Abstract
The principal subject on the land consolidation in the sloping paddy field area is the countermeasure to the distrupution of constructed ridge. The field investigation showed that the ridge distruption was caused by percolation water from the surface of slope. From the experimental result of the two-dimensional percolation flow analysis using Resistance-Network analogue, we have examined and discussed the effectiveness of various preventive measures for the ridge distruption. The obtained results were as follows:
1.Widening of ridge's width and laying of water block plate had little effect and were inefficient except an extreme case.
2.It was very effective to drain percolation water outward by the laying of underdrain or permeable layer on the lower part of ridge, because there was no percolation from the surface of slope.
3. The ridges constructed with scrupulous care showed an extreme decrease of the amount of percolation water with restrained permeability. Thus, this measures was highly effective.
Thus it was concluded that the most effective measures for preventing the ridge distruption is to make the simple drain on the lower part of ridge and to construct the ridge scrupulously.
Furthermore, using the 6-method, we have generalized the flow conditions of percolation water defined by the degree of finish of the construction of ridge, and showed that if the ratio of the coefficient of permeability between paddy fields and ridge are obtained, conditions can be indicated from Fig.6 in any situations.
