Measuring the apparent density change near a cyclically loaded displacement pile in sand

Following Vlasblom (1977) and Meijers (2007), a potential field with constant current I is applied to the outer set of conductors spaced vertically at 10 mm. The inner set of conductors spaced 3.3 mm apart is used to measure the voltage drop V within this section of the potential field. All conductors are made of 1.5 mm thick stainless steel rings and are isolated from each other and the remainder of the pile. Combined, I and V yield the apparent resistance. The field of vision of this measurement method is theoretically derived by Dijkstra (2009). He shows that this method averages a soil mass which is about 40 mm in diameter. With the sand used in the tests this corresponds to 267x the grain size d50.