厚冲积地层盾构掘进参数设定及地表变形规律研究

盾构掘进参数与地质条件密切相关,在厚冲积黄-黏土层中掘进参数计算及地表变形规律具有显著的地异性特征。通过统计分析济南轨道交通R1线直径6.68m盾构隧道现场实测数据,明确了盾构掘进参数设定范围和修正计算公式,探究了掘进参数间相关性及其对地表变形的影响规律。研究结果表明:盾构总推力、刀盘扭矩、土仓压力的理论计算修正系数分别为0.677~0.753、0.882~1.260、0.985~1.641;同步注浆量、出土量与掘进速度呈较强线性相关;盾构掘进参数对地表变形规律影响显著,最大地表沉降量及地层损失率随土仓压力的减小而增大,随掘进速度增大呈二次函数递减,随同步注浆率增大呈线性递减。

Study on Parameters Setting of EPB Shield Driving and Laws of Surface Deformation in Thick Alluvial Clay

The shield driving parameters are closely related to geological conditions, and its calculation and surface deformation pattern in thick alluvial loess-clay have significantly regional characteristics which vary greatly from place to place. The setting range of shield driving parameters and its modified formulas were determined through statistical analysis of the field measured data of 6.68m-diameter shield tunnels in the Jinan rail transit line R1. The correlation between driving parameters and its influence law on surface deformation were explored. The results demonstrate that the correction coefficient of theoretical calculation for thrust force, cutterhead torque, and chamber earth pressure are 0.677~0.753, 0.882~1.260, 0.985~1.641, respectively. The synchronous grouting amount and excavated earth amount present strong linear correlations with the shield driving speed. The shield driving parameters have significant effects on surface deformation. The maximum ground settlement and ground loss ratio increase with the decrease of chamber earth pressure. Both of the maximum ground settlement and ground loss ratio decrease as a quadratic function of driving speed, and decrease linearly with the increase of synchronous grouting rate.