In-situ measurement of stress of rebars in shaft lining during drilling sinking
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摘要: 介绍了温家庄铁矿副井钻井井壁施工期间钢筋应力的实测方案，分析了钻井井壁钢筋应力的变化规律，结果表明：施工期钻井井壁钢筋以受压为主，环向钢筋压应力大于竖向钢筋，钢筋应力变化阶段与施工工序相对应。漂浮下沉阶段钢筋应力呈现“双线性”特点，实测与理论计算应力相吻合；增加配重水阶段环向钢筋压应力减小而竖向钢筋压应力增加；首次注浆阶段钢筋压应力显著减小，个别钢筋出现拉应力；后 3 次注浆阶段钢筋压应力先增加后部分恢复，环向钢筋应力变化大于竖向钢筋；抽排配重水阶段环向钢筋压应力显著增加，竖向钢筋应力变化不大；二次补注浆阶段钢筋压应力先增加后恢复，但恢复幅度较前述注浆有所减小。施工完成后钢筋最大应力达到屈服应力的 41% 。Abstract: The stress-measuring scheme of rebars in the shaft lining of auxiliary shaft of Wenjiazhuang Iron Ore Mine during drilling sinking is introduced, and the variation of the measured stresses is discussed. The results show that the rebars bear compressive stress during drilling sinking, the compressive stress of the tangent-directional rebars is greater than that of the vertical one, and the variation phases of the stresses correspond to the sinking phases. During the floating and dropping phase, the stress curves present “bilinear” feature. During the water-adding phase, the compressive stress of the tangent-directional rebars decreases and that of the vertical one increases. During the first grouting phase, the compressive stress decreases significantly, and some rebars even bear tensile stress. During the sequent three grouting phases, the compressive stress increases first, then partially recovers. During the drainage phase, the compressive stress of the tangent-directional rebars increases and that of the vertical one changes little. During the additional grouting phase, the compressive stress increases first, then partially recovers a less part as compared to the preceding grouting. When the sinking is completed, the maximum compressive stress of the rebars reaches the yield stress of 41%. This installation stress should be considered when designing the shaft lining.
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Keywords:
- drilling sinking /
- shaft lining /
- stress of rebar /
- in-situ measurement
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