循环荷载下粉土液化流动特性拖球试验研究  

Dragging ball test on flow characteristics of liquefied silt under cyclic loading

作　　者：刘涛[1,2] 张美鑫[1,2] 崔逢 

机构地区：[1]山东省海洋环境地质工程重点实验室,山东青岛266100 [2]海洋环境与生态教育部重点实验室,山东青岛266100

出　　处：《海洋学报》2017年第3期115-121,共7页

基　　金：国家自然科学基金(41672272;41427803);中央高校基本科研业务费专项资助项目(201564017)

摘　　要：基于流体力学中的Stokes黏滞阻力理论,以振动台试验为基础,开发了一套测量液化过程中粉土流变特性的拖球试验装置。在铺有粉土海床的模型箱内埋设光滑小球,通过测量小球水平运动过程中所受阻力值的大小,计算粉土液化的表观动力黏度,分析粉土液化过程中的表观动力黏度与超孔压比之间的关系,以及液化后表观黏度与应变率的变化规律。试验结果表明,振动台试验下,孔隙压力表现为迅速上升,粉土迅速达到液化状态;振动过程对海床固结影响较大;粉土海床在未达到完全液化状态时(ru<1),表观黏度随超孔压比增大而减小,在液化状态下(ru=1),剪应力随应变率增大而减小,粉土呈现出剪切稀化的特点,为典型的非牛顿流体特征。According to the theory of Stokes Law, the test apparatus of flow characteristics of liquefied silt is developed based on the shaking table tests. A steel sphere, embedded in the test box, can be moved in the horizontal direction when the silt liquefaction occurs. Resistance force and velocity of the steel sphere are measured during sphere dragging, then apparent viscosity can be evaluated. Analysis the relationship between apparent viscosity and excess pore pressure ratio during silty liquefaction. The change of apparent viscosity and strain rate after silty liq- uefaction is researched. The result shows that, during the shaking table test, the pore pressure showed a rapid increase, and silt quickly reached a liquefied state; there was consolidation phenomenon in the soil bed, and vibration had a great influence on consolidation. Analysis found that, when the soil has not reached completely liquefied state （ru〈1）, the apparent viscosity decreases with increasing of excess pore pressure ratio; when it has reached liquefied state （ru= 1）, the shear stress decreases with increasing of strain rate, the silt is shear thinning non- Newtonian fluid.

关 键 词：粉质土 液化 流动特性 拖球试验 振动台试验 

分 类 号：P642.1[天文地球—工程地质学]