MSE Wall 1 EDITEDA unique attribute of Duffield Associates is our ability to provide both geotechnical and structural design services, which converge in the area of retaining structures.  We have extensive experience with the design and construction of “geotechnical retaining walls,” – reinforced slopes, geocell walls, geofoam in retaining walls, as well as more traditional “structural retaining walls” – cantilevered concrete retaining walls, etc. as well as hybrid types – sheet pile, cellular cofferdams, etc.  Our ability to design from both the geotechnical and structural perspectives, allows us to apply only one safety factor and achieve innovative and cost-effective designs.