Effect of sample size on the fluid flow through a single fractured granitoid

作     者：Kunal Kumar Singh Devendra Narain Singh Ranjith Pathegama Gamage 

作者机构：Geohazards and Engineering Geology Division Geological Survey of India Bandlaguda Hyderabad 500068 India Geotechnical Engineering Division Department of Civil Engineering Indian Institute of Technology Bombay Powai Mumbai 400076 India Department of Civil Engineering Monash University Clayton Melbourne Vic 3800 Australia 

出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)

年 卷 期：2016年第8卷第3期

页      面：329-340页

核心收录：

学科分类：08[工学] 080104[工学-工程力学] 0815[工学-水利工程] 0801[工学-力学（可授工学、理学学位）] 

基　　金：the IITB-Monash Research Academy,Indian Institute of Technology Bombay,Mumbai,India for providing the opportunity to work on this project supported and funded by BHP Billiton Ltd.,Melbourne,Victoria,Australia the Head,Civil Engineering laboratory,Monash University for providing necessary laboratory support 

主　　题：Rock massSingle fractureFluid flowSample sizeSize effectFracture roughness 

摘      要：Most of deep geological engineered structures, such as rock caverns, nuclear waste disposal repositories, metro rail tunnels, multi-layer underground parking, are constructed within hard crystalline rocks because of their high quality and low matrix permeability. In such rocks, fluid flows mainly through fractures. Quantification of fractures along with the behavior of the fluid flow through them, at different scales, becomes quite important. Earlier studies have revealed the influence of sample size on the confining stress-permeability relationship and it has been demonstrated that permeability of the fractured rock mass decreases with an increase in sample size. However, most of the researchers have employed numerical simulations to model fluid flow through the fractureJfracture network, or laboratory investigations on intact rock samples with diameter ranging between 38 mm and 45 cm and the diameter-to-length ratio of 1：2 using different experimental methods. Also, the confining stress, 03, has been considered to be less than 30 MPa and the effect of fracture roughness has been ignored. In the present study, an extension of the previous studies on ＂laboratory simulation of flow through single fractured granite＂ was conducted, in which consistent fluid flow experiments were performed on cylindrical samples of granitoids of two different sizes （38 mm and 54 mm in diameters）, containing a ＂rough walled single fracture＂. These experiments were performed under varied confining pressure （03 - 5-40 MPa）, fluid pressure （fp ≤ 25 MPa）, and fracture roughness. The results indicate that a nonlinear relationship exists between the discharge, Q, and the effective confining pressure, σeff., and Q decreases with an increase in σeff.. Also, the effects of sample size and fracture roughness do not persist when O＇eff. ≥ 20 MPa. It is expected that such a study will be quite useful in correlating and extrapolating the laboratory scale investigations to in-situ scale and further imp