西南某水电站坝肩抗力体长期稳定性分析

NUMERICAL LONG-TERM STABILITY OF DAM ABUTMENT RESISTANCE BODY FOR A HYDROPOWER STATION IN SOUTHWEST CHINA

水电工程对坝肩抗力体长期稳定性要求极高,因此,对于复杂岩土体坝肩抗力体在水推力作用下的稳定性评价显得尤为重要。西南某水电工程坝肩岩体普遍发育有蚀变岩,因此需对其抗力体长期稳定性进行评价。根据考虑蚀变岩体流变特性的黏-弹-塑性本构模型,对水库蓄水运行期抗力体边坡应力、形变场等特征进行了三维数值模拟研究。研究表明,坝肩抗力体在蓄水6个月后"三次应力场"基本形成,即此时抗力体处于最危险状态,可能会出现蚀变岩带与断层交叉部位的局部破坏;通过对蓄水5a后模拟得到的变形值及塑性区变化情况分析,得出坝肩抗力体整体上是长期稳定的。

Long-term stability of dam abutment resistance body is very important for a hydropower station.The abutment resistance body stability of complex rock mass dam under the action of water thrust is particularly important.There are widely altered rocks in the dam abutment of a hydropower station in Southwest China.On the basis of altered rock rheological property and its viscous-elastic-plastic constitutive model,the stress and deformation fields characteristics in the resistance body slope have been simulated with 3D numerical method during the reservoir operation period.The study results show that te third stress field is formed after 6months of water storage.The dam abutment resistance body is in the most dangerous situation.Local destruction between altered rock and fault may appear.According to the simulated deformation value and plastic zones after 5 years of water storage,the abutment resistance body of the whole dam is in a long-term stable state.