English：

After the steel grid structure is lifted or raised, the removal of temporary supports is a processwhere the structural support form and stress state undergo significant changes, usually based on designmodels for calculation, ignoring the impact of grid assembly errors on the final results. Taking the steelgrid roof of a certain high-speed railway station as the research object, the influence of different unloadingschemes on the internal forces and deformations after the overall lifting is studied. Based on three-3Dlaser scanning technology, the shape and size errors of the grid after ground assembly are analyzed, andthe MIDAS Gen finite element software is used to numerically calculate the unloading process based onthe real model. The differences between the calculation results of the real model and the designed modelare compared. The results show that, assembly errors cause the grid structure to no longer besymmetrical, reducing the uniformity of the reaction force of the jack support during the unloading processand increasing the risk of the unloading process.