求翻译：（1）准备工作：内容包括修筑便道、围堰筑岛和埋设护筒等施工项目。埋设的钢护筒顶端标高应高出原地面或围堰面50cm，护筒底端埋入原南百以下不少于1m范围内必须保证为粘性土并至少护筒底0.5m以下。是什么意思？

(1) Preparation: includes construction of access roads, cofferdams built island and laying casing and other construction projects. Buried steel casing top elevation of the cofferdam should be higher than the original ground surface or 50cm, the bottom casing buried in the former South one hundred wi

( 1) construction preparations: content including pavements, cofferdam tsukishima and planted, care and construction projects. planted in the care and top steel elevation should be higher than the original ground surface or cofferdams bottom 50 cm, care and buried in the original South 100 not less

(1) preparatory work: The content including constructs the access road, the coffer dam builds the island and the embedment protects construction projects and so on the tube.The embedment steel protects the tube peak elevation to be supposed to outdo in-situ surface or coffer dam surface 50cm, protec

(1) preparation: includes built access road, island of cofferdam and construction projects such as laying pipe. Laying of steel casings for the top level of should be higher than the original ground surface or cofferdam 50cm, buried at the bottom casing of the original southern hundred least 1M with

(1) preparatory work: The content including constructs the access road, the coffer dam builds the island and the embedment protects construction projects and so on the tube.The embedment steel protects the tube peak elevation to be supposed to outdo in-situ surface or coffer dam surface 50cm, protec