Research on an Electromagnetic Induction-Based Deep Displacement Sensor

Abstract

A novel deep displacement sensor based on the electromagnetic induction theory is investigated and designed, which can directly convert the varied sliding displacement and tilt angle at any depth within the landslide mass to the variation of mutual inductance, so it has advantages, such as simple sensor structure, high sensitivity, accurate positioning of sliding surface and position, a remote, as well as real-time and automatic monitoring toward the underground landslide mass over the conventional deep displacement monitoring methods. The structure design, sensing principle, and theory modeling for the proposed sensor are presented. In order to improve the sensor's performance, the complicated relationship between the landslide mass's sliding magnitude and direction, the sensor's geometric parameters, and its corresponding mutual inductance were derived by theoretical modeling. Furthermore, a series of ground-based testing experiments and theoretical modeling simulation are conducted and compared in detail, which not only initially shows the design feasibility and modeling effectiveness for the proposed sensor, but is also useful to give an in-depth understanding of the sensor property and optimize the sensor design.

Research on Structure Optimization and Measurement Method of a Large-Range Deep Displacement 3D Measuring Sensor

“…By measuring the displacement of each layer of rock and soil from N-1 measuring units in turn, the distributed flexible measurement of three-dimensional displacement from the surface to the depth of rock and soil mass can be realized. Figure 2 shows the prototype of the magneto-electric deep displacement 3D measuring sensor, which we designed before [32][33][34][35][36]. Each sensing unit has the same structure.…”

“…Here we only outline its working principle. More detailed description can refer our published works [32][33][34][35].…”

“…(4) Easy to realize remote, real-time and networked automatic monitoring. For these sensors, we have carried out in-depth research on sensor theory, measurement modeling, performance analysis and testing [32][33][34][35][36].For our proposed deep displacement 3D measuring sensor, the measurement ranges of horizontal and vertical displacement between two adjacent sensing units (height of the sensing unit is 70 mm) is 0-30 mm, which can meet the monitoring requirements of most landslides, but not necessarily able to meet the monitoring requirements of some large-scale landslides in the fast-changing or near-sliding stage, thus limiting the sensor's overall effectiveness on landslide early warning monitoring. At the same time, in order to adapt to the harsh and complex deep environment of rock and soil mass, the measuring device needs to have strong water-proof, anti-corrosion and compression resistance performance.…”

“…(4) Easy to realize remote, real-time and networked automatic monitoring. For these sensors, we have carried out in-depth research on sensor theory, measurement modeling, performance analysis and testing [32][33][34][35][36].…”

Displacement Measurement Realized By Near-field Coupling Between Multiple Coils

“…(4)(5)(6)(7)(8) A variety of sensing techniques have been developed for contactless displacement sensing in the past decades, for example, the eddy current, capacitive, optical, and inductive displacement sensors. (4,9,10) Optical sensors have better accuracy, stability, and linearity than all other sensors, but they are usually bulky and costly owing to the requirements of a laser, lens, and electronic components.…”