Ultrasonic has the characteristics of good directional, strong penetrating, clean and non-polluting, and able to penetrate the inside of the material to be tested. It is often used for flaw detection and reliability assessment of materials and welds in the fields of machinery and aerospace.
Ultrasound is often used to monitor the quality of the construction process and the acceptance of the project. In civil engineering, we use the penetration method. By accurately measuring the first wave's waveform and amplitude, and sound velocity, and then comprehensively analyzing its changes and sizes, we can infer concrete The internal structure, performance and composition of the product provide an effective basis for dealing with some engineering problems. In civil engineering, when pouring vibrated concrete structures, improper operations often cause some defects inside the structure. Because the quality of concrete often affects the use of concrete structures, more and more attention is paid to controlling the quality of concrete pouring One of the means to control the quality of concrete is to use ultrasonic non-destructive testing technology.
As a new type of synthetic material, in the late 1980s and early 1990s, countries such as Europe and the United States have begun a large number of research and development work. Tests and field applications have proved that they can improve the general fill withstand dynamic load and roadbed protection. Great effect. On the basis of absorbing advanced foreign experience in the early 1990s, my country began the development and research of geocells, and made major breakthroughs in the treatment of road bed diseases and the application of fixed loose media. With the further understanding of the characteristics of geocells, it has been found that it has the advantages of other geotechnical materials (geotextile, geomembrane, geogrid, geotextile bag, geonet, etc.), making it unique in many fields. prospect.
The geocell is a kind of three-dimensional grid structure material that uses high-strength polyethylene sheets, connected by ultrasonic welding and other methods, and is expanded into a honeycomb shape. It belongs to a special geosynthetic material. In rock engineering, it forms cushions with different apparent cohesion, different reinforcement strength and different depths together with soil, sand, stone and other fillers. These cushions can be placed in the required position according to the requirements of the project to reinforce the roadbed, slope protection, and build retaining walls. Its major feature is that it can complete a variety of difficult problems that are difficult to deal with by conventional methods in rock engineering, such as bridge head jumping, soft foundation subsidence, tumbling, and collapse. It has the characteristics of light material, wear resistance, aging resistance, chemical corrosion resistance, wide applicable temperature range, high tensile strength, good rigidity, toughness, strong impact resistance, relatively stable size, and convenient transportation. In the construction, the connection is simple and easy, and the construction method is simple, which simplifies the construction process and improves the construction speed; and can be used repeatedly.