| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for back-filling a pipe, requiring no material cost, capable of reducing a problem of the disposal of excavated sand and capable of properly performing back-filling on the whole pipe line ground. SOLUTION: Excavated sand 1a is crushed by a crusher 3, placed on a vibrating sieve in a classifier 4, and classified into blocks A, B, C, D and E. The block E is formed of gravel each piece of which has the size of 2.0 mm or more, and the block A is formed of silt and clay having the size less than 72μand removed as improper materials. The block D is formed of coarse sand, the block C is formed of medium sand, and the block B is formed of fine sand and they are to be used for back-filling. The fine sand, the medium sand and the coarse sand are mixed with mountain sand 5 at a suitable rate by a size adjusting machine 1 into a size structure of earth to be refilled most suitable for a pipe line ground 12. Improved earth to be refilled 8 is disposed in an improved earth to be refilled placing place 9, transported to a pipe burying site, and used for back-filling.</p> |
