Typical Instance of Development of Leveling Technology and Equipment

For the purpose of fulfilling the task set for the project of Key Technology Study for Leveling Prepared Rubble Base of Gravity Structure for Off-shore Harbors of Great Depth,investigation was conducted to development of leveling technology and equipment internationally.18 instances of leveling device have been obtained covering the development in 5 countries since 1960s,which fall into 6 categories according to their technical feature.Analysis has been made,as the commencement of the study work,to the advantages and disadvantages of the 6 categories of leveling devices.