大坝变形监测的若干问题──编写《混凝土大坝安全监测技术规范》中“变形监测”一章的一些思考

随着水电建设的发展，大坝安全监测工作日益受到重视，１９９０年我国第一部安全监测规范──“混凝土大坝安全监测技术规范”正式出版，但当时未编印该规范的条文说明。笔者作为该规范起草人之一，对编写该规范＂变形监测＂的思路及主要条文的编写依据进行了阐述，便于使用者更好地理解和执行该规范。本文对下列几个主要问题进行了较详细的补充说明：（１）变形监测工作的基本原则；（２）变形监测的精度要求；（３）边角网的建立、边角网设计、边角网观测；（４）交会法观测水平位移；（５）导线法观测水平位移；（６）基准线法观测水平位移：其中包括引张线法、视准线法、激光准直法；（７）垂线法观测水平位移和挠度；（８）精密水准观测垂直位移：垂直位移基准点位置的选定、闭合差的规定。

Problems about deformation monitoring for dams

Following the development of hydropower engineering more attention is paid on the safety monitoring for dams.The first Chinese safety monitoring norm-Technical Norm of Safety Monitoring for Concrete Dams-was published in 1990.In this norm there is no any explanation about its articles.To bring the users better understanding and implementing the norm,the author,as one of the norm's draftsmen,expounds the thinking of preparing the norm and bases of preparing the principal articles,and explains in detail the following problems:(1)basic principles for deformation monitoring,(2)requirements of accuracy of deformation monitoring,(3)design,implementation and application of side-angle net,(4) observation of horizontal displacements by using intersection,traverse and reference line methods.The reference line method includes the stretched wire,the visual base line and the laser aligning methods.(5) observation of horizontal displacements and deflections by using the plumb line method,(6) observation of vertical displacements by precise leveling,including selection of the datum point and stipulation of the closing error.