汶川大地震紫坪铺混凝土面板堆石坝震害现象与变形监测分析

EARTHQUAKE DAMAGE PHENOMENA AND DEFORMATION MONITORING ANALYSIS FOR CONCRETE FACED ROCKFILL DAM AT ZIPINGPU PROJECT DURING WENCHUAN EARTHQUAKE

2008年5月12日四川汶川发生8.0级大地震,震中烈度XI度,造成地面建筑物严重破坏。紫坪铺面板堆石坝坝高156m,距汶川地震震中17km,是地震灾区距地震震中最近、工程规模最大的一个高坝水库工程。紫坪铺大坝受地震影响,产生了一定的变形破坏,引起学术界和工程界广泛关注。依据大坝地震后宏观变形现象和变形监测资料,对大坝堆筑体和混凝土面板的变形破坏现象进行详尽的描述和分析;在此基础上综合分析认为,大坝变形特征以沉降为主,水平位移相对较小,大坝整体处于收缩压密状态,最大沉降发生在大坝顶部,量值为900～1000mm,沉降与坝高之比约为0.6%,大坝坝体和下游坝坡没有产生显著破坏,大坝结构功能受地震影响较小。

Earthquake occurred on May 12, 2008 in Wenchuan, Sichuan Province, with magnitude of 8.0 and epicenter intensity of XI, causing serious damage to the structures on ground. The dam height of Zipingpu concrete faced rockfill dam（CFRD） is 156 m and it is 17 km from Wenchuan earthquake epicenter, which is the largest high dam reservoir project and the nearest from earthquake epicenter in the earthquake area. Deformations and damages occurred due to the earthquake, attracting attentions from both academic and engineering fields. Detailed description and analysis are presented for damage due to deformations of dam embankment and concrete slabs based on macroscopic deformation phenomena after earthquake and deformation monitoring data. The comprehensive analysis results indicate that dam deformations are mainly settlement, and horizontal displacement is relatively small. Dam body is in the conditions of contraction and compaction. The maximum settlement occurs at dam crest, valuing 900 - 1 000 mm; and the ratio of the settlement to dam height is around 0.6%. No evident damages occurs in dam body and downstream slope; and structural function of dam is not seriously affected by the earthquake.