摘要
河道岸坡在地震和降雨作用下易发生崩滑,从而堵塞河道形成堰塞坝进而引发溃决洪水形成灾害链。为了清晰认识灾害链的演化过程及运动特征,以大岩山崩塌-堰塞坝-溃决洪水灾害链为研究对象,对其进行了全过程数值模拟。通过无人机航测获取了大岩山崩塌周围至下游10 km^(2)的地形数据,利用EDEM离散元数值模拟软件建立大岩山崩塌模型,反演崩塌堆积形成堰塞坝的过程;采用DB-IWHR模拟计算堰塞坝溃坝过程的流量过程线;以流量过程线作为洪水演进的上游边界条件,结合Flo-2D模拟溃决洪水的演进过程。模拟结果表明:大岩山崩塌堆积过程持续33 s,颗粒的最大崩落速度达到46.5 m/s,模拟结果的堆积范围与实际堆积范围吻合度较高;堰塞坝溃坝约1 h后流量达到最大值725 m^(3)/s;溃坝后洪水最大淹没深度为14.37 m,在溃口至下游1.5 km处的淹没深度几乎都在3 m以上,其下游淹没深度逐渐降低。河道岸坡崩滑形成灾害链的演化分析可为防灾减灾和应急救险提供理论依据。
The river bank slope is prone to slip under earthquakes and rainfall.In this way,river channels are blocked to form barriers and dams,leading to outburst floods and disaster chains.In order to recognize the evolution process and movement characteristics of the disaster chain,the whole process numerical simulation was carried out on the disaster chain of Dayanshan rockfall-barrier dam-outburst flood that was taken as the research object.The topographic data from the area around the rockfall of the Dayanshan to 10 km^(2) downstream were obtained by UAV aerial survey.EDEM(a simulation software that uses the Discrete Element Method)established the rockfall model of Dayanshan to obtain the inversion process of rockfall and accumulation forming a barrier dam.DB-IWHR was used to simulate the flow hydrograph of the barrier dam-breaking process.The flow hydrograph was taken as the upstream boundary condition of flood evolution and the evolution process of outburst flood was simulated with Flo-2D.The simulation results show that the collapse and accumulation process of Dayanshan lasts for 33 seconds.The maximum collapse velocity of particles reaches 46.5 m/s.The accumulation range of simulation results agrees with the actual accumulation range.The maximum discharge reaches 725 m^(3)/s about one hour after the break of the barrier dam.The maximum flood depth after the dam break is 14.36 m.Almost all the submerged depths from the collapse to 1.5 km downstream are more than 3 m.The downstream submerged depth gradually decreases.The evolution analysis of the disaster chain formed by the river bank slide can provide a theoretical basis for disaster prevention and reduction and emergency rescue.
作者
刘潇
吴彩燕
魏琪豪
王苗
LIU Xiao;WU Caiyan;WEI Qihao;WANG Miao(School of Environment and Resource,Southwest University of Science and Technology,Mianyang 621010,Sichuan,China;Tianfu Institute of Research and Innovation,Southwest University of Science and Technology,Chengdu 610299,Sichuan,China;Mianyang S&T City Division,the National Remote Sensing Center of China,Mianyang 621010,Sichuan,China)
出处
《西南科技大学学报》
CAS
2024年第2期54-61,共8页
Journal of Southwest University of Science and Technology
基金
四川省科技厅项目(2020YFS0389)
重大危险源测控四川省重点实验室开放课题(KFKT-2023-01)。
关键词
崩塌
堰塞坝
洪灾
灾害链
数值模拟
Rockfall
Barrier dam
Outburst flood
Disaster chain
Numerical simulation
