仿岩溶碳酸氢钙对酸性环境的响应及改性分散土的研究  

Study on the response of Calcium bicarbonate formed by pseudo-karstification to acidic environment and modified dispersive soil

作　　者：郭弘东 樊恒辉[1,2] 文纪翔 郭昊炜 鞠鹏 武智鹏 GUO Hongdong;FAN Henghui;WEN Jixiang;GUO Haowei;JU Peng;WU Zhipeng(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China;Institute of Geotechnical Engineering/Museum of Problematic Rock and Soil,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [2]西北农林科技大学岩土工程研究所/特殊岩土博物馆,陕西杨凌712100

出　　处：《中国水利水电科学研究院学报(中英文)》2025年第2期163-172,183,共11页Journal of China Institute of Water Resources and Hydropower Research

基　　金：国家自然科学基金项目(52079116)。

摘　　要：为提高仿岩溶碳酸氢钙对分散土的改性效果,通过控制反应的初始pH进行溶液指标测定试验,并开展分散性判别试验、团聚体水稳性试验及机理分析试验,研究酸性环境对制备仿岩溶碳酸氢钙的影响,评价仿岩溶碳酸氢钙加入分散土的改性效果,阐明酸性环境优化仿岩溶碳酸氢钙改性分散土的作用机理。结果表明:(1)随着溶液环境由中性(pH=7.00)向酸性(pH=6.00)转变,生成的仿岩溶碳酸氢钙的钙离子浓度由26.10 mmol·L~(-1)上升至37.30 mmol·L~(-1),增加了42.91%。(2)中性环境下生成的溶液与分散土的质量比为2.5∶1时,分散土改性为非分散土,其大于0.25 mm团聚体含量为19.54%,团聚体平均质量直径为0.210 mm;酸性环境下生成的溶液完全改性所需的质量比降至1.5∶1,改性土大于0.25 mm团聚体含量为23.47%,团聚体平均质量直径为0.247 mm,两项指标分别提升了3.93%和17.62%,溶液用量降低40%。(3)酸性环境下制备的仿岩溶碳酸氢钙的浓度增加,更多的H~+和Ca~(2+)作用于分散土,进一步降低其分散性。在实际工程中可在酸性溶液环境下制备反应液,以获得改性效果更佳的仿岩溶碳酸氢钙。To enhance the modification effect of Calcium Bicarbonate Formed by Pseudo-Karstification(CFPK)on dispersive soil,solution index determination tests,dispersibility discrimination tests,aggregate water stability tests,and mechanism analysis tests were conducted by controlling the initial pH of the reaction,in order to investigate the influence of acidic environment on the preparation of CFPK,evaluate the modification effect of CFPK on dispersive soil,and clarify the mechanism of how acidic environment optimizes the CFPK modification of dispersive soil.The results show that:(1)As the solution environment changes from neutral(pH=7.00)to acidic(pH=6.00),the calcium ion concentration of CFPK increases from 26.10 mmol·L-1 to 37.30 mmol·L-1 with a 42.91%increase.(2)Under neutral conditions,the mass ratio of the generated solution to dispersive soil required for complete modification is 2.5∶1,resulting in a content of aggregates larger than 0.25 mm of 19.54%and a mean weight diameter of 0.210 mm.Under acidic conditions,the required mass ratio is reduced to 1.5∶1,with a content of aggregates larger than 0.25 mm of 23.47%and a mean weight diameter of 0.247 mm,representing increases of 3.93%and 17.62%respectively,while the solution usage is reduced by 40%.(3)The increased concentration of CFPK prepared under acidic conditions,with more H+and Ca 2+acting on the dispersive soil,further reduces its dispersibility.In practical engineering,the reaction liquid can be prepared under acidic solution conditions to obtain CFPK with better modification effects.

关 键 词：分散土 岩溶系统 团聚体 酸碱度 机制 

分 类 号：TU411[建筑科学—岩土工程]