Bridge Scour Depth Monitoring Technology Research Around Bridge Foundation Based On Heat Conduction

In recent years, the accident of damaged bridge largely due to the instability of piers caused by the long-term scouring effect of river. Bridge scour has already become one of the most important reasons of bridge accidents. Therefore it is necessary to conduct the real-time monitoring of bridge scour situation, so that it can be timely warned before the bridge buckling and avoid unnecessary damage. Therefore, the main contents of this paper have the following sections:1. This paper designed a type of sensor that measure the bridge scour depth based on heat conduction. Heat conduction means the process that the heat is transferred from the high temperature portion of the object to low temperature portion or from the hot object to the cold object. Due to the different thermal diffusivity of different media, so the heat transfer rate in different media is also different.2. According to the theory of heat transfer bridge structure, we made A and B two types of sensors. A-type sensor is a temperature sensor based on DS18B20, B-type sensor is a thermistor temperature sensor based on Pt100.3. Using the made sensors and test equipment, we conducted simulation experimental study for the still air, the flowing air, the still water, the flowing water, the standard sand, the fine sand, the flowing mud, static mud, deposited soils and other environment media. Experimental data show that after 15 minutes the Environment Characteristic Value of the air is up to 180, the Environment Characteristic Value of the soil is about 110 and the Environment Characteristic Value of the still water are only 20, it is smaller in flowing water, its value is close to zero.4. Through the processing and analysis of the experiment data, we obtained the quantitative indicators Environment coefficient Ke determined environmental media. The treated experiment data shows that the Environment coefficient of the still air is about 8.8, the Environment coefficient of the flowing air is about 6.3, the Environment coefficient of soil is about3.8, the Environment coefficient of sand is about 3. The Environment coefficient of the still water is aboutl. In the flowing water and flowing mud environment, its Environment coefficient is smaller and close to zero. The analysis results have fully validated the feasibility and practicality of the sensor.5. This paper designed a complete bridge scour sensing monitoring system, it can achieve the real-time automatic monitoring for scour. Finally, we introduced the application of the sensor monitoring system for a specific project.Through a series of studies, the paper obtained the following conclusions:The sensor can clearly distinguish air, water, soil and other environment, and it can obtain the quantitative indicators Environment coefficient Ke determined environmental media. And the sensor also has some advantages, such as high anti-interference ability, high accuracy, high reliability, good heat resistance, high stability, low cost, good practicality etc. It can achieve the real-time automatic monitoring of the sensor monitoring system and has great significance for bridge scour depth monitoring system design.