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透水砂性地层开挖面上成膜特征是影响开挖面稳定性的关键因素,而地层孔隙特征与成膜特征量化关系的建立是进行相关分析的必要条件。通过在不同孔隙特征地层中开展渗透成膜试验,确定了地层孔隙特征和成膜特征的量化指标,基于二者量化关系的构建,研究了地层孔隙特征对泥浆成膜特征的影响规律。研究表明,地层滤失量曲线双参数模型可以描述地层滤失量变化特征,模型参数a,b可量化滤失量曲率特征、成膜时间和成膜阶段等成膜特征,具有明确的物理意义。基于参数a,b和孔隙体积v的幂函数关系,确定了地层孔隙特征和成膜特征的量化关系。研究成果可为泥水盾构穿越透水砂性地层合理确定泥浆配比方案和施工参数,保证开挖面稳定提供试验和理论基础。
The film-forming characteristics on the excavation surface of water-permeable sand strata are the key factors affecting the stability of the excavation face. The establishment of the quantitative relationship between the pore characteristics of the strata and the film-forming characteristics is a necessary condition for the correlation analysis. Through the experiment of infiltration film formation in different pore characteristics strata, the quantitative index of formation pore characteristics and film forming characteristics was determined. Based on the construction of the quantitative relationship between the two, the influence of formation porosity on the characteristics of mud film formation was studied. The results show that the two-parameter model of stratigraphic fluid loss curve can describe the characteristics of stratigraphic fluid loss, the quantitative and quantitative curvature characteristics of the model parameters a and b, the time of film formation and the stage of film formation, which have clear physical meaning . Based on the power function relationship between parameters a, b and pore volume v, the quantitative relationship between pore characteristics and film-forming characteristics was determined. The research results can provide experimental and theoretical basis for slurry shield through the permeable sand formation to rationally determine the slurry proportioning scheme and construction parameters and ensure the stability of the excavation face.