Study On Construction Technology Of Soil Pressure Balance Shield In Water-rich Sandy Pebble Stratum

Shield construction technology in our country has been developing for nearly 70 years,especially this year with the economic take-off,shield construction technology has also been rapid development,In a variety of geological conditions are engineering cases,Shield construction has become the most important construction method in subway construction.In the continuous development of construction technology and continue to adapt to a variety of geological conditions in the process of controlling shield machine configuration and shield machine construction parameters,It is undoubtedly the most important research in the shield construction technology.In the water-rich sand and gravel stratum,the earth pressure balance shield machine should be adopted.With the improvement of the construction level and construction technology,all the parameters of the construction tend to be perfect.This paper first introduces the selection of shield model under different geological characteristics,groundwater and other conditions,and how to determine the main function parameters of shield machine according to geological conditions,construction environment and engineering general situation before shield construction.Thus the shield machine type selection is carried out,and the configuration parameters of shield machine are optimized according to the engineering characteristics and construction requirements.Secondly,through experimental design,modeling and data analysis,construction parameters such as tunneling thrust and grouting pressure are further optimized according to thrust,torque,etc.The influence of the variation of soil pressure and grouting pressure on the construction efficiency and construction quality is also discussed.The reasonable matching optimization is made between the parameters and the problems of the pressure control of the shield construction,the improvement of the residual soil,the control of the shield attitude,the selection of the pieces of the shield and the reasonable range of the key parameters of the synchronous grouting,and the full study of the guiding system of the shield machine,the excavation system,the slag system,the residue improvement system,the installation system of the pipe,the grouting system,and the movement.The control parameters and control methods of important systems such as force system and control system provide reliable theoretical basis for shield construction.Finally,according to the engineering practice,the parameters are adjusted and perfected.According to the special strata in Chengdu,the safety,reliability,advanced technology and economy are taken into account,and a set of control measures and parameters for shield tunneling construction are formed.Finally,the purpose of guiding the construction is achieved,and it provides a meaningful reference for the shield construction under the same geological conditions in the future.