江垭大坝山体抬升的形成机制与趋势分析  

FORMATION MECHANISM AND TREND ANALYSIS OF LIFTING OF VALLEY AND DAM IN JIANGYA HYDRAULIC PROJECT

作　　者：王兰生[1] 金德濂[2] 骆诗栋 

机构地区：[1]成都理工大学环境与土木工程学院,四川成都610059 [2]湖南省水利厅,湖南长沙410007 [3]湖南澧水流域水利水电开发公司,湖南长沙410004

出　　处：《岩石力学与工程学报》2007年第6期1107-1115,共9页Chinese Journal of Rock Mechanics and Engineering

摘　　要：湖南省澧水流域娄水的江垭水利枢纽工程,大坝坝高131m,建在一区域性江垭大向斜的西北翼部,坝基下伏有厚层的承压热水含水层。水库于1998年蓄水以后,出现大坝和山体抬升变形现象,至2001年2月两岸山体最大抬升值达21.8 mm,一般为15～10mm;廊道中抬升最大值达34.5mm,平均31mm。根据系统的监测资料,对抬升成因提出空隙水压力增高卸荷回弹扩容机制,随后在MTS刚性压力试验机上开展了岩石力学模拟试验;结合大坝所处的特殊地质条件和监测数据,提出适合于江垭大坝抬升成因的向斜滑脱机制模式,并于2001年7月对发展趋势作出判断,认为在水位变动中,下伏基础总的趋势向卸荷方向发展,升降的变幅将逐渐缩小,整体趋向稳定。大坝的监测延续至今,监测资料证实了当年的判断和预测,大坝安全运行。Jiangya Hydraulic Project is situated in the basin of the Loushui River in Hunan Province, China. After the reservoir is impounded, significant lifting deformation of the dam along with its surrounding valley is observed The theory of the formation mechanism and the future forecasting are discussed. The 131 m high dam of Jiangya Hydraulic Project is located on the northwest limb of regional syncline（Jiangya syncline）, there exist a series of aquifers and impermeable layers. A hot water artesian aquifer is found right under the dam foundation. The reservoir impounding began in Aug. of 1998, and to Feb. 2001, the biggest lifting of both banks of the valley was measured 21.8 mm, generally 15 - 10 mm; the lifting of the grouting gallery in the dam was measured 34.5 mm with a mean value of 31 mm. Based on both the site investigation and data analysis, the hypothesis of dilatancy mechanical model, that the lifting deformation is caused by the pressure change resulting from moving interstitial water in rock mass is proposed. In order to verify the model, a rock mechanical simulation test has been carded out using the MTS stiff testing machine. The test result strongly supports the model. According to the results combined with in-situ geological analysis, the ＂syncline flexural slip＂ mechanism is believed to be responsible for the lifting of Jiangya dam and its surrounding banks. The authors also forecast that this lifting and subsiding phenomenon will reduce progressively, and eventually diminish. The latest data have confirmed the forecast made five years ago.

关 键 词：水工结构工程 山体抬升 水库蓄水 卸荷回弹 孔隙水压力 向斜滑脱 

分 类 号：TV31[水利工程—水工结构工程]