Prestressed concrete cylinder pipes(PCCPs),composed of concrete,a steel cylinder,mortar,and prestressing steel wires,are widely used in water conveyance and diversion projects.In this study,a DN3200 buried PCCP(PCCP-E...Prestressed concrete cylinder pipes(PCCPs),composed of concrete,a steel cylinder,mortar,and prestressing steel wires,are widely used in water conveyance and diversion projects.In this study,a DN3200 buried PCCP(PCCP-E)is taken as the research object.Considering a summer construction environment,numerical simulations are conducted for the entire life cycle of the pipe—from fabrication and storage to buried operation—under different steam curing regimes,to investigate the evolution of the temperature field and stress field of the core concrete.The results indicate that:(1)when the curing duration and demolding time remain unchanged,curing temperature has a significant influence on the temperature peak,temperature difference,and stress peak of the core concrete;higher curing temperatures lead to higher temperature and stress peaks and earlier peak occurrence,and compressive stress during the heating stage is prone to exceeding concrete strength,suggesting that the steam curing temperature should be reduced as much as possible while satisfying the design strength;(2)the constant temperature curing duration has little effect on the temperature peak,and a longer duration reduces the maximum inner–outer temperature difference during the cooling stage but increases tensile stress;(3)extending the heating and cooling durations effectively reduces the temperature peak,temperature difference,and stress peaks;and(4)earlier demolding increases tensile stress in the core concrete,although its overall influence is relatively limited.The findings provide useful guidance for the design and construction of PCCP projects and contribute to improving product quality.展开更多
文摘Prestressed concrete cylinder pipes(PCCPs),composed of concrete,a steel cylinder,mortar,and prestressing steel wires,are widely used in water conveyance and diversion projects.In this study,a DN3200 buried PCCP(PCCP-E)is taken as the research object.Considering a summer construction environment,numerical simulations are conducted for the entire life cycle of the pipe—from fabrication and storage to buried operation—under different steam curing regimes,to investigate the evolution of the temperature field and stress field of the core concrete.The results indicate that:(1)when the curing duration and demolding time remain unchanged,curing temperature has a significant influence on the temperature peak,temperature difference,and stress peak of the core concrete;higher curing temperatures lead to higher temperature and stress peaks and earlier peak occurrence,and compressive stress during the heating stage is prone to exceeding concrete strength,suggesting that the steam curing temperature should be reduced as much as possible while satisfying the design strength;(2)the constant temperature curing duration has little effect on the temperature peak,and a longer duration reduces the maximum inner–outer temperature difference during the cooling stage but increases tensile stress;(3)extending the heating and cooling durations effectively reduces the temperature peak,temperature difference,and stress peaks;and(4)earlier demolding increases tensile stress in the core concrete,although its overall influence is relatively limited.The findings provide useful guidance for the design and construction of PCCP projects and contribute to improving product quality.
