scholarly journals About the Uncertainty of Unconfined Compression Test Results on Cement Improved Soil

2014 ◽  
Vol 63 (1) ◽  
pp. 44-48
Author(s):  
Kohei SAWA ◽  
Yoshihisa NAKAYAMA ◽  
Natsuko KUSUMOTO ◽  
Yumi NAKATA
2020 ◽  
Vol 5 (1) ◽  
pp. 48-57
Author(s):  
Muhammad Toyeb

Shear strenght is a parameter to soils strenght analysis. Shear strenght can be obtained from laboratorium test that interpreted as stress and strain. Soil tests had done on soil stabilization of cement with mixing 5%; 10%; 15% of content. Soil tests were used by triaxial test of unconsolidated undrained (triaxial UU) with cell pressure at 50; 100; 200 kN/m2 and unconfined compression test. The test specimens were disturbed soil samples which compacted and remolded, and then carry out curing for 0; 3; 7; 14; 28 days. The laboratory test results were back analysis in Plaxis 2D by using Mohr-Coulumb and Hardening Soil model later. The Mohr-Coulumb and Hardening Soil model had deviator stress results was almost equal to the test results of triaxial UU and unconfined compression test. Especially of strain by Mohr-Coulumb model, shew the lower strain than be showed by triaxial UU test and unconfined compression test. The Hardening Soil model, provides fluctuating strain results of triaxial UU test because it is affected by the application of cell pressure (σ3) and it provides greater strain results from unconfined compression test.   Keywords: Triaxial UU, Unconfined Compresssion, Stress and Strain, Plaxis 2D


2015 ◽  
Vol 773-774 ◽  
pp. 1513-1517
Author(s):  
Norbaya Sidek ◽  
S. Abdul-Talib ◽  
N. Mohd Zain ◽  
N.R.N.A. Rashid ◽  
I.A. Abu Bakar

Peat soils have been known for their problematic characteristics which include high water content, high compressibility and low shear strength. In this study, an attempt was made to investigate the effect of 1 week addition of modified Urea-CaCl2liquid medium with and withoutSporosarcina pasteuriion the shear strength of unsterilized dried peat soil using the Unconfined Compression Test. After the treatment period, significant increase in the shear strength of the soil was found to be highest for peat + medium at 42 kN/m2, moderate for peat + medium +Sporosarcina pasteuriiat 27 kN/m2and unchanged for peat + water control at 24 kN/m2. Although the growth dynamics of all the microbes involved in the calcite formation in the treated peat soil were not known, the addition of the modified Urea-CaCl2liquid medium into the soil clearly had contributed to the marked increased in the shear strength of the soil. It is probable that the medium had promoted a better growth of indigenous calcite bacteria population in the soil which may have been suppressed by the slow growingS. pasteuriipopulation being added daily to the soil


Author(s):  
Jian Xiao ◽  
Zhiming Tan ◽  
Jingliang Chen

The unconfined compression test is widely used because of convenient specimen formation, simple experimental process, and low requirement for equipment. In view of the experimental characteristics, the axisymmetric mechanical model of a cylinder with horizontal friction was constructed and its elastic analytic solution was also deduced. The stress and the strain of the cylinder under unconfined compression with different boundary conditions were analyzed by using the analytical solution, and the failure characteristics of the cylinder under unconfined compression were studied and verified by laboratory testing. The results showed that the end restraint effect of the cylinder increased with the decrease of the height-to-diameter ratio and the increase of the Poisson ratio. When the end surface of the cylinder was constrained, the maximum tensile strain appeared in the middle of the cylindrical side; its value increased with the constraint effect, and greater loads were needed to make the same vertical displacement. The compressive strength derived from the current method would be too weak, and the compressive modulus of elasticity would be too great. If the end constraint was large, a small network crack first formed in the middle of the outer side of the cylinder, forming the double-tapered destruction. If the end face was weakly restrained, the cracks descended from the top to the bottom, and the specimens split.


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