为了研究圆形顶管施工引起的地层损失规律,开展了室内模型试验和数值仿真分析,室内试验中采用气囊放气模拟顶管施工过程中的地层损失,并用光纤光栅来测定其放气时的应变。结果表明:相比沉降,采用应变作为监测指标分析顶管施工的影响更具有实时性,灵敏度更高;开挖面上方土体沉降变形符合Peck公式规律,中心最大沉降量随管道埋深的增加而增大;沉降槽影响范围宽度主要与管道的管径及埋深有关,沉降槽宽度系数k随着D/H线性增加;随着地层损失增大地表最大沉降增大,随着间隙参数g的增大地表最大沉降值线性增大。
In order to study the formation loss caused by circular pipe jacking construction, indoor model tests and numerical simulation analyses are conducted. The airbag deflation is used to simulate the formation loss during pipe jacking construction, and the optical fiber grating is used to determine the strain during deflation. The results show that: The effect of using strain as a monitoring index to monitor the influence of pipe jacking construction is more real-time and has higher sensitivity than settlement monitoring. The settlement deformation of the square soil on the excavation surface conforms to the fitting law of Peck settlement formula. The maximum settlement of the center increases with the increase of the buried depth of the pipeline. The width of the settlement tank is mainly related to the pipe diameter and buried depth of the pipeline. The width coefficient of the settlement tank k increases with the increase of D/H. With the increase of formation loss, the maximum subsidence increases. The maximum subsidence value increases with the increase of the gap parameter g.
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