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为模拟黑色页岩化学风化中酸性水-页岩化学作用过程,本文对其进行氧化条件下的不同pH值H2SO4溶液的非平衡流动态腐蚀性试验,获得了黑色页岩化学腐蚀前后矿物变化、相对质量损失、次生孔隙率、纵波波速变化及微观结构特征的变化。通过单轴压缩试验,获得黑色页岩在不同浸泡时段的变形和强度特性规律,探讨了酸性水对黑色页岩化学作用的化学损伤和力学劣化的腐蚀效应及机制。研究表明,页岩试件在化学腐蚀后,易溶性矿物成分减小,黏土矿物增加,同时矿物胶结变得松散,矿物边缘变得模糊;页岩试件的相对质量损失与次生孔隙率随pH值减小和浸泡时间的增长而增大,而纵波波速则减小;其力学特性有从脆性破坏向延性破坏转化的趋势,单轴抗压强度和弹性模量有随pH值减小和浸泡时间的增长而减小的趋势。基于次生孔隙率,构建化学损伤变量来描述试件化学-力学损伤演化过程。分析酸性水-页岩化学作用的机理主要为:溶解作用、氧化作用、水解作用及离子交换吸附作用。
In order to simulate the chemical water-shale chemical interaction in chemical weathering of black shale, this paper tests the non-equilibrium flow dynamic corrosiveness of H2SO4 solutions with different pH under oxidation conditions and obtains the mineral changes before and after black shale chemical corrosion. Relative mass loss, secondary porosity, longitudinal wave velocity and microstructure characteristics. Through uniaxial compression test, the deformation and strength characteristics of black shale at different immersion time were obtained. The corrosion effect and mechanism of acidic water on the chemical damage and mechanical deterioration of black shale were discussed. The results show that after the chemical corrosion, the chemical composition of the shale samples decreases, the clay minerals increase, the mineral cement becomes loose and the edges of the minerals become fuzzy. The relative mass loss and secondary porosity pH value and immersion time increase, but the longitudinal wave velocity decreases. Its mechanical properties have the tendency to transform from brittle failure to ductile failure. The uniaxial compressive strength and elastic modulus decrease with the increase of pH and Soaking time and reduce the trend of growth. Based on the secondary porosity, chemical damage variables were constructed to describe the chemical-mechanical damage evolution of the specimen. Analysis of acidic water - shale chemical mechanism are mainly: dissolution, oxidation, hydrolysis and ion exchange adsorption.