某柔性管道（直径为1 000 mm )铺设在原状地基为岩石的地基上，管道下方应铺设的砂垫层厚度不小于（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='26169' and id < 2192920 and id<>'2192920' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='26169' and id > 2192920 and id<>'2192920' order by id asc limit 5