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一、概述电缆直接埋入地下不符合现代化城市建设要求。在新建或改建城市道路时,地下所有管线的近期或远期工程都应同时配合进行一次完成,以免路面反复开挖。有的城市明文规定,新建的道路在多少年之内不准开挖。修建电缆隧道,不仅造价太高,而且使用时还需要解决通风、防火等问题。所以,采用导管是比较理想的电缆铺设方法。导管有石棉水泥管、钢铁管和塑料管,前者比后两者均优越,例如:钢铁管在电缆通电时会产生涡流,消耗电能;塑料管在发生故障电流时,
I. Overview Cables buried directly underground do not meet the requirements of modern urban construction. When new or reconstructing urban roads, the near-term or long-term projects of underground pipelines should be completed at the same time in order to avoid repeated road excavation. Some cities expressly stipulate that new roads must not be excavated within a certain number of years. The construction of cable tunnels is not only costly, but also needs to solve problems such as ventilation and fire prevention. Therefore, the use of catheters is an ideal cable laying method. There are asbestos cement pipes, steel pipes and plastic pipes. The former is superior to the latter two. For example, steel pipes generate eddy currents when they are energized and consume electrical energy. When a fault current occurs in a plastic pipe,