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以云南地区某高速公路隧道为依托,针对隧道仰拱开裂状况,采用荷载-结构法建立隧道结构计算模型,分析外水压力、基底软化两种典型基底状况对隧道仰拱受力的影响,从而明确隧道仰拱病害成因。计算结果表明:外水压力和基底软化对仰拱结构受力的影响规律相一致,引起了衬砌结构内力重分布,改变了仰拱结构弯矩分布形态,仰拱弯矩由“驼峰状”分布向“鱼肚状”分布变化,弯矩最大值由两侧向仰拱中心转移;增大了仰拱结构偏心程度和应力集中情况,使仰拱结构受力条件恶化,易导致仰拱中心处发生拉裂破坏。比较而言,地下水的影响更为明显。外水压力和基底软化共同作用是引起本依托工程仰拱开裂的主要原因。
Based on an expressway tunnel in Yunnan Province, aiming at the cracking of the inverted arch of the tunnel, the load-structure method is used to establish the calculation model of the tunnel structure. The effects of external water pressure and basement softening on the stress of the tunnel arch are analyzed. Clear tunnel arch disease causes. The calculated results show that the influence of external water pressure and basement softening on the force of the inverted arch structure is consistent, which causes the redistribution of internal forces in the lining structure and changes the distribution of the bending moment of the inverted arch structure. The bending moment of the inverted arch consists of "hump The distribution of maximum value of bending moment changes from the two sides to the center of the inverted arch, which increases the degree of eccentricity and stress concentration of the inverted arch structure, worsens the stress conditions of the inverted arch structure, Crack in the arch center damage. In contrast, the impact of groundwater is more pronounced. External water pressure and softening of the substrate together is the main reason that caused the cracking of the back arch of this reliance project.