Square piles of reinforced concrete(RC)in marine environments are susceptible to chloride-inducedcorrosion.A novel reverse-seepage technique(RST)is applied to square piles to block the intrusion of chlorides.Thisresea...Square piles of reinforced concrete(RC)in marine environments are susceptible to chloride-inducedcorrosion.A novel reverse-seepage technique(RST)is applied to square piles to block the intrusion of chlorides.Thisresearch introduces a computational model designed to predict the lifespan of corrosion initiation in reinforced concretesquare piles when applied reverse-seepage pressure.The model considers the impacts of chloride binding and the tripletime-dependence property among the permeability,the corrected surface chloride concentration,and the diffusioncoefficient.The proposed numerical model is solved using the alternating direction implicit(ADI)approach,and itsaccuracy and reliability are evaluated by contrasting the computational outcomes with the analytical solution andexperimental results.Furthermore,the primary factors contributing to the corrosion of reinforced concrete square pilesare analyzed.The results indicate that applying RST can decrease the chloride penetration depth and prolong the lifespanof corrosion initiation in square piles.The water-cement ratio and reverse seepage pressure are the most influentialfactors.A water pressure of 0.4 MPa can double the life of concrete,and the durable life of concrete with a water-cementratio of 0.3 can reach 100 years.展开更多
最小二乘逆时偏移(least-squares reverse time migration,LSRTM)具有更高的成像分辨率、振幅保真性及均衡性等优势。然而,目前的LSRTM算法大多基于水平地表假设,在面对复杂地形时无法很好地适应剧烈的起伏地表。基于二阶常密度声波方程...最小二乘逆时偏移(least-squares reverse time migration,LSRTM)具有更高的成像分辨率、振幅保真性及均衡性等优势。然而,目前的LSRTM算法大多基于水平地表假设,在面对复杂地形时无法很好地适应剧烈的起伏地表。基于二阶常密度声波方程的LSRTM算法忽略了密度变化对振幅的影响,很难在变密度介质中取得保真的成像结果。为此,从一阶速度-应力方程出发,在曲线坐标系下推导相应的扰动方程和伴随方程,并通过伴随状态法给出梯度更新公式,最终实现基于贴体网格的起伏地表LSRTM算法。模型试算验证了算法的有效性和对复杂地表的适应性。结果表明,提出的算法能够消除起伏地表的影响、压制低频噪声、恢复高频成分、均衡成像振幅,实现地下变密度介质的高分辨率和高保真度成像。展开更多
基金Projects(52178371,52108355,52178321)supported by the National Natural Science Foundation of ChinaProject(202305)supported by the Research Project of Engineering Research Centre of Rock-Soil Drilling&Excavation and Protection,Ministry of Education,China。
文摘Square piles of reinforced concrete(RC)in marine environments are susceptible to chloride-inducedcorrosion.A novel reverse-seepage technique(RST)is applied to square piles to block the intrusion of chlorides.Thisresearch introduces a computational model designed to predict the lifespan of corrosion initiation in reinforced concretesquare piles when applied reverse-seepage pressure.The model considers the impacts of chloride binding and the tripletime-dependence property among the permeability,the corrected surface chloride concentration,and the diffusioncoefficient.The proposed numerical model is solved using the alternating direction implicit(ADI)approach,and itsaccuracy and reliability are evaluated by contrasting the computational outcomes with the analytical solution andexperimental results.Furthermore,the primary factors contributing to the corrosion of reinforced concrete square pilesare analyzed.The results indicate that applying RST can decrease the chloride penetration depth and prolong the lifespanof corrosion initiation in square piles.The water-cement ratio and reverse seepage pressure are the most influentialfactors.A water pressure of 0.4 MPa can double the life of concrete,and the durable life of concrete with a water-cementratio of 0.3 can reach 100 years.
文摘最小二乘逆时偏移(least-squares reverse time migration,LSRTM)具有更高的成像分辨率、振幅保真性及均衡性等优势。然而,目前的LSRTM算法大多基于水平地表假设,在面对复杂地形时无法很好地适应剧烈的起伏地表。基于二阶常密度声波方程的LSRTM算法忽略了密度变化对振幅的影响,很难在变密度介质中取得保真的成像结果。为此,从一阶速度-应力方程出发,在曲线坐标系下推导相应的扰动方程和伴随方程,并通过伴随状态法给出梯度更新公式,最终实现基于贴体网格的起伏地表LSRTM算法。模型试算验证了算法的有效性和对复杂地表的适应性。结果表明,提出的算法能够消除起伏地表的影响、压制低频噪声、恢复高频成分、均衡成像振幅,实现地下变密度介质的高分辨率和高保真度成像。
