Studies On Stability Analysis Of Deep Foundation Pit In Saturated Silty Sand Form High Rise Residential Building

Is the law of internal force and deformation of foundation pit engineering in the process of excavation,geotechnical workers have done a lot of research,and achieved fruitful results,but for deep foundation pit in saturated silty sand form high rise residential building,deformation measurement and numerical simulation of the mechanism are relatively less.With the development of large-scale city modernization construction of our country,will have a lot of building in the geological condition is very complex,as everyone knows,the construction in saturated sand stratum in the absence of reasonable support,easy to produce sand,piping etc..In addition,saturated sand also has high sensitivity and thixotropic properties,especially when the earthquake occurred under dynamic loading,prone to liquefaction phenomenon leads to soil failure endanger the building safety,Ningxia Pingluo earthquake is a typical example.The Yinchuan plain is the alluvial plain of the Yellow River,near to foundation soil for the Yellow River alluvial silty sand,resulting in loss of bearing capacity of foundation liquefaction,uneven surface subsidence,a large number of houses and buildings collapsed causing heavy casualties and property losses.If the construction is improper in practice,it is easy to cause structural subsidence,excessive deformation,and even lead to landslide accidents.So the harm for saturated sand soil can not be ignored.Therefore,this paper will take the Ningxia area of Yinchuan iron hair deep excavation Runfa lan ting high-rise commercial and residential building as the basis,using the numerical simulation method and combined with field monitoring results and precipitation construction program,study on the stability of the deep foundation pit of the sand.The main contents and conclusions are as follows:(1)The first is review the relevant literature at home and abroad,understanding the characteristics of deep foundation pit supporting structure of the research status,stress characteristics,classification,main city of high-rise buildings,especially the basic classification and structure characteristics of composite soil nailing wall master.Clear the main content of this study and research objectives.(2)According to the geological survey report,master the engineering characteristics of deep foundation pit sand stratum,lay a foundation for the subsequent of the calculation of parameter selection numerical simulation and analysis of the monitoring results.(3)The precipitation for the construction of deep foundation pit earthwork excavation and foundation pit supporting construction provides a dry environment,the important role toensure the structural stability of the deep foundation pit,and the pit excavation is one of the important processes,this paper studies the characteristics of the project specific to design the deep foundation pit dewatering plan.The number of dewatering wells,the structure of dewatering well and the selection of pumping equipment are obtained.(4)According to the characteristics of composite soil nailing wall,the finite element method is used to simulate the concrete construction project by using Midas-GTS software.The change of the ground settlement around the foundation pit,the horizontal displacement of the soil nailing wall and the axial force of the soil nailing along with the excavation process are analyzed emphatically.The results further reveal the change law of Yinchuan area saturated silty sand excavation.(5)Monitoring and measurement of the construction process are the best evaluation,a direct reflection of the construction of the supporting structure of the force changes,so the measurement of foundation settlement and displacement,and compared with the results of numerical simulation,put forward reasonable suggestions on construction.