一种估算MICP加固砂土体渗透系数的简便方法  

A Simple Model for Predicting Hydraulic Conductivity of MICP-Treated Sand

作　　者：王延宁 黄龙剑 李思侃 吴鸣[1] WANG Yanning;HUANG Longjian;LI Sikan;WU Ming(Department of Civil and Environmental Engineering,Shantou University,Shantou 515063,Guangdong,China)

机构地区：[1]汕头大学土木与环境工程系&广东省结构安全与监测工程技术研究中心,广东汕头515063

出　　处：《汕头大学学报（自然科学版）》2023年第1期3-12,F0002,共11页Journal of Shantou University：Natural Science Edition

基　　金：广东省自然科学基金项目(2022A1515011200);广东省科技计划项目(STKJ2021129);深部岩土力学与地下工程国家重点实验室开放基金课题项目(SKLGDUEK2005)。

摘　　要：基于Kozeny-Carman(K-C)方程和微生物诱导碳酸钙沉淀(Microbial Induced Carbonate Precipitation,MICP)技术原理,提出一种MICP加固砂土体渗透系数的简便算法.MICP产生的碳酸钙填充土体孔隙,采用电镜成像法得到碳酸钙晶体的粒径,推导得固化砂土体的孔隙比和颗粒平均比表面积.将固化砂土体的孔隙比和颗粒平均比表面积代入K-C方程,得到预测MICP加固砂土体渗透系数的简便算法,并经已有文献试验数据和研究结果验证,结果表明:孔隙比减小和颗粒平均比表面积增大导致MICP固化砂土渗透系数显著降低,算例一土体的渗透系数最终下降了93%-97%,算例二碳酸钙含量达到10%时,渗透系数下降了67%-92%;MICP固化砂土的渗透系数下降速率开始加固时最大,随着碳酸钙含量逐渐增加,渗透系数下降速率逐渐减小;初始渗透系数越大的土体,加固效果越明显,渗透系数的下降速率和下降幅值更大;该算法简便可靠,能较为快速和准确预测MICP加固砂土体的渗透系数,为工程实践提供了理论依据.Based on Kozeny-Carman equation and principle of MICP,the analytical formulation of determining hydraulic conductivity of MICP-reinforced sand is proposed.After MICP treatment,the pore space is filled by calcium carbonate particles,the diameters of the precipitated CaCO3 crystals are obtained by Scanning Electron Microscope,the void ratio and averaged specific surface area of soil particles are deduced.By substituting void ratio and the averaged specific surface area of soil particles into Kozeny-Carman equation,a simple model for predicting hydraulic conductivity of MICP-treated sand is obtained,and it is verified by existing datum and results.The results indicated that the decrease of void ratio and increase of averaged specific surface area of soil particles lead to the significant decrease of hydraulic conductivity,the hydraulic conductivity decreased by 93%-97%finally in example 1 and decreased by 67%-92%in example 2 when content of CaCO3 reaches 10%.With the gradual increase of CaCO3,the decrease rate of hydraulic conductivity decreases gradually.The larger the hydraulic conductivity is,the decrease rate and amplitude of permeability coefficient are greater.The simple and feasible model could be adopted for the use in engineering practice,predict hydraulic conductivity of MICP-treated sand quickly and accurately.

关 键 词：渗透 K-C方程 MICP 粒径 孔隙填充 

分 类 号：TU442[建筑科学—岩土工程]