摘要
锦屏二级水电站处于高地应力区域,引水隧洞开挖后岩体变形和稳定问题十分突出。从辅助洞取样制备含节理试件,采用MTS815.03岩石三轴试验机,开展了含天然节理大理岩试件的常规三轴压缩试验。试验中,节理面与最大主应力夹角θ为29.3°～56.0°,围压为5～40 MPa。通过试验结果分析,主要得到如下结论:(1)试件共有两类破坏形式:穿切节理面破坏和沿节理面滑移。试件破坏形式主要取决于节理面与最大主应力夹角大小。在试验围压范围内,围压高低对试件破坏形式没有影响。(2)试件变形特征取决于节理面与最大主应力夹角的大小,并受围压高低影响。(3)试件轴向变形曲线均具有较好的线性段,但其轴向等效弹性模量均显著低于完整岩石弹性模量。(4)试件强度首先取决于θ的大小,θ>40.0°的试件破坏强度与完整岩石相当;θ<40.0°的试件破坏强度较完整岩石有显著降低,不同节理强度差异是导致不同试件破坏强度差异的主要原因。
Jinping II Hydropower Station is a large-scale national key project located in a high geostress area. Thus, it is significant to study the deformation and strength properties of jointed rock mass in this area. Marble specimens containing natural joints were prepared from rock mass of the auxiliary tunnels. A series of compression tests on the jointed specimens were carried out by a MTS 815.03 triaxial testing machine for rock mechanics. In the tests, the angle 8 between the joint plane and the major principal stress ranged from 29.3° to 56.0°; the confining pressure ranged from 5 to 40 MPa. The results show that： （1） failure modes of the specimens can be classified into two types, one is shearing-failure across the joint plane and the other is sliding-failure along the joint plane： the failure mode mainly depends on the angle θ, which is not affected by the magnitude of confining pressure; （2） deformation behavior of the specimens mainly depends on the angle Oand is affected by magnitude of confining pressure; （3） it is evident that all the axial equivalent deformation modulus are less than the Young＇s modulus of intact rock; and （4） failure strength of the shear-failure specimens is equal to that of intact rock; tallure strength of the sliding-failure specimens is significantly decreased compared with that of intact rock, the discrepancy is mainly affected by strength difference of the joints contained.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2008年第10期2118-2123,共6页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金委员会、二滩水电开发有限公司雅砻江水电开发联合研究基金项目(50579088,50639090)
关键词
岩石力学
大理岩试件
天然节理
破坏形式
变形特性
rock mechanics
marble specimens： natural joints
failure modes
deformation behavior
