冻土条件下均质土堤漫顶溃决试验研究  

Experimental study on erosion process of homogeneous embankment breaching due to overtopping under frozen soil condition

作　　者：刘昉[1] 戚园春 吴敏睿 LIU Fang;QI Yuanchun;WU Minrui(State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300354,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300354

出　　处：《水利水电科技进展》2022年第6期21-27,共7页Advances in Science and Technology of Water Resources

基　　金：国家重点研发计划(2018YFC1508403)。

摘　　要：为了研究冻土条件下的溃堤机理,开展了弯道水槽概化模型试验。基于结构光的三维成像原理,提出了一种无干扰全方位的实时溃口三维参数测量方法,并结合温度传感器监测堤内温度变化,研究了冻土条件下均质土堤漫顶溃决过程中溃口形态的演变规律和溃决区域的水位、流速、流量变化特性。依据试验中溃口冲蚀特点,将溃堤过程划分为渗透过流、堤后冲蚀、横向展宽、冲淤平衡4个阶段,黏性土堤和非黏性土堤第2阶段、第3阶段分别以陡坎冲蚀和失稳坍塌为主要特征,且黏性土堤会出现明显的陡坎合并现象。试验结果还表明:冻结后土体间隙的冰晶体与土颗粒相互胶结,土体的黏聚力增大,溃口扩展速率及溃决区域的水位、流速变化率均减小,且黏性土堤受冻土深度的影响更加明显;冻土条件下堤防背水侧与堤顶的连接处薄弱易溃,应加强维护,且一旦溃堤应优先对临水侧进行封堵。A curve flume generalized model experiment was carried out to study the dike-break mechanism under frozen soil condition.Based on the three-dimensional(3-D)imaging principle of structured light,a non-interference and omnidirectional measurement method for the 3-D parameters of real-time breach was developed.Combined with the temperature sensor to monitor the temperature change inside the embankment,the evolution process of the breach and the variation characteristics of water level,velocity and flow rate in the failure area of the homogeneous embankment under frozen soil condition were studied.According to the characteristics of beach erosion,the process of embankment failure is divided into four stages,including infiltration and overflow,back-embankment scour,horizontal widening and balance of erosion and siltation.For both cohesive embankment and non-cohesive embankment,scarp scour and collapse instability are the main characteristics of the second and third stages respectively,and the phenomenon of scarp merger occurs obviously for the cohesive embankment.The test results also show that,the ice crystals in adjacent soil are cemented with the soil particles after freezing,the cohesive force of soil increases,and the expansion rate of the breach and the change rate of water level and velocity in the failure area decrease.In addition,the influence of the frozen soil depth on cohesive embankment is more obvious.The connection part between the backwater side and the top of the embankment is weak and easy to breach under frozen soil condition,so the maintenance should be strengthened,and the water side dike should be sealed first once the embankment breaks.

关 键 词：均质土堤 漫溢溃决 水槽试验 冻土条件 传感器 溃口 

分 类 号：TV143[水利工程—水力学及河流动力学]