Summary of doctrine
Description of mine detection
There are more advantages to mine detection, such as continuous, non-destructive, efficient, accurate, etc. Mine detection is made up of integrated hosts, antenna components and related software。
Mine detection is usually used extensively for archaeological, basic depth determination, glaciers, groundwater pollution, mineral exploration, dissolved holes, underground cable detection, layers, underground burials, road foundations and substrates, steel bars, cement structures, non-injury, etc。
Summary of doctrine
Description of mine detection doctrine
Basic theory
The launch antenna sends high-frequency wide-frequency short pulse electromagnetic waves to the medium to be measured, based on the transmission of electromagnetic waves in the impaired medium. If an imbalanced interface is encountered when an electromagnetic wave is launched, a partial reflection of the electromagnetic wave will occur, with a greater correlation between the reflection coefficient and the media constant of the detected medium. Radar hosts receive and process in a timely manner the reflection wave generated by this component, determine the velocity of electromagnetic wave transmission in the medium, depending on the medium's medium's medium constant and the conductivity rate, and analyse the reaction wave morphology, range, and change characteristics of the received interface or target when the electromagnetic wave is taken together。
Media constant
The meso-charging constant is a non-quantifiable physical volume that shows the ability of a substance to store polarized charge in addition to the field. The most important substance in the natural world is water, 81 is the medium constant, and the smallest is air, 1 value. An interface between two media with different mediated constants can give rise to different reflections of electromagnetic waves, the intensity of which is related to differences in the mediated constants and the conductivity of the two media. Even if the difference in the medium constant is as small as 1, it can produce a reflection that can be detected by radar。
Device introduction
Test equipment for mine detection
Product look
Product characteristics
1. Mine detection strengths
1. Portability
2. Gpr is non-destructive detection technology
3. Data collection is very fast
4. High accuracy of horizontal and vertical positions
2. Characteristics of iwaco mines (as compared to urban challenges)
1. Structural (one antenna)
System integration is high: radar antennas are integrated with the mainframe control module, free of many cable connections, with the greatest advantage of significantly shielding internal radar noise interference. Integrated design, on the other hand, has significantly reduced the process of on-site assembly of radars and improved their efficiency, while facilitating their transport and use。
2. Data transmission
The first wireless transmission mechanism: the radar and the upper-placer (the laptop computer) communicates by wireless means. It is only necessary to turn on the power supply, connect wifi to work, and it is possible to observe data collection on computers in real time, to analyse in situ, to observe anomalies in real time, and to locate anomalies, which are convenient。
3. Applicability
All chinese software, with a friendly interface, conforms to the usage habits of domestic engineers. Sets one-key parameters, which are self-adapted, easy to use and easy to learn, greatly improves working efficiency. Three working models (point, continuous, range) are adapted to various engineering applications。
Project examples
Mine detection field applications -- a tunnel project in guangdong
Tunnel overview
A rectangular frame or arch-shaped light-hole liner is used in the open-drilling tunnel segment, and a complex liner is used in the mine-based tunnel section, with a curved wall belt. (c) construction of structures, with a single layer of tube lined structure in the formation of the shield。
In the early stages of the mine-law tunnel, concrete was sprayed with c25 and second liners with water-resistant steel and concrete; in the main structure of the work well, concrete with water-resistant steel and concrete with shield-constructed tunnel tubes with c55, c60 and concrete with c20 concrete filled under the tracks。
Test basis
Mine detection is based on chinese industry standards:
1. Quality assessment criteria for railway tunnel works, tb 10417-98
2. Regulation on construction and acceptance of railway concrete and construction works, tb10210-97
3. Protocol for non-destructive quality testing of rail tunnel liners, tb10223-2004; and based on design requirements。
Testing requirements
1. Loss of primary thickness and steel arches
2. Internal and underlying deficiencies of the initial payment
(c) the lack of breech thickness and steel bands
(iv) two-line internal defects
Device selection
1. In tunnel engineering tests, mine detection has the advantage of being easy, fast and harmless。
2. The depth of the detection range is within 1 m and an antenna of 900 mhz can be used to identify the specifics of the tunnel。
Scan technology
1. Scan position
On-site wiring diagram
The wiring shall be based on vertically and supplemented by horizontally and each 5-10 m line shall be marked with a mileage。
During the construction phase of the tunnel, the two-channel tunnel systems shall be fitted with five lines of measurement on the arch, the right side, the right side, and the right side wall, respectively. The single-hole three lanes shall add two additional lines of detection to the bow of the tunnel, which shall be encrypted where the liner is defective。
(b) tests at the acceptance stage: a single-hole two-lane tunnel shall have a total of three measuring lines set up on the arch, to the right and to the right. The single-hole three lanes shall add two additional lines of detection to the bow of the tunnel, which shall be encrypted where the liner is defective。
2. Device parameter setting
1 work mode: continuous mode (no ranger, recommended ranger precise range, location of defects)
2 antenna type: 900m
3 measurement time window: 30ns (line thickness 40 cm, resolution of 30 ns at depth of 1 m)
4 antenna duration: 28 (ensure first wave near ladder frame)
5-message constant: 8 (taking into account that concrete conservation is short-lived and not of design strength)
6 scan speed: 120 scan/s (engine vehicle, even speed, matching on-site equipment moving speed)
7 automatic gain:-16 (recommended to be 2/3 based on wave size adjustments in the box, too large colour too heavy to facilitate the identification of defects, too low visibility of reflectors, and where local gain is needed to highlight the depth range to be screened)
Graphic analysis
Mine detection data analysis
Signal judgement
Mine detection image processing includes image interpretation and identification anomalies, based on an analytical interpretation of mine detection imagery on the one hand and an integrated analysis of engineering practices on the other。
Data interpretation
1. Condensed: the lined signal is of weaker size, even in wave shape, and does not even have an interface reflecting signal
2. Inconsistent: a high-reflective signal in a lined interface, a strong-reflective signal, inconsistent with the axis, faulty, general regionalization
3. Hole: the lined interface reflects a strong signal with typical insulated phase characteristics, usually a hyperbolic wave-form feature with a clear triangulation, with a strong reflection interface signal at its lower end and a significantly different time range for two groups of signals
4. Discrepancies: a lined interface reflecting a strong signal, with a striped long bar or triangle distribution, with a visible triangulation, usually with multiple reflection signals
5. Steel bands: a regular, continuous, powerful reflection signal for small moon teeth, with narrow bands
6. Steel frame: a dispersed, powerful reflection signal of the moon's teeth。
On-site image analysis
1. Arche data:
2. Archeological data:
Summary
Several factors affecting radar results
1. On-site factors:
Different conditions for on-site detection, differences in wiring, error in the positioning of stakes, etc.
2. Literal constants are assigned:
Literal constants are generally more reliable in field tests and can be selected where the thickness of concrete can be measured directly
3. Selection of equipment:
For different targets, a reasonable equipment configuration should be selected。
4. The impact of concrete age:
The tests for liners are often divided into tests for the construction process and acceptance tests for the completion (delivery) of the works, which are conducted on-site, sometimes shortly after concrete has been laid, and the intensity of concrete is still changing, its water content is unstable and its water content tends to be larger than that of the working hours, making it difficult to obtain exact values for its cement feed constants. The extracts from the test during the construction process are often small if they are taken by reference to the concrete medium electricity constant at the time of the inspection, which results in a large reading of the thickness of the liner. This was also one of the main causes of the controversy over the results of both the test and the acceptance test for the construction process
5. Objective identification:
Testers are required to have professional research knowledge and extensive field experience。
Everything starts from the point of view of the customer
