摘要
利用砂槽模型试验研究单层堤基的管涌侵蚀破坏过程,并建立单层堤基管涌侵蚀破坏发展过程的概化数学模型和数值模拟方法。结合模型试验结果和数值模拟结果,分析单层堤基管涌侵蚀破坏的机理及侵蚀破坏过程。研究管涌局部破坏的临界比降及不同渗径长度对管涌侵蚀破坏的影响。计算结果表明:①模型试验和数值模拟结果较好地揭示单层堤基管涌侵蚀破坏过程,即当上游水头低于临界水头时,管涌存在发生、发展和停止的过程。当上游水头大于临界水头时,管涌将持续发展并最终导致溃堤破坏,计算结果和试验结果吻合较好;②得到砂样内部的渗流场分布和一些难以观测到的数据,较好地解释模型试验的一些现象,提高对管涌溃堤机理和过程的认识;③单层堤基管涌破坏的临界水头和临界水平平均比降与砂层局部破坏的临界水平比降近似呈线性关系;④单层堤基管涌破坏的临界水平平均比降随着渗径长度的增大而增大,并且大体上呈线性关系。
Taking advantage of flume model test, the piping erosion process in single-stratum dike foundationss is investigated, and generalized mathematical model and numerical simulation method were established. In accordance with the model test and numerical simulation results, the mechanism and process of piping erosion in single-stratum dike foundations were analyzed. Using numerical simulation, the critical gradient in local erosion due to piping and the influence of seepage path length on piping erosion were studied. The results can be summarized as follows：① Model test and numerical simulation can both reveal the erosion process in single-stratum dike foundations; when hydraulic head is lower than the critical value, piping experiences the process of occurring, developing and ceasing, otherwise, erosion would extend until dike failure; ② Seepage distribution inside the sand specimen, difficult to monitor in model test, is obtained by numerical simulation; ③ The critical hydraulic head and average horizontal gradient approximately assume a linear relationship with the critical horizontal gradient of the local erosion in sand layers; ④The average critical horizontal gradient increases linearly as the seepage path length increases.
出处
《土木工程学报》
EI
CSCD
北大核心
2012年第8期140-147,共8页
China Civil Engineering Journal
基金
国家国际科技合作计划(2010DFA74520)
国家"十一五"科技支撑项目(2008BAB42B05
2008BAB42B06)
关键词
单层堤基
管涌
模型试验
临界比降
动态发展
数值模拟
single-stratum dike foundation
piping
model test
critical gradient
dynamic development
numerical simulation
