Xiaoxu Tian, Song Zhanping, Wang Tong, Xie Jiangsheng, Cheng Yun, Liu Zhi
School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, Xi'an, 710055, China.
Sci Rep. 2024 Dec 28;14(1):30788. doi: 10.1038/s41598-024-80658-x.
The existing calculation method for the surrounding rock pressure of shallow buried bias tunnel fails to account for the impact of the progressive failure characteristics of the surrounding rock and slope creep, thereby neglecting the additional pressure arising from slope creep. Therefore, the progressive instability failure mode of the surrounding rock of shallow buried bias tunnel was obtained by numerical simulation. Based on this, the theoretical analysis model of the additional pressure of shallow buried bias tunnel was established, and the calculation formula of the additional pressure was derived. Further analysis revealed that the larger the deformation rate of the surrounding rock, the shorter the time it takes for the additional pressure to reach its maximum value. When the deformation rate of surrounding rock increases to a certain value, there will be no additional pressure on the liner, that is, the pressure will be released when the surrounding rock is excavated. In such scenarios, if the strength of the first lining is inadequate, cracking or even collapse of the first lining may occur during excavation.
现有浅埋偏压隧道围岩压力计算方法未考虑围岩渐进破坏特性及边坡蠕变的影响，从而忽略了边坡蠕变产生的附加压力。因此，通过数值模拟得到了浅埋偏压隧道围岩的渐进失稳破坏模式。在此基础上，建立了浅埋偏压隧道附加压力理论分析模型，推导了附加压力计算公式。进一步分析表明，围岩变形速率越大，附加压力达到最大值所需时间越短。当围岩变形速率增大到一定值时，衬砌上不再有附加压力，即围岩开挖时压力会释放。在这种情况下，如果初支强度不足，开挖过程中初支可能会出现开裂甚至坍塌。
