Research On Dynamic Compaction Test And Numerical Simulation Of Collapsible Loss Ground Improved

Collapsible loess is one of the most widely distributed soils in China.It has the characteristics of large pores and vertical joints.When water is wet,the strength is significantly reduced,resulting in the collapse of the soil.The construction of a highway on a collapsible loess foundation will cause engineering problems such as settlement and instability in the upper roadbed if not handled properly,thereby shortening the service life of the expressway.Due to its simple equipment and convenient construction,the Qiangqin method can significantly improve the carrying capacity of the soil and has a remarkable economic effect.Therefore,it has been widely used in soil reinforcement.At present,there is relatively little research on the method of dynamic compaction in collapsible loess,and the key parameters in the construction of dynamic compaction are only determined by engineering analogy and experience,lacking in-depth research.Therefore,it is of great significance to carry out theoretical and experimental research on the application of the dynamic compaction method in collapsible loess.This paper use Chengde section of Chengzhang Expressway as a background for the consolidation of collapsible loess foundation.This article analyse the dynamic consolidation mechanism and the factors that affect the foundation reinforcement.Therefore,this article makes a systematic research of dynamic consolidation by experimental study and systematic research of dynamic consolidation by experimental study and data simulation.Detailed studies are as the follows:(1)Combining the studies of construction at home and abroad,which include the statement of the vibration theory,dynamic consolidation method,dynamic compaction method and dynamic replacing method,this article deeply analysis dynamic consolidation.According to the analysis of the parameters of dynamic compaction and soil,it is more clear to clarify the effect of foundation reinforcement.(2)Though the experimental analyses about collapsible loess foundation during experiment stage,such as observation on land subsidence,standard penetration text in the south of Fengning city during Chengde expressway,which belongs to Cheng Zhang highway.It turns out that when effective reinforced depth is above 5 meters,the foundation bearing capacity in consolidation text is 150 kPa.(3)Based on the real feature of collapsible loess foundation during experiment stage,this article used ABAQUS software to build the finite element model of highway's foundation and made data simulation during dynamic consolidation period.Compered the settlement between data simulation and field experiment,it verifies the reasonable of date simulation,then the displacement and the development of the plastic zone under the strong ramming impact load are analyzed and studied.It is of great significance for the result of research about dynamic compaction method used in collapsible loess.