抗水压多层衬砌分析模型及其应用研究

Analysis Model of Multi-layer Lining against Water Pressure and Its Application

  • 摘要: 隧道穿越岩溶多发地段时易承受较大水压荷载作用,相对传统的复合衬砌,抗水压多层衬砌可设置二道防水板,保证了衬砌的施工质量。基于此,文章提出了抗水压多层衬砌的分析模型,通过实例分析得出,内、外层衬砌间仅压弹簧的弹簧刚度系数增加时,内、外层衬砌弯矩基本不变,外层衬砌轴力减小,偏心距增大;内层衬砌轴力增加,偏心距减小。当水压荷载增加时,衬砌拱顶由大偏心受压状态变成小偏心受压,再逐渐逼至抗压极限承载状态,安全系数先增后减;拱腰、边墙处逐渐逼至抗压极限承载状态,安全系数逐渐减小;拱脚、仰拱处由小偏心受压状态变成大偏心受压状态,安全系数逐渐减小。

     

    Abstract: Compared with the conventional composite lining, the multi-layer lining loaded by large water pressure can reserve one more waterproof board and guarantee its construction quality when tunnel passes through karstprone section. This paper sets forth an analysis model of the multi-layer lining and comes to the following conclusions through a case study: when stiffness coefficient of the compression-only spring between inner lining and outer lining increases, bending moments of the inner and outer lining are basically unchanged and axial force of outer lining decreases and eccentricity increases while axial force of inner lining increases and eccentricity decreases. When water pressure load increases, the state of lining vault transfers from large eccentric compression into small eccentric compression state and then approaches compressive ultimate load bearing state and the safety factors increase at first and then decreases; state of haunch and side wall gradually approaches the ultimate load bearing state and the safety factors gradually reduce; the states of arch foot and inverted arch transfer from small eccentric compression to large eccentric compression and the safety factors gradually reduce.

     

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