| Liquefaction flow of the sand slope after earthquake is always a very important topic in geotechnical earthquake engineering,but also a difficult point.Through the investigation and study of the results of earthquake damage in recent years,the harm of liquefaction flow of sand slope caused by the earthquake should not underestimated,study on liquefaction flow mechanism of sand slope is the target of the tireless efforts of scholars at home and abroad.Previously,domestic and foreign scholars are mostly from solid mechanics to study liquefied flow of the slope,also achieved good results.In recent years,a new thinking to predict and analysis liquefaction flow mechanism of sand slope is based on fluid mechanics theory,this idea is also more practical significance.Therefore,this paper firstly reviews the typical earthquake liquefaction flow slip damage in recent 10 years,and introduce some measures to control liquefaction flow slip.The flow and deformation of the post-liquefaction sand were analyzed by VOF method.At the same time,the VOF method is used to study the effect of flow slide piles on post-liquefaction sand.Finally,the device of measure apparent viscosity of liquefied sand is designed,and the corresponding experimental was studied.The research contents of this paper include the following aspects:(1)This paper reviews several typical liquefaction flow slip damage in the earthquake in recent 10 years,including the location and harm of the earthquake,and then introduce some measures to control liquefaction flow slip.(2)Based on the fluid mechanics theory,the VOF method is used to analyze the flow deformation of the post-liquefaction sand.Firstly,the post-liquefaction sand are respectively considered as Newton fluid and power-law type non-Newton fluid.Then,established the two-dimensional model,and analyzes the influence of the viscosity of Newtonian fluid on the velocity of its flow through the fixed point and the influence of the consistency coefficient and flow index of the non-Newtonian fluid on the velocity of the fixed point.And the engineering strain of the post-liquefaction sand is compared with the existing experimental results,the correctness of the method is verified.Then established three-dimensional fluid model of post-liquefaction sand,the three-dimensional results of the velocity of the Newtonian fluid and the non-Newtonian fluid are compared with the two-dimensional results.The results show that the results of three-dimensional and two-dimensional are basically the same in the error range,and the correctness of the method is proved again.(3)Similarly,based on fluid mechanics theory,the post-liquefaction sand flow slip pushing pile effect was analyzed by using VOF method.Firstly,respectively established single pile model and fluid model of post-liquefaction sand,the fluid-solid coupling model of single pile and post-liquefaction sand is established by coupling condition.Based on this model,the peak response curves of the acceleration,displacement and stress of single pile are obtained,and analyzed the influence of the viscosity of Newton fluid and the consistency coefficient and flow index of non-Newton fluid to acceleration,displacement and stress of the pile.Then,the fluid-solid coupling model of pile group and post-liquefaction sand is established.Similar to the case of single pile,analysis the influence of viscosity and consistency coefficient and flow index to peak response of pile acceleration,displacement and stress,and got a different result from the case of single pile.(4)Based on the theory of boundary layer,the theoretical formula for solving viscosity of post-liquefaction sand is established.And then independently developed a set of experimental device to measurement fluid characteristics of liquefied sand,and carried out the corresponding experimental studying.The conclusions consistent with the expected results.Thus,proved applicability of the device and formula,which laid a foundation for the study of the fluid properties of post-liquefaction sand. |
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