土压平衡盾构掘进土量平衡及参数相关性分析

Analysis of Parameter Correlation and Soil Volume Balance of EPB Shield in Excavation

土压平衡盾构掘进时,一般是通过监测地表沉降数据对土仓压力进行调整,使盾构达到土压平衡状态,但该方法过于滞后,易造成不平衡掘进状况。故分析控制土量平衡的方法使盾构掘进时处于土压平衡状态,确保开挖面土层的稳定。阐述了土量平衡中的挖土量与排土量,得出使盾构达到土量平衡状态时,控制螺旋输送机转速与推进速度的比值(N/V),并总结出盾构掘进中土量平衡控制的标准。基于合肥地铁4号线隧道工程,对现场监测数据进行土量平衡分析,同时讨论关键参数的相关性,以保障盾构施工安全。结果表明:合肥地区类似工程盾构施工时可将N/V控制在0.162附近,此时盾构对土层扰动最小;土仓压力随着N/V和刀盘扭矩的增大而减小;总推力与N/V存在一定的相关性。

During the process of EPB shield tunneling,the pressure of soil compartment is usually adjusted by monitoring the surface settlement data to have the EPB shield reach the state of earth pressure balance,but this method is too old-fashioned,which is easy to cause unbalanced tunneling.Therefore,the method of soil volume balance is adopted to make the shield tunneling in the state of soil pressure balance,so as to ensure the stability of the soil layer at the excavation face.This paper expounds the amount of excavation and discharge in the soil volume balance,obtains the ratio of speed of screw conveyor and advancing speed(N/V)to make the shield reach the state of soil volume balance,and sums up the standard of soil volume balance control in shield tunneling.Based on the tunnel project of Hefei Metro Line 4,this paper analyzes the soil volume balance of field monitoring data,and discusses the correlation of key parameters,so as to ensure the safety of shield construction.The results show that:N/V can be controlled near 0.162 in the shield construction of similar projects in Hefei area,and the shield has the least disturbance to the soil;the pressure of soil compartment decreases with the increase of N/V and cutter head torque;the total thrust force is related to N/V.