库岸堆积层滑坡变形滞后响应机理与时效位移预测研究

Colluvial landslide is an important type of geological hazard during the operation of the Three Gorges Reservoir, and its deformation evolution often lag behind the change of rainfall and reservoir level, show the time lag effect, which brings a great challenge to landslide hazard prediction and disaster alert release. By adopting model experiment, laboratory test, mechanics modeling, theoretical analysis and intelligent calculation method, the hysteresis response mechanism of colluvial landslide deformation and deformation prediction were carried out in this project. The physical model research on reservoir colluvial landslide deformation response is carried out using the geomechanics model test technology, illustrate the corresponding relation of landslide deformation lag time and geotechnical parameter, water level, rainfall; The sliding soil softening test is used to study the rules of soil strength parameter under different soaking; In combination with model experiment and laboratory test results, the hysteresis response mechanism of colluvial landslide deformation is revealed based on the in-situ monitoring and numerical simulation, obtaining landslide deformation hysteresis function of different inducing factors; On this basis, combining intelligent calculation method, the time-effect displacement prediction model considering the hysteresis effect is established. The research results are used to reveal the deformation process of colluvial landslide and make emergency plan in major water conservancy project.

堆积层滑坡是三峡水库运行过程中重要的地质灾害，其变形演化往往滞后于降雨和库水位的变化，表现出时间滞后效应，这给滑坡灾害预测和准确发布灾害警情带来了极大的困扰。本课题综合运用室内试验、力学建模、理论分析及智能计算方法，对堆积层滑坡变形滞后效应和位移预测等前沿问题开展研究。采用地质力学模型试验技术开展库岸堆积层滑坡变形响应的物理模型研究，阐明变形滞后时间与岩土体参数、库水位及降雨量的对应关系；通过典型滑坡滑带土的软化实验研究，探讨不同浸泡时间段下滑带土强度参数变化规律；结合模型试验和室内试验结果，基于现场监测和数值模拟揭示堆积层滑坡变形滞后响应机理，获得滑坡不同诱发因素的变形滞后函数；在此基础上，应用智能算法建立考虑滞后效应的典型监测点时效位移预测模型。研究成果可为重大水利工程库岸堆积层滑坡变形演化分析和预测预报提供理论依据，具有较大的应用价值。

堆积层滑坡是三峡水库运行过程中重要的地质灾害，其变形演化往往滞后于降雨和库水位的变化，表现出时间滞后效应，这给滑坡灾害预测和准确发布灾害警情带来了极大的困扰。项目运用理论分析、模型试验、原位监测、数值模拟和智能算法相结合的研究方法，选取三峡库区典型滑坡开展了堆积层滑坡变形滞后响应机理和时效位移预测研究，研究成果为探究库岸滑坡的演化过程和精准开展监测预警提供理论支撑。取得的重要研究进展如下：. 1）以白家包滑坡为原型基于相似理论、相似材料试验进行物理模型试验设计，包括试验材料、数据采集系统和试验方案设计，建立考虑变形滞后效应的库岸堆积层滑坡物理模型试验平台；. 2）开展了不同工况下的物理模型试验，基于试验数据揭示了不同库水位下降速率和降雨强度作用下库岸堆积层滑坡变形滞后时间变化规律：库水位下降速率越大，滑坡地表变形的滞后时间越短；降雨强度越高，坡体的孔隙水压力变化的滞后时间越短，当降雨强度达到临界值时，孔隙水压力的滞后时间不再变化。. 3）依据理论分析、模型试验和室内试验成果，结合滑坡现场监测数据和滑坡渗流场与应力场的数值模拟，研究了不同库水下降速率、岩土体渗透系数下滑坡变形滞后时间的动态变化规律。. 4）构建了考虑变形滞后效应的滑坡位移预测模型。首先基于集对分析法确定滑坡的变形滞后时间；然后通过GM模型和BP模型对趋势项位移和偏离项位移进行预测。在对偏离项位移进行预测时，根据滑坡变形滞后时间选取最优影响因子作为BP模型的输入项；最后建立SPA-GM-BP模型对滑坡位移进行预测。