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, La

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

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

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"

 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)

LOCATION OF GEODYNAMIC

BENCHMARK AND FRACTURED ZONES

GEODYNAMIC BENCHMARK

Diagram and benchmark structure is established and constructed according to design drawings of the Consortium E4-EPT-Kiep (E4 Group / EPT) - Russia

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

II APPLICATION OF GNSS TECHNOLOGY TO

DETERMINE EARTH CRUST MOVEMENTS IN

THE SITE AREA OF NINH THUAN 1 NPP PROJECT

DIAGRAM OF GNSS TO MEASURE

DISPLACEMENT

Leica viva GS10 receiver

Horizontal accuracy: ≤ 3mm+0.1ppm Vertical accuracy: ≤ 3.5mm+0.4ppm

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

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

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

DIAGRAM OF GRAVITY

ZLS, GNUKV and Z400 machine

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

We use software package – GUST with some processing options as below:

- 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

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

GD04 GD05

GD16 GD03

GD25 GD24

GD23

GD22

GD20 GD27

GD26

GD28

GD29 GD30

GD18 GD19 GD02

GD06 GD12 GD01 GD15

GD13 GD14

GD07

GD08

GD09 GD17 GD10

GD11

1.28

x 10

1.275

1.27

1.265

1.26

5.7 5.72 5.74 5.76 5.78 5.8 5.82 5.84 5.86

x 10 Đơng (m)

5 mm

6

5

Vectơ dich chuyển

Elip sai số đo

Đới đia động lực lớp XII Đới đia động lực lớp XI

GD21

DIAGRAM OF DISPLACEMENT

VECTOR CYCLE 0-1

DIAGRAM OF DISPLACEMENT

VECTOR CYCLE 1-2

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

Intelligence Solutions,

Sustainable Success

Sincerely Thank!