摘要
异性层面剪切特性及水致劣化规律是巴东组地层岩体稳定性及地质灾害致灾机制研究的基础。以巴东组3类典型异性层面(粉砂质泥岩/泥质粉砂岩、泥质粉砂岩/泥灰岩、泥灰岩/泥岩)为研究对象,首先开展了3类典型异性层面的壁岩电镜扫描试验、天然及饱水状态下的壁岩单轴压缩试验,分析了巴东组典型异性层面壁岩微观特性及壁岩宏观力学性质的水致劣化规律。在此基础上,开展了天然和饱水状态下3类典型异性层面的室内直剪试验,研究了巴东组典型异性层面剪切特性,提出了异性层面基本摩擦角的预测公式。基于上述试验结果,分析了巴东组典型异性层面的水致劣化规律。研究表明:(1)巴东组异性层面壁岩黏土矿物含量及微观结构对异性层面剪切特性的水致劣化规律具有重要影响;(2)异性层面的基本摩擦角介于两侧壁岩对应的同性结构面的基本摩擦角之间,且更接近强度较低一侧壁岩同性结构面的基本摩擦角;(3)异性层面的水致劣化系数主要受控于强度较低一侧壁岩的软化系数;(4)巴东组粉砂质泥岩/泥质粉砂岩、泥质粉砂岩/泥灰岩及泥灰岩/泥岩间异性层面的劣化系数分别为0.915、0.951和0.731。
Shear property and water-induced deterioration of discontinuities with different joint wall material(DDJM) play an important role in studies on stability of rock mass and mechanism of geological hazards in the Badong formation. Scanning electron microscope tests and uniaxial compression tests under natural and saturated conditions were firstly conducted on three typical DDJM(silty mudstone/argillaceous siltstone, argillaceous siltstone/argillaceous limestone, and argillaceous limestone/mudstone) to investigate microscopic characteristics of joint walls and water-induced deterioration of the macro mechanical property. Shear properties of these three types of DDJM under natural and saturated conditions were then studied by direct shear tests. A formula to predict the basic friction angle of DDJM was proposed. The results indicate that: 1) the water-induced deterioration of shear property of DDJM is greatly affected by the content of clay minerals and microscopic structure of their joint walls;2) the basic friction angle of DDJM falls between that of discontinuities with identical joint wall material(DIJM) same with two joint walls of DDJM, and is close to value of DIJM with joint walls same with the softer side of DDJM;3) the coefficient of water induced deterioration of DDJM is mainly controlled by softening coefficient of the softer joint wall;4) the coefficient of water-induced deterioration of these three types of DDJM(silty mudstone/argillaceous siltstone、argillaceous siltstone/argillaceous limestone、argillaceous limestone/mudstone) in the Badong formation are 0.915, 0.951 and 0.731, respectively.
作者
吴琼
王晓晗
唐辉明
刘超远
姜耀飞
徐艳君
WU Qiong;WANG Xiao-han;TANG Hui-ming;LIU Chao-yuan;JIANG Yao-fei;XU Yan-jun(Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074,China;Shenzhen Investigation & Research Institute Co.Ltd,Shenzhen,Guangdong 518026,China;Wuhan Comprehensive Transportation and Urban Construction Design Institute,First Highway Consultants Co.Ltd,China Communications Construction Company (CCCC) Wuhan.Hubei 430056,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2019年第5期1881-1889,1897,共10页
Rock and Soil Mechanics
基金
国家自然科学基金面上项目(No.41877259)
湖北省自然科学基金面上项目(No.2018CFB666)
国家重点研发计划项目(No.2017YFC1501301)~~
关键词
巴东组
异性层面
微观特征
剪切特性
水致劣化
Badong formation
discontinuities with different joint wall material(DDJM)
microscopic characteristics
shear property
water-induced deterioration
