THE EFFECT OF SOIL CONDITIONS ON THE OPERATION OF EARTHMOVING PLANT

The productivity of various types of earthmoving plant has been assessed on a number of road construction sites and related to the soil conditions measured by means of the moisture condition test. Factors that have been related to the moisture condition value include speed of travel while loaded, speed of travel while empty, depth of rut produced by a single pass of the machines, loss of productivity due to bogging down, and the times of loading and unloading. The results provide information from which the effects of soil conditions on the rate of production, and hence costs, in the earthmoving operations can be derived for a number of types of equipment. Main conclusions reached, however, pertain to the minimum moisture condition value at which various types of machine can operate effectively. A formula has been obtained from an analysis of the data which provides a means of determining the moisture condition value necessary for operation, at any given speed of travel, of motorised scrapers and dump trucks with rigid chassis. (Author/TRRL)