Objective Since Tianhe Road Station of Guangzhou Metro Line 10 is located in the upper soft-lower hard strata with a complex surrounding environment, the arch-cover method is planned for its construction. Ground settlement induced by the conventional arch-cover method is relatively large, it is necessary to develop a new construction method with smaller ground settlement amount.

Method The project overview of this station is introduced. Two numerical models based on the main body underground excavation methods are established: the arch-cover method with center columns (hereinafter referred to as the "column model") and the arch-cover method without center columns (hereinafter referred to as the "non-column model"). Vertical displacements of the two models after construction, and ground settlements at each monitoring point under different working conditions are comparatively analyzed. A ground settlement-sensitive working condition (the corresponding process is the removal of the center partition wall) is selected to further compare and analyze the changes in vertical displacement and vertical stress before and after the operation. The reliability and effectiveness of the simulation results is verified by an indoor model box test.

Result & Conclusion  Ground settlement presents a symmetrical distribution law with the central axis as the axis; the ground settlement at the central axis is the largest, and gradually decreases as the distance from the central axis increases. The new arch-cover method with added center columns causes smaller ground settlement than the conventional method, as the columns effectively control vertical displacement. Since the removal of the center partition wall is a sensitive working condition for ground settlement, and the new method with added center columns may lead to a relatively large increase in vertical stress during construction, a careful selection of column materials is essential. The model box test confirms the reliability of the numerical simulation results and proves the effectiveness of center columns in controlling crown settlement and ground settlement.