江垭大坝运行期抬升变化趋势分析

Analysis on uplift trend of Jiangya dam during operation period

江垭大坝蓄水后,通过坝体垂直变形测点发现大坝及近坝山体产生了持续抬升的现象。经研究论证,认定抬升的主要机制是坝基下分布的承压热水含水层D2y水头增大,引起岩体有效应力降低,导致岩体发生回弹扩容。在过往研究的基础上,结合1998~2019年与抬升相关的大坝安全监测资料,通过因子分析等方法论证回弹扩容机制解释大坝抬升现状的有效性,并得出大坝抬升趋于稳定的结论。

After impoundment of Jiangya dam,the continuous uplift of dam and its surrounding moun⁃tain is discovered by measuring points for vertical deformation.Research identifies that the primary mechanism of continuous uplift is the head increase in confined hot water aquifer under dam foundation,which leads to the decrease of effective stress and the rebound deformation of rock mass.By the factor analysis based on dam safety monitoring data from 1998 to 2019,the effectiveness of applying rebound deformation mechanism to explain the dam uplift is verified,and the conclusion that the dam uplift is getting stable is obtained.