TRAFFICABILITY ON TWO-LAYERED GROUND (TILLAGED SOIL AND HARD PAN)

在土（丰浦砂）密度、土层厚度、接触载荷、滑移等不同试验条件下进行了车轮通过性试验。通过测量位于土槽透明侧壁内的300个标记的移动来显示剪切应变和体积应变的分布及其随车轮旋转的变化。在此基础上，详细讨论了牵引力、土体压实、滑移下沉等力学背景。在此基础上，编制了有限元程序，并利用该程序对车轮的走行现象进行了分析，并与试验结果进行了对比，说明了其优越性。特别是在车轮转角不大的情况下，试验中标志点的移动和有限元中节点的位移与分析结果进行了直接比较，两者吻合较好，特别是确定了牵引力逐渐增大，达到最大值，然后减小到最小值，并在土层厚度为零时突然增大到最大值，这是因为对于刚性基底上的土层的高密度和高滑移，土层厚度减小。这与货车德瓦耳斯状态方程中压力与体积的关系相似。另一方面，它被证实，牵引杆拉力单调增加作为土层厚度的刚性基础上的低密度和低滑移土层的减少。这与理想气体的波义耳定律中压力和体积之间的关系相似。

The experiment for trafficability of wheel has been performed in various test conditions of soil (Toyoura sand) density, thickness of soil layr, contact load, slippage, etc. The distributions of shear strain and volumetric strain and their variations with a wheel rotation were shown by measuring the displacements of soil from the movements of 300 markers located inside the transparent side wall of soil bin. Based on them, the mechanical backgrounds for the drawbar-pull, the soil compaction, slip sinkage, etc.are discussed in detail. Further, the finite element program was developed and by use of the program the traveling phenomenon of wheel was analyzed and its pertience is shown by comparing with the test results. Especially, the direct comparison of the test and the analytical results is done on the movements of markers in tests and the displacements of nodal points in finite elements and they coincided fairly well with each other for states that an angle of wheel rotation was not large.In particular, it is confirmed that the drawbar-pull increases gradually reaching a maximal value, then decreases into a minimal value and increases abruptly up to the maximum value in the zero thickness of soil-layr as a thickness of soil-layr decreases for a high density of soil-layr on the rigid base and a high slippage. It is similar to the relationship between a pressure and a volume in van der Waals' state equation for imperfect gas. On the other hand, it is confirmed that the drawbar-pull monotonically increases as a thickness of soil-layr decreases for a low density of soil-layr on the rigid base and a low slippage. This is similar to the relationship between a pressure and a volume in Boyle's law for perfect gas.