Most shield tunnels in urban soft clay or mudstone strata are constructed by Earth Pressure Balance shield (EPB shield). When tunneling in similar strata, the clay soils may clog easily in the cutter head, soil chamber or screw conveyor. In mudstone stratum, assessing a reasonable conditioning state of clay soil is key to ensuring improved shield tunnelling efficiency. The fluidity and adhesion of clay soil are important evaluation indexes of the soil conditioning effect of clay soil. In order to explore the factors affecting the conveying properties of screw conveyor under certain pressure difference in medium-weathered mudstone strata, the changes of clay soil fluidity and adhesion under foam improvement were studied through slump and mixing tests. A screw conveyor model device was developed, and its torque, bearing capacity and discharging efficiency under different soil chamber pressure conditions are comprehensively analyzed combined with the fluidity and adhesion of the soil to help optimize a reasonable slump value of clay soil according to the change of soil chamber pressure in practical engineering. In-situ data from the Ziyang Line of the Chengdu Metro show that the recommended slump value of mudstone stratum can effectively improve soil discharging efficiency and ensure construction safety.

中文翻译：

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土壤调理和螺旋输送特性 中等风化泥岩地层土压平衡隧道掘进的室内试验


城市软粘土或泥岩地层中的盾构隧道大多采用土压平衡盾构（EPB 盾构）建造。在类似的地层中掘进时，粘土很容易堵塞刀盘、土壤室或螺旋输送机。在泥岩地层中，评估粘土的合理调节状态是确保提高盾构掘进效率的关键。黏土的流动性和粘附性是评价黏性土土壤调节效果的重要指标。为探究中等风化泥岩地层中一定压差下螺旋输送机输送性能的影响因素，通过坍落度和混合试验研究了泡沫改良下黏土流动性和粘结性的变化。研制了螺旋输送机模型装置，结合土体的流动性和粘附性，综合分析了其在不同土室压力条件下的扭矩、承载能力和卸料效率，以期根据实际工程中土室压力的变化优化粘土的合理坍落度值。来自成都地铁紫阳线的原位数据表明，泥岩地层的推荐坍落值可以有效提高土壤排放效率，保证施工安全。