In response to safety issues such as structural cracks caused by hydration heat effects of mass concrete in water transport engineering,based on the Shanghai Dongdaying lock project,a finite element numerical simulation software is adopted to establish a concrete structure model of the lock head base slab.A comparative analysis is conducted on hydration heat effects before and after the installation of cooling water pipes in the base slab.The results show that the temperature of the base slab first increases and then decreases,with the maximum internal temperature reaching 61.9 ℃.The external surface is under tension while the interior is under compression,and the surface tensile stress exceeds the allowable limit.The most critical area is located near the corners along the side edges of the top surface.After installing cooling water pipes,the cooling rate increases to 1.83 ℃/d,the peak temperature decreases by 6.4 ℃,and the maximum internal-external temperature difference is reduced to about 25 ℃.To address the localized cracking risk on the side edges of the slab,thermal insulation measures for the side formwork are added,reducing the temperature difference at characteristic points by 15 ℃ and the maximum stress by 58%.As a result,the overall thermal stress of the structure remains below the allowable value.The combined effect of internal cooling water pipes and external thermal insulation curing effectively mitigates the impact of hydration heat and suppresses crack development in mass concrete.