混凝土坝顶部的垂直位移,主要受温度变化时材料热胀冷缩的影响。当坝体混凝土温度场已经稳定只随季节变化时,坝顶高程一般都是夏秋上抬,冬春下降,在一定变化范围内作周期变动。但是四十年代投入运用的我国东北丰满重力坝(图1),其坝顶垂直位移却出现了一种特殊情况:从1959年开始系统观测到1979年二十年间,左岸坝段和河床坝段抬高了 The vertical displacement of concrete dam top is mainly affected by the material’s thermal expansion and contraction when the temperature changes. When the dam concrete temperature field has been stable only with seasonal changes, the crest elevation are generally summer and fall lift, winter and spring decline, make changes within a certain range of cyclical changes. However, in the 1940s, the vertical displacement of the Fengman dam in northeastern China (Figure 1), which was put into operation in the 1940s, showed a special situation. From the system observation of 1959 to the twentieth year of 1979, the left bank dam section and riverbed dam section Elevated