Monitoring And Numerical Simulation Of Deep Foundation Pit Support In Alluvial-diluvial Strata In Western Jinan

In recent years,China's economy has made remarkable achievements.Urban construction not only extends from traditional overground buildings to underground space in space,but also naturally involves the excavation of deep foundation pits.At the same time,the scale and speed of construction are as fast as the pace of life,so the safety of foundation pits becomes more and more important.The trend of development and change of foundation pit is deep and great.For the engineering site,the new development trend needs new engineering construction technology to support.This hot issue in the engineering field comes at the historic moment.It is very important for the foundation pit engineering to study the deformation stability monitoring and safety of deep foundation pit.Based on the example of deep foundation pit support in alluvial and diluvial strata of Jinan West Passenger Station,this paper compares and analyses other support forms with detailed investigation report in the construction process,and concludes that the design of Pile-anchor support forms is economical and reliable.In view of the special problems of foundation pit,the construction technology of anchor cable leakage blocking is discussed and studied.It is hoped that this paper can provide an example for the surrounding or similar projects.This paper introduces the basic general situation of the project of Jinan Quanxi Business Center.According to the compact terrain and complicated underground pipelines around it,the engineering geological conditions of the site are analyzed.Referring to the relevant codes and design requirements of foundation pit monitoring,the monitoring items and monitoring alarm values of the foundation pit are formulated.At the same time,the monitoring items of the first-grade foundation pit should be emphasized.In addition,relevant monitoring points are arranged for specific sections to support the comparison of simulation results.After calculating the earth pressure,the embedded depth and cantilever depth of the pile,and the reinforcement of the pile body,the inversion results show that the pile-anchor support scheme meets the requirements of the code,and the results and process are simulated and analyzed by the basic rationalization software.This paper uses FLAC3D software to model and simulate the deformation and settlement of foundation pit,and compares it with the field monitoring data.The deformation law of supporting pile and foundation pit is also simulated,which can guide the design and selection of reasonable pile parameters.Through the comparison and analysis of the two results,the deformation law of foundation pit is consistent and the data are close in the horizontal and vertical displacement of the soil behind the pile and foundation pit.In the aspect of the axial force of anchor cable,although the numerical deviation of force is relatively large,the force relationship between the two layers of anchor cable is consistent,and there are some deviations in part,but there are still some deviations.The general trend is the same,which shows that it is reasonable and feasible to use FLAC3D software to simulate foundation pit engineering.Because engineering involves soil anisotropy,compaction degree,interaction between supporting structure and simulated soil,etc.,it may lead to inconsistency between the statistical results of field monitoring data and the simulation results of FLAC3D numerical software.The values of these parameters should be as accurate as possible.