Let's take a look at geomembrane testing.

In order to improve the construction, operation and management level of the artificial anti-seepage system of the sanitary landfill of domestic waste, timely discover and repair the leakage and repair of the high-density polyethylene (HDPE) geomembrane (hereinafter referred to as the geomembrane or anti-seepage membrane) in the anti-seepage system. Damage to ensure its reliability and safety. Geomembrane testing is suitable for detecting broken holes in the anti-seepage geomembrane in the landfill area and leachate treatment facilities after the landfill is completed, and detecting the leakage and pollution range of the leachate during the operation of the landfill and after the landfill is closed. In addition to relevant regulations, the detection of leakage and damage of the anti-seepage geomembrane of the landfill shall also comply with the current relevant national standards.

Geomembrane testing method:

The geomembrane detection test uses a high-voltage pulse power supply, and a voltage is applied to the upper and lower sides of the geomembrane through the power electrode to fix the two power electrodes. A fixed electrode and a moving electrode are arranged in the detection area on the upper part of the geomembrane. The position of the fixed electrode remains unchanged, and the shape of the movable electrode is (1m ~ 5m) x (1m ~ 5m). Before detecting the predicted range, it is necessary to inspect the welded joints in the range to prevent the leakage caused by the current welded joints from affecting the detection of the surface of the high-density polyethylene film. During the measurement, apply a high voltage pulse to the power electrode, measure the potential difference between the fixed electrode and the moving electrode, and record the potential difference until all measurement points are measured.

Geomembrane detection Due to the electrical insulation of the geomembrane, when the geomembrane is intact, no or only a small amount of current flows through the power supply circuit, and the potential difference is evenly distributed across the entire area. When a hole appears in the geomembrane, the insulation of the membrane at the position of the hole will be destroyed, and the current will pass through the hole, distorting the potential difference at that position. Therefore, the holes can be accurately positioned.

The working principle of geomembrane testing:

(1) Working principle: When the water supply pipeline leaks, the water sprayed from the pipeline will rub against the leakage port and collide with the surrounding medium, causing vibrations of different frequencies. The leak detector of the heating pipeline will produce water leakage sound. In the damaged part of the pipeline, when water leaks, sound waves will form and spread to both sides of the pipeline in a sinusoidal manner, causing the pipeline to vibrate. At the same time, the fast-flowing water at the rupture will impact the medium around the pipe, causing water leakage with a special frequency. And it is transmitted to the ground through surrounding media and pipelines. Look for leaks in the water supply network. It is the basic principle of leak detection to use the leak acoustic method to detect the leak point separately.

(2) The types of water leakage can usually be divided into three types:

Leakage friction sound: refers to the sound produced by the friction between the water sprayed from the pipeline and the leakage. Usually the frequency is 300 ~ 2500 Hz, which spreads far along the pipeline. The propagation interval is usually related to water pressure, pipe material, pipe diameter, interface, leakage shape and size, etc. Within a certain range, the sound of water leaking from exposed points such as doors and fire hydrants can be heard.

Head impact sound: refers to the sound produced by the impact of the water sprayed from the pipe with the surrounding medium. It spreads to the ground in a funnel shape through the soil, and can be detected by a leak detector or a listening stick on the ground. Its frequency is usually between 100 and 1500 Hz. Tap water leak detector.

Moderate friction sound: refers to the sound produced by surrounding particles (such as soil particles, sand particles, etc.). ).) The water sprayed from the pipes collide with each other at low frequency. When the listening stick is inserted near the leak point. It can be heard, which provides a basis for the final confirmation of the missing points. At first, the commonly used leak detection equipment was to capture these three sounds. Accurately locate the leak point.