裂隙单元修正等效渗透率模型及其验证  

A MODIFIED EQUIVALENT PERMEABILITY MODEL OF FRACTURE ELEMENT AND ITS VERIFICATION

作　　者：王臻[1,2] RUTQVIST Jonny 左建平[2,3] 戴瑛[1] 

机构地区：[1]同济大学航空航天与力学学院,上海200092 [2]劳伦斯伯克利国家实验室地球科学部,美国伯克利ca94720 [3]中国矿业大学煤炭资源与安全开采国家重点实验室,北京100083

出　　处：《岩石力学与工程学报》2013年第4期728-733,共6页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2010CB732002;2011CB013800);北京市科技新星计划项目(2010B062)

摘　　要：采用裂隙单元表征裂隙网络,引入裂隙单元等效渗透率的概念,按照流量等效的原则计算其大小,然而阶梯状裂隙单元造成渗流流程的增加,同时压差不变导致流量的减少,为解决这一问题,用裂隙在网格中的实际流程长度与裂隙迹长之比来修正裂隙单元等效渗透率,并且针对复杂裂隙网络,对其进行预处理——删除孤立裂隙、死端裂隙、孤立裂隙簇等非连通裂隙。用此修正模型对单裂隙、相交裂隙、复杂裂隙网络进行渗流数值模拟,并与理论解及离散裂隙网络模型方法渗流结果进行比较,结果显示:研究区域下游出口总流量及出口处流量分布均取得较好一致性;同时,此裂隙单元修正等效渗透率模型也能反映出裂隙岩体渗流的非均质和各向异性。A conceptual model of fracture element is presented that characterizes the discrete fracture network with fracture elements.We calculate the equivalent permeability of fracture element based on the principle of equivalence of flux between a single fracture and a square element.But the＂stair-case＂fracture elements increase the length of flow path,and result in a decrease of flux with an unaltered hydraulic pressure difference.To solve this problem,we modify the fracture elementary permeability through considering the ratio of length of flow path to fracture length;and for the complex fracture network,the isolated fractures,dead-end parts of fractures and the isolated fracture clusters are deleted to build up a connected fracture configuration.To verify the modified equivalent permeability model we perform fluid flow simulations on a series of single fracture,intersecting fractures and complex fracture network.The calculated total flow rate and flux distribution along the downstream outlet are consistent with the analytical results and discrete fracture network model results.The modified equivalent permeability model can also characterize the heterogeneity and anisotropy of fluid flow in fractured rock mass.

关 键 词：岩石力学 裂隙单元等效渗透率 等效多孔介质模型 离散裂隙网络模型 裂隙岩体 

分 类 号：TU45[建筑科学—岩土工程]