降雨型堆积层滑坡中长期预报前期有效降雨量计算方法研究
Study of an Effective Rainfall Calculation Method for Early and Medium Term Forecasts of Accumulation Landslides Induced by Rainfall
黄晓虎 1董雨休 1易武 1郭飞 1黄海峰1
作者信息
- 1. 三峡库区地质灾害教育部重点实验室(三峡大学),湖北宜昌 443002;三峡大学土木与建筑学院,湖北宜昌4430023;三峡滑坡国家野外科学观测研究站,湖北宜昌 443002
- 折叠
摘要
降雨阈值是降雨型堆积层滑坡进行预警预报的关键性指标之一.合理的有效降雨量计算方法是获取精确降雨阈值的重要手段,也是进行准确预警预报的前提.选取徐洼滑坡、王家坡滑坡、谭家湾滑坡以及土地湾滑坡为研究对象,分别代表小型、中型、大型、特大型降雨型堆积层滑坡.首先分析降雨作用下降雨型堆积层滑坡的变形特征.然后,引入"一个降雨过程"统一影响滑坡变形的降雨过程,结合"位移速率影响度"概念,设计一套前期有效降雨量计算方法,并与传统的前期有效降雨量计算方法进行对比验证.结果表明:(1)小型、中型、大型、特大型的降雨型堆积层滑坡的变形与降雨过程密切相关,进入蠕动变形阶段后,滑坡的累积位移曲线存在明显的"阶跃"特征;(2)降雨型堆积层滑坡位移速率存在"滞后衰减"现象,单体滑坡的"滞后衰减"时间T近似为一个固定值,并与滑坡的稳定性演化特征基本吻合;(3)结合"一个降雨过程"和"位移速率影响度"建立的考虑"滞后衰减"的前期有效降雨量计算方法与滑坡变形持续时间和滑坡变形速率的契合度较好,在滑坡的预警过程中存在明显的优势.
Abstract
The rainfall threshold is a key indicator for the early warning and prediction of accumulation landslides induced by rainfall.A reasonable and effective rainfall calculation method is an important means to obtaining an accurate rainfall threshold and a premise for accurate early warning and forecasting.In this paper,the Xuwa,Wangjiapo,Tanjiawan and Tudiwan landslides were taken as research objects,representing small,medium,large and super-large rainfall-type accumulation landslides,respectively.First,the deformation characteristics of rainfall-type accumulation landslides under the action of rainfall were analyzed.Then,a"one rainfall process"was introduced to unify the rainfall processes affecting landslide deformation,and combined with the concept of a"displacement rate impact degree",a set of calculation methods for early effective rainfall were designed and compared with traditional calculation methods.The research findings showed that(1)the deformation of small,medium,large and super-large rainfall-type accumulation landslides is closely related to the rainfall process.After entering the creep deformation stage,the cumulative displacement curve of landslides has obvious"step"characteristics.(2)There is a"lag decay"phenomenon in the displacement rate of the rainfall accumulation layer,and the"lag decay"time T of a single landslide is an approximately fixed value,which is basically consistent with the stability evolution characteristics of landslides.(3)Combining the"one rainfall process"and the"displacement rate impact",the calculation method of early effective rainfall considering"lag attenuation"has a good fit with the duration of landslide deformation and the landslide deformation rate,which has obvious advantages in the landslide early warning process.
关键词
降雨型堆积层滑坡/滑坡预报/前期有效降雨量/滞后衰减Key words
accumulation landslide induced by rainfall/landslide forecast/early effective rainfall/delayed attenuation引用本文复制引用
基金项目
三峡库区地质灾害教育部重点实验室(三峡大学)开放基金项目(2022KDZ16)
国家青年科学基金项目(42007237)
国家青年科学基金项目(42107489)
出版年
2024
NETL
NSTL
万方数据