干密度对砂岩土水特征曲线影响及微观机理  

Influence of Dry Density on Soil-Water Characteristic Curve andMicroscopic Characteristics of Sandstone

作　　者：杨昕 颜梦秋 郑嘉男 YANG Xin;YAN Meng-qiu;ZHENG Jia-nan(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China;Hainan Institute of Zhejiang University,Sanya 572025,China;Shanghai Institute for Advanced Study,Zhejiang University,Shanghai 201203,China)

机构地区：[1]浙江大学建筑工程学院,杭州310058 [2]浙江大学海南研究院,三亚572025 [3]浙江大学上海高等研究院,上海201203

出　　处：《科学技术与工程》2024年第34期14772-14777,共6页Science Technology and Engineering

基　　金：国家自然科学基金(52306205)。

摘　　要：中国广泛分布砂岩地层,其水力特性影响工程稳定性。干密度是土水特征曲线的重要影响因素,但其对砂岩土水特征曲线的影响机制尚不明确。为了探究不同干密度砂岩土水特征曲线及其微观特性,采用压力板仪开展了不同干密度砂岩土水特征试验,提出了考虑干密度的砂岩土水特征曲线模型,同时,基于扫描电镜(scanning electron microscope, SEM)和压汞测试分析了不同干密度砂岩微观特性,揭示了干密度对砂岩土水特征曲线影响的微观机理。研究表明:干密度越大,砂岩持水能力越强;干密度对砂岩进气值和残余饱和度均有影响,且砂岩进气值随着干密度的增大呈近似线性增长;不同干密度砂岩孔径分布均为单峰形态,随着干密度的增大,砂岩峰值孔隙半径逐渐减小;干密度较高的砂岩,颗粒排列紧密,孔隙半径较小,主要以中等和小孔隙为主,而干密度较低的砂岩,颗粒排列松散,孔隙半径大,包括大小不等的孔隙。研究可为非饱和砂岩工程安全提供一定的参考。Sandstone formations are widely distributed in our country,and their hydraulic characteristics affect the engineering stability.Dry density is an important factor affecting soil-water characteristic curve,but the mechanism of its influence on soil-water characteristic curve of sandstone remains unclear.In order to explore the soil-water characteristic curves and microscopic characteristics of sandstones with different dry densities,soil-water characteristic tests of sandstones with different dry densities were carried out by using pressure plate instrument,and a model of sandstones soil-water characteristic curve considering dry densities was proposed.Meanwhile,microscopic characteristics of sandstones with different dry densities were analyzed based on scanning electron microscope and mercury injection test,and the microscopic mechanism of the influence of dry densities on sandstones soil-water characteristic curves was revealed.The results show that the higher the dry density,the stronger the water holding capacity of sandstone.Dry density has an effect on both intake value and residual saturation of sandstone,and the intake value of sandstone increases approximately linearly with the increase of dry density.The pore diameter distribution of sandstones with different dry density is unimodal,and the peak pore radius of sandstones decreases gradually with the increase of dry density.Sandstones with higher dry density have tight grain arrangement and small pore radius,which are mainly medium and small pores,while sandstones with lower dry density have loose grain arrangement and large pore radius,including pores of different sizes.The research can provide some reference for the engineering safety of unsaturated sandstone.

关 键 词：干密度 砂岩 土水特征曲线 微观机理 

分 类 号：TU431[建筑科学—岩土工程]