【摘要】 提出了一种非稳态渗流条件下岩石材料气体渗透特性参数的计算方法。首先将气体滑移方程代入非稳态渗流偏微分方程,利用Picard-Newton差分迭代格式建立非稳态渗流方程的数值解。基于此数值解,对非稳态渗流气压变化曲线进行拟合,利用最小二乘原理反算确定最优的绝对渗透率和滑移因子。算例表明,计算稳定收敛,对步长和随机误差不敏感,同时能够准确捕捉渗透性能参数的微小变化。最后,利用该方法成功测试了位于中国高放废物处置首选预选区的甘肃北山坑探设施硐室掌子面花岗岩的气体渗透特性。提出的方法所需输入数据的获取手段简单,核心算法便于数值实现,可以应用于地下工程围岩的气体渗透性能测试。更多还原

【Abstract】 To test the gas permeability of rock under unsteady flow condition, a new method of calculating the gas permeability was proposed in this paper. Klinkenberg’s equation was firstly imported into the partial differential equation of unsteady flow. A numerical solution of this partial differential equation was then generated by using Picard-Newton’s difference scheme. Based on this numerical solution, a new method of searching the optimal absolute permeability and slip factor of rock was proposed by fitting the variation of gas pressure under unsteady flow condition with least-square method. The numerical calculation in this method was proven to be stable, convergent and insensitive to step size and random errors, and the slight variation of absolute permeability and slip factor can be successfully captured. Finally, some granite samples from the surrounding rock of the Beishan exploration tunnel, which was located in the pre-selected area for China’s high-level radioactive waste disposal, were tested and the absolute gas permeability and slip factor were successfully identified by the proposed method. The input data needed in the proposed method can be easily obtained by simple indoor test and the key algorithm is convenient for numerical realization. Thus it can be applied to the gas permeability test of surrounding rock materials in underground engineering.更多还原