Supporting Structure Selection And Case Analysis Of Comprehensive Pipe Gallery In Deep Soft Ground

With the development of the city,all kinds of underground pipelines are complicated and crisscrossed.The problems of "spider web" and "zipper" have become increasingly prominent.As one of the solutions to such problems,the comprehensive pipe gallery is widely used in various types of projects such as transportation and municipal administration.In view of the unique characteristics of long span,large depth and long period of construction,the characteristics and applicability of foundation pit supporting structure in common deep soft soil foundation in China are discussed in this paper.According to the structure selection of the foundation pit in an underground comprehensive Gallery in Wenzhou,the structure selection of the supporting mode is used to make use of the three dimensional whole.The time and space analysis method is used to compare the application effect of different support forms in deep soft soil comprehensive pipe gallery foundation pit,and the rationality of the support structure is analyzed with the field monitoring data.The main contents and conclusions are as follows:(1)selection of supporting structure for foundation pit of comprehensive pipe gallery in deep soft soil foundationIn this paper,based on the investigation of supporting structure for deep foundation pit of deep soft soil in Wenzhou area,the design scheme comparison and selection of foundation pit are introduced in detail.The three dimensional analysis of steel sheet pile and three shaft method pile is carried out in the whole time and space.Then according to the analysis results,the support structure is selected for different sections,and the design of the supporting structure is optimized.The bored piles with high cost,slow construction speed and uncontrollable construction quality are eliminated,according to different foundation pit.In profile and surrounding environment,two kinds of retaining structures are adopted: steel sheet pile and three axis pile.Because the three dimensional analysis has both quantitative and qualitative analysis,it is more pertinent to choose the results according to the analysis results,and it is easier to meet the safety and economic requirements of the foundation pit support.(2)monitoring study on foundation pit of underground complex pipe gallery in deep soft soil foundation.This part mainly expounds the monitoring of three supporting sections of the pipe gallery in the construction process of the deep soft soil comprehensive pipe gallery in Wenzhou area.The main monitoring project is the horizontal displacement of soil and the analysis of the monitoring data of the three places.It is found that the horizontal displacement and change speed of the soil in most of the monitoring points are within the range of the design target..The correctness of the type selection of the supporting structure is verified.In order to ensure the accurate monitoring of the horizontal displacement of deep soil,the following five aspects should be considered: the length of the inclinometer,the quality and the density of the packing,the deviation of the inclination of the borehole,the stability time and the initial value of the soil layer around the inclinometer,and the stability time of the inclinometer probe.In the process of foundation pit excavation,the horizontal displacement of deep soil soil is approximately linear with the change of depth,and the relationship is nonlinear when the foundation pit is excavated after the construction of the basement.