土坝变形主要包括坝体的垂直位移与水平位移。目前,在土坝外部变形观测中,多数水库由于缺乏仪器,水平位移观测没有普遍展开。根据不完全统计,在大中型土石坝中,进行水平位移观测的只占20～30％。虽然有些水库也建立了水平位移观测项目,但由于观测人员 Earth dam deformation mainly includes the vertical displacement and horizontal displacement of the dam. At present, in the observation of external deformation of earth dam, most reservoirs have not been widely developed because of lack of instruments. According to incomplete statistics, only 20-30% of horizontal displacement observations are made in large and medium-sized earth-rock dams. Although some reservoirs have also established horizontal displacement observation projects, due to observers