滑坡泥石流演进关键参量协同分析与灾害预测方法

Landslide turning into debris flow is a continuous changing process,in which the mass movement induced by local shear deformation of the soil on the slope is transferred to mud flow induced by continuous shearing.It is also the process from the failure slope to the specific fluid under certain conditions. Because of the high frequency, unexpected and unforecast of the landslide and debris flow,its evolution process and mechanism is analyzed collaboratively by multi parameters,in which the study is aimed at the landslide and debris flow induction and evolution process induced by rainfall,the internal causes of soil source control including the composition and structure of soil and rock,the debris flow risk sensitive factors,strength,shear liquefaction,etc.. In the analysis the regional or local in situ investigation,the in situ or laboratory tests including rainfall disaster statistics,scanning electron microscope(SEM), soil dispersion,ESP test,large scale direct shear tests and trixial tests and ring shear tests,and the numerical simulation method including the foundation of soil continuous shear strength attenuation constitutive model are used with some parameters for the debris flow continuous movement scale and sediment control.By the study,the evolution mechanism of landslide and debris flow would be obtained and the disaster scale would be forecast,which has the prosperous prospects for the rapid assessment of debris flow risk and the high accuracy forecast.

滑坡泥石流演进是坡面土体局部剪切变形所致的整体运动向连续剪切流动的不断变化过程，也是坡面土体破坏后在一定条件下转化为特定流体的过程。针对滑坡、泥石流灾害仍呈高发态势，灾害突发性、异常性和难以预见性日显突出的现状，以降雨作为滑坡泥石流诱发和演进过程研究的主线，以土石组成和结构、泥石流风险敏感参量、土体强度、应力应变和剪切液化性等演进过程的土源控制性内因为突破点，通过现场地质调查、降雨灾害观测统计、扫描电镜、土体分散度、ESP值测试、大型直剪和三轴试验、环剪试验等技术与方法，结合地形地貌、沟道坡度等泥石流继续运动和沉积控制参量以及土体连续剪切强度弱化本构模型，开展滑坡泥石流演进过程和机理多关键参量协同分析，揭示滑坡泥石流演进机理并预测灾害影响范围，建立滑坡泥石流风险快速评价和针对性高准确度研判方法，这对我国泥石流基础研究和防灾减灾技术水平提升，国家防灾减灾规划具有重要的理论意义和应用价值。

滑坡泥石流演进是局部剪切变形所致的坡面土体由整体运动向连续剪切而流动的不断变化过程，是坡面土体从弹塑性体或粘弹性体破坏后在一定条件下转化为特定流体的过程。降雨是滑坡泥石流的诱发因素和演进过程的控制因素，土石组成和结构、分散性和渗透淋滤特性，强度和剪切液化性等是滑坡泥石流演进过程的土源控制性内因，地形地貌、沟道坡度等关键因子是泥石流继续剪切运动与停积的控制参量。本项目从滑坡泥石流降雨和地质灾害调查统计分析的诱因参量宏观研判、滑坡泥石流体颗粒分析、扫描电镜（SEM）、分散度和ESP 值测试、不同含水量下的三轴剪切试验和大型直剪试验以及斜坡稳定性分析等揭示降雨条件下土体强烈分散、强度降低致使低滑坡泥石流堆积体稳定性降低而失稳的过程。通过自制土柱入渗试验和试验过程中土体含水量、孔隙水压力的精细量测，获得一定密度和粒径组合下，降雨入渗过程中土体含水量和孔隙水压力的变化规律，并在环剪试验基础上获取滑动面土体连续剪切条件下，孔隙水不能及时消散导致孔隙水压力不断增加和土体强度降低的连续剪切强度弱化过程和机理。建立降雨地质灾害统计宏观研判、泥石流土体内因补充、强度弱化本构模型灾害影响范围预测的泥石流风险评估方法。开展浙江省上杭县紫金山金铜矿区应用实践。通过矿区降雨地质灾害统计分析的宏观研判、堆浸矿渣泥石流风险内因试验和分析，基于滑动土体长距离运动剪切强度弱化本构模型，在地形地貌控制参量下进行江山岽排土场、一天门堆浸渣场和紫金山金铜矿二选厂泥石流运动范围数值模拟，预测可能的泥石流发生规模和影响范围，为矿区泥石流防灾避灾提供参考，具有较高的经济价值。