UTM Projection International Engineering Measureme

yxfbbiedtj · Wysłany: Śro 15:58, 30 Mar 2011

UTM Projection International Engineering Measurement Analysis of deformation and satisfaction

1 Calculation of deformation ChuLinh-CocSan Vietnam hydropower project located in the province of Dum LaoCai River, the river is a tributary of the Red River of the level. It includes both up and down stairs diversion type hydropower station, which root in the station and the Valley Hill Station, including the secondary development of a hydropower project, the two dams, factories, Block 2, a channel, two tunnels and a pressure steel pipeline, with a total installed capacity of 75.1MW. Tunnel inlet elevation 1300m, MongSen elevation 700m, an increase of holes; to CocSan plant, tunnel outlet at elevation 180m. Tunnel length 12.3km, and out of outlet ends of the excavation, the middle 11 adit. Survey area Longitude: 103.52, with a central meridian longitude to be 102. ; Center latitude B about 22.20. Fluctuation range of elevation 180 ~ 1900m, considering the surface and through plants, dams and other hydraulic structures based surface elevation, whichever is the average elevation of 820m. First calculate the radius of curvature, shown in Table 1. According to the international Association of Geodesy and Geophysics (IUGG) International 1975 ellipsoid defined, that is: long axle a = 6378140m, minor axis b = 6356755.288. Part of the formula: Factory ■ r-2 eccentricity: =; reference ellipsoid average radius of curvature Rm = c / V; reference ellipsoid prime vertical radius of curvature of N = C / V; reference ellipsoid meridian radius of curvature of M = c / V. Table 1 reference ellipsoid and then computing the radius of curvature radius of curvature for the 0m elevation projection plane deformation calculated as the front cover 72mm, exceeded regulatory requirements, the need for satisfaction, in Table 2. Table 2 Calculation of deformation changes in elevation of 3.2 Compensation Plane deformation of satisfaction programs: (1) the average investment to the test area surface elevation 450m, the total displacement is about zero; (2) the average investment to the test area surface elevation 820m, the total deformation still exceeds the 5crrotkm (Table 3, Table 4). Table 3 Projection Planes cover the Height / m ellipsoid prime vertical radius of curvature of N / ka-a by the poor / the center of longitude measured in radians L / arc with arbitrary longitude / program select the first l of Yeda Zhong,[link widoczny dla zalogowanych], et al: International Engineering Surveying The UTM projection analysis of deformation and cover 93 Therefore, the use of a test of the control program of a network, that is the central meridian longitude of 102 ~ 0 projection zone, and the projection plane to take 450m for the height, length of the deformation will be effectively compensated for easy practical work, to meet regulatory requirements, conducive to the construction survey and setting out. 4 Conclusion by calculating the table, set the latitude of 23 degrees, with the UTM projection Gauss calculated the central meridian at different distances from the corresponding deformation, rendering the deformation curve (see Figure 2), summed up some of the features UTM. Cover the surface without considering the elevation of the case: (1) deformation on the central meridian about 40cm/km, and the reference ellipsoid deformation of the same sign, can not change the elevation to cover the projection plane; (2) what the central meridian of the 180km, The difference is about ± 1o45 Department, deformation value is zero; (3) deformation of the region does not exceed 5cm/Km [168.4km, 190.9km], [a 190.9km, a 168.4km] that error by [1. 39,1 o52], [a 1o52, 1. 39 I 1]. (4) deformation of the region does not exceed 2.5cm/km [174.3km, 185.6km], [a 185.6km, a 174.3km] that error by [1. 42,1 o49], [A l . 49,1. 42 I 1]. (5) compared with the Gauss projection deformation: the deformation of the value of the two projection showed symmetric, but the Gaussian projection distortion are positive, and the farther away from the central meridian the greater the deformation, while the UTM projection is not. (6) 3. Gauss range ± 153.8km with the deformation of 0.29m, UTM was a 0.1m; 6. Gauss ± 302km range with the deformation of 1.13m, UTM, compared with 0.78m. Conclusion: 6. Zoning, the use of UTM projection distortion better. The area is not involved in construction, it is recommended that better use of Gauss projection, distortion is small, easy to compensate by changing the length of the deformation of surface elevation, to facilitate construction survey.