Aiming at the problem that some security factors in large scale construction projects are difficult to be discovered in time and easily cause accidents, a low-power long-distance data acquisition and transmission scheme using LoRa wireless sensor network is proposed. Firstly, the improved linear integer programming (IILP) model is used to deploy sensor nodes, which is used to collect security risk data. Then, an ARM processor with a high-performance Cortex-M3 architecture is used by the LoRa node to interconnect the LoRa module via the SPI bus for data communication. Finally, the LoRa node sends the data collected by the sensor to the LoRa gateway through the wireless signal, and the data is stored in the cloud database through the TCP/IP protocol. Experimental tests are carried out in actual subway construction projects. The temperature and humidity sensors, deep horizontal displacement sensors, supporting shaft force sensors and groundwater level sensors are installed on the nodes to monitor real-time safety risk factors in the construction process. It is found that under the premise of ensuring more than 90% of the data transmission success rate, the proposed communication distance can be as far as 700 m. Compared with several other schemes, the proposed scheme can show better performance in terms of throughput and network delay. The simulation results of sensor deployment show that the improved ILP model can improve the performance of sensor deployment and save hardware cost to a certain extent. In addition, the proposed scheme combines the advantages of LoRa technology with the characteristics of low maintenance cost and long service life, and has a good reference significance for the application of Internet of Things technology in large-scale construction projects.
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