为保证运营期某隧道衬砌结构安全提供理论依据,需提出排水量与衬砌水压荷载之间的关系。通过ABAQUS数值模拟软件,将模型中隧道排水系统和初支统一视为一层排水介质,简化为一维第三类边界条件,并利用温度场与渗流场的对应关系,使用温度场模拟渗流场,在保证精度的同时,极大的提高了计算效率。对数值模拟出的变量关系进行曲线拟合,以得到简化计算公式。研究表明,对于本工程,流量与水压1个月内迅速下降并稳定。初支渗透性减小,隧道压力水头增加。当表面渗透系数K≤3×10^-5 d^-1时,可认为初支不透水,承担全部水压;当K≥3 d^-1时,可认为初支完全透水,不承担水压力,不影响隧道排水;当表面渗透系数3×10^-5≤K≤3 d^-1时,稳定水头高于设计水头,承担部分水压力。拟合公式可以合理反应表面渗透系数、水头、排水量、时间的相互关系。
In order to provide a theoretical basis for the safety of a tunnel lining structure during operation, the relationship between water discharge and lining water pressure load is necessary to be put forward. By means of ABAQUS numerical simulation software, the tunnel drainage system and the initial supporting in the model are integratedly taken as a layer of drainage medium, and then simplified into an one-dimensional third type boundary condition, while the calculation efficiency is greatly enhanced at the same time of ensuring the accuracy by adopting the corresponding relationship between temperature field and seepage field through simulating the seepage filed with the temperature field. Moreover, the curve fitting is made on the numerically simulated variate relationship, and then a simplified calculation formula is obtained. The study result shows that both the flow rate and water pressure are rapidly dropped and stabilized within one month for this project. The permeability of the initial supporting decreases along with the increase of the pressure head of the tunnel. When the permeability coefficient 3×10^-5≤K≤3 d^-1, it can be considered that the initial supportingis impervious and bears the total water pressure. When 3×10^-5≤K≤3 d^-1, the initial supporting is considered to be completely permeable and do not bear water pressure, which does not affect the drainage of tunnel. When its surface permeability coefficient of 3×10^-5≤K≤3 d^-1, the stable water head is higher than that of design, and then it bears a part of the water pressure.The fitting formula can reasonably reflect the relationship among surface permeability coefficient, water head, water discharge and time.
Water Resources and Hydropower Engineering
blocking groundwater and limiting discharge