Study of Power Tillers at the Moist Paddy Land

No. 2 Reaction Force of the Soil to the Wheel Surface

Abstract

From the motion of the tractor wheels, and the internal stress of the soil by the wheel motion to the soil, we could obtain the reaction forces to the wheel.
1) On the compressible soil, from the founda-mental idea the amount of the soil that will be compressed is to be proportional to the amount that has already been compressed, we obtained the reaction forces to the wheels, and we found the distribution of the forces to the wheel surfaces, the supporting forces of the soil, and the rolling resistances.
2) As the moisture in the soil has been increased, the soil that has been compressed can not support the load, and will be broken or flowed plastically. In these case, we can used the idea of the limit of supporting force introduced by Caquot.
3) But the internal friction angles of the soil in the Caquot's equation are not constant at the case like the swampy paddy land. Then we know that we must find the relations between the depth of the soil and the internal friction angles experimentally.