(1. College of Pipeline and Civil Engineering，China University of Petroleum，Qingdao，Shandong 266580，China；2. Geotechnical Research Institute，Hohai University，Nanjing，Jiangsu 210098，China；3. Hunan Provincial Key Laboratory of Hydropower Development Key Technology，Mid-south Design and Research Institute，Changsha，Hunan 410014，China)
Abstract：The mechanical properties of clastic rock of dam foundation in a hydropower station in virtue of conventional physical and deformation analysis are very complex. Triaxial rheological tests were therefore conducted using the automatic triaxial servo-instrument to investigate the rheological properties and permeability of such rock under hydro-mechanical coupling. The axial，lateral and volumetric deformation curves versus time were measured and the rheological deformation properties and rheological rate law were discussed accordingly. The evolution process of permeability during rheological period was analyzed in detail. The scanning electron microscope(SEM) experiments were performed for the rock specimens after failure to study the mechanism and mode of macro-micro failure. The results show that the clastic rock has a pronounced rheological behavior. The rheological curves have a transient period initially，a steady period thereafter and an accelerated period finally at the last loading step. The rheological deformation were increased when the stress and seepage pressure applied were increased and were reduced if the confining pressure was increased. The finally failed specimen have the characteristics of large axial compression deformation，obvious ductile volumetric dilation and large steady rheological rate. The relationship between the rheological rate and the applied stress can be described by an exponential function. The coefficients of permeability fluctuate during the rheological process possibly because of the heterogeneity of specimens，but overall decrease. During the stage of steady period，the coefficients of permeability decrease linearly. It is shown that the fluctuation has no significant effect on the permeability evolution. Furthermore，the permeability coefficients decrease as the confining pressures increase.
[1] XU D R，GU X X，LI P C，et al. Meso-proterozoic-neoproterozoic transition：Geochemistry，provenance and tectonic setting of clastic sedimentary rocks on the SE margin of the Yangtze Block，South China[J]. Journal of Asian Earth Sciences，2007，29(5/6)：637–650.
[2] 蒋凌志，顾家裕，郭彬程. 中国含油气盆地碎屑岩低渗透储层的特征及形成机制[J]. 沉积学报，2004，22(1)：13–18.(JIANG Lingzhi，GU Jiayu，GUO Bincheng. Characteristics and mechanism of low permeability clastic reservoir in Chinese petroliferous basin[J]. Acta Sedimentologica Sinica，2004，22(1)：13–18.(in Chinese))
[3] 何满潮，景海河，孙晓明. 软岩工程力学[M]. 北京：科学出版社，2002：1–15.(HE Manchao，JING Haihe，SUN Xiaoming. Engineering mechanics of soft rock[M]. Beijing：Science Press，2002：1–15. (in Chinese))
[4] AGUST G，TRINE H S，BELINDA L，et al. Effects of internal structure and local stresses on fracture propagation，deflection，and arrest in fault zones[J]. Journal of Structural Geology，2010，32(11)：1 643–1 655.
[5] 孙 钧. 岩土材料流变及其工程应用[M]. 北京：中国建筑工业出版社，1999：387–400.(SUN Jun. The rheology and engineering application of the geotechnical material[M]. Beijing：China Architecture and Building Press，1999：387–400.(in Chinese))
[6] 王思敬. 论岩石的地质本质性及其岩石力学演绎[J]. 岩石力学与工程学报，2009，28(3)：433–450.(WANG Sijing. Geological nature of rock and its deduction for rock mechanics[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(3)：433–450.(in Chinese))
[7] 徐志英. 岩石力学[M]. 北京：中国水利水电出版社，1991：69–92. (XU Zhiying. Rock mechanics[M]. Beijing：China Water Power Press，1991：69–92.(in Chinese))
[8] 孙 钧. 岩石流变力学及工程应用研究的若干进展[J]. 岩石力学与工程学报，2007，26(6)：1 081–1 106.(SUN Jun. Rock rheological mechanics and its advance in engineering applications[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(6)：1 081– 1 106.(in Chinese))
[9] ZHANG Y，XU W Y，GU J J，et al. Triaxial creep tests of weak sandstone from the deflection zone of high dam foundation[J]. Journal of Central South University of Technology，2013，20：2 528–2 536.
[10] ZHANG Z L，XU W Y，WANG W. Triaxial creep tests of rock from the compressive zone of dam foundation in Xiangjiaba hydropower station[J]. International Journal of Rock Mechanics and Mining Sciences，2012，50(1)：133–139.
