Movement Control in the La Aceña Dam using Differential GPS

1. BACKGROUND

It is possible to integrate real-time acoustic monitoring technology in the control of hydraulic infrastructure and reservoir slopes, especially by using differential GPS. This particular technology allows for 3D model calibration, in finite elements, of slope and dam deformations, delimiting the margin of error to under a centimeter. It confirms or invalidates the structure’s new control tools and acoustic monitoring.

2. OBJECTIVES

1. Integrate knowledge of current surveying and remote sensing technologies in dam slopes and hydraulic infrastruc-ture acoustic monitoring; specifically differential GPS. 2. Apply an automatic control system using differential GPS that allows acoustic monitoring and prediction of slope and hydraulic infrastructure deformations in real time. 3. Analyze the different factors contributing to the deformation of slopes and dams: temperature, water height, struc-tural characteristics, geomorphology and geotechnical engineering of the foundation, for at least one full hydrologi-cal year in an actual case. 4. Establish an applicable methodology to other actual cases to design and implement an expert system of slope and dam acoustic monitoring that integrates surveying and remote sensing technologies. 5. Apply an expert system to an actual case, chosen due to its importance and the extent of existing knowledge.

3. TRABAJOS REALIZADOSThe various jobs performed in the field of Surveying and Geodesy are:

· Bibliographical collection and review.· Market research to find the right tools and techno-logy available on the subject in Spain and other Euro-pean universities, especially the Universty of Graz in Austria. · Adjusting the equipment, installation and establish-ment of baseline measurements to maximize accuracy.· Conducting pilot-scale tests to determine the local GPS satellite availability, the optimal time for static measu-rements and the optimal distance of the baseline for the study area. · Design of equipment required for data transmission to a computer center in the Engineering and Morpho-logy Department of the Technical University of Madrid (UPM). · Selection of the mathematical and software model used to process data in order to ensure lower margins of error and elimination of systematic errors. · Development, contrast and debugging of topographic measurements using the theoretical calculation results carried out by the finite element technology.

The various jobs performed in the field of geotechnical en-gineering and rock mechanics include:

· Bibliographical collection and review of published stu-dies on the different factors influencing the deformation of slopes and dams.· Studying and reviewing of all the existing information on the prototype’s ground-dam interaction.· Development and tuning using the simplified FLAC3D model.· Adjusting the model.

In the integration of real-time dam acoustic monitoring to a system prototype, the following tasks are accomplished:

· Documenation: Collecting information on real-time acoustic monitoring technology in hydraulic infrastruc-tures and dam slopes in neighboring countries where these new objectives are already achieved. · Pilot testing in laboratory: In order to ensure the pro-totype works correctly, it will be tested with laboratory equipment to verify the acoustic monitoring system’s functionality. · Validation of the obtained prototype after conducting pilot tests in the laboratory.· Study of patents.

www.intercontrol.es Cs-Te-03-001

TECHNOLOGY

CASE STUDY

Instrumentation Equipment

TECHNOLOGY

CASE STUDYInstrumentation Equipment

www.intercontrol.es Cs-Te-03-001

4. EQUIPMENT USED

TEAM

The project was carried out with the collaboration of the Technical University of Madrid (UPM). The UPM has background in research projects focusing on geo-technical engineering, hydrology, and acoustic moni-toring. The project has been planned to consider the UPM’s involvement in all phases, and in various degrees of participation.

LABORATORY AND EXPERIMENTATION INSTRUMENTS

A highly-accurate system using Differential GPS techno-logy was proposed, comprised of:

· 2 fixed control stations (measuring points).· 1 reference station in an area not susceptible to landslides.· 1 data processing center.

CONTROL STATIONS

Control points are spread throughout areas most sus-ceptible to movement. They consist of a highly accura-te L1 frequency GPS receiver and a data transmission system control center. Each of these control points must be affixed to a stable support. They do not require power since they are al-ready fitted with photovoltaic cells. These cells provide electric power to function and batteries to remain in operation in case of bad weather. The communication between the control points and data processing center is wireless so that each station functions independently without the need for wiring.

REFERENCE STATION

This station is the same as a control station but is placed in an area free of possible landslides. This is the reference against which to measure the control point movements. Like the monitoring stations, its installation is wireless and therefore independent.

RADIO RECEPTION EQUIPMENT

This is how the control station and reference stations wirelessly stay connected with the data processing center. It is located next to the data processing center.

DATA PROCESSING CENTER

This consists of a server that processes and stores data through specialized software specifically for this use. It sends real-time data via the internet and provides a continuous power supply to anticipate possible power outages.

TECHNOLOGY

CASE STUDYInstrumentation Equipment

www.intercontrol.es Cs-Te-03-001

TECHNOLOGY

CASE STUDYInstrumentation Equipment

www.intercontrol.es Cs-Te-03-001