Trafficability of Wheels on Farm Lands with Hard Pan (Two-Layer Soil)

1)非垂直贯入试验装置的开发，使我们能够改变从90（垂直）到30度，每15度和土层深度的贯入角度。利用该装置测量了垂直和水平土反力随贯入角和土层深度的变化。此外，采用滑移线法分析了竖向贯入时土体的反力。试验结果与理论分析结果吻合较好。2）研制了行走性能试验装置，该装置通过直线轴承系统将车轮系统与小车连接起来，使车轮系统在下沉量变化时不发生倾斜，接触载荷保持恒定。提出了一种新的测量土壤变形的方法：在车轮表面安装几百个直径为5mm的标记物 关于我们 并将其印成黑十字形，以适当的间距用水固定在亚克力板的内壁上，并随土颗粒的运动而运动。4）对次加载面模型进行了扩展，以描述大滑移时土体变形引起的各向异性。5）引入次加载面模型，编制了弹塑性变形有限元程序。该程序对车轮与土壤接触面的边界条件进行了改进，使滑移满足库仑摩擦。此外，还编制了保持接触载荷恒定的控制程序，从而可以分析带滑移的沉陷。6）利用有限元程序，在与试验相同的条件下进行了数值计算。分析结果较好地反映了试验结果中的净牵引力、轴向扭矩、轮面法向应力和切向应力以及土壤变形的变化趋势。少

1) The non-vertical penetration test apparatus was developed, which enables us to alter a penetration angle from 90 (vertical) to 30 degrees in every 15 degree and a depth of soil layer. By the use of this apparatus the vertical and horizontal soil reaction with variations of a penetration angle and a depth of soil were measured. Besides, the soil reaction for the vertical penetration was analyzed by the slip-line method. The good coincidence of the experimental and the analytical results was attained.2) The test apparatus for traveling performance was developed, in which the wheel-system is connected with the carriage through a linear bearing system so that it does not incline and the contact load is kept constant even when a sinkage changes. Further, the T-shaped sensors are attached to the wheel surface in order to measure distributions of a normal and tangential stress.3) A new method for measuring soil deformation was developed: A few hundred markers, the diameter of which is 5mm … More and which are printed a black cross, are fitted on the inside wall of an acryl plate by water in appropriate intervals and move with a movement of soil particles.4) The subloading surface model was extended so as to describe the induced anisotropy which proceeds with the deformation of soil for a large slippage.5) Introducing the subloading surface model, the programming of the finite element method for elastoplastic deformation was developed. In this program the boundary condition in the contact surface between a wheel and soil was improved so as to slip satisfying the Coulomb friction. Further, the controlling program for keeping the contact load constant was incorporated, by which the sinkage with a slip became able to be analyzed.6) By the use of the finite element program the numerical calculation was per formed under the same conditions as those in the experiments. The analytical results express well the trends of experiments for the net traction, the axle-torque, the normal and tangential stress on wheel surface and the deformation of soil. Less