| As China’s urban construction advancing rapidly,foundation pit engineering emerges in large numbers,and excavates deeper and deeper.Now it faces increasingly complex environmental conditions.Because it faces many risks,easily initiates accidents,so foundation pit supporting design becomes a hot spot in geotechnical engineering.In this study,Taking the deep foundation of All-China Women’s Federation Office Building for example,according to the basic principle of foundation pit supporting,combined with the engineering geological condition,taking the depth of excavation and surrounding environment characteristics into consideration,we decide to use the scheme of pile-anchor retaining for supporting design finally.The conclusions are as follows:1.The scheme of foundation pit supporting is very important,because it relates to the safety of foundation pit engineering and engineering cost.Therefore,before the foundation support scheme finalized,we must analyze all the factors which affect the foundation pit support and the the relationship between them This paper summarizes the main factors including the engineering geological conditions,excavation properties and deformation mechanism of instability,the surrounding environment,safety and reasonable and can be implemented,new technology,&new material application and the development level of economy and society For the deep foundation pit engineering with excavating depth over 15m in this area,it is appropriate by using the scheme of pile-anchor retaining.2.Summary the pit design theory,including the calculation method of earth pressure theory and supporting design theory.The foundation pit supporting is designed in equivalent beam method which using rankine’s earth pressure theory.Then,use Lizheng software to check the design The results prove that the scheme of the foundation pit supporting is reasonable.3.According to the relevant specification,the anchor bar and slope-retaining pile are designed,and the stability of the foundation is checked,including the overall stability checking,overturning checking and anti-uplift checking.The result proves that the scheme of the foundation pit supporting is reasonable.4.In order to ensure safety of the construction of foundation pit engineering successfully,always mastering the state of the foundation pit,actualizing informatization construction,the deformation monitoring scheme is made practically,including horizontal displacement at the top of enclosure pile,settlement at the top of enclosure pile,horizontal displacement of deep ground,axial force of anchor bolt,reinforcement stresses,deformation of the surrounding buildings.Use the grey prediction model of GM(1,1)to predict the deformation of foundation pit,and the results is good.Through analyzing the monitoring data of the foundation pit,the foundation pit is proved to be steady,which supports this engineering design is reasonable.Through studying on the scheme of supporting of All-China Women’s Federation Office Building,the design of supporting structure and the scheme of deformation monitoring,we can provide a reference for similar project s in the same region in the future.So,it has practical value. |
