{"id":2566,"date":"2022-01-20T10:08:39","date_gmt":"2022-01-20T07:08:39","guid":{"rendered":"https:\/\/geotechru.com\/?post_type=news&p=2566"},"modified":"2022-02-17T15:23:35","modified_gmt":"2022-02-17T12:23:35","slug":"gpr-technologies-in-the-road-industry","status":"publish","type":"news","link":"https:\/\/geotechru.com\/gpr-technologies-in-the-road-industry\/","title":{"rendered":"GPR technologies in the road industry"},"content":{"rendered":"

Maintaining highways in good working order requires timely and efficient types of repair work. Based on the diagnostic results, a full range of quantitative characteristics of road sections is obtained: the modulus of elasticity on the surface of the road structure, the coefficient of adhesion, the evenness of the surface, etc. However, they reflect only the state of the surface of the structure, without answering the question of what are the underlying causes of the appearance of defects in the road structure. Generally, the most common repairs are clearing drainage ditches and pavement reinforcement. Strengthening pavements is an expensive undertaking. Still, according to studies of specialists dealing with these issues, all this gives only a temporary result for 2-3 years, since very often the very cause of subsidence and cracks is not determined and defects reappear on the new coating.<\/p>\n

GPR is used in the survey and design, construction, reconstruction, repair, and maintenance of highways. GPR is equipment that allows determining the thickness of the structural layers of the pavement, as well as the internal structure of the soil environment in the form of continuous soil-hydrogeological sections to a depth (depending on the central frequency at which the device operates) from 0.5 to 30 m respectively, with a resolution capacity of 0.005 to 0.5 m. In this case, the number of drilling operations is significantly reduced, since only control drilling is performed.
\nThe tasks solved using GPR technologies in the road industry:<\/p>\n

1. Surveying and designing highways:<\/strong><\/p>\n

\u2022 survey of soil and hydrogeological conditions of the area;
\n\u2022 determination of the position of the groundwater level;
\n\u2022 assessment of the depth of a reservoir or river in the place of the future bridge crossing and setting the geometrical dimensions of the channel bottom;
\n\u2022 determination of the location and size of utilities;
\n\u2022 exploration and assessment of reserves of useful strata of materials and soils in open pits;
\n\u2022 assessment of the impact of roads on the environment (e.g. when crossing swamps), etc.<\/p>\n

2. Scientific support of road construction projects:<\/strong><\/p>\n

\u2022 prospecting and determination of reserves of road-building materials and overburden rocks in near-highway quarries;
\n\u2022 installation of the remaining reserves of useful strata in open pits during construction;
\n\u2022 assessment of the thickness of the layers of the newly built road structure;
\n\u2022 monitoring the density and moisture content of the laid materials;
\n\u2022 determination of ice thickness on technological roads and winter roads, etc.<\/p>\n

3. Reconstruction and repair of highways:<\/strong><\/p>\n

\u2022 inspection of existing highways and identification of the cause of the destruction of road sections;
\n\u2022 determination of the thickness of the old road surface for subsequent regeneration;
\n\u2022 assessment of the continuity of the culvert along the path of water infiltration in the soil through the joints of the culvert links;<\/p>\n

4. Road maintenance:<\/strong><\/p>\n

\u2022 determination of the bearing capacity of road structures through the thickness of the layers and the moisture content of the subgrade soils;
\n\u2022 predicting the position of the sliding curves and the possible violation of the stability of the slopes of the embankments;
\n\u2022 assessment of the homogeneity of the subgrade soil;
\n\u2022 monitoring the behavior of road structures;
\n\u2022 assessment of the rate of freezing and thawing of the subgrade during the thaw period, etc.<\/p>\n

High-performance, non-destructive, and environmentally friendly GPR technologies can significantly reduce construction and operating costs. At the same time, the reliability of road structures is significantly increased due to the high reliability of the initial geological information. According to experts and scientists working in the road industry and having extensive experience in the application of GPR technologies, the time has come when GPR works can be included in every project of construction, reconstruction, and repair of highways.<\/p>\n

Principle of operation<\/strong><\/p>\n

GPR technologies are based on the phenomenon of reflection of electromagnetic waves from surfaces (boundaries of pavement layers), on which the electrical properties of the environment (materials from which the pavement layers are made) change. The main parameter of the environment is its dielectric constant (\u03b5). The higher the contrast of the values of dielectric constants, the more clearly the boundaries of the environment are distinguished, the electromagnetic wave in the soil (or other research environments) is reflected from the boundaries of layers with excellent dielectric properties. The structure of the GPR includes emitting (source) and receiving (receiver) antennas. The source emits an electromagnetic wave of a given frequency in the form of a finite one and a half period impulse. At each point of the distance, a track is recorded – the dependence of the signal amplitude on the time of arrival of the reflection. A set of tracks along the entire distance makes up a radarogram.<\/p>\n

\n\n \t\t\n\t\t\t\t