Application Research on the River-crossing Elevation Measurement Method for Underwater Tunnels
Aiming at the problem that it is difficult to carry out long distance river-crossing elevation measurement with traditional geo-metric leveling survey,this paper adopts GNSS river-crossing elevation survey to carry out elevation transmission,analyzes the toler-ance of GNSS field survey data,obtains the geodetic height differences of leveling points,and converts them into orthometric height differences.The results show that the discrepancy between the orthometric height differences measured by GNSS river-crossing eleva-tion survey is relatively small,meeting the specification tolerance requirements.The trigonometric leveling method of total stations was used to verify the results of GNSS river-crossing elevation measurement.The measurement results of trigonometric leveling were basi-cally consistent with the results of GNSS elevation difference observation,and the height difference is within the allowable range.The results show that both GNSS river-crossing elevation measurement and total station reciprocal observation can effectively solve the river-crossing elevation measurement of long-distance underwater tunnels.The observation results have high accuracy,meet the require-ments of the tolerance of second-order level measurement,and provide a reliable elevation control datum for the successful completion of river-crossing tunnels.
NETL
NSTL
万方数据
