摘要
为了揭示发育薄弱区对管涌发展的影响机制,进行了管涌砂槽模型试验和颗粒流数值模拟,建立了3组模型,以研究孔隙通道的空间发育对颗粒运移过程的影响,分析了土体内部细颗粒运移引起管涌破坏的动态过程。根据数值模拟结果,分析了管涌发展过程中试样细观及流体的变化规律,并与砂槽模型试验结果进行了比较,模拟与模型试验结果较吻合。结果表明,薄弱区越发育,压力分布调整的趋势越强,颗粒运移的趋势相应增加,达到破坏需要的时间越短。数值模拟获得的临界水力梯度与室内试验以及理论分析结果均比较接近,证明了采用颗粒流程序研究管涌问题是合理的,对研究存在薄弱区的砂土管涌现象具有明显的优势和广阔的应用前景。所揭示的结果有益于管涌机制的更深入研究。
In order to show the mechanism of piping development considering development of weak zone, three models are built by means of flume model tests and PFC3D software to study the influence of the extended pore channels on particle migration process. The dynamic process of piping caused by the transportation of fine particles in the soil is studied by sand launder model test of piping and numerical simulation of PFC. Based on the results of the numerical simulation, the rules of the sample＇s meso-movement and the liquid＇s movement are studied and are compared with the results of sand launder model test. The simulation results agree well with the model test results. The result indicates that the larger the size of weak region, the greater the pressure change, the more loss of particles, the shorter the time to failure is. The result indicates that the critical hydraulic gradient derived by numerical simulation is nearly equal to that derived by sand launder model test and theoretical analysis. Therefore, researching the piping by PFC is reasonable, there are great practical significance and broad application prospects for the study of piping development considering development of weak zone. The results are valuable to further probing into the piping mechanism in sandy soils.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2014年第12期3627-3635,共9页
Rock and Soil Mechanics
基金
中央高校基本科研业务费专项资金资助(No.2014B04914)
国家自然科学基金项目(No.51309086)
教育部博士点新教师基金(No.20110094120002)
中央高校专项科研基金(No.2011B07214)
关键词
离散元法
细观模型试验
管涌机制
发育薄弱区
薄弱区
discrete element method
mesomechanical model test
piping mechanism
development of weak zone
weak area
