摘要
位于浙江省西部衢北地区的杨家泥石流是典型的水体冲蚀形成的低频性沟谷型泥石流。结合杨家泥石流所处的地质环境背景,首先在分析其分区特征、类型和成因机制,评价泥石流易发性及危害程度的基础上,利用统计分析方法确立暴雨强度指标;然后采用力学计算和极限平衡分析理论,构建强降雨作用下冲沟水动力学冲蚀启动模型,确定临界径流深度;再构建降雨—泥水位—流量相结合的递进式分层次综合预警体系;最后于2012年10月在杨家泥石流冲沟开展单沟泥石流远程自动化监测网络体系建设,实施远程监测控制和预警。研究表明:杨家泥石流冲沟呈小流域封闭状,汇水区、形成—流通区和堆积区分区特征明显,杨家泥石流是由特大暴雨激发的、低频的、一次性爆发规模为小型的稀性水石流,为中易发泥石流;冲沟形成区松散物源地表径流深度超过1.0 m时,处于临失稳状态,松散物质易被冲刷侵蚀,可将此临界径流深度作为是否冲蚀启动泥石流的有效判据,并结合暴雨强度指标(R<2.8)和泥石流洪峰流量(Q_(d)=31.83 m^(3)/s)确定泥石流综合预警指标;监测期间(2012-10-26—2022-10-10)研究区最大降雨发生于2019-06-19,经计算R=2.4<2.8,冲沟区处于安全雨情,沟道泥水位未达到地表径流的警戒限值,不具备泥石流形成启动的水动力条件,沟内流量(最大值为1.70 m^(3)/s)正常,未达到洪峰流量,未有泥石流发生或沟道堵塞等不良现象,此期间冲沟区较为稳定,再次发生泥石流的可能性小。建立以水动力学冲蚀启动特征参数为主的综合监测网络体系,可作为低频性沟谷型泥石流系统防灾控制的技术方法。
The Yangjia gulley debris in Zhejiang Province is a typical low frequency gully debris flow formed by water erosion.Based on the background of geological environment,the subarea characteristics,types and formation mechanism of debris flow are analyzed,and the susceptibility and hazard of debris flow are also evaluated.Then the rainstorm intensity index is established by statistical analysis method.In addition,through mechanical calculation and limit equilibrium analysis theory,the hydrodynamic erosion initiation model is established to determine the critical runoff depth under rain condition.Based on these studies,the progressive hierarchical comprehensive early warning system is constituted by combining rainfall,mud water level and flow index.Finally the remote automatic monitoring network system of debris flow is built up from October,2012 for monitoring control and early warning.The results show that the Yangjia gully is a small enclosed watershed with distinct zoning characteristics of catchment area,formation circulation area and accumulation area.The debris flow is a low frequency,small scale and diluted water stone flow triggered by extremely heavy rainstorm.The susceptibility of debris flow is moderate,and it will harm the village area at the downstream of the gully,and the degree of harm is relatively high.When the surface runoff depth of loose material sources in the gully formation area exceeds 1.0 m,these loose materials are in a critical unstable state and easy to be eroded.This critical runoff depth can be used as an effective criterion to determine whether the debris flow is started by erosion,and the comprehensive early warning index of debris flow can be determined by combining the R value of rainstorm intensity and flood peak flow Q d of 31.83 m^(3)/s.Through remote automatic monitoring,the R value(2.4)is less than 2.8 during the monitoring period(2012-10-26—2022-10-10),the gully area is in a safe rain situation,and the gully mud level does not reach the warning limit of surface runoff,so ther
作者
徐兴华
肖双粟
冯杭建
吕庆
Xu Xinghua;Xiao Shuangsu;Feng Hangjian;LüQing(Institute of Geology and Mineral Resources,Zhejiang Institute of Geosciences,Hangzhou 310007,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)
出处
《吉林大学学报（地球科学版）》
CAS
CSCD
北大核心
2024年第3期919-932,共14页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(42277132,42230702)
浙江省基础公益研究计划项目(LGF21D020001,LTGG23D020001)
浙江省重点研发计划项目(2021C03159)
浙江省自然资源厅科技项目(2021-77)
浙江省地质矿产研究所科技创新基金(ZD2020KJ05)
2020年中央自然灾害防治体系建设资金项目(2020-04)。
关键词
低频性
沟谷型泥石流
水力冲蚀
临界径流深度
远程监测
综合预警
low frequency
gully debris flow
hydraulic erosion
critical runoff depth
remote monitoring
comprehensive early warning
