Improved Leveling Approach and Its Application in Civil Engineering

摘要

An improved leveling method based on an updated definition of leveling is proposed for application in civil engineering projects. The approach is defined as the measurement of the elevation difference between the elevation of the sight line at level station Z(L) and the benchmark height Z(B), where the leveling staff is placed. Under the updated leveling definition, sight line length needs to be measured (modern instruments have this function), but the line lengths between the level station and leveling benchmarks do not have to be the same. The improved approach exhibits four advantages: It eliminates the impact of a possible sight line inclination caused by inaccurate instrument adjustment and additional systematic factors that affect the sight line inclination; it reduces the required number of level stations needed for a job, thereby reducing the time required to conduct measurements; it eliminates the need to find locations for the instrument station that have equal sight line lengths, that is, the instrument can be set up in a location where many leveling benchmarks can be seen; and by eliminating the frequent changes in the position of the level instrument, the total measurement cost is reduced.