结构面对板岩力学特性影响研究

STUDY ON EFFECTS OF DISCONTINUITIES ON MECHANICAL CHARACTERS OF SLATE

运用单弱面理论研究含单组结构面的板岩岩体抗压强度随结构面方位的变化情况,建立了相应的一维、三维抗压强度的变化规律。将该规律运用到南水北调西线的板岩试验结果分析中,研究结果表明:(1)运用单弱面理论建立的强度变化规律较好地吻合了单轴、三轴试验结果,可以认为正确反映了板岩的强度变化规律;(2)当结构面倾角在51.7°左右时,板岩的抗压强度取得最小值;并以此为对称中心,倾角向大小两个方向变化时,抗压强度逐渐增大,到一定角度后将变为岩块的强度;(3)板岩的破坏形式随结构面的变化而不同,可以产生沿结构面滑移、剪切破坏及复合破坏3种类型的破坏形式;(4)围压的增大会使得板岩的破坏方式由复合破坏向剪切破坏转变,结构面的密度对岩体的强度影响不大。

Single discontinuity theory is used to analyze the change of rock mass strength with the discontinuity inclinations; and the relationship between them is set up to explain the compression results. Then the results are used to the slates from the engineering of the west route of South-to-North Water Transfer Project, and the modeling results accord with the experiment ones. Some conclusions are drawn from the analysis as follows： （1） the single discontinuity theory can explain the phenomena of uniaxial and tfiaxial compression test on the slates; and the results can be used to the engineering： （2） the compression strength gets the minimal value when the discontinuity inclination is 51.7°; then it will increase towards two sides till reaching to the intact rock mass strength; （3） the deformation forms change with the different discontinuity inclinations, and the specimen can be damaged by sliding along discontinuities, shear failure and the combination of the two modes： and （4） the failure mode changes from the combined failure to shear failure when the confining pressure increases. The increment of the discontinuities number brings little effects to the rock mass strength.