[11] LI Y S，XIA C C. Time-dependent tests on intact rocks in uniaxial compression[J]. International Journal of Rock Mechanics and Mining Sciences，2000，37(3)：467–475.
[12] 蒋昱州，徐卫亚，王瑞红. 角闪斜长片麻岩流变力学特性研究[J]. 岩土力学，2011，32(增1)：339–345.(JIANG Yizhou，XU Weiya，WANG Ruihong. Investigation on rheological mechanical properties of hornblende plagioclase gneiss[J]. Rock and Soil Mechanics，2011，32(Supp.1)：339–345.(in Chinese))
[13] 王如宾，徐卫亚，王 伟，等. 坝基硬岩流变特性试验及其流变全过程中的渗流规律[J]. 岩石力学与工程学报，2010，29(5)：960–969.(WANG Rubin，XU Weiya，WANG Wei，et al. Experimental investigation on creep behaviors of hard rock in dam foundation and its seepage laws during complete process of rock creep[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(5)：960–969. (in Chinese))
[14] 李小春，王 颖，魏 宁. 变容压力脉冲渗透系数测量方法研究[J]. 岩石力学与工程学报，2008，27(12)：2 482–2 487.(LI Xiaochun，WANG Ying，WEI Ning. Research on measuring method of permeability by using storage variable transient pulse method[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(12)：2 482–2 487.(in Chinese))
[15] SOULEY M，HOMAND F，PEPA S，et al. Damage-induce permeability change in granite：a case study at the URL in canada[J]. International Journal of Rock Mechanics and Mining Sciences，2001，38(2)：297–310.
[16] TANG C A，THAM L G，LEE P K K，et al. Coupled analysis of flow，stress and damage(FSD) in rock failure[J]. International Journal of Rock Mechanics and Mining Sciences，2002，39(4)：477–489.
[17] 朱珍德，张爱军，徐卫亚. 脆性岩石全应力–应变过程渗流特性试验研究[J]. 岩土力学，2002，23(5)：555–563.(ZHU Zhende，ZHANG Aijun，XU Weiya. Experimental research on complete stress-strain process seepage characteristics of brittle rock[J]. Rock and Soil Mechanics，2002，23(5)：555–563.(in Chinese))
[18] 阎 岩，王恩志，王思敬，等. 岩石渗流–流变耦合的试验研究[J]. 岩土力学，2010，31(7)：2 095–2 103.(YAN Yan，WANG Enzhi，WANG Sijing，et al. Study of seepage-rheology coupling experiment of rocks[J]. Rock and Soil Mechanics，2010，31(7)：2 095–2 103.(in Chinese))
[19] 黄书岭，冯夏庭，周 辉，等. 水压和应力耦合下脆性岩石流变与破坏时效机制研究[J]. 岩土力学，2010，31(11)：3 441–3 446. (HUANG Shuling，FENG Xiating，ZHOU Hui，et al. Study of aging failure mechanics and triaxial compression creep experiments with water pressure coupled stress of brittle rock[J]. Rock and Soil Mechanics，2010，31(11)：3 441–3 446.(in Chinese))
[20] 张 玉，赵海斌，徐卫亚，等. 某水电站坝基挠曲破碎带工程力学特性试验研究[J]. 岩土力学，2013，34(12)：3 437–3 445.(ZHANG Yu，ZHAO Haibin，XU Weiya，et al. Experimental investigations on engineering mechanical properties of sandstone in the deflection fractured zone in dam foundation of a hydropower station[J]. Rock and Soil Mechanics，2013，34(12)：3 437–3 445.(in Chinese))
[21] 张 玉，徐卫亚，赵海斌，等. 碎屑砂岩三轴压缩下强度和变形特性试验研究[J]. 岩土力学，2014，35(3)：666–674. (ZHANG Yu，XU Weiya，ZHAO Haibin，et al. Experimental investigation on strength and deformation properties of clastic sandstone under triaxial compression[J]. Rock and Soil Mechanics，2014，35(3)：666–674.(in Chinese))
[22] YANG C H，DAEMEN J J K，YIN J H . Experimental investigation of creep behavior of salt rock[J]. International Journal of Rock Mechanics and Mining Sciences，1999，36(2)：233–242.
[23] FABRE G，PELLET F. Creep and time-dependent damage in argillaceous rocks[J]. International Journal of Rock Mechanics and Mining Sciences，2006，43(6)：950–960.
[24] MA L，DAEMEN J J K. An experimental study on creep of welded tuff[J]. International Journal of Rock Mechanics and Mining Sciences，2006，43(2)：282–291.
2014, Vol. 33 
