Mechanical plant, vehicles and stored materials, including spoil and other heavy loads, should stay outside an excavation's zone of influence unless a competent person, such as a geotechnical engineer, designed its ground support to carry those loads. The zone of influence depends on the ground and is the area within which loads may affect the excavation, including causing collapse. Figure 2 contrasts shoring built for vehicle and material loads, which may be needed where space around the excavation is tight, with shoring designed only for the load of the excavated faces.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.