河口船闸钢筋混凝土受盐水入侵影响的结构耐久性设计参数研究

Structural durability design parameters of reinforced concrete in estuary shiplock affected by salt water intrusion

河口船闸在服役过程中会受其下游海水入侵的影响,加之船闸运行时由于频繁灌泄水作用,使得船闸结构受盐水干湿交替的频次较海洋潮汐环境更高,混掺盐水高频率干湿交替的复杂环境下船闸钢筋混凝土(RC)易受腐蚀,结构耐久性问题突出。然而,针对河口船闸RC结构的耐久性设计参数目前未见明确的规范条文规定。为此,通过现场实测数据,推求得到了船闸工程建成后环境水中腐蚀因子对结构物的腐蚀程度,结合我国现行与混凝土耐久性相关的设计规范,经对比分析初定了河口船闸RC结构的耐久性设计参数(强度等级、水胶比、保护层厚度等)。在此基础上,综合考虑大体积混凝土在施工过程中的水化放热所引起的工程质量问题,依托既有工程的相关设计资料,提出了针对河口船闸RC受盐水入侵影响的结构耐久性设计参数建议值,以期为实际工程设计提供数据参考和技术支撑。

During the service process,the estuary ship-lock was affected by the downstream seawater intrusion,coupled with the frequent irrigation and discharge of water during the operation of the ship-lock,the ship-lock structure is subject to a higher frequency of drying-wetting alternations based on the mixed salt water than that of marine tidal environment.The reinforced concrete(RC)structure of ship-lock is susceptible to corrosion under the complex environment of high frequency drying-wetting alternations of mixed salt water,and the structural durability issues is prominent.However,the durability design parameters of estuary ship-lock RC structure have not been specified in standards.Therefore,for this paper′s investigations,the corrosion degrees of environmental water corrosion factors on the ship-lock structure after the ship-lock engineering complete were deduced on the basis of field measurements.Combined with the current design standards related to RC durability in China,the durability design parameters of estuary ship-lock RC structure are preliminarily determined,including the concrete strength grade,water-binder ratio,cover layer thickness,etc.On this basis,considering the engineering quality problems caused by hydration and heat release of mass concrete during the construction process and relying on the relevant design data of existing projects,the proposed values of RC structural durability design parameters for estuary ship-lock affected by salt water intrusion are put forward.The findings of this paper can provide data reference and technical support for practical engineering design.