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

142Table 36 outlines the amount of improvement in load support provided by unreinforcedmatrix soil versus load carried by the pier of the same cross section. In general the trend canbe outlined that the long 610 mm piers have shown a better performance in load carryingcapacity and improvement through stress increase and stiffening of the soil than short 305mm piers. As an exception, piers composed of loess and fiber demonstrated stiffnessbehavior results inconsistent with a general trend, where longer 610 mm pier has shown to beless effective in load bearing capacity.Another conclusion that was drawn from Table 36 has shown that the piers subjected tobulging or internal deformation mechanisms of failure, such as aggregate pier, sand, andloess, fiber composition piers featured a relatively unchanged or declined stiffness ratio asthe loads approached critical or ultimate conditions.Bearing CapacityWhile two primary modes of failure were considered where plunging and bulgingmechanisms were of a main concern, some of the piers featured a more complicatedmechanism of failure through combination of both plunging and bulging processes.Some of the piers, bearing capacities of which were not evaluated due to a complicatedmechanisms of failure, included partially cemented aggregate piers, loess and cementcomposition piers, as well as, piers composed of loess and fibers.Having partially cemented aggregate piers to undergo a more complex mechanism of failurewas attributed with the shift in zone of pier bulging for the aggregate piers with cemented100 mm top portion, and unknown impact of cementing of bulb on plunging mechanism offailure. Therefore, partially cemented aggregate piers could not be evaluated throughconventional methods of evaluating bearing capacity since no pure bulging or pure plungingwas observed.