Study On Excavation Support For Midea Road Tunnel In Foshan Passing Through Under G105

Due to the continuous development of social economy and the rapid increase of people's demand,more and more tunnels and underground projects such as urban subway,interchange(or underpass),municipal comprehensive pipeline,highway tunnel,underwater tunnel and so on should be constructed.With the increasing tension of urban construction land,the cost of urban land use is also increasing.In order to further adjust the use structure of urban land and save urban land,urban underground space has been continuously developed and utilized,and a large number of underground projects such as tunnels,subway,underground shopping malls have emerged.With the development and utilization of these underground spaces,a large number of deep foundation pit projects emerge as the times require.This paper is a study on the construction support scheme and structure design of G105 tunnel project under Mei Avenue in Beijiao Town,Foshan City,Guangdong Province.In the design process,combined with the tunnel engineering geological investigation report of this project,the supporting structure design and checking calculation of the deep foundation pit under the tunnel are carried out.Firstly,by analyzing the geological conditions of the underpass tunnel engineering site,the importance grade of the underpass foundation pit is determined;secondly,after determining the site conditions of the underpass tunnel foundation pit,the distribution of underground pipelines and the adjacent buildings,the best foundation is selected by comparing the practicability of different supporting modes in the underpass tunnel foundation pit longitudinally.Pit support scheme,and check the strength and stability of the support design of the scheme.Finally,according to the condition of foundation pit and geological investigation,the monitoring and design of foundation pit is carried out,and the whole process of supporting structure and surrounding environment of foundation pit is monitored andmeasured,which provides dynamic information for construction and design.By analyzing,researching and judging the testing data,the construction can be guaranteed smoothly and the surrounding environment of foundation pit can be reduced as much as possible.Environmental impact.According to the complexity of the foundation pit site and geology,the excavation depth and surrounding environment of the foundation pit,the grade of the foundation pit under the tunnel is two,which determines the selection of the supporting structure and the application of the corresponding algorithm.According to the different supporting depth,the single and different combination of steel sheet pile support,bored pile support and internal support support support are used to design the foundation pit support structure.The cross-treatment scheme between tunnel and subway shield is optimized,and the supporting structure is excavated by using the deep foundation pit positioning software.The checking of overall stability,anti-overturning stability and anti-uplift ensures that the supporting structure of the foundation pit not only meets the safety requirements,but also saves the construction cost.The monitoring design of the foundation pit is carried out for the supporting construction of the foundation pit,and the monitoring and measurement of the supporting structure,foundation pit and surrounding environment are carried out in the whole process to ensure the safety of the supporting construction and structure..