水布垭地下厂房围岩渗控效应数值模拟与评价

 为减小水布垭地下厂房厂区渗漏并改善厂房围岩的渗透稳定性，工程设计采取防渗帷幕、排水孔幕和排水洞等防渗排水措施。为确保数值计算的稳定性和收敛性，采用Signorini型变分不等式和自适应罚函数相结合的稳定渗流分析方法，对厂房围岩的长期渗控效应进行计算分析；同时，采用基于等效模拟的整体模型分析和基于精细模拟的子模型分析相结合的方法，以减小有限元建模难度并协调计算量和计算精度之间的矛盾。建立评判渗流计算成果合理性的直观准则，即稳定渗流自由面在任意均匀介质内部必连续光滑且不产生回弯，除非自由面穿过渗透性相差悬殊的2种介质之间的界面。结合厂房围岩渗压监测数据，阐明运用上述方法求解含排水孔幕渗流问题的可行性和有效性，论证渗控设计的合理性和进一步优化的可能性。研究成果对类似工程渗控措施的优化设计具有指导意义。

NUMERICAL SIMULATION AND ASSESSMENT OF SEEPAGE CONTROL EFFECTS ON SURROUNDING ROCKS OF UNDERGROUND POWERHOUSE IN SHUIBUYA HYDROPOWER PROJECT

To reduce the seepage of the underground opening in Shuibuya hydropower project and improve the seepage stability of the surrounding rocks,a seepage control system including grouting curtain,drainage hole array and drainage tunnels is designed and deployed. The long-term seepage control effects of the surrounding rocks of the underground powerhouse are performed by a stationary seepage analysis method combining the variational inequality formulation of Signorini(s type with an adaptive penalty Heaviside function to guarantee the numerical stability and convergence. Meanwhile,the difficulty in finite element mesh generation is reduced and the calculation time and modeling accuracy are balanced with a global model of equivalent modeling and a submodel of accurate modeling for drainage hole array. Intuitive criteria for assessment of the reasonability of the numerical results are established,namely stationary seepage free surface in any homogeneous medium must be continuous,smooth and can not be return-curved,unless it intersects with an interface between two media of distinct permeabilities. By making comparison with the measurements of pore water pressures in the surrounding rocks,the feasibility and effectiveness of the proposed model are demonstrated. The reasonability of the design of the seepage control system and the possibility of its further optimization are illustrated. The research results are helpful for optimization design of the seepage control system in similar projects.