Pore structure variation characteristics of a Chinese local mudstone before and after the first cycle of wetting and drying  

一种中国地方泥岩首次干湿循环前后的孔隙结构变化特征

作　　者：ZHANG Qing-song LIU Zhi-bin TANG Ya-sen DENG Yong-feng LUO Ting-yi MENG Fan-xing 张清淞;刘志彬;唐亚森;邓永锋;罗婷倚;孟繁星

机构地区：[1]Institute of Geotechnical Engineering,Southeast University,Nanjing 211189,China [2]National Demonstration Center for Experimental Road and Traffic Engineering Education,Southeast University,Nanjing 211189,China [3]Guangxi Beitou Highway Construction&Investment Group Co.,Ltd.,Nanning 530028,China

出　　处：《Journal of Central South University》2025年第2期582-596,共15页中南大学学报(英文版)

基　　金：Project(41877240)supported by the National Natural Science Foundation of China。

摘　　要：As a typical sedimentary soft rock,mudstone has the characteristics of being easily softened and disintegrated under the effect of wetting and drying(WD).The first cycle of WD plays an important role in the entire WD cycles.X-ray micro-computed tomography(micro-CT)was used as a non-destructive tool to quantitatively analyze microstructural changes of the mudstone due to the first cycle of WD.The test results show that WD leads to an increase of pore volume and pore connectivity in the mudstone.The porosity and fractal dimension of each slice of mudstone not only increase in value,but also in fluctuation amplitude.The pattern of variation in the frequency distribution of the equivalent radii of connected,isolated pores and pore throats in mudstone under WD effect satisfies the Gaussian distribution.Under the effect of WD,pores and pore throats with relatively small sizes increase the most.The sphericity of the pores in mudstones is positively correlated with the pore radius.The WD effect transforms the originally angular and flat pores into round and regular pores.This paper can provide a reference for the study of the deterioration and catastrophic mechanisms of mudstone under wetting and drying cycles.泥岩作为一种典型的沉积软岩,在干湿作用下具有易软化、易崩解的特点。干湿循环的首个周期在整个干湿循环中起着重要作用。在本研究中,利用X射线显微计算机断层扫描(micro-CT)作为一种无损手段来定量化研究首次干湿循环作用引起的泥岩微观结构变化。测试结果表明,首次干湿循环使泥岩的孔隙体积和孔隙连通性增加。不仅每一层泥岩切片的孔隙度和分形维的数值在增加,而且其整体的波动幅度也增加。在干湿循环作用下,泥岩中连通、孤立孔隙和孔喉等效半径的频率分布变化模式满足高斯分布。孔径相对较小的孔隙和孔喉增加最多。泥岩孔隙的球形度与孔隙半径呈正相关。干湿循环作用将泥岩中原本棱角分明的扁平孔隙转化为圆形规则孔隙。泥岩中不同球形度的孔隙具有不同的形态特征,随着球形度的增加,孔隙形态更接近裂缝。本文可为泥岩在干湿循环作用下的劣化、灾变机理研究提供参考。

关 键 词：MUDSTONE wetting and drying cycle X-ray micro-computed tomography pore structure pore morphology 

分 类 号：TU45[建筑科学—岩土工程]