Water-induced physicochemical and pore changes in limestone for surrounding rock across pressure aquifers  

作　　者：WU Daguo PENG Jianhe XIA Zhenzhao 

机构地区：[1]School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei 230009,China [2]Anhui and Huaihe River Institute of Hydraulic Research,Hefei 230088,China [3]School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China

出　　处：《Journal of Mountain Science》2024年第9期3186-3200,共15页山地科学学报（英文）

基　　金：funded by the National Key R&D Program of China(2023YFC3806800).

摘　　要：Osmotic water alters the physicochemical properties and internal structures of limestone.This issue is particularly critical in tunnel construction across mountainous regions with aquifers,where pressurized groundwater can destabilize the limestone-based surrounding rock.Thus,systematic research into the physicochemical properties and pore structure changes in the limestone under pressurized water is essential.Additionally,it is essential to develop an interpretable mathematical model to accurately depict how pressurized osmotic water weakens limestone.In this research,a specialized device was designed to simulate the process of osmotic laminar flow within limestone.Then,four main tests were conducted:mass loss,acoustic emission(AE),mercury intrusion porosimetry(MIP),and fluorescence analysis.Experimental results gained from tests led to the development of a“Particle-pore throat-water film”model.Proposed model explains water-induced physicochemical and pore changes in limestone under osmotic pressure and reveals evolutionary mechanisms as pressure increases.Based on experimental results and model,we found that osmotic pressure not only alters limestone composition but also affects pore throats larger than 0.1μm.Furthermore,osmotic pressure expands pore throats,enhancing pore structure uniformity,interconnectivity,and permeability.These effects are observed at a threshold of 7.5 MPa,where cohesive forces within the mineral lattice are surpassed,leading to the breakdown of erosion-resistant layer and a significant increase in hydrochemical erosion.

关 键 词：Water rock reaction Geochemistry Osmotic pressure Pore scale study LIMESTONE Pressure aquifer 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]