Andrew Schofield, as a geotechnical engineer in 1954, developed novel air-photo analyses that located low cost road pavement materials in Malawi. He returned to Cambridge University Department of Engineering where in 1958 he originated Critical-State Soil-Mechanics and in 1963 the Cam-clay model in the theory of plasticity (it combined Drucker's plastic stability criterion with a dissipation function for a water saturated aggregate of soil grains held together by effective forces at grain contacts to predict plastic volume and shear deformation of granular media). In UMIST his calculation of costs and benefits of Thames tidal flood prevention (Nature 1970 pp1203/4) led to the building of the Thames Barrier. In UMIST he developed a pore-water pressure transducer that extended the scope of Soviet Maj. Gen. G. I Pokrovski's centrifuge testing to study effectively stress in models. Returning to Cambridge he modelled both the quasi-static liquefaction of a "Mississippi river crevasse", and the dynamic liquefaction in a water saturated embankment in a model-scale earthquake with data capture of dynamic pore pressures for US Army Engineers Waterways Experiment Station (WES). Finally his Cambridge Phenomenon company Andrew N. Schofield and Associates Limited built the WES Army Centrifuge facility.