mass formation mechanism.Based on engineering geological conditions have established landslide mass 3D computational model,analyzed landslide mass stabilities under natural,rainfall and earthquake conditions.The study has shown that the stability of the landslide is better under natural condition,basically stable under earthquake condition,possibly in a state of instable under rainstorm condition.The studied results can provide basis for construction drawing design stage water diversion line water supply truck tunnel No.16 entrance position selection,also provide reference for red beds mudstone area similar project analysis and assessment.