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

121The group efficiency results were calculated at service load level of 2 mm and 5 mm of topof the pier settlement. The level of group efficiency for the ultimate load at 10 mm ofsettlement was also calculated.Table 28: Stress, stiffness and deflection comparison measurements for aggregate piergroup load test results and group efficiency in comparison to a unit cell pierService load UltimatePier type 1Aggregate PierSingle PierLength(mm)k at δ top =2 mm(kPa/mm)σ at δ top= 2 mm(kPa)σ at δ top= 5 mm(kPa)σ at δ top= 10mm(kPa)δ tell-tale atδ top = 10mm(mm)Ratioδ tell-tale /δ top atδ top = 10(mm)GroupEfficiencyat 2mmGroupEfficiencyat 5mmGroupEfficiencyat 10mm305 64 129 247 406 0.44 0.04 0.4 0.4 0.4610 176 352 704 949 3.80 0.4 0.4 0.5 0.6Loess - 22 67 158 285 - - - - -Aggregate PierUnit Cell305 174 348 588 908 1.30 0.13 1.0 1.0 1.0610 441 894 1,330 1,533 2.80 0.3 1.0 1.0 1.0Loess - 139 278 685 1101 - - - - -Aggregate PierGroup of 2305 241 483 1,345 2,146 3.90 0.4 0.7 1.1 1.2610 630 1,260 2,521 3,017 0.40 0.04 0.7 0.9 1.0Loess - 321 642 1055 1609 - - - - -Aggregate PierGroup of 4305 433 867 2,254 3,406 4.80 0.5 0.6 1.0 0.9610 798 1,596 3,105 3,947 1.5 0.2 0.4 0.6 0.6Loess - 514 1028 1891 2719 - - - - -Aggregate PierGroup of 5305 765 1,529 3,233 4,150 3.50 0.4 0.9 1.1 0.9610 1,755 3,511 4,375 4,825 1.00 0.1 0.8 0.7 0.6Loess - 514 1028 1891 2719 - - - - -Aggregate PierGroup of 6305 1,537 3,073 4,100 4,898 7.00 0.7 1.5 1.2 0.9610 1,567 3,134 5,361 7,068 0.10 0.01 0.6 0.7 0.8Loess - 509 1018 1486 1886 - - - - -Legend:1 all scaled piers were constructed using cone beveledtamper headk – stiffness modulus (kPa/mm)δ top - deflection at the top of the pier (kPa)δ tell-tale - deflection at the bottom of the pier (mm)σ – stiffness of the pier (kPa)Ratio δ tell-tale / δ top = δ tell-tale /10mmConversions:1 m = 3.3 ft1 mm = 0.0394 in1 kPa = 0.145 psi1 kg/m 3 = 0.0624 pcfGroup efficiency values obtained in small-scale testing were also compared to the groupefficiency parameters obtained on full-scale piers tested by different researchers and are