盐池灌区环境水和岩土浸出液对泵站及渠道混凝土腐蚀破坏原因分析

Corrosion Damage Analysis of Pumping Station and Canal Concrete by Environmental Water and Rock and Soil Leaching Solution in Yanchi Irrigation Area

盐池灌区的三道井泵站和干渠混凝土出现裂缝、酥松、隆起、滑塌、钢筋腐蚀,造成防渗功能丧失,输水能力降低。对泵站和渠道沿线环境水水质、岩土浸出液、土壤土质取样化验表明,环境水中的Cl^-、SO_4^(2-)含量超标,与混凝土内部的Ca(OH)2、3CaO3·SiO2·3H2O等不稳定物质产生化学反应,混凝土体积膨胀导致结构破坏。土壤母质中含有的大量盐分通过渠道渗漏溶解于水并进入地下水中,对混凝土产生强腐蚀,干湿交替环境加快了混凝土的破坏。因此,在工程改造时,应消减这些不稳定物质的化学侵蚀,采取增加防渗减少渠道水渗漏,采用抗硫水泥增加混凝土自身耐腐蚀性,优选混凝土拌合骨料,增加混凝土结构密实度等措施减少有害离子对混凝土的侵蚀。

The concrete of Sandaojing pumping station and main canal in Yanchi irrigation area has cracks,spongy,heave,collapse and corrosion of reinforcement,resulting in loss of anti-seepage function and reduction of water delivery capacity.The environmental water quality,rock and soil leaching solution and soil quality along the pumping station and canal are analyzed.The results show that the content of Cl^-,SO_4^(2-)in the environmental water exceeds the standard,which reacts with Ca(OH)2、3 CaO3·SiO2·3 H2O and other unstable substances inside the concrete,and the concrete volume expansion leads to structural damage.A large amount of salt contained in the soil parent material is dissolved in the water through the channel and enters into the underground water,which causes strong corrosion to the concrete,and the alternation of dry and wet environment accelerates the destruction of concrete.Therefore,the chemical erosion of these unstable substances should be reduced in the process of engineering transformation.Measures should be taken to reduce the erosion of these unstable substances,such as increasing seepage prevention and reducing channel water leakage,using sulfur resistant cement to increase the corrosion resistance of concrete,optimizing concrete mixing aggregate and increasing the density of concrete structure.