Safety Monitoring and Stability of Building Foundation Pit Based on Fiber Bragg Grating Sensor

Numerical simulation and field monitoring were carried out to study the stability of foundation pit and adjacent historical run during excavation. A foundation pit in the southern new city of Nanjing was used as the research background. The whole process of foundation pit excavation was simulated by MIDAS numerical simulation software. According to the results of numerical simulation, the monitoring scheme of foundation pit and runway is designed by using FBG differential pressure sensor and FBG inclination sensor. The monitoring results show that the surface settlement value of the foundation pit and the horizontal displacement value of the soil are both within the safe range, and the influence of foundation pit excavation on historical runway is within 10m. The surface settlement gradually increases the increase of excavation depth, and the maximum settlement is 19mm, less than the design limit of 30mm. The horizontal displacement of the foundation pit soil is large in the middle and small at the two ends. The maximum horizontal displacement of the soil in the monitoring section is 6.02mm, less than the design limit of 15mm and the stability of the foundation pit is good. The field measurement results are similar to the numerical simulation results, and it is feasible to use numerical simulation methods to guide the design of construction and monitoring schemes.