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

132C(I) + C(K) – Group EfficiencyThe group efficiency was calculated for all the cement type I and type K composition groupsof piers where the comparison between stiffness of single pier and multiple piers was made.The stiffness, modulus and settlement results were obtained from the stress-settlement curvesand summarized in Table 32.The group efficiency results were calculated at service load or at 2 mm and 5 mm level ofdisplacement. The level of group efficiency for the ultimate load at 10 mm of settlement wasalso calculated.Table 32: Stress, stiffness and deflection comparison measurements for C(I) + C(K)group load test resultsService loadUltimatePier typeC(I) + C(K)Single PierC(I) + C(K)Unit CellC(I) + C(K)Group of 2C(I) + C(K)Group of 4C(I) + C(K)Group of 5C(I) + C(K)Group of 6Ratio δ telltale/ δ top atk at δ top = 2σ at δ top = δ tell-tale at δ topGroup Group GroupLengthσ at δ top = 2 σ at δ top = 5mm10 mm = 10 mmEfficiency at Efficiency at Efficiency at(mm)mm (kPa) mm (kPa)δ top = 10(kPa/mm)(kPa) (mm)2mm 5mm 10mm(mm)305 454 908 1,418 1,806 8.8 0.9 1.0 1.0 1.0610 542 1,083 1,841 2,065 9.2 0.9 1.0 1.0 1.0305 320 640 968 1,147 11.4 1.1 0.7 0.7 0.6610 397 794 1,241 1,460 7.5 0.8 0.9 0.7 0.7305 633 1,266 2,023 2,400 8.1 0.8 0.7 0.7 0.7610 771 1,542 2,209 2,869 6.3 0.6 0.7 0.6 0.7305 961 1,921 3,151 3,609 9.8 1.0 0.5 0.6 0.5610 N/A N/A N/A N/A N/A N/A N/A N/A N/A305 1,188 2,377 3,647 4,225 9.5 1.0 0.5 0.5 0.5610 1,574 3,148 4,148 4,630 10.2 1.0 0.6 0.5 0.4305 1,677 3,355 3,820 4,096 12.3 1.2 0.6 0.4 0.4610 1,448 2,896 4,818 5,672 8.6 0.9 0.4 0.4 0.5Legend:k – 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 pcfObtained group efficiency values were also compared to the ones obtained on full-scale pilestested by different researchers and are presented in Table 33.