基于高密度电阻率成像技术的MICP浆液入渗过程监测研究  

Characterizing the Infiltration Process of MICP Treated Sand Soil Using Electrical Resistivity Tomography

作　　者：兰润扬 林锴 唐朝生[1] 章君政 施斌[1] LAN Runyang;LIN Kai;TANG Chaosheng;ZHANG Junzheng;SHI Bin(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学地球科学与工程学院,南京210023

出　　处：《高校地质学报》2024年第5期577-584,共8页Geological Journal of China Universities

基　　金：国家重点研发计划课题(2020YFC1808101);国家杰出青年科学基金项目(41925012);国家自然科学基金重点项目(42230710);江苏省自然科学基金项目(BK20211087);南京大学2023年大学生创新训练项目(202310284080Z)联合资助。

摘　　要：微生物诱导碳酸钙沉淀(MICP)技术是一种生态环保、前景广阔的土体改性方法,其改性效果与浆液的入渗特征密切相关。为此,提出将高密度电阻率成像(ERT)技术用于MICP浆液入渗过程监测。文章通过开展模型试验,对石英砂试样进行混合一步注浆法MICP处理,同时对试样持续进行ERT监测及电导率分析,获取了试样的三维电阻率变化特征,处理完成后测定了试样中碳酸钙含量的空间分布。结果表明:(1)MICP反应过程中,砂土与注浆液电导率随尿素分解而逐渐升高;(2)注浆液的迁移分布对砂土内部低电阻区的分布规律起主导作用,而碳酸钙沉淀的影响较小;(3)在MICP处理过程中,碳酸钙沉淀的生成与注浆液的迁移渗透相互作用,共同影响改性效果;(4)ERT技术可有效监测MICP处理区电阻率的时空演化特征,准确反映注浆液渗透迁移情况,进而评价改性效果。研究结果表明,采用ERT技术监测MICP改性土体过程具有可行性,为评价和优化微生物矿化改性效果提供了新的技术思路和方向。Microbial induced calcium carbonate precipitation(MICP)is an environmentally friendly and promising technique for ground improvement.However,the treating process is closely related to the infiltration characteristics of the slurry Therefore,a monitoring method applying electrical resistivity tomography(ERT)technique to MICP slurry infiltration process is proposed.MICP treatment was performed on the quartz sand by one-step mixed-grouting method.ERT monitoring and conductivity analysis were performed during the process.The three-dimensional resistivity variation of sand samples was obtained.After the treatment,the distribution of calcium carbonate content was determined.The results indicates that:(1)The electrical resistivity increased when the urea generally hydrolyzed during the MICP reaction.(2)The distribution of low electrical resistivity area was mainly dominated by the diffusion and mixing process of the grouting fluid.(3)During the MICP treatment,carbonate precipitation and infiltration of grouting fluid interacted,jointly affecting the reinforcement effect.(4)The resistivity spatiotemporal evolution can be effectively traced by ERT,which could accurately reflect the infiltration of treating suspension and then evaluate the reinforcement effect.This experiment demonstrates the permeability of ERT applying on MICP reinforcing,provides new ideas and research direction on MICP application.

关 键 词：微生物诱导碳酸钙沉淀 高密度电法 入渗过程 土体电阻率 

分 类 号：P642[天文地球—工程地质学]