(1. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China;2. PowerChina Chengdu Engineering Corporation Limited,Chengdu,Sichuan 610072,China;
3. Sinohydro Bureau 7 Co.,Ltd.,Chengdu,Sichuan 610213,China;4. School of Civil Engineering,
Southwest Jiaotong University,Chengdu,Sichuan 610031,China)
Abstract:It is an effective method for soft and fractured rock mass to obtain the deformation parameters of surrounding rock by in-situ conventional bearing plate tests. However,it is be restricted by the site condition and the results is significantly size effective due to the structural surrounding rock mass. Relying on the diversion tunnel of a hydropower station in Liangshan Prefecture,conventional bearing plate test was modified,which can be performed with multisize bearing plates flexibly and efficiently during construction of tunnel,to reasonably determine the deformation characteristics and parameters of lamellar and fractured slate. The results show that:(1) the dark black and extremely thin carbonaceous slate was poor integrity,the stability of surrounding rock was very poor in addition with groundwater softening;due to the compaction of stratification plane,weakly water softening and relatively strong block,the gray sandy slate was better stability. (2) the rock mass was significantly anisotropic on account of the extremely fractured macro-meso structural plane,which also resulted in the significantly size effective of tested deformation parameters by conventional bearing plate tests. The secant and envelope modulus, and ,decreased with the increasing of diameter of bearing plate D. (3) in order to diminish the size effect of bearing plate,it is suggested to perform tests with multi-sized bearing plates on the same position for the modified in-situ small tonnage and efficient bearing plate test. Then exponential function can be used to fit the measured deformation modulus and further determined the more reasonable deformation parameters of surrounding rock mass. Based on it,the proposed deformation modulus of carbonaceous slate and sandy slate of the diversion tunnel were = 42.9 MPa, = 60.8 MPa and = 238.3 MPa, = 691.3 MPa,respectively. This study provides an efficient method for weak and fractured surrounding rock mass to rapidly determine the deformation parameters, and provides a reference for the similar excavating tunnel in the future.
XIE H,PEI J,ZUO J,et al. Investigation of mechanical properties of fractured marbles by uniaxial compression tests[J]. Journal of Rock Mechanics and Geotechnical Engineering,2011,3(4):302-313.
[2]
WU A,WANG J,ZHOU Z,et al. Engineering rock mechanics practices in the underground powerhouse at Jinping I hydropower station[J]. Journal of Rock Mechanics and Geotechnical Engineering,2016,8(5):640-650.
[3]
ZHONG Z,DENG R,LV L,et al. Fracture mechanism of naturally cracked rock around an inverted U-shaped opening in a biaxial compression test[J]. International Journal of Rock Mechanics and Mining Sciences,2018,103:242-253.
[4]
ZHOU X P,WANG F H,QIAN Q H,et al. Zonal fracturing mechanism in deep crack-weakened rock masses[J]. Theoretical and Applied Fracture Mechanics,2008,50(1):57-65.
[5]
ZHOU X P,XIA E M,YANG H Q,et al. Different crack sizes analyzed for surrounding rock mass around underground caverns in Jinping I hydropower station[J]. Theoretical and Applied Fracture Mechanics,2012,57(1):19-30.
