Evaluation Method of Loose Characteristics of EPB Shield Slag Considering the Formation Heterogeneity and Plastic Fluidization Process
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摘要: 对土压平衡盾构渣土出土量进行准确评估，有利于渣土处理处置工艺、处理能力、处理成本的确定。基于土力学中土的三相组成理论分析了渣土松散特性计算原理并推导出评估公式，形成土压平衡盾构渣土松散特性的评估方法。结合土工试验（密度和含水量试验），采用该评估方法测定出松散系数，并与工程计量结果进行对比分析，结果显示：不考虑地层不均和塑流化过程的渣土松散系数为1.50，只考虑地层不均的松散系数为1.52，只考虑塑流化的松散系数为1.53，同时考虑地层不均和塑流化过程的松散系数为1.54，工程实际计量所得松散系数为1.64。由此可见，塑流化过程是主要因素，地层不均为次要因素，其结果与现场计量结果虽有差距但考虑地层不均和塑流化过程的松散系数与之趋近。该方法为渣土松散系数的确定提供一种新的方法和思路，同时为渣土量的准确预测提供基础数据的获取方法。Abstract: Accurate assessment of the EPB shield slag is conducive to the determination of the slag treatment process, treatment capacity, and treatment cost. Based on the three-phase composition theory of soil in soil mechanics, it analyzes the calculation principle of the loose characteristics of slag soil and deduces the evaluation formula, and forms the evaluation method of the loose characteristics of the slag soil of EPB shield. Based on the geotechnical test (density and water content test), the coefficient of looseness was determined by this evaluation method and compared with the engineering measurement results. The results show that the loose coefficient of the slag soil without considering the formation unevenness and plastic fluidization is 1.50, the loose coefficient only considering the formation unevenness is 1.52, the loose coefficient only considering the formation plastic fluidization is 1.53, the loose coefficient considering the formation unevenness and plastic fluidization is 1.54, and the loose coefficient obtained by the actual measurement of the project is 1.64. It can be seen that the plastic fluidization process is the main factor and the formation unevenness is the secondary factor. The results are in good agreement with the actual measurement results. This method provides a basic data acquisition method for the accurate prediction of the amount of residual soil.
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Key words:
- EPB shield slag /
- stratum unevenness /
- plastic fluidization /
- evaluation method
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表 2 隧洞断面各岩土层及其渣土物理指标
岩土层 天然密度/（g·cm−3） 含水率/% 平均干密度/（g·cm−3） 强风化板岩 2.64 3.81 2.54 中等风化板岩 2.66 2.28 2.60 微风化板岩 2.72 1.86 2.67 渣土 2.12 22.72 1.73 
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表 3 隧洞特征断面岩土层干密度取值结果
项目 岩土
类别断面分区
面积/m2断面总
面积/m2岩层干
密度
/（g·cm−3）断面平均
干密度
/（g·cm−3）断面加权
平均干密度
/（g·cm−3）岩土层 强风化 3.10 28.28 2.54 2.60 2.63 中等风化 9.84 2.60 微风化 15.34 2.67
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