The principle of operation and the use of GPR

the person has been for a long time is always interesting, how and what is happening on the ground and in its depths. We are interested in what and where, and most importantly how to lie, even if we did not put there. To meet these needs produces special machinery and equipment. Today, there are a plurality of devices for the study, research, studying the Earth’s surface and its interior. Also developed instruments to ensure the safety of human life activity. That instrument is the “AB 400” is based on the GPR.

image002image001

So what is GPR?

GPR – this radar sensing device (GPR), for subsurface studies aimed at obtaining detailed information about the object in real time. GPR is based on the phenomenon of reflection of high-frequency electromagnetic signal from the boundaries of objects other than the environment they are located electrical performance .

image003

GPR it is a unique geophysical instrument, because GPR allows trained operators to “see” through the stone, earth and water. Practically there is no such protection, which could hide from GPR its secrets: emptiness and foreign bodies, changes in density and structure, hidden internal structures in general almost any anomalies – all this for GPR pages of an open book. The boundaries of the successful use of GPR are huge:

– geology and mining;

– examination and road construction;

– examination of reinforced concrete structures and pipelines;

– historical and archaeological research;

– search, mapping and survey of underground utilities;

– the study and repair of bridges;

– environmental assessment of soil and structures;

– Search groundwater and underground tanks;

– the study of reservoirs, study of the characteristics of snow and ice;

– search for treasures;

– examination of tracks;

– construction;

– horizontal directional drilling – and this is not the full range of application GPR .

The main advantages over other methods of GPR:

  • compactness in GPR create a minimum of inconvenience for Research in densely populated areas and areas of dense building. Using GPR does not damage the environment and does not violate the ecological balance;
  • Use GPR requires no additional hardware and powerful sources of energy. GPR is equally effective in the study of vertical, inclined and horizontal surfaces. GPR makes measurements almost any, including silnoperesechёnnom landscape, on any surface – soil, sand, clay, stone, snow, ice. GPR is used and any artificial surfaces – concrete, concrete, brick, and so on;
  • application used in GPR GPR method of diagnostics is at the hour of the most promising for accurate characterization of the object. Compared with other methods, GPR diagnosis of underlying acts of GPR, is characterized by high speed combined with low energy consumption;
  • and most importantly, GPR uses a non-destructive method of investigating and monitoring – GPR. Through the use of GPR manufacturing and research costs are reduced in tens, and in some cases, hundreds of times, and thus the cost-effectiveness of the project with the use of GPR is much higher!

    What is a ground penetrating radar and its operating principle

    GPR (GPR) survey is carried out using a special tool – GPR, which is an electronic device. GPR researchers receive continuous section of the environment in which the diagnosis is made. Wherein the depth of investigation can reach 20 meters. Recording is carried out in the examination data file that allows you to continue to pursue the study and documentation of the material by means of computer equipment.

    The principle of operation of GPR is entirely based on the radar: emission and fixation of reflected electromagnetic pulses. The pulse produced by the device and by means of the radiator (antenna) is sent to the medium being investigated. The medium can be any material concrete, soil, brick wall, etc. The medium may be non-uniform structure, and that reflects the device.. On the basis of these studies revealed a variety of voids and inclusions of other materials.

    GPR – non-destructive method of research and monitoring. Its use can significantly reduce costs. For example, , search for cable runs under the ground with the help of GPR is greatly simplified, and given the fact that many of the existing factories there is no documentation on the paved once the piping and cable trays, the effect of using GPR increases significantly.

    As a rule, study GPR GPR antenna unit moves along the surface of the medium. Radiation and reception of reflected signals of the environment occurs through a certain distance. This distance is called “sensing step.” The minimum increment value can be measured by only a few millimeters.

    Once the antenna is adopted reflected signal, it is supplied to the device registration information; usually in the laptop is used as a recorder. This unit made a record of the data in the file. After the analysis of the recorded data and structuring engineer diagnostician company conducting GPR examination, receives “section of the test environment.” Another name for this section – georadar profile .

    Most often, such a profile is in the radiogram. Radiogram is an array of deep echoes. Another name radiograms – wave pattern .

    The advantage of GPR

    In recent years, it has become very popular to conduct GPR examination. This method of diagnosis is the most promising way to determine the characteristics of the test environment. This is a promising direction of development in the field of geophysical research. Advantages of GPR and GPR method of diagnosing

    • High resolution GPR and noise immunity to distorting signals along with the speed of the economy and makes the research method is very attractive for modern managers and organizations. Spending at the territory of the GPR expertise, you can get reliable information about soil properties, their composition, finding dangerous voids under buildings or in their immediate vicinity, and more. For example, the study reinforced foundation using GPR can detect its failure to take action and help even before the foundation shifts occur.
    • When conducting GPR studies do not require large production areas. Since the entire research complex – small size equipment. This is a significant advantage, allowing to make the research even in basements or tanks.
    • The use of this diagnostic method significantly reduces the costs of drilling. It provides the researcher with georadar details on the underlying layers of the soil and its structure. Drilling measuring and control wells in this case is carried out in a smaller number and exactly where you need it.

