Study On The Active Earth Pressure Of Corner Effect In Deep Foundation Pit At Loess Area

Based on the second phase of Gaokeshangdu deep foundation pit engineering in Xi’an, according to real-time monitoring data and the numerical simulation, the deformation and stress of supporting structure and the deep foundation pit caused by soil excavation can be studied. Through the finite element model, the different influence factors can be created to compare and study the relationship between the excavation pit angle effect and factors.The main content can be summarized as the following:(1) Based on the design and information of construction, a supporting structure and surrounding soil field monitoring, which include monitoring points, monitoring methods, monitoring frequency and alarm value, can be to established.(2) Based on the monitoring data, by researching the action of retaining pile with anchor combined support, it can be obtained corner effect, the stress and deformation characteristics of retaining pile, soil after the pile and anchor cable. By using the grey theory to analysis relationship between design parameters and foundation pit monitoring data, in order to obtain sensitivity of the factors influencing foundation pit deformation and stress.(3) By building three-dimensional finite element model, comparing simulation results with the actual monitoring results, it is analysis and summary that the deformation and spatial effects of supporting structure and the soil.(4) Through finite element model, the different influence factors, which include the different forms and distribution of load, excavating types and ratio of length and width, are researched for the effect of PSR. Establish relational graph of influenced factors and effect pit angle distance, the effect distance will be increased by increasing depth. With the increasing upper load and L/B, the effect distance will be decreased. For the central island excavation and basin excavation, The larger width of the excavation, the greater the pit angle Effect.The results provide the reference and law about the research of the displacement near excavation pit angle in Northwest loess region, and it has a significance on optimized designing and saving investment fund.