基于实例推理系统的滑坡预警判据研究

Research on early warning criterion of landslides using case-based reasoning

为研究滑坡预警预报指标,建立了31个典型岩质滑坡组成的滑坡数据库,基于滑坡数据库、工程类比和模糊综合评判方法开发了滑坡实例推理系统。首先将滑坡特征属性分为6大项:破坏模式、滑面倾角、滑面类型、边坡岩体结构、边坡倾角、滑坡的诱发因素(降雨、地下水、水库蓄水、开挖、爆破、地震),用11个特征值表示边坡的特征属性;其次采用比值法相似度计算理论在滑坡数据库中搜索与目标边坡最相似的滑坡,通过工程类比给出滑坡预警判据建议值;最后依据模糊综合评判模型修正建议值,得到预警判据确认值,形成滑坡实例推理系统。以锦屏一级水电站为例,通过计算找到了滑坡数据库中与锦屏一级水电站左岸边坡最为相似的5个滑坡实例;其中大冶铁矿狮子山滑坡和安家岭露天矿滑坡有较为完整的变形监测数据,深入分析类似边坡变形破坏过程,分4个阶段给出了锦屏一级水电站左岸边坡预警判据建议值;并建立边坡预警判据修正的模糊综合评判模型,修正相似边坡预警判据,给出锦屏一级水电站左岸边坡进入加速变形阶段的位移速率阀值的精确区间为1.0～1.2 mm/d。

In order to study the early warning index of landslide, a landslide database composed of 31 typical rock landslides is established; and based on the database a landslide case-based reasoning system is developed using engineering analogy and fuzzy comprehensive assessment model. The feature attribute of landslide is divided into 6 items, including failure mode, dip angle of slip plane, slip-zone type, rock mass structure, slope angle, inducing factors in landslide （rainfall, groundwater, reservoir impoundment, excavation, blasting and seismic peak acceleration）, whereupon the characteristics of properties of slope is represented by 11 eigenvalues. The most similar slopes are searched from the database using theory of similarity based on ratio method; and the suggested warning criterion is given based on engineering analogy; and then revised criterion is get based on fuzzy comprehensive assessment model. Taking Jinping I hydropower station for example, five landslides that are most similar with the slope at left bank of Jinping I hydropower station are got. Anjialing open-pit mine landslide and landslide in eastern open pit in Daye among the result have intact deformation monitoring data, so in terms of four periods the early warning criterion of the slope at left bank of Jinping I hydropower station is given, based on deep analysis of deformation and failure process of the similar slopes. A fuzzy comprehensive assessment model is established to revise the criterion mentioned above; and exact interval of （1, 1.2） mm/d is given which determines the displacement rate threshold when the slope at left bank of Jinping I hydropower station develops into the accelerated deformation stage.