摘要
通过室内模拟试验,系统探究了苏南地区黄龙组、青龙组(泥灰岩、瘤状灰岩)及船山组四类典型碳酸盐岩的溶蚀规律.基于区域地质调查,选取代表性岩样开展不同pH(2~5)的酸性溶液(硫酸/盐酸)及地下水状态(静止/流动)下的溶蚀试验,分析溶蚀量、溶蚀速率及其主控因素.结果表明:青龙组泥灰岩溶蚀量最大(静止6.422 g,流动6.537 g),船山组灰岩溶蚀量最小(静止0.048 g,流动0.078 g),溶蚀量主要受矿物组成、结构及比表面积控制;在低pH(2~3)下,硫酸溶蚀能力普遍优于盐酸,并以黄龙组灰岩和青龙组泥灰岩溶蚀为典型;当pH≥4时,规律不显著;流动状态溶蚀量显著高于静止状态(尤其在低pH时),这是因为水流可清除表面沉淀,维持持续溶蚀;溶蚀速率随pH降低而增大,且流动状态使溶蚀转折点(慢速→快速阶段)提前12~48 h;除瘤状灰岩外,其余岩样在pH=2时均呈现“慢速→快速”两阶段溶蚀,转折时间受酸的类型及方解石含量影响;青龙组瘤状灰岩因结构软弱,溶蚀速率波动显著,流动状态下易发生物理破碎.本研究揭示了苏南地区碳酸盐岩溶蚀的主控机制,为区域岩溶发育预测及工程灾害防控提供了理论依据.
This study systematically explored the dissolution laws of four typical carbonate rocks in Huanglong Formation,Qinglong Formation(mudstone,nodular limestone),and Chuanshan Formation in the southern Jiangsu region through indoor simulation experiments.Based on regional geological surveys,representative rock samples were selected to conduct dissolution tests under different pH(2~5),acidic solutions(sulfuric acid/hydrochloric acid),and groundwater conditions(static/flowing),analyzing the amount,rate,and main controlling factors of dissolution.The results showed that Qinglong Formation has the highest dissolution amount of mudstone(6.422 g at rest and 6.537 g at flow),while Chuanshan Formation has the lowest dissolution amount of limestone(0.048 g at rest and 0.078 g at flow),mainly controlled by mineral composition,structure,and specific surface area.At low pH(2~3),sulfuric acid generally has better dissolution ability than hydrochloric acid,and the dissolution of Huanglong Formation limestone and Qinglong Formation marl is typical.The pattern is not significant when pH≥4.The amount of dissolution in the flowing state is significantly higher than that in the static state(especially at low pH),because the water flow can remove surface sediment and maintain continuous dissolution;the dissolution rate increases with decreasing pH,and the flow state advances the dissolution transition point(slow to fast stage)by 12-48 hours;except for nodular limestone,all other rock samples exhibit a two⁃stage dissolution process of"slow to fast"at pH=2,with the transition time influenced by acid type and calcite content;due to its weak structure and significant fluctuations in dissolution rate,the nodular limestone of Qinglong Formation is prone to physical fragmentation under flowing conditions.This study reveals the main controlling mechanism of carbonate rock dissolution in the southern Jiangsu region,providing a theoretical basis for predicting regional karst development and preventing engineering disasters.
作者
郭书兰
阎长虹
黄厚旭
黄凯
殷帅
俞良晨
Guo Shulan;Yan Changhong;Huang Houxu;Huang Kai;Yin Shuai;Yu Liangchen(School of Civil Engineering,Anhui Jianzhu University,Hefei,230601,China;School of Earth Science and Engineering,Nanjing University,Nanjing,210023,China;School of Resources and Environmental Engineering,Hefei University of Technology,Hefei,230009,China)
出处
《南京大学学报(自然科学版)》
北大核心
2025年第6期1039-1049,共11页
Journal of Nanjing University(Natural Science)
基金
国家自然科学基金(42507268,42302323)
国家资助博士后研究人员计划(GZC20250309)
安徽建筑大学引进人才及博士启动基金(2022QDZ26)。
关键词
碳酸盐岩
溶蚀规律
室内试验
苏南地区
carbonate rock
dissolution law
indoor experiments
southern Jiangsu region
