深厚冲积层冻结井筒外层井壁结构可靠性分析

    Reliability Analysis on Outer Shaft Lining Structure of Freezing Shaft in Deep Alluvium

    • 摘要: 双层高强钢筋混凝土井壁是我国深厚表土层冻结法凿井中的主要支护结构,为了优化冻结井筒高强井壁可靠性设计,采用概率极限状态设计方法替代传统的容许应力设计法,以丁集矿副井外层井壁501 m层位为研究对象,用ANSYS有限元程序对深厚冲积层冻结井筒外层井壁结构的可靠性进行分析。结果表明:有限元模拟得出该层位外壁的可靠性指标为2.98,与JC法理论计算结果基本相符。外层井壁可靠性影响因素按重要程度依次为冻结压力、混凝土轴心抗压强度、厚径比和配筋率。

       

      Abstract: Double high strength reinforced concrete wall is main support structure for deep surface soil freezing drilling in China. In this study, probability limit state design method is proposed to replace allowable stress design method in order to optimize the reliability design of high strength shaft lining in freezing shaft. Taking 501 m of outer sidewall of Dingji auxiliary well as the research object, the reliability of outer sidewall structure of deep alluvial frozen wellbore was analyzed by ANSYS finite element program. The results show that the reliability index of the coal mine at this depth is 2.98 and there is almost no difference between value of theoretical calculation and finite element simulation analysis. The importance for influence factors of outer shaft wall reliability from the large to the small is freezing pressure, axial compression strength of concrete, thickness-to-radius ratio and reinforcement ratio according to sensitivity analysis in ANSYS software.

       

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