毛细透排水带在渠道防冻胀中的应用

Application of Capillary Permeable Drainage Belt in Anti-frost Heave of Canal

为了解决渠道混凝土衬砌板由于冻胀引起的隆起、滑塌等破坏问题,在对宁夏固海扩灌挖方段渠道混凝土衬砌板结构破坏的部位、程度和形式进行调查、分析的基础上,采用在基土中埋设毛细透排水带和排水管排除基土中的地下水,并对渠道混凝土板的冻胀量进行观测、分析。结果表明:在冻胀性土层上渠道的混凝土板发生冻胀破坏的原因是渠道基土中的含水量过大;利用毛细透排水带进行排水,能有效排除渠道基土中的地下水;渠道采用防渗、保温和排水相结合的结构形式,能有效防止混凝土板冻胀破坏的发生。经过2个冻融期的观测,采用组合方式可以将渠道的混凝土冻胀量降低到6 mm以内,有效降低了渠道冻胀的破坏,同时不会因排水对渠道基土造成流失,有利于渠堤边坡的稳定。毛细透排水带能有效排除渠道基土的地下水,防止渠道混凝土冻胀破坏的发生,显著提高渠道的运行年限。

The location,degree and damage form of canal structure in Guhai expansion and excavation section are investigated and the canal constructed in frost-heaving soil layer are analyzed.The cause of the frost heave of canal concrete slab is the excessive water content in the foundation soil of the canal.The water in the foundation soil of the channel is discharged by means of the natural physical phenomena of the capillary,siphon,gravity and surface tension of the capillary drainage zone,combined with the Canal lining.The anti-frost heave measures of the canal are studied experimentally.The results show that the combination of lining structure,canal seepage prevention,heat preservation and drainage can effectively prevent the frost heave of the canal,and the combined method can effectively control the frost heave of the canal within 6 mm,which effectively reduces the damage caused by the frost heave of the canal.At the same time,the drainage should not cause the loss of the foundation soil of the canal,which is beneficial to the stability of the canal embankment slope.