地下金属管道在我国几类主要土壤中的腐蚀状况及其与土壤性质的关系

A STUDY ON CORROSION OF UNDERGROUND PIPELINES AND ITS RELATION TO SOIL PROPERTIES IN MAJOR SOILS OF CHINA

地下金属管道在滨海盐土、盐化潮土及黄潮土等弱度淋溶型土壤中腐蚀严重,10年内即可出现多处穿孔,最大孔蚀速率可达1.5毫米/年。穿孔多少主要与土壤的电阻率、含盐量和含氯量有关,其中氯离子含量的影响最大。在砂姜土、棕壤、黄垆土、褐土、栗钙土等中度淋溶型土壤中腐蚀较轻,一般10年内不会出现穿孔。强度淋溶的鳝血水稻土、红壤性、赤红壤性水稻土及赤红壤腐蚀最轻,最大孔蚀速率<0.01毫米/年。处于嫌气状态的南方沼泽性水稻土地区,由于出现微生物腐蚀,最大孔蚀速率可达0.5毫米/年。

Underground metal pipelines are severely corroded in weakly leached soils such as coastal solonchak, salinized fluvo-aquic soil and yellow fluvo-aquic soil. Within 10 years they can be perforated at a number of points, with a maximum rate of hole corrosion of 1.5 mm/yr. The number of perforated holes is associated with such factors as the resistivity, salt content, and chloride content of soil, of which the chloride content is the most important. In moderately leached soils such as Shajiang soil, brown earth, dark loessial soil, cinnamon soil and castanozam, the pipelines arc corroded less severely, and commonly no perforation will take place within 10 years; while in strongly leached soils such as paddy soils with Fe-humic coatings, paddy soils developed on red earth and lateritic red earth, as well as lateritic red earths, they are corroded most slightly, with a maximum rate of hole corrosion of 0.01 mm/yr. Yet, in areas of boggy paddy soil under anaerobic conditions in South China, the maximum rate of hole corrosion may be up to 0.5 mm/yr, due to a corrosion by microbes.