地铁行车荷载下土体动强度和动应力-应变关系

通过对南京地铁三山街站底部的原状淤泥质粉质粘土进行循环三轴仪的室内动三轴试验 ,采用一定的动应力频率、不同的动应力比以及不同的固结状态来模拟地铁行车荷载及隧道周围土体 .研究了在地铁行车循环荷载长期作用下 ,淤泥质粉质粘土的动强度和动应力 -动应变的变化规律 .实验结果表明 ,淤泥质粉质粘土的动强度随动荷载循环次数的增加而降低 ,在设计基础时 ,所取土的强度指标必须根据一次列车的动荷载大小及其循环次数而定 ;淤泥质粉质粘土在地铁列车循环荷载作用下的动应力 -动应变关系的形式仍可用R .L .Kondner的双曲线关系描述 ;土体的动剪切模量、动抗剪强度等具有随动应变值的变化而变化的规律

Dynamic Strength and Dynamic Stress-strain Relation of Silt Soil under Traffic Loading

Through laboratory tests on original silt soil of Sanshan Station Nanjing subway by using the typical triaxial test machine,definite dynamic stress frequency and different dynamic stress ratio,different consolidation state is adopted to simulate the traveling train loading and soil condition. The thesis studies the dynamic strength and stress-strain relation of silt soil under subway traffic loading.And the research shows that the dynamic strength falls as the cycle of the dynamic loading increases,and when we design the foundation,soil intensity should be decided according to the traffic loading and cyclic times.It also shows that the dynamic strength and stress-strain relation of silt soil under subway traffic loading can be described as R.L.Kondner hyperbola.In addition,the research educes the rules of the dynamic elasticity modulus and dynamic shear strain of the silt soil.