有自由面的裂隙网络稳定渗流试验与数值分析  

Experimental and numerical analysis of steady seepage in fractured network with free surface

作　　者：张旭 盛建龙[1,2] 叶祖洋 周新[1,2] ZHANG Xu;SHENG Jian-long;YE Zu-yang;ZHOU Xin(College of Resources and Environmental Engineering,Wuhan University of Science and Technology,Wuhan,Hubei 430081,China;Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources,Wuhan,Hubei 430081,China)

机构地区：[1]武汉科技大学资源与环境工程学院,湖北武汉430081 [2]冶金矿产资源高效利用与造块湖北省重点实验室,湖北武汉430081

出　　处：《岩土力学》2024年第3期878-884,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.42077243,No.42072300)。

摘　　要：为探究裂隙网络含自由面的稳定渗流特性,设计可视化的二维裂隙网络渗流试验装置,通过调节裂隙网络模型的上、下游水头开展一系列裂隙网络渗流试验,依次记录自由面水头高度和渗流流量大小;同时基于有限元软件COMSOL Multiphysics中的Darcy接口,建立等比例二维裂隙网络数值模型,复现试验工况并与试验结果对比分析。对比发现试验结果与模拟结果基本吻合,这验证了试验结果的有效性以及数值模拟的准确性。研究结果表明:影响自由面变化的主要因素为上、下游水头高度及二者高度差:渗流水力梯度越大,自由面位置的下降越快;渗流水力梯度相同的水力条件,上、下游水头越高,形成的自由面水头越高,自由面降落曲线也越陡。其中,若上、下游水头高度不处于近似的水平,二者对于自由面位置的影响存在较大差异。自由面变化的基本规律符合Dupuit公式的表述。稳定渗流的水力梯度与平均流量仅在流量较小时符合线性相关,随着水力梯度的增加,二者关系呈现明显的非线性。This study focuses on investigating the steady seepage characteristics of fracture network with free surface.A visual two-dimensional fracture network seepage test device was designed to conduct a series of fracture network seepage tests by adjusting the upstream and downstream heads of the fracture network model,and recording the height of free surface head and seepage flow.Additionally,a two-dimensional fracture network numerical model with equal proportions was established using the Darcy interface of the finite element software COMSOL Multiphysics.The test conditions were reproduced in the numerical simulation and compared with the test results.The findings demonstrate that the test results are basically consistent with the simulation results,which verifies the effectiveness of the test results and the accuracy of the numerical simulation.The results show that the main factors affecting the change of free surface are the height of upstream and downstream heads and the height difference between them.A larger seepage hydraulic gradient leads to a faster drop in the position of the free surface.Under the same hydraulic condition of seepage hydraulic gradient,higher the upstream and downstream water heads result in higher the free surface water heads and steeper falling curve of free surface.Notably,if the upstream and downstream water head heights are not at similar levels,their influence on the position of the free surface differs greatly.The basic laws of free surface change align with Dupuit formula.The hydraulic gradient of steady seepage is linearly correlated with the average flow rate only when the flow rate is small,while with increasing hydraulic gradient,the relationship becomes noticeably nonlinear.

关 键 词：稳定渗流 裂隙网络 自由面 透水层 渗流水力梯度 水头 

分 类 号：TU458[建筑科学—岩土工程]