For the stability analysis of the surrounding rock mass of an underground powerhouse, reliable mechanical parameters of the rock mass and appropriate analysis methods are highly important. This paper discusses the rationality of using the mechanical parameters of the representative volume element (RVE) of a jointed rock mass as equivalent mechanical parameters and using the equivalent continuity method to simulate the excavation of a large underground powerhouse in a jointed rock mass, with the underground powerhouse of the Wuyue pumped storage power station as an example. Initially, the discrete fracture network (DFN) and synthetic rock mass (SRM) of the jointed rock mass were established. The size of the RVE of the rock mass was determined to be 23 m × 23 m × 23 m through numerical tests. The mechanical parameters of the RVE were used as the equivalent mechanical parameters of the rock mass. Then, the two-dimensional numerical calculation of the excavation of the main powerhouse was carried out using the equivalent continuous method and the discontinuous method. The mean relative error between the deformation of the surrounding rock calculated by the two methods is 8.24 %, which shows that the equivalent continuous method can calculate the overall deformation after excavation of a large underground powerhouse in a jointed rock mass. Furthermore, the three-dimensional equivalent continuous numerical calculation of underground powerhouse excavation is carried out by using the equivalent mechanical parameters determined by the RVE and Hoek–Brown criterion. Compared with the actual measurement results of the multipoint displacement meter, the mean relative error of the calculation result based on the RVE is 12.37 %, and the mean relative error of the calculation result using the Hoek–Brown criterion is 20.37 %, indicating that the numerical calculation using the mechanical parameters of the RVE of the jointed rock mass as equivalent mechanical parameters can consider the size effect of the jointed rock mass and reduce the error of the numerical calculation. Our results are expected to provide guidance for evaluating the stability of an underground powerhouse.

中文翻译：

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考虑节理岩体尺寸效应的大型地下厂房开挖等效连续数值模拟


对于地下厂房围岩的稳定性分析，可靠的岩体力学参数和适当的分析方法非常重要。讨论了以节理岩体代表体积元（RVE）力学参数作为等效力学参数，采用等效连续性法模拟节理岩体中大型地下厂房开挖的合理性，以五岳抽水蓄能电站地下厂房为例。初步建立了节理岩体的离散裂隙网络（DFN）和合成岩体（SRM）。通过数值试验确定岩体RVE尺寸为23 m×23 m×23 m。采用RVE的力学参数作为岩体的等效力学参数。然后，采用等效连续法和间断法对主厂房开挖进行二维数值计算。两种方法计算的围岩变形平均相对误差为8.24%，表明等效连续法可以计算节理岩体中大型地下厂房开挖后的整体变形。此外，利用RVE和Hoek-Brown准则确定的等效力学参数，对地下厂房开挖进行三维等效连续数值计算。与多点位移计的实际测量结果相比，基于RVE的计算结果的平均相对误差为12。37 %，采用Hoek-Brown准则计算结果的平均相对误差为20.37 %，表明以节理岩体RVE力学参数为等效力学参数进行数值计算可以考虑节理岩体的尺寸效应节理岩体，减少数值计算的误差。我们的结果有望为评估地下电厂的稳定性提供指导。