A Precise Measurment of Soil Deformation under the Wheel

軟弱地盤を走行する農機,建機などの研究において,車輪下の土の変形を解明することは走行性の向上のため重要である｡そこで従来法と比較し精密に走行車輪下の土の変形を計測できるシステムの開発を行った。すなわち,土槽側壁の内側に設置したマーカの土に伴う動きを連続的に写真撮影し,平面位置検出装置により土中の変位分布を計測し,これより有限要素解析における方法を用いて土中ひずみ分布を算定する。砂地盤上で剛性車輪を供試して走行実験を行い,土中のひずみ分布を明らかにし,その特性を論じた。It is required to clarify soil deformation under a wheel in order to improve the tractive performance of the off-the-road vehicles, e. g. farm machinery and construction machinery. A new system which is able to measure soil deformation more precisely than the existing methods is developed. A series of photographs for the displacements of the markers which are stuck inside a soil bin wall is taken. The coordinates of the positions of the markers are read from the photographs using the coordinate detecting device. To calculate the strain of soil from the coordinates of the markers, a method used in the finite element analysis is employed. The experiments for the rigid wheel were carried out on sand stratum. The measured strain distribution in the sand is discussed from the mechanical point of view