微生物固化土不排水剪切特性试验研究  

Experimental Study on Shear Behaviour of Microbially Solidified Soil in Undrained Triaxial Tests

作　　者：季一帆 谢立全[1] 马士力 郑永来[1] 李文麟 JI Yifan;XIE Liquan;MA Shili;ZHENG Yonglai;LI Wenlin(College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《施工技术（中英文）》2024年第15期117-122,共6页Construction Technology

基　　金：国家自然科学基金(51479137);广西科技重大专项项目(AA23062054)。

摘　　要：微生物诱导碳酸钙沉淀为高效的土体加固技术,因其具有可快速增强土体强度和稳定性等特点逐渐在工程中得到应用。为探究围压和碳酸钙含量对微生物固化土力学性能的影响,对不同碳酸钙含量的饱和固化土进行不同围压作用下的三轴固结不排水剪切试验,研究固化土应力-应变、孔隙水压力-应变变化规律,分析碳酸钙含量对土体初始切线模量、破坏包络线和临界状态线的影响规律,并建立碳酸钙含量与试验参数之间的关系式。试验结果表明,碳酸钙可提高土体峰值强度,碳酸钙的填充作用使胶结后的土体残余强度高于未胶结土体。围压和碳酸钙含量对固化土孔隙水压力-应变关系的影响不同,随着围压的增大,孔隙水压力峰值增大,发生负孔隙水压力的轴向应变增大。随着碳酸钙含量的增加,孔隙水压力峰值增大,但发生负孔隙水压力的轴向应变减小,可知固化土更易发生剪胀。随着碳酸钙含量的增加,土体破坏包络线和临界状态线均发生上移。Microbially induced calcium carbonate precipitation is an efficient soil reinforcement technique,which is gradually applied in engineering because it can rapidly enhance the strength and stability of soil.To investigate the influence of confining pressure and calcium carbonate content on the mechanical properties of microbially solidified soil,different saturated microbially solidified soil samples with varying calcium carbonate contents are subjected to triaxial consolidated undrained shear strength tests under different confining pressures.The study aims to explore the stress-strain characteristics and pore water pressure-strain behavior of microbially solidified soil under different confining pressures and calcium carbonate content conditions,and analyzes the influence of calcium carbonate content on the initial tangent modulus,failure envelope,and critical state line.The relationship between calcium carbonate content and test parameters is established.The test results show that calcium carbonate can increase the peak strength of soil,and the filling effect of calcium carbonate leads to higher residual strength in microbially solidified soil compared to the residual strength of untreated soil.The effects of confining pressure and calcium carbonate on the pore water pressure-strain behavior exhibit distinct patterns.Increasing confining pressure results in larger axial strains corresponding to negative pore pressures,while with the increase of calcium carbonate content,the axial strains corresponding to negative pore pressures gradually decrease,indicating that microbially solidified soil is more prone to dilatancy.Failure envelope and critical state line both move upward with the increase of calcium carbonate content.

关 键 词：固化土 碳酸钙 抗剪强度 切线模量 试验研究 

分 类 号：TU441[建筑科学—岩土工程]