InquiryWhat equipment is used for deep-level horizontal displacement monitoring of dams?
Release time：
2025-07-30
Dike deep-level horizontal displacement monitoring is a key link in the safety management of hydraulic engineering projects. Its core goal is to capture the tiny deformation of the soil or structure inside the dam body through high-precision equipment
Dike deep-level horizontal displacement monitoring is a key link in the safety management of hydraulic engineering projects. Its core goal is to capture the tiny deformation of the soil or structure inside the dam body through high-precision equipment, to provide scientific basis for flood control dispatching, structural reinforcement, and disaster warning. Currently, this field has formed a technical system with the dominant role of the theodolite, supplemented by GNSS displacement monitoring stations, and innovative directions of array and segmental displacement meters, where each device meets different scenario needs through differentiated design.
1. Leveling instrument: The "benchmark tool" for deep-level horizontal displacement monitoring
The inclinometer, with its core principle of directly measuring the tilt angle and calculating the displacement, has become the preferred equipment for deep horizontal displacement monitoring of structures such as earth-rock dams and concrete dams. Its working principle is based on the gravity accelerometer sensing the tilt change of the inclinometer tube caused by the deformation of the soil, and converting the angle data into displacement through the built-in tilt chip. For example, the fixed inclinometer adopts a high-precision MEMS micro electro-mechanical system, which can monitor the tilt change of 0.001° level in real time, corresponding to the displacement resolution of the millimeter level.
In terms of equipment installation, the inclinometer needs to work in conjunction with the inclinometer pipe: the inclinometer pipe is pre-embedded inside the dam body, and a guide groove is set inside the pipe to ensure that the inclinometer probe slides in a specific direction. During monitoring, the probe measures the tilt angle section by section along the guide groove, and the deep horizontal displacement curve is obtained through integration. This design allows it to cover a depth range of 30-100 meters, making it suitable for long-term monitoring of key locations such as the dam foundation and dam shoulders.
Technologically, the inclinometer has three major characteristics: First, it has a high degree of automation, supporting scheduled data collection and real-time transmission. Second, it has strong anti-interference capability, with a 304 stainless steel shell and IP68 protection level that can resist corrosion from groundwater. Third, it has good data continuity, achieving full-depth deformation coverage through segmented measurement. For example, a certain model of inclinometer uses imported tilt chips and full temperature compensation algorithms, maintaining a measurement accuracy of ±0.01° even in environments between -30℃ and 80℃.
ii. GNSS Displacement Monitoring Stations: The "Eyes of Space" for Surface and Near-Surface Displacements
GNSS displacement monitoring stations achieve real-time monitoring of the surface and shallow-level horizontal displacement of the dam body through satellite positioning technology, and their core value lies in constructing a three-dimensional deformation field. The equipment adopts差分 RTK technology, combining the collaborative computing of the reference station and the measuring station, to improve the accuracy of horizontal displacement measurement to the millimeter level. For example, a certain model of monitoring station supports Beidou/GPS dual-mode positioning, with static accuracy of ±2.5mm horizontally and ±5mm vertically, meeting the stringent requirements of dam safety monitoring.
In terms of equipment design, the GNSS monitoring station adopts a modular architecture: the antenna unit integrates a chokes coil and magnetic absorbing material, effectively reducing multipath effects; the communication module supports multi-protocol transmission of 4G, LoRa, and WiFi, ensuring real-time data feedback; the power supply system is equipped with a 30W solar panel and a 20AH battery, allowing continuous operation in environments ranging from -40℃ to 85℃. In addition, the device has an integrated independent alarm function, which can automatically trigger a text message or platform warning when the displacement amount or rate exceeds the threshold.
In terms of application scenarios, GNSS monitoring stations and inclinometers complement each other: the former focuses on surface and near-surface displacement monitoring, while the latter targets deep deformation. The data fusion of the two can construct a full-section deformation model of the dam body. For instance, in the monitoring of concrete gravity dams, GNSS monitoring stations can capture the horizontal displacement at the dam crest, while inclinometers monitor deep sliding of the dam foundation, providing a dual guarantee for structural stability assessment.
Three, Array and Segmental Displacement Meters: The "Breakthrough" of Innovative Technology
1. Array strain gauge: a "panoramic scanner" for three-dimensional deformation
The array-type displacement meter achieves independent XYZ-axis displacement calculation for each measuring unit through the built-in MEMS acceleration meter array, breaking through the limitations of traditional inclinometers that can only measure single-directional displacement. Its core advantages include: First, the three-dimensional deformation monitoring capability, which can simultaneously capture horizontal, vertical, and lateral displacements; second, high-density measurement, with a typical segment length of 0.5-1 meter, suitable for fine monitoring in complex geological conditions; third, data continuity, by constructing a full-depth deformation curve through segmented measurement.
However, there are challenges with the customized cost and complex maintenance of the array displacement meter. For example, its length needs to be customized in advance according to the depth of the inclinometer well, with a delivery cycle of several weeks, and a fault in a certain section of the measuring unit requires overall return to the factory for maintenance, resulting in a high cost of use.
2. Segmental displacement meter: flexible assembly of a "modular solution"
The segmental displacement meter adopts a single segment free splicing design, with each segment equipped with an independent measuring module, and data is transmitted in series through the 485 bus. Its innovations include: First, it flexibly adapts to different depths, allowing users to freely combine the number of segments according to project needs; second, it is convenient to maintain, and a single segment failure can be replaced locally without the need to return the entire device to the factory; third, it optimizes costs, and the equipment can be reused in multiple projects, reducing the total cost of ownership.
Technically, the segmental displacement meter has similar measurement accuracy to the array type, while also supporting automated online monitoring and early warning. For example, a certain model of equipment, by connecting to the cloud platform, can achieve real-time display of displacement, threshold trigger alarm and historical data traceability, providing intelligent decision support for engineering management.
IV. Key Considerations for Equipment Selection
The selection of deep-level horizontal displacement monitoring equipment for dams needs to comprehensively evaluate three major factors: First, the monitoring depth and accuracy requirements, deep-level monitoring gives priority to inclinometers or array-type displacement meters, and GPS monitoring stations can be used for shallow-level monitoring; second, environmental adaptability, the equipment needs to have waterproof, anti-corrosion, low-temperature resistance and other characteristics to cope with the complex working conditions of the reservoir; third, cost and maintenance convenience, segmental displacement meters are more economical in long-term monitoring projects, while inclinometers are suitable for scenarios with extremely high accuracy requirements.
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