It is necessary to use the technology of Shenyang monitoring instrument during basic stakeout
The editor of Shenyang monitoring instrument learned that the skills of setting up the theodolite or total station on the shore of the bridge are not enough to meet the needs of the surveyor and the driver of the piling boat for real-time communication, resulting in low piling power.
With the increase of bridge spans, such as the construction of bridges across rivers and seas, the setting up of pile foundation projects is even 1 or 2 kilometers offshore, and the amount of calculation and stakeout operations is constantly increasing. The editor of Shenyang Monitoring Instrument learned The skill of setting up the theodolite or total station on the shore to stake out the bridge has been unable to satisfy the needs of the surveyor in real-time communication with the operator of the piling boat, resulting in low piling power.
(I) GPS-RTK operation principle
GPS-RTK is generally used for piling positioning. The use of this skill requires the construction of GPS reference stations and rover stations, and the use of computers, laser rangefinders and other detection tools. The detailed positioning principle is as follows: the GPS reference station is set at the control points on both sides of the bridge, and no less than 2 GPS-accepted antennas are continuously installed on both sides of the piling stern, during which the GPS acceptance system is continuously real-time through RTK Monitor and accept the geodetic coordinates of the antenna and the orientation of the pile frame relative to the piling boat's roll, pile frame inclination, pitch angle, etc., and then establish a pile positioning model, which includes the transformation model of the positioning coordinates, GPS receiving antenna, and pile frame And the geometric function between the beatings, and finally using the software system for precise calculation, the detailed coordinates, penetration and azimuth of the pile can be accurately measured.
(Two) detailed use of GPS-RTK
When GPS-RTK instructs the position of the piling boat, it needs to rely on a computer to perform real-time positioning instead of the center of the piling. This is not satisfactory before the manual on-site calculation. When using GPS-RTK, input the pile position coordinates of the design channel in the computer first, then input the real-time GPS measurement data into the computer, and then calculate the difference between the designed pile position and the actual measurement of the pile frame orientation. Poor, and direct the pile boat to accurately position and piling.
This general skill is applicable to the water area of a wide bridge location area. It is difficult to locate the base of the water area by conventional measuring instruments. For example, after a bridge has 48 steel pipe piles, 3 points on all steel pipe piles are used. Use the coordinates to measure, calculate the center coordinates of the steel pipe pile and the design value, and then compare them, and then verify the measurement effect. In addition, the ordinary total station is used to perform the polar coordinate detection. You can see the detection between the two. The results are very different. It can be seen that it is very necessary for us to use GPS-RTK measurement skills when staking out the roots, relying on the technical advantages of GPS real-time dynamic positioning to improve the accuracy of piling positioning.