摘要
三峡库区岸坡表层岩体的风化特性及其稳定性受温度和湿度等气候环境显著影响。为了研究温湿循环作用对三峡库区岸坡粉砂质泥岩的劣化效应,将其加工后的标准岩石试样进行不同循环次数的温湿循环作用,然后测试其单轴压缩力学性能,分析其应力-应变曲线、强度、变形、破裂特征及能量特征。结果表明,随着粉砂质泥岩试样受温湿循环作用的次数从0增加到5,其单轴抗压强度、弹性模量、变形模量、总能量、可释放弹性能及其占比均与温湿循环作用次数呈近似的线性负相关关系,降幅分别达到49.21%、53.11%、57.78%、42.29%、58.7%和32.45%;而消耗能及其占比与温湿循环作用次数近似呈正相关关系,增幅分别达到80.86%和215.27%。细观上,温湿循环作用使粉砂质泥岩颗粒间的黏结力降低,从而使其颗粒间发生破坏时的强度减小、脆性增加、黏性降低,其变化幅度与温湿循环次数呈正相关关系;同时,颗粒间黏结力降低幅度在岩体内不是均匀分布的,而是由表及里呈一定的梯度变化,越靠近表面,其降低幅度越大。从而使得岩石试样在单轴压缩变形破坏过程中易于产生横向膨胀的张拉型翼裂纹或斜向的张拉-剪切混合型翼裂纹,岩块破碎,宏观上表现出脆性降低,塑性增加的劣化特征。
The mechanical properties and stability of shallow rock mass in Three Gorges Reservoir area are significantly affected by climate and environment conditions.This paper examine the deterioration effect of cyclic temperature and humidity climatic environment due to diurnal variation on the weathering damage and mechanical properties of silty mudstone.The standard rock samples processed from silty mudstone are subjected to different numbers of high-low temperature and humidity cycles.Then the mechanical properties under uniaxial compression are tested to analyze the stress-strain curve,strength,deformation,fracture properties and energy characteristics.The results show that,with the number of temperature and humidity cycles increasing from 0 to 5,the uniaxial compression strength,elastic modulus,deformation modulus,total energy,elastic energy and its proportion of silty mudstone are linearly and negatively correlated with the number of temperature and humidity cycles.The values are decline by 49.21%,53.11%,57.78%,42.29%,58.7%and 32.45%,respectively.The dissipated energy and its proportion are positively correlated with the cyclic number,and their growths are 80.86%and 215.27%,respectively.On the mesoscopic scale,the bonding force between silty mudstone particles after cyclic temperature and humidity treatments is weakened,leading to the decrease of strength,the increase of brittleness and the reduction of viscosity between particles.The amplitude of variation is positively correlated with the number of temperature and humidity cycles.Meanwhile,the reduction amplitude of bonding force between particles is not uniformly distributed in the rock mass,but shows a certain gradient variation from surface to interior,and the closer to the surface,the greater the reduction amplitude.These changes make it is easier to produce tensile airfoil cracks or oblique tensile-shear mixed airfoil cracks due to transverse expansion of silty mudstone specimen under uniaxial compression.The specimen is even more incomplete.On the macrosco
作者
叶四桥
梁炳新
曾彬
龙小爽
彭飞
YE Siqiao;LIANG Bingxin;ZENG Bin;LONG Xiaoshuang;PENG Fei(School of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Key Laboratory of Geological Hazards Mitigation for Mountainous Highway and Waterway,Chongqing Municipal Education Commission,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《工程地质学报》
CSCD
北大核心
2021年第3期593-601,共9页
Journal of Engineering Geology
基金
中国博士后科学基金项目(资助号:2019M653343)
重庆市博士后科学基金项目(资助号:cstc2019jcyj-bshX0125).
关键词
温湿循环作用
粉砂质泥岩
单轴压缩
力学特性
能量演化
Cyclic temperature and humidity treatment
Silty mudstone
Uniaxial compression
Mechanical property
Energy evolution