[6]
李祥俊,穆万鹏,刘忠富,等. 坝基断层岩体原位直剪与变形试验研究[J]. 东北水利水电,2016,34(8):53-55.(LI Xiangjun,MU Wanpeng,LIU Zhongfu,et al. Test study of deformation and direct shear in situ for fault rock of dam foundation[J]. Water Resources and Hydropower of Northeast China,2016,34(8):53-55.(in Chinese))
[7]
冯树荣,蒋中明,钟辉亚,等. 向家坝水电站左岸坝基挤压破碎带变形特性试验研究[J]. 岩土力学,2015,36(增2):539-544.(FENG Shurong,JIANG Zhongming,ZHONG Huiya,et al. Experiment study of deformation characteristics of broken rock mass under dam foundation at left bank of Xiangjiaba hydropower project[J]. Rock and Soil Mechanics,2015,36(Supp.2):539-544.(in Chinese))
[8]
王明明,刘俊伟,汪大洋,等. 断层岩岩体承载力和变形特性研究[J]. 科学技术与工程,2020,20(23):9 546-9 550.(WANG Mingming,LIU Junwei,WANG Dayang,et al. Study on bearing capacity and deformation characteristics of fault rock mass[J]. Science Technology and Engineering,2020,20(23):9 546-9 550.(in Chinese))
[9]
冯文凯,易小宇,葛 华,等. 大光包滑坡滑带碎裂岩体原位钻孔剪切试验研究[J]. 岩土工程学报,2017,39(9):1 718-1 723.(FENG Wenkai,YI Xiaoyu,GE Hua,et al. In-situ borehole shear tests on cataclastic rock mass of Daguangbao landslide[J]. Chinese Journal of Geotechnical Engineering,2017,39(9):1 718-1 723.(in Chinese))
[10]
周洪福,聂德新,陈津民. 深部破碎岩体变形模量的一种新型试验方法及工程应用[J]. 吉林大学学报:地球科学版,2010,40(6):1 390-1 394.(ZHOU Hongfu,NIE Dexin,CHEN Jinmin. A New Experimentation Method and An Example of Deformation Modulus for Deep Cracked Rock Mass[J]. Journal of Jilin University:Earth Science,2010,40(6):1 390-1 394.(in Chinese))
[11]
张强勇,王建洪,费大军,等. 大岗山水电站坝区岩体的刚性承压板试验研究[J]. 岩石力学与工程学报,2008,27(7):1 417-1 422. (ZHANG Qiangyong,WANG Jianhong,FEI Dajun,et al. Testing study of rigid pressure-bearing plate of dam zone rock mass in Dagangshan hydropower station[J]. Chinese Journal of Rock Mechanics and Engineering,2008,27(7):1 417-1 422.(in Chinese))
[12]
李 金,杜建彬,张宜虎,等. 某核电工程地基岩体变形参数取值方法研究[J]. 岩石力学与工程学报,2019,38(增1):2 988-2 996. (LI Jin,DU Jianbin,ZHANG Yihu,et al. Study on the method for determining deformation parameters of foundation rock mass in a nuclear power project[J]. Chinese Journal of Rock Mechanics and Engineering,2019,38(Supp.1):2 988-2 996.(in Chinese))
[13]
凡远行,谢红强,卓 莉,等. 基于现场承压板试验的岩体变形参数及修正方法[J]. 四川大学学报:工程科学版,2015,47(增2):61-66.(FAN Yuanxing,XIE Hongqiang,ZHUO Li,et al. Deformation Parameters Based on Bearing Plate Test and Its Correction Method[J]. Journal of Sichuan University:Engineering Science,2015,47 (Supp.2):61-66.(in Chinese))
[14]
戚绍礼,魏星灿,钟志彬,等. 川西某引水隧洞工程多尺度地质环境特征分析[J]. 铁道勘察,2021,47(4):48-53.(QI Shaoli,WEI Xincan,ZHONG Zhibin,et al. Study on the multi-scale geological environment of diversion tunnel in Western Sichuan[J]. Railway Investigation and Surveying,2021,47(4):48-53.(in Chinese))
[15]
张占荣,盛 谦,杨艳霜,等. 基于现场试验的岩体变形模量尺寸效应研究[J]. 岩土力学,2010,31(9):2 875-2 881.(ZHANG Zhanrong,SHENG Qian,YANG Yanshuang,et al. Study of size effect of rock mass deformation modulus based on in-situ test[J]. Rock and Soil Mechanics,2010,31(9):2 875-2 881.(in Chinese))
[16]
喻 勇,肖国强,王法刚. 岩体变形模量的尺寸效应[J]. 岩土力学,2003,24(增1):47-49.(YU Yong,XIAO Guoqiang,WANG Fagang. Size effects on deformation modulus of rock[J]. Rock and Soil Mechanics,2003,24(Supp.1):47-49.(in Chinese))
[17]
郑文棠,徐卫亚,宁 宇,等. 节理玄武岩体变形模量的尺寸效应和各向异性[J]. 工程地质学报,2010,18(4):559-565.(ZHENG Wentang,XU Weiya,NING Yu,et al. Scale effect and anisotropy of deformation modulus of closely jointed basaltic mass[J]. Journal of Engineering Geology,2010,18(4):559-565.(in Chinese))
[18]
张占荣. 地下洞室岩体变形模量的尺寸效应研究[J]. 工程地质学报,2011,19(5):642-647.(ZHANG Zhanrong. Size effect to rock mass deformation modulus for underground house[J]. Journal of Engineering Geology,2011,19(5):642-647.(in Chinese))