Mechanical behavior of EICP-treated calcareous sands under high confining pressures  

作　　者：Qian Zhang Weimin Ye Wei Su Qiong Wang Yonggui Chen 

机构地区：[1]Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai,200092,China [2]Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai,200092,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第3期1816-1827,共12页岩石力学与岩土工程学报(英文)

基　　金：funding support from the National Nature Science Foundation of China(Grant No.42030714).

摘　　要：Calcareous sands are widely distributed on the coral reefs,continental shelf,and seashores between 30north and south latitude and are commonly utilized as filling materials for the construction of artificial islands and infrastructure foundations.In this study,calcareous sands were cemented by enzymatically induced carbonate precipitation(EICP)technique.Drained triaxial tests were conducted on the EICPtreated calcareous sands.Results showed that the specimens with different cementation levels exhibited different responses in mechanical behavior.The differences in the sand fabric after consolidation under a relatively high confining pressure resulted in the untreated specimen exhibiting a higher peak strength compared to the lightly cemented specimen.High confining pressures exhibited a strongly inhibiting effect on dilatancy,which could be counteracted by increasing the cementation level.The EICP-treated specimen could have one or two yield points(smaller-strain and larger-strain yields).For lightly cemented specimens,the smaller-strain yield stress decreased under high confining pressures due to the partial carbonate bonding degradation during consolidation.The stress line of untreated particle breakage(UPB)was a critical boundary to distinguish failure mode in the p′-q space.For the EICP-treated specimens,the yield stress located above or below the UPB stress line indicates the simultaneous or sequential breakage of the carbonate bonds and sand particles,respectively.Accordingly,the EICPtreated specimen exhibited brittle or ductile properties.Failure mode transformation could be triggered by increasing cementation level or confining pressure.

关 键 词：EICP technique Calcareous sand Bonding degradation Yield strength Failure mechanism 

分 类 号：TG1[金属学及工艺—金属学]