某电站模型洞围岩位移反分析及预测研究

张河湾抽水蓄能电站位于河北省井陉县测鱼镇甘陶河干流上。电站安装4台单级混流可逆式水泵水轮机组,总装机容量为1000 MW。地下厂房开挖尺寸(长×宽×高)为151.1 m×23.4 m×48.3 m。为进一步研究地下厂房围岩稳定性和优化设计参数,在地下厂房近旁进行了模型洞围岩观测试验研究,依据模型洞围岩收敛位移、钻孔多点位移、锚杆应力观测结果,进行了反分析,计算结果:水平应力2.52～2.88 MPa,应力比值0.7～0.8,弹性模量26.0 GPa。依据反分析的围岩初始地应力及变形参数,对主厂房及主变室围岩位移及应力分布进行了预测,结果表明,围岩变形均较小,且与地下厂房围岩位移实测值一致性较好。

Back analysis and prediction for displacement of surrounding rock around model tunnel of a powerstation

Zhanghewan Pumped Storage Station was provided with four sets of pump-turbine units with a total capacity of 1000 MW,and its underground powerhouse was 151.1 m,23.4 m and 48.3 m in length,width and height,respectively.In order to further study the stability of the surrounding rock around powerhouse cavern and to optimize the design parameters,observation and experimental study were carried out for the surrounding rock around a model tunnel near the underground powerhouse.And,back analysis was done on the basis of the observed results of convergence,multi-point displacement and anchorage bar stress,and the calculated results were as follows: horizontal stress 2.52～2.88 MPa,stress ratio 0.7～0.8 and elastic modulus 26.0 GPa.According to the initial geostatic stress and deformation parameters obtained by the back analysis,a prediction for displacement and stress distribution of the surrounding rock around the machine hall and the main transformer chamber was conducted,and it was indicated that the deformations of the surrounding rock were smaller and coincident with the measured values of displacement.