Horizontal displacement is an important parameter reflecting the mechanical properties of structures. The horizontal displacement of representative points such as foundation, dam and building is measured with observation instruments and equipment, and the regularity of horizontal displacement is analyzed. The purpose is to understand whether the state of buildings and foundations under internal and external loads and foundation deformation is normal, and provide basis for safe operation of the project According to. Linear displacement sensor can be used for horizontal displacement measurement of civil and structural engineering, which provides massive data support for the booming Internet of things technology.
The horizontal displacement of steel structure, concrete structure or earth rock structure building is usually caused by the action of water and temperature load, uneven settlement of dam foundation, creep deformation of dam body and dam foundation, volume growth of concrete material itself, compression (or consolidation) of dam soil material. The horizontal displacement of wood structure is larger than that of steel structure, concrete structure or earth rock structure. The commonly used measurement methods include collimation line method, tension line method, vertical line method, laser alignment method, displacement sensor method, etc.
The collimation line method establishes a fixed vertical plane parallel to or passing through the dam axis through the collimation line of optical measuring instrument as the datum plane, and regularly observes the deviation between the point position and the datum plane. This method is suitable for the observation of horizontal displacement of the top of concrete building and that of earth rock structure.
The tension line method uses the stainless steel wire tensioned between the two working base points as the reference line, and measures the relative displacement between the measuring point and the steel wire along the line, so as to determine the horizontal displacement of the point. This method is suitable for the measurement of horizontal displacement of concrete dams with linear shape.
The vertical line method takes the plumb line of the dam body or dam foundation as the datum line, and uses the coordinate instrument to measure the relative displacement between the vertical lines and the points at different elevations of the dam body along the line. The deflection curve of the dam body along the vertical line can be drawn from the horizontal displacement observation data of different elevation measuring points on the vertical line. This method is also called deflection observation. It is suitable for all kinds of concrete dams and is the main project of dam safety automatic monitoring.
The laser collimation method uses the laser beam instead of the line of sight of the optical measuring instrument to collimate. This method is suitable for linear concrete dams and can simultaneously measure the horizontal and vertical displacements of the measured points. But the cost is high, the maintenance is difficult, and it is greatly affected by the air refraction.
Displacement sensors are mainly used for automatic mechanical displacement measurement, position positioning and size measurement of mechanical parts, but they are also widely used for horizontal displacement measurement of civil structures or foundations. The displacement sensor has the advantages of large range, multiple models, high precision and good stability. It is convenient to form a detection system with various measuring and controlling instruments and computers to realize the purpose of automatic measurement and control.
The resistance linear displacement sensor is a kind of classical displacement measuring component. Its structure and principle are simple, the failure rate is low, and the cost performance is very high. Sensor absolute position output displacement sensor, output DC voltage signal. It can be converted into standard analog voltage signal, current signal or digital signal according to the needs of the matching measurement and control system to meet the needs of high-precision measurement or signal long-distance transmission. It is a displacement sensor commonly used in automatic production measurement and control system or civil engineering monitoring system.
