Analysis Of Shield Tunneling Posture And Segment Damage Control Measures In Soft Soil Layer

In the process of shield tunneling,the shield body is affected by various factors around the shield.The forward route is actually similar to the serpentine shape.The actual forward trajectory and movement trend deviate from the designed line.When the deviation degree reaches or even exceeds the preset control requirements,the shield posture should be adjusted to ensure that the tunneling track meets the design and use requirements.Under the current construction methods and measures,the deviation of shield tunneling mainly occurs in the construction process,and the setting and adjustment of relevant parameters play a key role in the change of attitude,especially in soft soil layer.Therefore,it is necessary to take measures to correct in time to ensure that the deviation between the actual track and the designed line and between the lines meets the design requirements.In addition,in the driving operation,the segments that have been assembled or are being assembled will sometimes be damaged to a certain extent,which affects the quality of the tunnel itself and the normal and continuous use in the later stage.Therefore,it is necessary to strictly control this to avoid similar situations.By analyzing the influence factors of shield tunneling posture and segment damage,this paper summarizes the prevention measures for attitude deviation and segment damage in engineering construction.According to the characteristics of shield tunnel structure construction and soft soil layer,combined with relevant influencing factors,the control methods and measures are proposed.Taking a practical engineering case as an example,the relevant links in the process of tunneling are analyzed.The main conclusions are as follows:(1)During the construction of shield tunnel,the tunneling posture is affected by thrust,direction,travel difference,geological environment and assembled segments.By analyzing these factors,stress conditions of shield machine and segment structure.The reason for deviation of tunneling posture is released.Through adjusting the relevant parameters,the actual tunneling posture and the designed lines are fitted to determine the effective control method of tunneling posture.(2)Different factors in the process of tunneling will affect the segment structure in different ways.In serious cases,it will even cause great changes in the stress situation of segments,and then damage the structure itself.Based on the analysis of relevant factors in the process,methods and measures are proposed for different factors to solve the segment damage problem under different stress conditions,so as to ensure that the operation process meets the process requirements and segment construction quality.(3)Regard to the posture deviation and segment damage phenomenon encountered in the construction of one shield tunnel construction,the above mentioned methods have been adopted.The corresponding excavation process and assembly process are adopted at the same time.The precast structure of segments have been optimized to reduce the force deviation and eccentricity.Thefollow-up operation has reached the control target of the specification and the design,and passed the practical engineering inspection.