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采用模型试验和数值模拟方法,研究单轴压缩载荷下带裂纹直墙拱形隧道在不同的裂纹面与隧道垂直边墙之间的夹角?时围岩损伤破坏规律。试验采用水泥砂浆制作成具有不同夹角?的直墙拱形隧道模型,养护30 d后进行加载。数值模拟采用混凝土损伤塑性模型,计算出隧道周边各点的应力和裂纹尖端的应力强度因子,与模型试验结果吻合较好。结果表明,拱肩处的裂纹会降低隧道的整体稳定性及强度,在裂纹尖端及侧壁产生很大的应力集中,但随着?角度的变化,强度降低的程度有所不同;当?=60?和?=130?时,裂纹对其整体稳定性及强度的影响最大,其裂纹尖端的应力集中现象最为明显,而且破坏应力峰值仅为无裂纹模型的40.9%和41.8%。
By using the model test and the numerical simulation method, the damage and rupture law of the surrounding rock at different angles of crack and the vertical wall of the tunnel under uniaxial compressive load are studied. The experiment uses cement mortar to make the straight-walled arch tunnel model with different included angles, and then loads it after curing for 30 days. Numerical simulation The plastic damage plastic model is used to calculate the stress at each point around the tunnel and the stress intensity factor at the crack tip, which is in good agreement with the model test. The results show that the crack at the arch shoulder will reduce the overall stability and strength of the tunnel and produce a great concentration of stress at the tip and the sidewall of the crack. However, with the change of the angle, the degree of strength reduction will be different. 60? And? = 130 ?, the crack has the most significant influence on its overall stability and strength. The crack tip stress concentration is the most obvious, and the failure stress peak value is only 40.9% and 41.8% of the crack-free model.