扰动条件下细粉质砂土浆体流场PIV试验研究

The Flow Field of Fine Silty Mortar under Perturbation Condition by PIV

为了研究细粉质砂土在扰动状态下的快速固结沉积的机理,本文对黄河三角洲地区的粉细质砂土在扰动状态下的流场变化规律以及物理性质变化规律进行PIV(particle image velocimetry)实验分析。结果表明,扰动引起侧边孔隙水压力增大,导致土层的力场由重力场主导主编变为扰动力场主导;结合PIV流场分析可知扰动区域分为上部的下沉重力流,下方形成上升的扰动流,底部由土压力主导的沉积区;并结合沉积土体取样分析,颗粒分选呈现抛射迁移规律,细颗粒在抛射过程呈现密度差,流体在流动过程中呈现速度差分选;通过试验现象以及力学分析建立浆体流膜分选理论分析模型,与PIV测试试验结果分析较为吻合,能够有效解释扰动条件下粉细质砂浆体流场运动及颗粒分选规律,并为相关工程提供理论基础。

In order to study the mechanism of rapid consolidation and deposition of fine sand under disturbance,particle image velocimetry(PIV)experiments were carried out to analyze the flow field and physical properties of fine sand under disturbance in the Yellow River Delta.The results show that the lateral pore water pressure increases due to disturbance,which leads to the change of force field of soil layer from the editor dominated by gravity field to that dominated by disturbance field;From PIV flow field analysis,it can be seen that the disturbance area is divided into the upper subsidence gravity flow,the lower part forms the ascending disturbance flow,and the bottom part is dominated by earth pressure.Combined with the sampling analysis of sedimentary soil,the particle sorting shows the law of jet migration,the density difference of fine particles in the jet process,and the velocity differential selection of fluid in the flow process.Through experimental phenomena and mechanical analysis,a theoretical analysis model of slurry membrane separation was established,which is in good agreement with the analysis of PIV test results.It can effectively explain the flow field motion and particle separation law of fine powder mortar under disturbance,and provide a theoretical basis for related projects.