Tài liệu Slide application of gnss technology for determining earth crust movements ninh thuan 1 nuclear power plant

THE 14th CONFERENCE OF SCIENCE AND TECHNOLOGY APPLICATION OF GNSS TECHNOLOGY FOR DETERMINING EARTH CRUST MOVEMENTS - NINH THUAN 1 NUCLEAR POWER PLANT Co Phuoc Trieu, Binh Van Trinh, Lau Ngoc Nguyen Ho Chi Minh City, September 2015 1 CONTENT I. INTRODUCTION II. APPLICATION OF GNSS TECHNOLOGY TO DETERMINE EARTH CRUST MOVEMENTS IN THE SITE AREA OF NINH THUAN 1 NUCLEAR POWER PLANT PROJECT III. CONCLUSIONS 2 I. INTRODUCTION • Research on Earth crust movements is one of fields of geodesy. • Today, the determination of the Earth crust movements by geodetic method is recognized as the most reliable to predict earthquakes and is one of the important basis for studying the tectonic processes taking inside the Earth. • In the world, GNSS technology (Global Navigation Satellite System) has been applied to measure Earth crust movements since the 1980. • In Vietnam, this application is still modest and new. Starting from 2004 to 2008 had the theme of "Research and application of GPS technology to determine tectonic movement on Lai Chau - Dien Bien and establishment of Song Ma GPS geodynamic network serve for natural disaster monitoring Northwest Vietnam area". 3  Practically Ninh Thuan 1 Nuclear Power Plant Project can be seen as the     first in Vietnam applying GNSS technology to measure a geodynamic monitoring network on the factory area and the vicinity. This network is aimed to assess systematic Earth crust movements, clarify geodynamic regime parameters such as data on velocity, gradients and direction of modern vertical and horizontal movements of individual crustal blocks in the NPP site vicinity. Geodynamic monitoring network of Ninh Thuan 1 Nuclear Power Plant Project is designed to ensure strict requirements on layout, density. Location of benchmarks is placed on fracture or near the fracture to assess accurately the displacement (if any) of them. Geodynamic monitoring network of Ninh Thuan 1 Nuclear Power Plant Project is measured combining two methods: horizontal displacement (measured using GNSS technology) and vertical displacement (Geometrical leveling). 4 LOCATION OF GEODYNAMIC BENCHMARK AND FRACTURED ZONES GEODYNAMIC BENCHMARK Diagram and benchmark structure is established and constructed according to design drawings of the Consortium E4EPT-Kiep (E4 Group / EPT) - Russia 5 II. APPLICATION OF GNSS TECHNOLOGY TO DETERMINE EARTH CRUST MOVEMENTS IN THE SITE AREA OF NINH THUAN 1 NPP PROJECT 1. Monitoring horizontal displacement Observation session length is 24 hours, ensure each point shall be observed at least 72 hours, recording interval is set to 15 seconds. 6 DIAGRAM OF GNSS TO MEASURE HORIZONTAL DISPLACEMENT EQUIPMENT TO MEASURE HORIZONTAL DISPLACEMENT Leica viva GS10 receiver. Horizontal accuracy: ≤ 3mm+0.1ppm Vertical accuracy: ≤ 3.5mm+0.4ppm 7 2. Monitoring vertical displacement • To measure the vertical displacement, we use geometrical levelling with accuracy equivalent to National levelling Class I. • The levelling procedure has been carried out following the National technical regulations on building vertical network QCVN11: 2008/BTNMT. • All misclosure are smaller than 3mm√L as request 8 DIAGRAM OF LEVELING TO MEASURE VERTICAL DISPLACEMENT EQUIPMENT TO MEASURE VERTICAL DISPLACEMENT Digital level Leica DNA-03 Accuracy: Mh = 0.3mm/1km. Invar barcode staff – length: 3m 9 3. Gravity measurement and adjustment of levelling network •We use the “relative” measurement method: Determine difference of gravity anomaly. Thus, the starting and the finishing point for a gravimetric route have to be the gravity points at the higher level. •The gravity corrections are applied to the measured geometrical height differences before adjustment. •The levelling network is adjusted as free network. 10 DIAGRAM OF GRAVITY MEASUREMENT NETWORK EQUIPMENT TO MEASURE GRAVITY ZLS, GNUKV and Z400 machine Accuracy: ≤ 0.02 mgal. 11 4. GNSS data processing In order to obtain required accuracy for single baseline processing and network adjustment, the coordinates of original point must be determined with an accuracy of centimeter in ITRF2008. At first, we sent the GPS data collected at origin point to the automatic GPS processing service. This service provide horizontal accuracy of 1 ÷ 2cm and from 2 ÷ 4 cm for vertical accuracy in ITRF2008. As a result, coordinates in ITRF2008 of origin point was determined with allowable precisions. i. Single baseline processing We use software package – GUST with some processing options as below: 12 - Satellite network: GPS (USA) và GLONASS (Russia) Observations: Double differenced carrier phase L1, L2 and L3 Satellite elevation cut-off angle: 5-10 Satellite ephermerides: final precise IGS Antenna phase center mode: IGS_05 Weighting scheme: Sin(e), in which e is satellite elevation. Ambiguity resolution: Resolve wide-lane first and then narrow-lane ambiguities - Tropspheric delay: Estimation every 2.0 hours using GMF mapping function - Atmospheric model : UNB4 - Session length: 24 hours 13 ii. 3D space adjustment method •Regarded baseline vector components received from single baseline processing as measurements for free adjustment to provides 3D coordinates (X, Y, Z) of the points in the network. •Then, convert the 3D coordinates (X, Y, Z) to coordinates (North, East) on the horizontal datum ITRF2008. 5. Computationally horizontal and vertical displacement vectors •Implemented for 3 cycles: Cycle 0, Cycle1 and Cycle2 •Compute displacement vectors by taking difference of coordinates and elevation of the same points between two successive cycles 14 DIAGRAM OF DISPLACEMENT VECTOR CYCLE 0-1 DIAGRAM OF DISPLACEMENT VECTOR CYCLE 1-2 6 x 10 GD25 GD24 1.28 GD23 GD22 1.275 GD21 GD20 GD27 B?c (m0 GD26 1.27 GD29 GD30 GD02 GD28 GD19 GD18 GD03 GD16 GD15 GD12 1.265 GD05 GD04 GD01 GD06 GD13 GD14 GD07 GD08 GD09 1.26 GD17 GD10 5 mm GD11 5.7 5.72 5.74 5.76 5.78 5.8 5.82 Đông (m) Vectô dich chuyeån Ñôùi ñia ñoäng löïc lôùp XII Elip sai soá ño Ñôùi ñia ñoäng löïc lôùp XI Ranh khaûo saùt phuïc vuï löïa choïn ñia ñieåm 5.84 5.86 5 x 10 Ñöôøng bôø bieån 15 III. CONCLUSIONS The results obtained after 3 geodynamic monitoring cycles allow a preliminary assessment about speed of Earth crust movements at the location of Ninh Thuan 1 NPP and site vicinity. - Horizontal displacement: The most of points have differences in coordinates between two consecutive cycles are smaller than the limit of measurement error showing that they have neither no displacement or a displacement, if any, within scope of the measurement error. - Vertical displacement: The differences between two successive cycle’s values (height and height difference) are smaller than tolerance (3 × measurement error). Thus there is not any conclusion about vertical displacement between these two consecutive cycles. In other words, there is neither no displacement or a displacement, if any, within scope of the measurement error. 16 Intelligence Solutions, Sustainable Success Sincerely Thank! 17