Change of soil mechanical properties due to triaxial sample size

Skuodis, Šarūnas; Dirgėlienė, Neringa; Lekstutytė, Ieva

doi:10.3846/mbmst.2019.006

Cited by 3 publications

(3 citation statements)

References 16 publications

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“…Despite the difficulty in transporting and drilling, large-sized soil sample specimens might represent the actual soil specimens in the field. This difference in the UCS value of the cohesive soil from the smallest specimen diameter to the largest specimen diameter was relatively smaller than that mentioned in [14,20]. Both studies were conducted on specimen size effects using the triaxial test.…”

Section: Effect Of H/d Ratio On Ucsmentioning

confidence: 77%

Effect of Specimens’ Height to Diameter Ratio on Unconfined Compressive Strength of Cohesive Soil

Gebresamuel

Melese

Boru

et al. 2023

Studia Geotechnica Et Mechanica

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The undrained shear strength (Su) and cohesion (Cu) of cohesive soils are frequently determined using an unconfined compression test. However, the test results are heavily dependent on specimen size. This causes uncertainty in geotechnical analyses, constitutive models, and designs by overestimating or underestimating the shear strength of cohesive soils. Therefore, the study aims to assess the effect of the height-to-diameter ratio on the unconfined compressive strength (UCS) of cohesive soil. The soil specimen was tested on a compacted cylindrical specimen at the maximum dry density and optimum moisture content with a height to diameter (H/D) ratio of 1–3 for 38, 50, and 100 mm specimen diameters. Disturbed sample specimens were considered for the laboratory program. Accordingly, the standard Proctor compaction test determines soil classification and compaction characteristics. The unconfined compression test was performed for undisturbed and compacted remolded states of various diameters of cohesive soil specimens to investigate the strength variation with the specimen variation in H/D ratio. The laboratory test results revealed that cohesive soil's unconfined compression strength value drops rapidly with height-to-diameter ratios and the soil specimens’ diameter increases. However, the UCS value was stable at H/D ratio from 1.75 to 2.25. As the specimens’ diameter and H/D ratio increased, the peak UCS value axial strain decreased. Similarly, the gap between the axial strains of peak UCS value for the smallest and the most significant H/D ratio decreased with increase in the specimens’ diameter.

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Section: Effect Of H/d Ratio On Ucsmentioning

confidence: 77%

Effect of Specimens’ Height to Diameter Ratio on Unconfined Compressive Strength of Cohesive Soil

Gebresamuel

Melese

Boru

et al. 2023

Studia Geotechnica Et Mechanica

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“…(1) Many scholars [27][28][29] have studied the size effect of soil and found that when the aspect ratio of the samples is 2 : 1 and the minimum size is 10 times larger than the maximum particle size, the final test results are less affected by the size of samples (2) Limitations in the size of the test apparatus used in this paper: the apparatus used was designed to be used for in situ CT scanning during permafrost loading to facilitate comparison with the fine view structures obtained from subsequent CT scans After the specimen is saturated, the isotropic consolidation is performed on the specimen, the pressure was stabilized until the axial strain rate was less than 0.01 mm/h, the specimen was frozen under pressure for 70 min to make the internal temperature of the specimen uniform. After freezing was completed, it was loaded according to different strain rates and stopped loading at 20% strain rate limit.…”

Section: Methodsmentioning

confidence: 99%

Strength Distribution and Damage Constitutive Model of Frozen Sand under Rate-Dependent Evolution

Song

Yang

et al. 2022

Shock and Vibration

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Study of the compressive strength and damage constitutive model of frozen sand has an important significance for construction design and prevention-control of soil destabilization damage in frozen soil engineering. In this paper, a new triaxial apparatus was used to carry out a series of triaxial compression tests of frozen sand under different confining pressure and strain rate, based on which a segmental strength criterion is established to describe the damage of microelement strength of frozen sand. Assuming that the microelement strength of frozen sand obeys the Weibull distribution, a statistical damage constitutive model of frozen sand is established by statistics and continuous medium mechanics. Based on the test data, the model parameters were calculated and the relationship between the strength distribution parameters, the strain rate, and the confining pressure was obtained. Finally, the calculated values of the damage constitutive model are compared with the experimental values, and it is found that the model can simulate the stress-strain process curve of frozen sand well and can reflect the transition of the curve from elasto-plasticity to strain-hardening when the strain rate increases from low to high. The results of this study have an important significance in engineering construction of cold regions and artificial ground freezing projects.

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“…Wang [21] conducted a triaxial shear test for consolidation and drainage under different conditions, and explored the effects of grain size and confining pressure on the shear characteristics of coral sand in terms of critical confining pressure and shear strength, respectively, and found that the effect of grain size on strength mainly depends on the change of pore ratio. Skuodis [22] found that when the particle size of sand is small, its strength parameters are basically not affected by the sample size, and therefore it is feasible to use a small-sized frozen sand sample.…”

Section: Introductionmentioning

confidence: 99%

Study on Influence of Confining Pressure on Strength Characteristics of Pressurised Frozen Sand

Song

Yang

2022

Sustainability

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In order to reveal the influence law of freezing pressure and confining pressure on the strength characteristics of frozen sand, with the self-developed high-pressure frozen soil triaxial instrument, the triaxial compression tests of frozen sand under different freezing pressures and confining pressures were carried out. The test results show that the freezing pressure will not change the stress–strain curve of the frozen sand. Similar to the confining pressure, the freezing pressure influences the strength of the frozen soil in two ways: strengthening and weakening. The threshold confining pressure resulting from the test was about 45 MPa. Through comparison of the initial elastic modulus with the secant elastic modulus at 0.5 times the strength, it is found that the initial elastic modulus is more appropriate to use in engineering calculations. The internal friction angle is greatly affected by the freezing pressure, and cohesion shows little change with the freezing pressure. Compared with the test results and other constitutive equations, it is found that the constitutive equation established in this paper considering the effect of freezing pressure can better describe the stress–strain relationship of the pressurised frozen sand.

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Change of soil mechanical properties due to triaxial sample size

Cited by 3 publications

References 16 publications

Effect of Specimens’ Height to Diameter Ratio on Unconfined Compressive Strength of Cohesive Soil

Effect of Specimens’ Height to Diameter Ratio on Unconfined Compressive Strength of Cohesive Soil

Strength Distribution and Damage Constitutive Model of Frozen Sand under Rate-Dependent Evolution

Study on Influence of Confining Pressure on Strength Characteristics of Pressurised Frozen Sand

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