Design And Comparison Analysis Of Deep Foundation Pit Support Scheme

In recent years,the population of large and medium-sized cities in China has been rising steadily.Due to the dense population and limited urban space,the development of underground space has become a trend,especially in the north and south of Guangzhou and Shenzhen and coastal cities.The number of deep foundation pit projects is also increasing.Due to the differences in geology and surrounding environment,the depth of foundation pits is different,and the construction difficulty is not the same.It is particularly important to select the appropriate type of support structure during the construction process.The deep foundation pit support project has the characteristics of strong system and high complexity,and is one of the core issues in the construction of foundation pit engineering.The construction quality of the foundation pit support is closely related to the construction quality of the construction process such as excavation and drainage of the foundation pit.In the excavation of foundation pits,it is necessary to comprehensively consider the influence of various factors.It is especially important to control the stress and deformation of foundation pits during excavation.At present,the theory of deep foundation pit excavation and support stress is gradually improving.In the construction,it is necessary to strengthen the monitoring and measurement work,so as to achieve the whole process monitoring,so that all the work contents in the operation can achieve good results.This paper refers to the relevant literature,analyzes the main influencing factors of foundation pit support deformation,and focuses on the displacement and settlement of foundation pit support structure.Based on the previous research and analysis,combined with the deep foundation pit engineering theory knowledge and its own Practical experience and the specific construction environment and conditions of a deep foundation pit project,in-depth study of the design scheme and monitoring data of the foundation pit support structure,the main results are as follows:1.Combining relevant theories,this paper reasonably selects the appropriate type of foundation pit support structure.Through the study of earth pressure calculation theory and design calculation method of deep foundation pit support structure,according to the actual construction site conditions,suitable suitable The foundation pit support form,that is,the cast-in-place pile plus two concrete support supports,the groundwater control adopts the concrete concrete bite pile,the deep well dewatering and decompression,and the recharge measures.2.The design of the supporting scheme of the concrete support system with two concrete piles is carried out,and the construction process is monitored throughout the whole process.The main methods of monitoring are deep horizontal displacement(slope measurement),settlement of foundation pit top,internal force of retaining pile,surrounding road settlement,surrounding environment change,monitoring of groundwater level,etc.,and some data from monitoring are summarized and analyzed..The results show that the displacement of the retaining structure will change with the continuous advancement of the foundation pit excavation.The cast-in-place pile plus two concrete inner support retaining structures can better control the deformation of the foundation pit.By comparing the measured results of the field with the calculation results of the calculation software of the foundation pit and the deep foundation pit,it is shown that the deformation calculated by the rational deep foundation pit is larger than the actual monitoring deformation,which proves that the design of the project has a large The safety reserve proves that the design of this scheme is reasonable.3.The foundation pit engineering has strong complexity,multi-factor and regionality,and the theoretical calculation results are different from the actual monitoring data.The smooth construction of the foundation pit engineering is inseparable from the theoretical guidance.By analyzing the actual monitoring data,it can also verify the rationality of the design scheme and provide security for the normal construction of the deep foundation pit.The foundation pit engineering has a strong regionality.The results of this study can provide some reference and reference for the design and actual construction of similar deep foundation pit supporting structure schemes.