Study On Horizontal Pile-soil Behavior Of Support Piles In Deep Foundation Pit In Loess Area Based On Soil Arching Effect

With the rapid development of the construction of city rail traffic in the western region,the subway construction in loess area is increasing.The subway deep excavation support design is the most important tache,therefore through further research on the supporting role of pile soil,analysis of soil arching effect factors play,so as to support the reasonable spacing between adjacent piles set deep foundation and effective support to provide certain theoretical support.The results of this study will provide useful suggestions for the more effective use of soil arching effect in the practical projects,optimizing the design of foundation pit support and reducing the cost of the project.Based on the existing research results,based on the deep excavation project of Xi'an subway Qinglong Temple transfer station,firstly,using the research methods of indoor model test,strictly follow the construction process of excavation and supporting layer stratification in practical engineering test,research and analysis of the condition of loess strata of deep foundation pit under circular cross-section pile,displacement of pile and pile the bending moment changes in pile soil mass under the action of the in-depth analysis of the soil arching between piles formation,development,failure process,relationship between factors and pile spacing,excavation depth,soil properties,moisture content and other effects.Then combined with the finite element numerical simulation method,on the one hand,without considering the pile body strengthening is simulated and compared with the model test,further analysis of soil arching effect gradualchange soil pile and pile,and their influence factors;on the other hand to consider strengthening the situation between piles is simulated and analyzed and piles of retaining under the arch effect form of comparative studies,analysis of the existence and strengthen the body to strengthen body strength of the soil arching effect and influence of the supporting structure stability.A comprehensive analysis of the model test and numerical simulation that based on the pile spacing is 2D,soil particles have a significant wedge and the stress concentration,the soil arching effect is significant,the soil arch bearing capacity in test groups under the condition of pile spacing is the strongest,gradually decreases with the increasing of the bearing capacity of pile spacing the.In addition,in order to ensure the safety of soil between piles bearing under the premise,by reducing pile reinforcement strength between piles and pile soil allows the relative displacement of the soil particles will help to produce effective wedge,should focus on the main force deflection and stress,the soil arching effect play a more significant.