紫坪铺混凝土面板堆石坝地震剪胀特性探讨

为判断混凝土面板堆石坝地震后体积剪胀或剪缩问题,基于紫坪铺混凝土面板堆石坝汶川地震前后坝体若干测点的实测数据,根据4个节点构成的单元面积进行变形统计分析,对坝体单元的剪胀剪缩特性进行了探讨。分析了断面D0+251和D0+371的水平位移、竖直位移及各单元的面积变化,得到混凝土面板堆石坝地震变形规律为坝体断面缩小、坝体边坡向内部收缩,尤以最大断面附近收缩较为明显,且随坝体高程降低收缩量减小;坝体不同部位单元面积的变化与其所处位置和周围的应力状态相关,坝体整体上各个单元面积减小,而处于坝顶附近和边缘的个别单元由于顶部面板脱空和单元面积剪胀引起面积增大,从而为今后的施工设计和计算校核提供了依据。

Study on Seismic Shear Dilatancy of Zipingpu CFRD

Based on the deformation of Zipingpu CFRD measured before and after Wenchuan earthquake, the statistical analysis for the area of element composed by 4 measured points is conducted to study the seismic shear dilatancy and contraction behavior of the dam. The horizontal displacement, vertical displacement and the area of two cross sections are analyzed. It is shown that the area of cross section reduced in action of seismic and the slop of dam shrunk to internal. The shrinkage in the largest cross section is obviously and the shrinkage decreased with the height. The variation for the area of dam is related with the position and stress state. The element area of the dam decreased but those on the top increased for voiding beneath the cement concrete slab and the dilatancy of the element. So, it provides the basis for construction design and verification of calculation.