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

134CHAPTER 6: DISCUSSIONThis section presents the discussion of the analyzed results by means of conclusions,observations and trends based on the graphed and tabulated data provided in the previouschapter. Additional tables were constructed as necessary for better interpretation of theresults. Several different criteria were considered when drawing the conclusions such asmaterial composition of the pier, relative pier length, performance of different shape tampingbeveled heads and comparison of the results on basis of service and ultimate load conditions.Aggregate Piers Compacted via Different Shape Tamper HeadsThis section will present the evaluation of results obtained for the aggregate piers compactedvia different shape tamper heads, performance of which will be analyzed with respect tostiffness and load-bearing capacity of the piers.Stress-SettlementAs it can be recalled, the piers constructed at the initial stage of the research study werecompacted using various beveled tamper heads and were placed in stiff soil conditions. Thecompaction of the test bed material was performed on the dry side of optimum moisturecontent, and therefore, little to no bulging was observed. As a consequence no significantlateral stress was developed between the pier and matrix soil materials.To evaluate the performance of each beveled head, the preliminary stress-settlement modulusresults were plotted in Figure 57 and Figure 58. The composed charts outlined the behaviorof the piers compacted via cone, truncated cone, flat and wedge heads constructed at 305 mmand 610 mm lengths, as well as, supplemented with the stress-settlement results for theunreinforced matrix soil. No tell-tale sensors were implemented at this stage of testing and,therefore, no bulging or plunging mechanisms of failure were evaluated.