In order to ensure the effectiveness and accuracy of the detection results of underground pipelines, all underground pipeline detection equipment put into use should be properly checked. Instrument verification involves the reliability verification of each instrument and the uniform verification of several instruments of the same type. Then, in order to ensure the effectiveness and accuracy of the detection results of underground pipelines, all underground pipeline detection equipment put into use should be calibrated.
Instrument verification involves the reliability verification of each instrument and the uniform verification of several instruments of the same type. So what verification work should be done before using the underground pipeline detector? The instrument consistency verification includes the plane positioning consistency verification and the depth determination consistency verification of similar underground pipeline detection equipment. It should be carried out on a single, known underground pipeline or pipeline section with relatively simple pipeline laying conditions.
The stability calibration of a single underground pipeline detector should use the same working parameters to repeat the detection of the underground pipeline at the same location and under the same interference environment for no less than 2 times at different times. The maximum difference should not be greater than the tolerance requirements of the relevant regulations. The detection results should reflect the reproducibility of the method over time. Consistency verification of multiple underground pipeline detectors: On the premise of meeting the consistency of a single unit, count the mean square error of the positioning accuracy and depth-setting accuracy of multiple instruments to see if they meet the requirements of relevant regulations.
The consistency check and method test of multiple instruments should be carried out at the same time, the same detection parameters should be selected, and the same location and the same interference environment should be carried out. That is to say, the consistency check should be carried out on a known underground pipeline. By using the same signal application method on a single pipeline with a known plane position and depth, with similar working frequency, transmission power and transmission and reception distance, record. And count the error between the detection position and detection depth of each instrument to be calibrated and the actual pipeline position and depth. The calibration of the underground pipeline detector can be carried out at the same time as the detection method test, and shall meet the following requirements: 1. The test site and test conditions shall be representative and targeted; 2. The test shall be performed on a known pipeline section within the scope of the survey area 3. The test should be carried out separately for different types, materials, and buried depths of underground pipelines and different geophysical conditions; 4. Different types and models of underground pipeline detectors to be put into use should all participate in the test; 5. The test content of ground penetrating radar should include wave velocity measurement, antenna frequency, sampling frequency selection, etc.; 6. The method test of other geophysical instruments except underground pipeline detector and ground penetrating radar shall be conducted according to the industry standard "Urban Engineering Geophysical Detection Specification" CJJ7 requirements are implemented.
7. The mean square error of positioning and depth determination of all underground pipeline detectors put into use shall meet the requirements of relevant regulations. All kinds of instruments that do not meet the requirements after calibration shall not be put into use.
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