盾构隧道开挖引起的地表沉降规律

The Ground Settlement Monitoring of a Shield Tunnel

地表沉降值是衡量开挖方式是否合适的关键指标,因此监测和预测地表沉降有重要的实际意义。在文中,根据对盾构法开挖隧道引起的地表沉降监测资料,做出了观测断面中心点的速度直方图和观测断面中心点位移随盾构机推进的位移变化图。通过分析,发现当盾构机到达测量断面前5m～8m后,地表测点的变形达到最大隆起值,然后测点的变形速度为负值,开始向下运动;在盾构机通过测量断面大约2 5m后,测点位移几乎不再增加,变形速度也变得很小。

The ground settlement is one of the key indexes for judging whether the excavation method of an underground structure is appropriate, so it is very important to observe and predict the settlement of the ground surface. The settlement of the ground surface is measured for a shield tunnel at some profiles and the settlement curves are analyzed. Based on the observed results, the figures are drawn of the settlement velocities and the displacement development with the advance of the shield at the midpoints of the measured profiles; at the same time, the above three figures are analyzed in details. The following conclusions are drawn: the test points begin to settle and stop upheaving the displacement of the ground surface is also positive when the shield machine passed through the measured profile and is 5m～8m away from it; the displacement hardly increases and the velocity is very little when the shield machine passed through the measured profile and is 25m away from it; and so on.