MICP固化花岗岩残积土的崩解特性  

Disintegration Characteristics of MICP-treated Granite Residual Soils

作　　者：陈欣 安然 张先伟[2] 陈昶 袁童 CHEN Xin;AN Ran;ZHANG Xian-wei;CHEN Chang;YUAN Tong(Institute of Urban Construction,Wuhan University of Science and Technology,Wuhan 430081,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)

机构地区：[1]武汉科技大学城市建设学院,武汉430081 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071

出　　处：《长江科学院院报》2025年第2期138-144,171,共8页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金项目(12102312);岩土力学与工程国家重点实验室开放基金项目(SKLGME021018)。

摘　　要：花岗岩残积土具有强吸水性、遇水易崩解特性,为工程建设带来潜在的安全隐患。微生物诱导碳酸钙沉淀(MICP)技术作为一种新型加固方法可显著改良土体崩解性能。为了探究MICP固化花岗岩残积土的崩解特性,对素土样和不同胶结液浓度的MICP固化土样进行崩解试验,并基于X射线衍射图谱和扫描电镜图像分析MICP固化机理。研究表明:素土样崩解过程分为表面吸水剥落、土体软化、完全解体3个阶段,固化土样可分为强行水侵、裂隙发育、剧烈侵蚀和崩解稳定4个阶段;在MICP作用下,残积土崩解曲线由完全崩解特征转变为不完全崩解;随着碳酸钙含量增加,土体抗崩解能力得到明显增强;碳酸钙晶体主要分布在土颗粒表面、孔隙以及接触点上,在土体内分别发挥着包裹、填充和胶结作用,是改良残积土崩解特性的重要原因。研究成果可为土体崩解性能的改良研究提供参考。Granite residual soil is highly absorbent and prone to disintegration in the presence of water,which poses potential safety hazards for engineering construction.Microbial-induced calcium carbonate precipitation(MICP),as a new reinforcement method,can significantly improve the disintegration properties of soils.Disintegration tests were conducted on natural and MICP-treated soil samples with different cementation concentrations,and the disintegration mechanism was analyzed based on X-ray diffraction spectra and scanning electron microscope(SEM)images.Results reveal that the disintegration processes of the natural soil samples can be divided into three stages:surface water absorption and spalling stage,soil softening stage stage,and complete disintegration stage.In contrast,the MICP-treated samples exhibit four stages:forced water intrusion stage,fissure development stage,intense erosion stage,and stable disintegration stage.Under MICP treatment,the disintegration curve of the residual soil transitions from complete disintegration to incomplete disintegration characteristics.With the increase of calcium carbonate content,the disintegration resistance can be obviously enhanced.Calcium carbonate crystals are mainly distributed on sample surfaces,within pores and at contact points,playing crucial roles in encapsulating,filling,and cementing soil particles,which are the main reasons for improving the disintegration characteristics of residual soils.These findings provide valuable references for enhancing the disintegration properties of residual soils in engineering applications.

关 键 词：花岗岩残积土 MICP 崩解性能 矿物分析 微观结构 

分 类 号：TU431[建筑科学—岩土工程]