草炭土路基填筑过程力学特性试验  

Experimental Study on Mechanical Characteristics of Turfy Soil Under Roadbed Filling

作　　者：刘飞[1] 佴磊[1] 吕岩[1] 徐丽娜[1] 

机构地区：[1]吉林大学建设工程学院,长春130026

出　　处：《吉林大学学报（地球科学版）》2011年第2期505-510,共6页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(40772169);吉林大学2010年研究生创新研究计划资助项目(20101061)

摘　　要：采用GDS应力控制三轴仪模拟实际草炭土路基填筑过程,通过控制排水阀和加载速率,研究不同排水和加载速率条件下路基草炭土孔压、变形、应力路径以及强度的变化特征。试验结果表明:不同的试验条件对初始路基填筑阶段各力学指标影响较小,认为草炭土各力学特性变化趋势依赖于初始的固结状态;比较第二剪切阶段后各曲线的变化可以看出,不排水加载使得孔压无法消散并急剧增加,有效应力迅速降低,地基土强度快速减弱;快速加载使得孔压变化量、地基变形量较大,地基强度降低较快,不利于路基的稳定性;而慢速加载则与之相反,但会增加加载的时间和耽误工期。By using GDS stress-controlled triaxial instrument to simulate the roadbed filling process,the variation characteristics of pore pressure,strain,stress path and strength were studied by controlling the drain valve and loading rate.The test results show that each mechanical index has less change at initial roadbed filling under different test conditions,so that the variation of mechanical index depends on the initial consolidation state.Comparing the developments of every curve change from the second shear stage,undrained loading condition makes the effective stress decrease rapidly because the pore pressure cannot dissipate but increase sharply.Fast loading makes increment of pore pressure and roadbed strain large,and makes the foundation strength decreased,which is unfavourable to the stability of roadbed.Oppositely,slow loading let foundation strength decrease slowly but will add loading time and detain construction time.

关 键 词：草炭土 路基填筑 孔压 力学特性 

分 类 号：TU411[建筑科学—岩土工程]