Temperature–Load Stress Analysis of Ultra-Long Pool Structures Based on Distributed Fiber Optic Sensing and Finite Element Analysis

Ultra-long pool structures used in mine water treatment projects are typical large-volume concrete structures that are highly susceptible to cracking due to the combined effects of cement hydration heat, seasonal temperature variations, and internal water pressure. Such cracking can compromise the durability and long-term service performance of the structure. In this study, distributed fiber optic sensing and finite element analysis were conducted to observe the response of ultra-long pool structures under thermal–load effects. System comparison shows that the average error between the monitored peak thermal strain values and the corresponding simulated values is within 9%. Parametric analysis using the validated simulation model indicates that the hydration protocol with temperatures of 15 °C (casting), 55 °C (peak), and 15 °C (stable), a temperature drop of −20 °C, and loading conditions in sub-pools 3+6 and sub-pools 1+3+5 are the most unfavorable scenarios for inducing tensile stress. When a temperature drop of −20 °C is combined with loading conditions in sub-pools 3+6 or sub-pools 1+3+5, the tensile stress in the pool structure increases by 30% compared to the stress induced by loading alone. This indicates that during the service life of the pool structure, extreme temperature variations combined with mechanical loading may result in localized cracking. This study provides a comprehensive understanding of ultra-long pool behavior during construction and service phases, supporting effective maintenance and long-term durability.