| Excavation and support are the basic contents of mining engineering,and the main content of deep foundation pit engineering is the design and construction process of excavation and support,which are quite similar to mining engineering such as mine construction.The cast-in-place pile + transverse support structure has many advantages,such as low investment,low consumption of materials,high safety,small structural deformation,high degree of construction mechanization and high safety of system,especia lly the application of small deformation and saving investment in gravel stratum.Based on the actual project of "a deep foundation pit supporting structure of a subway in Chengdu",and based on the basic work of theoretical research,design and calculation of supporting structure and construction safety monitoring,this paper systematically studies the design analysis and construction safety monitoring of grouting pile and horizontal support supporting structure.The following achievements were mainly obtained:(1)According to the domestic and international studies,the characteristics of the deep foundation excavation,the form of the support structure,the shape of the deformation and the principles of design are discussed in depth.(2)Discusses the deep foundation pit supporting structure strength,internal force and deformation analysis and calculation of elastic foundation beam method "m" method theory.(3)Taking a deep foundation pit supporting structure of a subway in Chengdu as an example,the paper calculates the settlement amount of soil pressure,bending moment,shear force,displacement and the surrounding surface of foundation pit under different working conditions by using the "m" method,and verifies its stability.The calculation results all meet the technical standards for safety control of foundation pit construction.(4)According to the current construction safety monitoring standard of foundation pit in China,the monitoring items,contents,methods and control standards of the foundation pit project during excavation construction are introduced.Then the construction of the foundation pit project is monitored in detail,and the monitoring data obtained is analyzed in detail and evaluated accordingly.(5)By comparing the design value and monitoring value of pile body displacement and horizontal bracing shaft force of foundation pit supporting structure,it is found that the drainage measures should be strengthened during foundation pit excavation construction.It’s a reference to the deep excavation in Chengdu in the future. |
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