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

45To perform all the required testing and produce quality results, the test piers had to be spacedat a minimum radial distance to prevent interference, thus, the test bed had to bereconditioned multiple times to accommodate all the test piers (See Figure 20).Every pier was built at 305 mm or 610 mm shaft lengths. Being able to fit a certain numberof piers per each tests bed, every set of tested piers eventually had to be removed, and thesurrounding matrix soil had to be prepared for the installation of the next set of piers. Theprocess of test bed preparation included removal of the matrix soil, remolding of the largeclods of the soil and placement and recompaction of the soil.The excavation of the test bed material was performed to a depth of 610 mm, due to thelength of the scaled piers being 305 mm for the short/floating piers or 610 mm for long piers.A stiff and well compacted layer of loess was expected to be prepared at the depth elevationof 610 mm, in the Lower Zone of 610 mm pier, for the purpose of having the bottom bulb oflong piers to be placed against a stiff layer of soil. Shorter 305 mm piers were not confinedby a stiffer layer of soil at the tip to simulate a floating foundation.The test bed had to be reconditioned a total number of four times for the following piers to beinstalled:Single piers compacted via various shape beveled tamper heads (cone, truncatedcone, flat and wedge).Single piers composed of various aggregate, cement and loess mixesGroups of aggregate piers and cement type I and K composition piersEvery test stage lasted approximately one month and, therefore, the top layer of soil at thesurface was exposed to the room air temperature and, thus, was continuously subjected to airdrying and losing moisture through evaporation. This was mitigated to some degree bycovering the test pit with a tarp. Therefore, after performing excavation of the matrix soil itwas important to moisture condition and thoroughly mix soil mass prior to placement and