库岸堆积层滑坡间歇性活动机理与预报判据研究

Colluvial landslides affected by the effect of seasonal rainfall and reservoir water in the Three Gorges Reservoir often behave intermittent movement characteristics. The establishment of prediction criteria based on movement mechanism is an urgent scientific problem to be solved in order to avoid wrong decide. Landslide movement intensity is related to inducing factor intensity and action time, shear strength of sliding soil. The Tangjiaoyihao landslide and Baishuihe landslide were taken as examples. Field monitoring and numerical simulation were used to research response process and response difference of landslide underground water under the influence of reservoir water and rainfall. The periodic fluctuation of reservoir water and seasonal rainfall causing the effect of pore water pressure was considered. The relationship between landslide displacement and intensity and action time of pore water pressure was established. Self-made circulating seepage instrument was adopted to simulate the cyclic change of pore water pressure. The shear strength weakening of sliding soils under the cyclic effect of pore water pressure was researched by means of ring shear tests and GDS stress controlled triaxial tests. The mechanism of strength weakening of sliding soils was discovered through microcosmic tests.Physical modeling test was used to model the movement process of Baishuihe landslide. The landslide comprehensive prediction criteria considering the intensity of external force and strength weakening of sliding soil was established The research has important scientific significance on discovering the evolution law of colluvial landslides and improving the landslide prediction level.

三峡库区堆积层滑坡在季节性降雨与库水周期性波动的影响下多呈现间歇性活动特征，实际预报过程中常造成决策者的误判，建立基于滑坡活动机理的预报判据已成为亟待解决的科学问题。滑坡活动强度与诱发因素作用强度和时间、滑带土强度关系密切。本项目拟对塘角1号滑坡和白水河滑坡开展精细监测和数值模拟，研究库水与降雨作用下滑坡地下水响应过程以及不同作用强度下地下水响应的差异性；考虑库水周期性波动与季节性降雨引起的孔隙水压力作用，建立孔隙水压力作用强度和时间与滑坡位移的关系；利用循环渗透仪模拟孔隙水压力循环变化，通过环剪试验和GDS应力路径三轴试验研究循环孔隙水压力作用下滑带土强度弱化规律，从微观上揭示滑带土强度弱化机理；开展滑坡物理模型试验模拟滑坡变形破坏过程，建立考虑滑坡外力作用强度和内部损伤（滑带土弱化）的堆积层滑坡综合预报判据。研究成果对揭示堆积层滑坡演化规律和提高滑坡预测预报水平具有重要的科学意义。

库区堆积层滑坡在季节性降雨与库水周期性波动的影响下多呈现间歇性活动特征，实际预报过程中常造成决策者的误判，建立基于滑坡活动机理的预报判据已成为亟待解决的科学问题。项目采用空-天-地一体化立体观测技术系统研究了库岸堆积层滑坡间歇性活动特征，揭示了堆积层滑坡活动性与外界诱发因素的关系；建立了库岸堆积层滑坡活动性和孔隙水压力量化模型，从滑坡稳定性和孔隙水压力等角度揭示了外在作用因素对滑坡间歇性活动的影响规律；采用等速剪切、变速剪切、循环渗透剪切等不同剪切条件下揭示不同剪切速率和水位波动条件下滑带土强度的弱化规律；采用三轴固结不排水剪切试验系统研究含水率、循环孔压作用下滑带土强度变化规律，揭示了循环孔隙水压力作用下滑带土强度弱化规律；采用人工智能和数值模拟技术预测随外界因素变化库岸堆积层滑坡变形强度；综合采用光学遥感、模式试验和数值分析等方法，建立了基于滑坡破坏模式、斜坡结构特征和内在机理的堆积层滑坡综合预警判据，实现了单体、区域滑坡灾害预警。通过本项目的研究，掌握了堆积层滑坡活动性与外界诱发因素的关系，探究了循环孔隙水压力作用下滑带土强度的弱化规律，从内外作用因素两个方面揭示了库岸堆积层滑坡间歇性活动机理，建立了基于滑坡结构和内在机理的堆积层滑坡综合预报判据。基于堆积层滑坡的研究成果， 发表 SCI论文8篇，国内核心论文2篇，培养博士生3名，研究生7名。项目研究成果在我国防ZC环境保障、国家电网特高压线路运维、全国地质灾害风险示范、贵州和重庆等地大型堆积层滑坡预警工作得到了广泛应用。