基于核磁共振与波速测试的风化砂岩吸水性特征研究  

Characteristics of water absorption capacity of weathered sandstone based on nuclear magnetic resonance and wave velocity testing

作　　者：牛然 蒋小伟[1] 闫永帅 欧阳恺皋 孙献春 闫宏彬 万力[1] NIU Ran;JIANG Xiaowei;YAN Yongshuai;OUYANG Kaigao;SUN Xianchun;YAN Hongbin;WAN Li(MOE Key Laboratory of Groundwater Circulation and Environmental Evolution,China University of Geosciences(Beijing),Beijing 100083,China;School of Hydraulic Engineering,Yellow River Conservancy Technical Institute,Kaifeng,Henan 475004,China;Beijing Urban Construction Rail Transit Construction Engineering Co.Ltd.,Beijing 100088,China;Yungang Research Institute,Datong,Shanxi 037034,China)

机构地区：[1]中国地质大学(北京)地下水循环与环境演化教育部重点实验室,北京100083 [2]黄河水利职业技术学院水利工程学院,河南开封475004 [3]北京城建轨道交通建设工程有限公司,北京100088 [4]云冈研究院,山西大同037034

出　　处：《水文地质工程地质》2025年第2期63-71,共9页Hydrogeology & Engineering Geology

基　　金：山西省科技重大专项计划项目(202201150501024)。

摘　　要：水是岩石风化破坏的关键因素,高吸水性岩石一般更易受到风化破坏,但一直缺少原位评估岩石吸水能力的方法。为探究岩石吸水能力的控制因素,以云冈石窟不同风化程度砂岩为研究对象,采用核磁共振技术测得岩石样品的孔隙度和孔径分布,建立砂岩自由吸水率与密度、孔隙度、孔径的关系。结果表明:砂岩自由吸水率与密度呈线性关系,但两者的斜率与风化程度有关;砂岩自由吸水率与孔隙度、小孔(0.1~1.0μm)占比均呈正相关性,其中孔隙度是控制砂岩自由吸水率的主要原因,孔隙结构是控制砂岩自由吸水率的次要原因;由于波速受孔隙度和孔隙结构控制,自由吸水率与波速有良好的线性关系,因此提出可以通过原位测试波速估算岩体表层自由吸水率。本研究加深了对风化砂岩吸水性控制机理的认识,并提出了一种可以原位获得石质文物自由吸水率的方法,对石质文物保护具有重要的指导意义。Water is a key factor in the weathering and erosion of rocks,and highly porous rocks are generally more susceptible to weathering.However,there has been a lack of in-situ methods for assessing the water absorption capacity of rocks.To investigate the controlling factors of rock water absorption capacity,sandstone with different degrees of weathering collected from the Yungang Grottoes were selected as the study material.Nuclear magnetic resonance(NMR)technology was employed to test the porosity and pore size distribution of rock samples,and to establish the relationship between the free water absorption rate of sandstone and its density,porosity,and pore size.The results indicate that there is a linear relationship between the free water absorption rate and the density of sandstone,with the slope of the relationship being influenced by the degree of weathering.Additionally,the free water absorption rate of the sandstone is positively correlated with porosity and the proportion of small pores(0.1-1.0μm),with porosity being the primary controlling factor and pore structure being the secondary controlling factor.This study deepens our understanding of the mechanisms controlling the water absorption of weathered sandstone.Furthermore,since wave velocity is also influenced by porosity and pore structure,a good linear relationship was observed between the free water absorption rate and wave velocity.Therefore,it is suggested that the free water absorption rate of rock mass can be estimated by in-situ testing of wave velocity.

关 键 词：孔隙度 吸水性 声波速度 孔径分布 核磁共振 

分 类 号：P641.1[天文地球—地质矿产勘探]