G MS THESIS_final version_Maxim Prokudin.pdf - Digital Repository ...

67All, aggregate, cementitious and loess composition piers were allowed seven days for curingand the compressive strength of the cementitious composition mix materials was evaluatedby preparing and testing total number of 30 concrete sample cylinders. Each sample was 76mm in diameter and 152 mm in length. The testing samples were allowed to cure for 28 daysand were axially loaded until failure in a compression machine (See Figure 36).Figure 36: 28 day compressive strength testLoad-Settlement DAQ ApproachLoading MechanismAs previously outlined, the strength of the pier is dependent on lateral pressure developedwithin matrix soil, and the shear strength within the pier element itself.Depending on the amount of confinement provided by the matrix soil and length of the pier,the two main mechanisms of failure were plunging (305 mm piers) with tip resistance andskin friction being mobilized and by means of bulging (610 mm piers) where tip movementwas limited. See Figure 37 and Figure 38 for schematic drawings representing the bulgingand plunging failure modes.