两种气体作用下非饱和江边吹填砂三轴试验研究  

Triaxial compression test on unsaturated riparian hydraulic fill sand under action of two gases

作　　者：吴炎 胡坤[2] 姜马欢 李荟楠 彭哲 WU Yan;HU Kun;JIANG Mahuan;LI Huinan;PENG Zhe(Department of Architecture and Environmental Engineering,Changzhou University Huaide College,Taizhou 214500,China;School of Urban Construction,Changzhou University,Changzhou 213164,China)

机构地区：[1]常州大学怀德学院建筑与环境工程系,江苏泰州214500 [2]常州大学城市建设学院,江苏常州213164

出　　处：《人民长江》2024年第2期211-215,230,共6页Yangtze River

基　　金：中国博士后科学基金面上项目(2021M703507);江苏省产学研合作项目(BY2021208);泰州市科技支撑计划(社会发展)项目(SSF20210062)。

摘　　要：为了研究非饱合土体中充入空气或CO_(2)气体所导致的土样不同物理力学性质,以长江边的吹填细砂为对象,通过改变细砂的含水率,往土样通入空气和CO_(2),采用固结不排水三轴试验分析了两种不同气体作用下细砂的应力-应变曲线及抗剪强度指标。研究结果表明:两种气体在低围压下使得细砂的应力-应变曲线表现为应变软化型,高围压下曲线为硬化型。围压作用下充CO_(2)细砂具有低孔隙率和高密实度特征,导致充CO_(2)细砂的抗剪强度大于充空气的细砂。在高围压下,细砂颗粒联系更加紧密,更多依靠颗粒骨架传递应力,使得两种气体作用下细砂抗剪强度的差别变小。细砂含水率从4%增至12%时,充CO_(2)细砂的黏聚力是充空气细砂黏聚力的2.62~4.37倍,据此可在工程建设中对有机质含量高的非饱合细砂充入CO_(2)气体,以起到加固土体的效果。In order to study the different physical and mechanical properties of unsaturated soil filled with air or CO_(2),this study focused on the hydraulic reclamation fine sand along the Changjiang River.We manipulated water content of the fine sand samples filled with air and CO_(2)respectively and carried out a consolidated undrained triaxial compression test on them.We analyzed the stress-strain curves and shear strength indexes of the fine sand under the action of air and CO_(2).The results indicated that the fine sand′s stress-strain curves exhibited a strain softening type under low confining pressure and a hardening type in high confining pressures.Fine sand filled with CO_(2)had low porosity and high compactness,resulting in greater shear strength compared to fine sand filled with air.In high confining pressures,the fine sand particles were more closely interconnected,and stress transfer was more relied on the particle skeleton,so the difference in shear strength of fine sand under the action of two gases was reduced.Increasing the water content of fine sand from 4%to 12%,the cohesion force of fine sand filled with CO_(2)were 2.62 to 4.37 times larger than that of fine sand filled with air.The effect of different gases on the internal friction angle of fine sand can not be ignored,which lies a theoretical basis for unsaturated fine sand consolidation by filling CO_(2)into it.

关 键 词：CO_(2) 非饱和土体 细砂 含水率 三轴试验 

分 类 号：TU411.6[建筑科学—岩土工程]