| 盾构静-动态泥浆渗滤成膜及支护效率控制方法 |
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| 引用本文： | 金大龙,袁大军,毛家骅.盾构静-动态泥浆渗滤成膜及支护效率控制方法[J].中国公路学报,2022,35(12):154-167. |
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| 作者姓名： | 金大龙 袁大军 毛家骅 |
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| 作者单位： | 1. 北京交通大学 隧道与地下工程教育部工程研究中心, 北京 100044;2. 北京交通大学 土木建筑工程学院, 北京 100044 |
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| 基金项目： | 国家自然科学基金青年科学基金项目(52008021)；高速铁路基础研究联合基金项目(U1834208)； 国家重点基础研究发展计划(“九七三”计划)项目(2015CB057800) |
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| 摘 要： | 近年来，泥水盾构在越江跨海隧道中被广泛应用，隧道开挖面“泥浆-土水”相互平衡作用是工程安全的关键。盾构泥浆能否成膜、动态掘进泥膜是否存在、动态泥膜如何发挥支护作用等问题受到广泛关注，理清这些问题是保障开挖面稳定的基础。对此，基于多相流理论提出了泥浆“渗滤-成膜-生长”瞬态力学模型，探明了泥浆的流体特性和地层的水力传导性质的时空变化规律，揭示了盾构停机静态成膜和掘进动态成膜机制，并通过静、动态成膜2个实例计算验证了理论方法的适用性。研究结果表明：盾构静态停机状态下通常为全断面泥膜，泥浆以面力形式进行支护，盾构掘进时表现为动态局部泥膜，泥浆压力可较长距离前向传递，以渗透力的形式发挥作用；盾构掘进时开挖面泥膜分布为多辐扇形的局部泥膜，可分为泥膜渐变区和无泥膜区，无泥膜区域靠近先行刀臂，随着刀盘转速的增加，泥膜的厚度和泥膜面积逐渐减小；实际工程中，可以从泥浆材料和掘进参数两方面提升泥浆的支护作用，一方面根据地层-泥浆粒径比和泥浆黏度双控指标进行泥浆配置，另一方面宜降低盾构刀盘转速，同时适当增加掘进速度，充分发挥局部泥膜的支护作用，提高泥浆的支护效率和开挖面的稳定性。研究成果对泥水盾构施工安全有一定的指导意义。
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| 关 键 词： | 隧道工程 泥水盾构 渗滤理论 动态泥膜 成膜判据 支护效率 |
| 收稿时间： | 2021-06-24 |
A Novel Approach for Filter Cake Formation During Static-dynamic Shield Tunneling and Its Support Efficiency Control Method |
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| JIN Da-long,YUAN Da-jun,MAO Jia-hua.A Novel Approach for Filter Cake Formation During Static-dynamic Shield Tunneling and Its Support Efficiency Control Method[J].China Journal of Highway and Transport,2022,35(12):154-167. |
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| Authors: | JIN Da-long YUAN Da-jun MAO Jia-hua |
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| Affiliation: | 1. Key Laboratory for Urban Underground Engineering of Ministry of Education, Beijing Jiaotong University, Beijing 100044, China;2. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China |
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| Abstract: | In recent years, slurry shield machines have been widely used to build tunnels under the sea or rivers. During shield tunneling, knowledge of the slurry-soil-water interactions is crucial for engineering safety. Whether the slurry can generate a filter cake, whether the dynamic filter cake can be maintained, and how to determine the support efficiency of the dynamic filter cake are important topics in this field. In this study, a transient model for the “infiltration-cake formation-growth” process of slurry was determined based on the multiphase flow theory. The effects of slurry movement and particle deposition were considered in this model. The hydraulic parameters of the slurry and soil structure varied with time and spatial location. The formation mechanism of the filter cake under static and dynamic states is also discussed. The proposed model was validated using laboratory experiments and field measurements. The results indicate that the filter cake fully covers the tunnel face during the standstill of the shield machine, and that the slurry pressure supports the tunnel face in the form of surface forces. During shield driving, the filter cake is covers the tunnel face locally, and the slurry pressure supports the tunnel face in the form of volume forces (i.e., seepage forces). The slurry pressure can transform dynamically over a long distance, which significantly reduces the support efficiency. The filter cake is distributed in the form of a multi-spoke fan-shaped cake, which can be divided into cake zones and cake-free zones. The cake-free zone is close to the forward spoke. Both the thickness and area of the filter cake decreased with the rotation speed of the cutter head. In engineering practice, the support efficiency of the local filter cake can be improved by adjusting the slurry materials and driving parameters of the shield machine. The particle size of the soil and bentonite, as well as the slurry viscosity, are critical for filter cake formation. In addition, a low rotation speed of the cutter head and a high advance rate of the shield machine can contribute to the support efficiency as well as the face stability. This study provides a reference for the construction of tunnels using slurry shield machines. |
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| Keywords: | tunnel engineering slurry shield infiltration-filtration theory dynamic filter cake formation criterion support efficiency |
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