砂岩渗透性演化特性的孔隙率分布细观模拟分析

发布时间：2018-05-13 06:10

本文选题：砂岩 + 孔隙率分布　；参考：《工程力学》2014年11期

【摘要】：通过不同围压下的三轴渗透试验,获得砂岩全应力-应变过程中渗透率变化数据。基于试验结果,建立砂岩试件离散元颗粒流数值模型,模拟得到砂岩压缩变形过程中体应变、孔隙率分布和黏结断裂特征。考虑围压效应,从细观机制上解释了动态孔隙率分布对渗透性演化特性的影响。研究结果表明,低围压下砂岩出现贯通的剪切带,裂隙易张开,对渗流具有显著的促进作用。围压越高,砂岩试样的黏结断裂数量和范围越大,裂隙数量增多,但裂隙和孔洞也容易被压密,从而对渗流起抑制作用。贯通的张开裂隙会大幅增加渗透性,而曲折间断的张开裂隙只会小幅增加渗透性,周围被闭合裂隙和压密的孔洞包裹的完全孤立的张开裂隙则对渗透性贡献很小。
[Abstract]:Through the triaxial permeation test under different confining pressures, the permeability variation data of sandstone during the whole stress-strain process are obtained. Based on the experimental results, a numerical model of discrete element particle flow of sandstone specimen is established, and the body strain, porosity distribution and cemented fracture characteristics are obtained by simulation during compression deformation of sandstone. Considering the confining pressure effect, the effect of dynamic porosity distribution on permeability evolution is explained from the meso-mechanism. The results show that under low confining pressure, there is a through shear zone in sandstone, and the cracks are easy to open, which can promote the seepage obviously. The higher the confining pressure is, the larger the number and range of bonding fracture is, the more the number of fractures is, but the more easily the fractures and pores are compacted, so the seepage can be restrained. Through the open fissure will greatly increase permeability, while the zigzag open crack will only slightly increase permeability, and the completely isolated open fissure surrounded by closed cracks and compacted holes will contribute little to the permeability.
【作者单位】：华侨大学岩土工程研究所;大连理工大学土木与水利学院;中国矿业大学深部岩土力学与地下工程国家重点实验室;
【基金】：国家重点基础研究发展计划(973)项目(2011CB013503) 国家自然科学基金项目(51374112) 中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金项目(SKLGDUEK1304) 福建省自然科学基金计划项目(2014J01160)
【分类号】：TU45

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