Analysis on thermal stress of ultra-long basement based on XFEM and stress trajectory visualization

Abstract

Research is conducted on the cracking problem of the side walls of ultra-long seamless basement structures under high-temperature and sunny construction environments in summer. Long term temperature monitoring was conducted on a basement under construction in the Modern Service Industry Park of Honggutan District, Nanchang City. The temperature field was simulated using the commercial finite element software Abaqus,and the measured results were compared with the simulation results to verify the rationality of the theory of simulating the temperature field of sunlight. Based on the theory of simulating the temperature field of sunlight, numerical simulation experiments were conducted using the Extended Finite Element Method (XFEM) to analyze the temperature and stress fields of complete basementstructures of different lengths in high-temperature sunlight environments. The differences in stress and critical cracking temperature difference of basement side walls of different lengths under the same temperature field were compared. Abaqus software was redeveloped using a principal stress trajectory visualization program written in Python, and a complete principal stress trajectory diagram of the basement structure was drawn. The analysis results show that under the same temperature gradient, the change in basement length has no significant effect on the magnitude of the principal stress on the side walls. The critical temperature difference between the upper and lower parts of the basement that caused the side wall to crack did not change significantly. Under the effect of uneven expansion, the crack shape of the basement side wall is in the shape of a "八". In high-temperature construction environments, the temperature rise of the basement ceiling should be carefully monitored to avoid excessive temperature differences between the upper and lower parts of the structure, which may cause the side walls to crack.