| 摘要 |
<p>PROBLEM TO BE SOLVED: To make it possible to effectively utilize the housing capacity of lands developed for housing lots to the max. possible extent, to save the labor and costs of work and to prevent the failure of impervious sheets by discarded materials, etc., and the consequent infiltration of sewage and harmful materials into the ground water. SOLUTION: The impervious sheets 14 which prevent the percolation of the sewage, etc., into the strata 13 from the bases 11 and slopes 12 of the lands developed for housing lots are laid on the surfaces of the bases 11 and the slopes 12. Ditches are formed in the central parts of the bases 11 and water collecting pipes 15 having water passage holes are disposed therein so that the rain water, etc., flowing down along the impervious sheets 14 is gathered by these water collecting pipes 14 and is then led to the prescribed sewage lands developed for housing lots. Not sand and soil layers but protective boards 16 are laid atop the impervious sheets 14.</p> |
