【摘要】 <正> 用活动觇牌视准线法观测大坝的水平位移时,一般是将经纬仪安置于视准线一端的固定工作基点上,后视另一端的固定工作基点,构成固定的基准线。这种观测方法,照准误差随着坝体的增长、大气的抖动而增大。此外,由于测站至后视点与至位移点距离不等,以致存在调焦误差。本文提出中点设站分段观测方法,对于较长的大坝,在不增加或不改变原有设更多还原

【Abstract】 This paper describes the method of sectional observation with subsidiary stations for horizontal displacement of long dams. In comparison with the general moving target method, it can help decrease pointing error and error of focussing. As a result, the accuracy of observation for dam horizontal displacement is improved.更多还原