Military Engineering Experimental Establishment

Shortly after the end of the Second World War the establishment developed the MEXE method as a means of quickly assessing the carrying capacity of arch bridges, particularly for military traffic. The method was developed by Alfred Pippard of Imperial College, London. The bridge's span, arch thickness and depth of fill were input into an equation or nomogram to determine a provisional acceptable axle loading. This was then modified by a number of additional factors to determine a maximum permissible loading, which could be used to assess which military vehicles could use the bridge. It was a quick and simple process but provided no assessment of the actual stresses or deflections of the bridge. It was later adapted to civilian use.[10]

The MEXE probe, also known as the Soil Assessment Cone Penetrometer or MEXE Cone Penetrometer, is a piece of equipment developed by MEXE to estimate the California bearing ratio (CBR) of a subgrade (soil) in the field.[11] It is a pointed cone attached to a spring-loaded handle by extension spindles. The device is pushed into the ground and a scale reads off the estimated CBR value. It is a quick and simple means of estimating the CBR of the top 0.5 metres of subgrade but is less accurate than the more involved standard CBR test. Expertise is required where granular material is present in the soil.[12] The use of the MEXE Probe can be dangerous where underground services are present.[13]

MEXE were pioneers in the field of terrain evaluation, where the terrain is assessed and categorised based on a number of characteristics.[14][15] Areas were divided into facets of land broadly homogeneous in morphology, water regime and surface material from a 1:50,000 scale map. Similar facets were grouped into recurring landscape patterns whilst anomalous parts of facets were split off as subfacets.[16] This became known as the MEXE system and allows detailed terrain intelligence to be extrapolated from similar terrain in the region and provided to the commander on the ground. The system was implemented at a wide variety of scales from theatre and army corps (where the facets might be tens of kilometres in size) down to the battalion level. At smaller scales there are increased difficulties in identifying all of the anomalies as sub-facets. The data provided ranges from assessments of how good-going the terrain is for travel to possible sources of building materials. A terrain forecast can be issued, similar to how weather forecasts are issued for aircrew.[15] The method works well in stable ecosystems but struggles in developing countries and tropical climates where land use is continuously evolving.[16]