The Key Technology Research Of Tunneling Parameters Of Shield Tunneling Crossing Buildings And Rivers In Nanjing Subway Of Composite Ground

Shield construction technique in the important application in underground engineering isbecoming more and more widely, has become the main method of metro tunnel construction inour country. With metro tunnel construction in major cities across the country large-scale input,geological conditions of difference this problem increasingly prominent, the shield constructiontechnology put forward higher requirements: shield tunneling parameters selection incompound formation, shield tunneling effect on building, content, parameters selection ofshield crossing river and protection measures, etc.This article takes Nanjing metro line3TA-14standard macros~interval as thebackground, through information research, theoretical analysis, formula deduction,experimental research and numerical simulation of the integrated research methods, the Nanjingarea under the geological conditions of composite shield shield tunneling parameters, andthrough building, content, rivers influence analysis. The main research results are as follows:(1) According to the theory of shield construction parameters calculation formula, aimingat the condition of the composite under the geological conditions of shield advance, deducedthe shield in compound formation in accelerating the thrust and torque calculation formula.(2) Based on the theory of selecting suitable soil bin pressure can effectively control thefront shield excavation face stability and surface settlement; Appropriate increase soil binpressure can reduce the influence of shield excavation of soil loss.(3) In compound formation, the attitude control of shield machine adjust Angle size withinthe5mm/m, at the same time set the grouting amount to140%~175%of the theoretical value,in order to improve the grouting effect, reduce ground deformation.(4) According to the numerical simulation and formula derived formula of compoundformation sedimentation tank, and it is concluded that in compound formation sedimentationtank in the half width of3.5i.(5) Of shield tunnel excavation less influence of rock-socketed pile foundation, pilefoundation in the tunnel axis bending is the largest, the maximum of3.15mm, but by reducingof shield thrust, reduce the propulsion speed to control the deformation of pile foundation.(6) Shield crossing river mainly two aspects of the stability of the excavation face andtunnel buoyancy. Strictly control the soil bin pressure, guarantee the unearthed amount96%ofthe theoretical value; Reduce the pressure of grouting, and improve the grouting quantity for thetheoretical value of140%~180%; Control of shield tunneling posture, reduce the number ofrectifying.