MRT-LBM-based numerical simulation of seepage flow through fractal fracture networks  

作　　者：FAN Huo ZHENG Hong 

机构地区：[1]State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock & Soil Mechanics, Chinese Academy of Sciences [2]Institute of Mountain Hazards and Environment, Chinese Academy of Sciences [3]University of Chinese Academy of Sciences

出　　处：《Science China(Technological Sciences)》2013年第12期3115-3122,共8页中国科学（技术科学英文版）

基　　金：supported by the National Basic Research Program of China("973"Project)(Grant No.2011CB013505);the National Natural Science Funds for Distinguished Young Scholar(Grant No.50925933)

摘　　要：The study on seepage flow passing through single fractures is essential and critical for understanding of the law of seepage flow passing through fracture networks and the coupling mechanisms of seepage field and stress field in rock masses.By using the fractal interpolation to reconstruct a natural coarse fracture,as well as taking into account the microstructure of the fracture,the numerical simulation of seepage flow passing through the coarse fractures with two distinct vertical scaling factors is conducted based on the MRT-LBM model of the lattice Boltzmann method.Then,after obtaining the length of the preferential flow pathway,the permeability of the two kinds of fractures is estimated respectively.In view of difficulties in locating the preferential flow pathway of natural fracture networks,by numerical tests a transect permeability weighted algorithm for estimating the fracture network permeability is proposed.The algorithm is not specific to one or more particular preferential flow pathways,but considers the contribution of each section to hinder the fluid passing through the medium.In order to apply the new algorithm,by capturing the structure of fracture networks based on the image-processing technique,the numerical simulations of seepage flow passing through two groups of natural fracture networks is carried out,the permeability is forecasted and the partial flows are reproduced for both cases.It is found that the preferential flow pathway emerges at the beginning of evolution,then is strengthened subsequently,and finally reaches a steady status.Furthermore,by using the proposed method some details on local flow can be clearly observed such as backflows and vortices at local branches can exist simultaneously and so forth,suggesting the validness of the proposed method for multiscale simulations of seepage flow.

关 键 词：MRT-LBM fractal interpolation fracture networks seepage flow simulation microcosmic mechanism 

分 类 号：O357.3[理学—流体力学]