胶结剂对花岗岩残积土微生物固化特性的影响规律  

Research on the Effect of Cementing Agents on the Biocemented Characteristics of Granite Residual Soil

作　　者：张永杰 刘涛 黄万东 曹俊 黄金鑫 欧阳健 ZHANG Yong-jie;LIU Tao;HUANG Wan-dong;CAO Jun;HUANG Jin-xin;OUYANG Jian(School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,Hunan,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114

出　　处：《中国公路学报》2023年第8期181-189,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51878071,52178416);湖南省教育厅重点项目(20A020);湖南省自然科学基金项目(2022JJ30615);优势特色重点学科创新性项目(18ZDXK08)。

摘　　要：为系统分析胶结剂对花岗岩残积土微生物固化特性的影响规律,分别考虑氯化钙、氯化镁与乙酸钙等3种胶结剂以及4种固化次数,进行微生物固化花岗岩残积土的室内试验,对不同工况的固化试样分别开展无侧限抗压强度(UCS)、碳酸盐生成率、崩解、X射线衍射(XRD)和扫描电子显微镜(SEM)试验,以此分析胶结剂与固化次数对花岗岩残积土力学特性的影响规律及其固化机理。研究结果表明:试验采用的3种胶结剂下,花岗岩残积土的固化效果均随固化次数的增加而提升,固化次数相同时,氯化钙、氯化镁、乙酸钙3种胶结剂对花岗岩残积土的固化效果依次减弱;固化最佳工况为氯化钙固化14次试样,无侧限抗压强度达到1045 kPa,崩解系数降至9%;固化次数较少时固化试样存在明显的不均匀性,其随固化次数的增加而得到改善,但其改善效果随固化次数增加而减弱;不同胶结剂反应产生的碳酸盐沉淀晶体形态不同,其主要附着在土体颗粒表面和颗粒之间,所起胶结作用是改善花岗岩残积土固化试样宏观物理力学特性的根本原因。In order to systematically analyze the effect of cementing agents on the biocemented characteristics of granite residual soil,three cementing agents,including calcium chloride,magnesium chloride and calcium acetate,and four kinds of cementing times were considered to conduct laboratory tests on microbial cementing of granite residual soil.Unconfined compressive strength(UCS),carbonate content,disintegration,X-ray diffraction(XRD)and scanning electron microscopy(SEM)tests were carried out on cemented specimens for different working conditions.Based on the above tests,the effect of cementing agents and cementing times on the mechanical properties of granite residual soil and its cementing mechanism were analyzed.The results show that the cementing effect of granite residual soil under the three cementing agents used in the tests all increased with the increase of cementing times.The cementing effect of the three cementing agents,calcium chloride,magnesium chloride and calcium acetate,on the granite residual soil decreases in order when the cementing times are the same.The optimal cementing condition is for specimen under 14 treatments to be cemented with calcium chloride,with an unconfined compressive strength of 1045 kPa and a disintegration coefficient of 9%.Cemented specimens with a low number of cementing have significant inhomogeneity,which improves with the increase in the number of cementing,but the improvement effect decreases with the increase in the number of cementing.Different cementing agents induce different forms of carbonate precipitation crystals,which are mainly attached to the surface of soil particles and between particles.The cementing effect is the fundamental reason for improving the macroscopic physical and mechanical properties of granite residual soil cementing specimens.

关 键 词：路基工程 花岗岩残积土 微生物固化 崩解系数 微观结构 

分 类 号：U416.1[交通运输工程—道路与铁道工程]