      Types of work

      Application of GPR is very wide, but it can be divided into two groups of activities. Each of these groups are characterized by their methods and ways of processing information:

      1. The solution of geological and hydrogeological problems:
        • The mapping of geological structures – restoration of geometric borders;
        • The definition of the properties and structure of various deposits. Identify the level of the passage of groundwater. Determination of the thickness of the individual layers of the soil and the boundaries between the different areas;
        • The definition of the thickness of the ice cover;
        • The study of the water layer thickness and determination of deposits pallet;
        • The definitions of the depth of soil freezing;
          1. Search for individual objects and engineering constructions in emergency situations:
            • Search cable routes;
            • Search for pipelines;
            • The definition of the boundaries of the production of burial;
            • Identify the location of trapped or flooded basements;
            • The definition of voids in dangerous proximity to the operated buildings.

              Inspection of the quarries and geological surveys

              As you may have heard or read, ground penetrating radar – a device that provides rapid and detailed scanning of the ground. High mobility GPR combined with the possibility of non-destructive scanning the ground (without test drilling) with high detail make GPR unique among other equipment used in geophysics. Due to the information received, it is possible to make the right decision when carrying out the work, resulting in engineering surveys are less expensive. When GPR studies it is possible to display the results of the soil conducted by scanning a 3D-model of the medium under study.

              Thanks to the GPR studies made possible the construction of geological sections, search for and exploration of reserves of mineral deposits, determining the position of the ground water level, ice thickness, depth and profile of the bottom of the ponds, the provisions of sinkholes and voids, glaciological studies – this is not a complete list of those tasks which geology decides by scanning GPR soil. But a number of problems geology solves only GPR. For example, carrying out mapping of geological structures, ie the definition of contact rocks with different dielectric constant is only possible with the use of GPR.

              image004

              When geotechnical investigations using GPR opportunities for ground scanning in research in the field of engineering geology, hydrogeology and of permafrost; geotechnical investigations for construction; determine the level of groundwater, zones of increased watering; identify areas of development of dangerous geological processes (karst, slumping, etc..).

              The use of GPR in the survey and evaluation of the quarries can save a lot of money, because the development of the ground at mining operations can be carried out thanks to the GPR continuously maximizing the useful production, as ground penetrating radar provides a clear definition of the boundaries between different rocks and minerals.

              image005

              Search for hidden objects

              Modern GPR shine soil to a depth of 100 meters. Seeking the object should be comparable in size with a depth of, and should be a contrast with its environment properties.

              Normally used in GPR signal frequencies from 50 to 1500 MHz, thereby expanding search capabilities hidden objects in the structures and the ground on the most deep.

              As the practice shows, in different environments GPR can detect:

              • object with linear dimensions of 3-5cm at depths of up to 1m;
              • object with linear dimensions of 5-10 cm at a depth of up to 2m;
              • object with linear dimensions of 10-15 cm at depths up to 5m;
              • object with linear dimensions of 15-30sm at depths of up to 10m;
              • object with linear dimensions of 1m at depths of up to 50m;

                The main advantage of GPR compared to other devices used in geophysics – its versatility, which allows the use of ground penetrating radar not only directly in geophysics, to solve its various problems. GPR is used in geology, construction, ecology, archeology and many other fields of activity, in other words, wherever you want to carry out an effective search for hidden objects.

                The use of GPR in prospecting has great potential, which today allows Geophysics GPR successfully search for hidden objects in the most difficult of situations.

                Survey of building structures and foundations

                When there was the instrument – GPR, it became clear what the helper received in connection with the construction industry and in particular reinforced concrete construction. GPR using a non-destructive method of subsurface sensing is an indispensable instrument for the examination of the internal condition of reinforced concrete. GPR does not break with the general structural integrity. When working with concrete GPR is determined by the quality and the internal state of concrete structures (bridges, buildings, foundations, piles, etc.).

                image006

                Thanks to the GPR surveys the opportunity to study the performance of building structures. GPR scans the internal structure and determines the state of deformation of buildings and engineering structures. Also GPR defined geometrical and physical parameters of the underground parts of the foundations of buildings, foundations and piles.

                In a survey of reinforced concrete structures and buildings GPR produces general scan determines the location of the reinforcement, utilities, mortgages, thickness w / w plates, the presence of cavities and voids, the presence / absence of waterproofing (especially GPR helps in cases when it is necessary to examine w / b construction without violating the protective layer). GPR is also used in the construction of quality control and detection of objects in the structures before drilling or drilling. GPR survey can detect pre-engineering services and therefore avoid any damage and costly repairs later.

                image007

                Detection and Communications Survey

                To date, the detection of hidden communications (cables, pipelines, reservoirs, tanks, tanks, septic tanks, etc.) GPR in urban areas is becoming more popular. The reason is that often available communication schemes and plans have significant differences with reality, and sometimes simply not available. In this case, to work without GPR survey area is not highly desirable, GPR gives the opportunity to avoid the inevitable accidents.

                image008

                Increased demand for GPR studies to search for communication usually comes from the organizations involved in trenchless laying of underground utilities in city conditions (horizontal directional drilling). Obtained with GPR information about the presence and position in the lateral and depth of underground utilities on the axes of horizontal drilling provide trouble-free work carried out in the shortest possible time and with minimal cost.

                Municipal and repair services of ground penetrating radar is used to determine the location and depth of the hidden communication, survey terrain before digging as well as for the discovery of places breakthroughs in the pipeline. Using GPR allows for a successful job search sites fluid leaks from underground pipes and hidden in the walls.

                Thanks to the GPR sensing can find even the most difficult to detect plastic, concrete and other non-metallic pipes. Unlike metal detectors and GPR locators are powerless.