基于矿物溶解理论的砂岩化学损伤动态模型  

Dynamically Chemical Damage Model for Sandstone Based on MineralDissolution Theory

作　　者：梁艳玲 霍润科[1,2] 宋战平[1,2] 穆彦虎 秋添 宋子羿 LIANG Yanling;HUO Runke;SONG Zhanping;MU Yanhu;QIU Tian;SONG Ziyi(School of Civil Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730050,China)

机构地区：[1]西安建筑科技大学土木工程学院,西安710055 [2]西安建筑科技大学陕西省岩土与地下空间工程重点实验室,西安710055 [3]中国科学院西北生态环境资源研究院,冻土工程国家重点实验室,兰州730050

出　　处：《材料导报》2024年第8期159-165,共7页Materials Reports

基　　金：国家自然科学基金(41172237,52178393);冻土工程国家重点实验室开放基金(SKLFSE202107)。

摘　　要：酸腐蚀环境下岩石物理力学性质的劣化本质上由岩石矿物的溶解引发的孔隙微裂隙的扩展贯通所致。为研究酸性环境下砂岩矿物的溶解特性,选择pH=1、3的盐酸溶液为腐蚀环境,借助X射线衍射试验鉴定砂岩矿物成分及含量,测试不同浸泡周期下溶液的pH值、阳离子浓度、岩样的质量及其纵波波速,并通过矿物溶解理论与化学动力学原理,建立反映整个腐蚀过程的砂岩化学损伤动态模型。研究结果表明:酸性环境下砂岩的损伤主要由长石和方解石的溶解所致,矿物溶解反应分为界面吸附、界面交换、解吸附三个步骤,且步骤最慢者对整个反应起控制作用。矿物溶解速率与H+浓度的n次幂成正比,且0<n≤1,其数值与矿物自身特性和溶液pH值有关。酸-岩反应具有较强的时间依赖性,其速率随腐蚀时间的延长逐渐减小而后趋于稳定,且溶液pH值越小,腐蚀时间越长,砂岩劣化越严重。pH=1、3的盐酸溶液作用下,通过化学损伤模型得到的砂岩孔隙度与通过纵波波速得到的孔隙度随腐蚀时间的变化规律具有较好的一致性,验证了模型的有效性与合理性。研究结果可为酸化学环境下岩体工程的安全性评估与灾害防治提供理论参考。The deterioration of the physical and mechanical properties of rock under an acidic environment is essentially caused by the dissolution of rock minerals and further the expansion and penetration of pores and microcracks.To study the dissolution characteristics of sandstone minerals in an acidic environment,pH=1,3 HCl solution was selected as the corrosive environment.The composition and content of sandstone minerals were identified by X-ray diffraction test,and the pH value of the solution,cation concentration,mass,and longitudinal wave velocity of samples were tested under different immersion periods.The dynamic chemical damage model for sandstone reflecting the corrosion process was established based on the mineral dissolution theory and chemical kinetic principle.The results show that the damage of sandstone in an acidic environment was mainly caused by the dissolution of feldspar and calcite.The mineral dissolution can be divided into three steps:interface adsorption,interface exchange,and desorption,and the slowest one plays a controlling role.The dissolution rate was proportional to the nth power of the H+concentration,and the value of n(0<n≤1)was related to the properties of minerals and the pH value of the solution.The acid-rock reaction was time-dependent;the reaction rate decreased with the corrosion time and tended to be stable.The sandstone deteriorated more seriously with the lower pH value and longer corrosion time.Under the action of pH=1,3 HCl solution,the change laws of sandstone porosity with corrosion time,obtained by the chemical damage model,was in good agreement with that obtained by the longitudinal wave velocity,which verified the validity and rationality of the model built in the study.The finding can provide theoretical references for safety assessment and disaster prevention of rock mass engineering under an acidic environment.

关 键 词：砂岩 矿物溶解 化学损伤模型 孔隙度 纵波波速 

分 类 号：TU451[建筑科学—岩土工程]