盾构下坡掘进对推进阻力的影响研究

以神华新街6°煤矿斜井盾构工程为背景,针对盾构下坡掘进工况,通过建立盾构上作用的水土压力载荷与坡度的数学关系模型,推导出推进阻力与坡度的数学公式。结合工程实例,计算水平掘进与6°下坡掘进各推进阻力值,并利用MATLAB软件绘制下坡掘进时推进阻力随坡度变化的曲线。结果表明:1)6°下坡掘进的总推进阻力相对于水平掘进仅减小了约8%,坡度小于13°时,可通过水平掘进时的推进阻力减去重力沿掘进轴线上的分量来近似求得,且偏差小于10%;2)总推进阻力会随坡角的不断增大而减小;3)当坡度大于50.4°后,盾构有自动向下滑移的趋势,刀盘将自动压紧开挖面,导致刀具自动嵌入开挖面,增加了启动扭矩与换刀的难度。

Research on Influence of Shield Boring Downhill on Thrusting Resistance

The model of mathematical relationship between water and soil pressure on shield and gradient of slope is established; the mathematical relationship between shield thrusting resistance and slope gradient is deduced; the shield thrusting resistance when boring horizontally and downhill by 6° are calculated; and the curves of relationship between shield thrusting resistance and slope gradient are described by software MATLAB, by taking shield bored inclined shaft of Xinjie Mine in Inner Mongolia for example. The results show that: 1) Compared to boring horizontally, the total thrusting resistance of shield when boring downhill by 6° is 8% smaller. The total thrusting resistance of shield when boring downhill by 6° nearly equals to that subtracting component of gravity along axial line from total thrusting resistance of shield boring horizontally when the gradient is less than 13°. 2) The total shield thrusting resistance decreases with the gradient increase. 3) The shield will slide downhill when the gradient is larger than 50.4°； as a result, the cutters on cutterhead would be invaded into excavation face which would induce hard torque start and cutter replacement.