摘要
为建立一个微生物固化土体的本构模型,分析研究了微生物固土机理,发现微生物诱导碳酸盐沉积(MICP)过程中形成的碳酸钙所起作用主要是增强相邻土颗粒之间连接,增大土体刚度,使其在相同应变下可承担更高应力.故将微生物固化处理后的土体看成未处理的砂土(只考虑填充作用影响)和新产生的碳酸钙胶结两部分,分别进行计算模拟,而二者的刚度之和为处理后土体的总刚度.为了对MICP过程形成的碳酸钙胶结进行模拟,提出了一个临界状态计算模型,该模型包括胶结的屈服面方程、硬化规律和流动法则,将其与已有的砂土计算模型配合使用,可对各种微生物固化砂土体的应力应变特性进行计算模拟.将提出的本构模型理论计算结果与微生物固化土体的三轴压缩试验结果进行对比,结果表明,所提出的模型能够反映微生物固化土体的应力应变规律.
In order to establish a constitutive model of MICP-cemented sand,the mechanisms of soil improvement by microbial induced carbonate precipitation (MICP) are investigated.The results show that the function of the calcite induced by microbe is to increase the stiffness of soil by enhancing the connection between soil particles,thus resulting in the high bearing capacity of MICP-cemented sand.Therefore,the MICP-cemented sand can be regarded as untreated sand (only considering the effect of filling effect) and the newly produced calcium carbonate cementation,which are simulated separately.They are then combined to give the overall stiffness of the MICP-cemented sand.For simulating the cementation mechanics of the calcite induced by microbe,a critical state model is proposed,which includes a yield surface equation,hardening law and the flow rule of cementation.It is able to simulate different stress-strain relationships of MICP-cemented sand by combining the existing constitutive calculation model of sand.The theoretical results of the proposed model are compared with those of triaxial compression tests,which indicate that the proposed model can reflect the stress-strain relationship of MICP-cemented sand.
作者
刘鹏
邵光辉
黄容聘
Liu Peng;Shao Guanghui;Huang Rongpin(School of Civil Engineering,Nanjing Forestry University,Nanjing 210037,China;Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Nanjing Forestry University,Nanjing 210037,China)
出处
《东南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2019年第4期720-726,共7页
Journal of Southeast University:Natural Science Edition
基金
国家自然科学基金资助项目(51809139,51578293)