Department of Mechanical Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, China.
Department of Intelligent Manufacturing, Wuyi University, Jiangmen, Guangdong, China.
PLoS One. 2019 Mar 13;14(3):e0212923. doi: 10.1371/journal.pone.0212923. eCollection 2019.
Soil is the medium that balances the soil and water pressure on the excavation surface of an earth pressure balance (EPB) shield machine, and the soil flow plasticity directly affects the working performance of the shield machine. The spiral shear stress is the main determinant of the soil flow plasticity. During the progress of the EPB shield screw conveyor normal operation, the shear effects between the muck in the spiral tube and the screw shaft, as well as the flight, are different from the shear action, such as the direct shear or the vane shear. The direct or vane shear test is now widely used to evaluate soil flow plasticity. To better investigate the shear properties between the soil and the shield conveyor casing, a model screw conveyor was developed. Based on the analysis of the stress conditions and the movement of the conditioned soil plug, the theoretical calculation model of the equivalent helical shear stress of the EPB shield screw conveyor was deduced based on the steady-state equilibrium conditions of moment of momentum. The conditioned standard sand was used in the indoor tests. The results of the indoor test of the model machine verified the rationality and effectiveness of the theoretical model. The model provides an important theoretical basis and references for the design and optimization of soil conditioning during shield tunneling.
土壤是土压平衡（EPB）盾构机开挖面水土压力平衡的介质，土壤流塑性能直接影响盾构机的工作性能。螺旋剪切应力是土壤流塑性能的主要决定因素。在 EPB 盾构机螺旋输送机正常运行过程中，螺旋管内渣土与螺旋轴以及叶片之间的剪切作用与直接剪切或叶片剪切不同。目前，直接剪切或叶片剪切试验被广泛用于评价土壤流塑性能。为了更好地研究土与盾构输送机套管之间的剪切特性，研制了一种模型螺旋输送机。基于对条件土塞的应力条件和运动的分析，根据动量矩的稳态平衡条件，推导出 EPB 盾构螺旋输送机等效螺旋剪切应力的理论计算模型。在室内试验中使用了经过调理的标准砂。模型机的室内试验结果验证了理论模型的合理性和有效性。该模型为盾构隧道施工中土壤调理的设计和优化提供了重要的理论依据和参考。
