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开挖面的稳定性是盾构隧道施工技术的关键。针对目前考虑坡度因素的盾构隧道开挖面极限支护力计算尚未见到报道的现状,基于筒仓理论,采用极限平衡分析法,引入线路坡度角,建立了迎坡施工条件下,盾构隧道开挖面极限支护力的计算模型,推导了相应的计算公式,并进行了实例分析,结果表明:该方法具有很好的可靠性,可用于同类工程的设计与施工。在此基础上,进一步计算得到了不同坡度时的盾构隧道开挖面极限支护力的大小,探讨了线路坡度对开挖面极限支护力大小的影响,主要得出了以下结论:开挖面极限支护力随线路坡度增大而呈线性显著增大;而开挖面前方土体破裂角随线路坡度增大反而线性减小,且两者之和可视为一常数。可见,线路坡度的存在对开挖面支护力的影响较大,不能简单地等同为平坡条件,设计、施工过程中应予以充分考虑。
The stability of excavation surface is the key to shield tunnel construction technology. According to the silo theory, using the limit equilibrium analysis method, the gradient angle of the line is introduced to establish the shield support for shield tunneling The calculation model of ultimate supporting force for tunnel excavation surface is deduced. The corresponding calculation formulas are deduced and the case analysis is carried out. The results show that the method has good reliability and can be used in the design and construction of similar projects. On this basis, the limit support force of shield tunnel excavation face with different slope is calculated, and the influence of line slope on the limit support force of excavation face is discussed. The main conclusions are as follows: The limit support force of digging surface increases linearly with the increase of the slope of the line, while the fracture angle of the soil in front of the excavation surface decreases linearly with the increase of the slope, and the sum of the two can be regarded as a constant. It can be seen that the existence of the slope of the line has a great influence on the supporting force of the excavation face and can not be simply equal to the flat slope condition. During the design and construction, it should be fully considered.