A laboratory for study of earthmoving soil mechanics was developed by the Research Dept. of Caterpillar Tractor Co. Its principal facilities are soil bins for testing scale models of earthmoving equipment, in two sizes. Scale models have many advantages, including lower cost of construction, greater flexibility in the range of parameters that can be investigated, and closer control of test conditions. Models are best suited to basic studies of soil/machine relationships, and to comparative tests of configurations and operating conditions.
The paper discusses considerations involved in applying the theory of similitude to earthmoving, the assumptions that were necessary, and some of their implications. The scope is limited to the processes of cutting and loading soil. The importance of qualitative realism in model testing is stressed.