Effects of seepage pressure on the mechanical behaviors and microstructure of sandstone  

作　　者：Xuewei Liu Juxiang Chen Bin Liu Sai Wang Quansheng Liu Jin Luo 

机构地区：[1]State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China [2]Faculty of Engineering,China University of Geosciences,Wuhan,430074,China [3]Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province,School of Civil Engineering,Wuhan University,Wuhan,430072,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第6期2033-2051,共19页岩石力学与岩土工程学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.U22A20234 and 42277170);Hubei Province Key Research and Development Project(Grant No.2023BCB121).

摘　　要：Surrounding rocks of underground engineering are subjected to long-term seepage pressure,which can deteriorate the mechanical properties and cause serious disasters.In order to understand the impact of seepage pressure on the mechanical property of sandstone,uniaxial compression tests,P-wave velocity measurements,and nuclear magnetic resonance(NMR)tests were conducted on saturated sandstone samples with varied seepage pressures(i.e.0 MPa,3 MPa,4 MPa,5 MPa,6 MPa,7 MPa).The results demonstrate that the mechanical parameters(uniaxial compressive strength,peak strain,elastic modulus,and brittleness index),total energy,elastic strain energy,as well as elastic strain energy ratio,decrease with increasing seepage pressure,while the dissipation energy and dissipation energy ratio increase.Moreover,as seepage pressure increases,the micro-pores gradually transform into meso-pores and macro-pores.This increases the cumulative porosity of sandstone and decreases P-wave velocity.The numerical results indicate that as seepage pressure rises,the number of tensile cracks increases progressively,the angle range of microcracks is basically from 50-120to 80-100,and as a result,the failure mode transforms to the tensile-shear mixed failure mode.Finally,the effects of seepage pressure on mechanical properties were discussed.The results show that decrease in the effective stress and cohesion under the action of seepage pressure could lead to deterioration of strength behaviors of sandstone.

关 键 词：Rock mechanics Mechanical property Seepage pressure Numerical simulation MICROCRACKS 

分 类 号：TU45[建筑科学—岩土工程]