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在参考相关文献以及做了一定数值模拟分析后进行了黄土无衬砌隧道的大型振动台试验的研究。振动台试验的研究结果表明:埋深越深峰值加速度越小,埋深浅的隧道和地下结构要加强抗震措施;隧道洞口部由于刚性变化较大峰值加速度相比沿隧道其它位置要大,在隧道洞口部一定范围内要提高抗震水准;隧道直墙中下部是最易破坏的部位,而隧道仰拱会出现拉裂缝,最终这两处会形成贯通的破坏区,在输入0.8 g的峰值加速度后测得的加速度峰值曲线变缓,在0.8g的峰值加速度处出现拐点,表明此时隧道围岩进入塑性。进行振动台试验的数值模拟分析表明:在输入0.9 g的峰值加速度计算得到的隧道安全系数为1.07,而在输入1.0g的峰值加速度时隧道的安全系数低于1.0,隧道破坏。试验和数值模拟都说明黄土无衬砌隧道具有很强的抗震性能。
After referring to the related literatures and doing a certain numerical simulation analysis, a large-scale shaker test of the tunnel with no loess was carried out. The results of shaking table test show that the deeper the depth is, the lower the peak acceleration is, and the shallow buried tunnel and underground structure should strengthen the anti-seismic measures. The larger peak acceleration of the tunnel entrance due to the rigidity changes is larger than other locations along the tunnel. In the middle of the tunnel, the middle and lower parts of the straight wall are the most vulnerable parts, and the arch of the tunnel will appear to pull the cracks, and eventually the two will form a through failure area. After inputting the peak acceleration of 0.8 g The measured peak acceleration curve slowed down, the inflection point appeared at the peak acceleration of 0.8g, indicating that the surrounding rock of the tunnel entered plasticity at this time. The numerical simulation of shaking table test shows that the calculated tunnel safety factor is 1.07 at the peak acceleration of 0.9 g, and the safety factor of the tunnel is less than 1.0 when the peak acceleration of 1.0 g is input. The tunnel is destroyed. Both tests and numerical simulations show that the loess tunnel without lining has strong anti-seismic performance.