scholarly journals THE INCREASING OF UNDRAINED SHEAR STRENGTH AND SHEAR MODULUS OF SOFT BANGKOK CLAY BY SILICA POWDER USING UNCONFINED COMPRESSION TEST WITH BENDER ELEMENT

2020 ◽  
Vol 18 (69) ◽  
Author(s):  
Pithan Pairojn
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Compression Test ◽  
Undrained Shear Strength ◽  
Unconfined Compression ◽  
Bender Element ◽  
Unconfined Compression Test ◽  
Silica Powder ◽  
Undrained Shear

scholarly journals Undrained shear strength of the heavily consolidated clay

2013 ◽  
Vol 45 (2) ◽  
pp. 207-216 ◽  
Author(s):  
Joanna Stróżyk ◽  
Matylda Tankiewicz
Keyword(s):  
Shear Strength ◽  
Compression Test ◽  
Clayey Soil ◽  
Triaxial Compression ◽  
Undrained Shear Strength ◽  
Engineering Practice ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Unconfined Compression Test ◽  
Undrained Shear

Abstract Undrained shear strength of the heavily consolidated clay. The undrained shear strength (cu) is considered one of the most basic parameter characterizing soils in engineering practice. The particular importance of cu is in the case of clayey soil. This parameter also is the basis for the classification of soil according to the ISO standard. The undrained shear strength usually is determined from unconfined compression test or from triaxial compression test. In the simple way it can be estimated from the fall cone penetrometer test as index parameter. In the presented work the results of unconfined compression tests for very stiff, heavily consolidated clay were shown. All analysed clay specimens were taken from the large depth, up to 303 m below terrain level. The tests results: undrained shear strength (cu) and unconfined compression strength (qu) were discussed in the relation on in situ consolidation stress, Atterberg’s limits and the indicatory test - fall cone test results

Effect of the Time on the Undrained Shear Strength and Permeability of Clay-Wooden Sawdust Mixtures Used to Improve Landfills Liner

2020 ◽  
Vol 857 ◽  
pp. 311-318
Author(s):  
Omar Hamdi Jasim ◽  
Doğan Çetin
Keyword(s):  
Shear Strength ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Unconfined Compression Test ◽  
Remarkable Effect ◽  
The Impact ◽  
Undrained Shear

This study aims to assess the impact of time on sawdust usage to enhance the behavior of the clay used in landfills. The soil used in this paper was brought from Büyükçekmece region / Istanbul. Four proportions (1, 2, 3 and 5) of the sawdust were added as a percentage of the dry weight of the soil. Soil-sawdust mixtures were compacted with the optimum water content corresponding to each percentage and samples were extracted. The extracted samples were divided into two groups, the immediate tests were performed on the first group while the second group was kept in special containers for long-term tests after 90 days. A series of undrained unconsolidated triaxial tests (UU) and unconfined compression tests (UCS) were performed on the specimens and compared with the row soil, in the immediate tests, the results from the UU triaxial test showed that the undrained shear strength was increased as the sawdust content increased and then decreased, it was conducted that the optimum sawdust content was 3%, it was increased the undrained shear strength by (39.5%) and (41.44%) for UU triaxial and Unconfined compression tests respectively. After 90 days of the curing period, it found that 2% is the optimum sawdust content, it was increased the undrained shear strength by (202.51%) and (176.64%) for UU triaxial and unconfined compression test respectively. In the immediate and long-term tests, the coefficient of permeability increased by (66.66) and (94.44%) as the sawdust increased from 0 to 5 % respectively. Sawdust increases the hydraulic conductivity of the clay. It can be concluded that the sawdust usage has a remarkable effect on the shear strength of the clay for both immediate and long-term tests.

scholarly journals An Investigation on the Effect of Calcite Bacteria Seeding on Shear Strength of Peat Soil via an Unconfined Compression Test

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
Keyword(s):  
Shear Strength ◽  
Liquid Medium ◽  
Compression Test ◽  
Peat Soil ◽  
High Water Content ◽  
Unconfined Compression ◽  
Water Control ◽  
Unconfined Compression Test ◽  
Sporosarcina Pasteurii ◽  
Modified Urea

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

Structure characteristics and mechanical properties of kaolinite soils. II. Effects of structure on mechanical properties

2006 ◽  
Vol 43 (6) ◽  
pp. 601-617 ◽  
Author(s):  
Y -H Wang ◽  
W -K Siu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Shear Modulus ◽  
Critical State ◽  
Soil Structure ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Undrained Shear Strength ◽  
Interparticle Forces ◽  
Undrained Shear

This paper reports the effects of structure on the mechanical responses of kaolinite with known and controlled fabric associations. The dynamic properties and strength were assessed by resonant column tests and undrained triaxial compression tests, respectively. The experimental results demonstrate that interparticle forces and associated fabric arrangements influence the volumetric change under isotropic compression. Soils with different structures have individual consolidation lines, and the merging trend is not readily seen under an isotropic confinement up to 250 kPa. The dynamic properties of kaolinite were found to be intimately related to the soil structure. Stronger interparticle forces or higher degrees of flocculated structure lead to a greater small-strain shear modulus, Gmax, and a lower associated damping ratio, Dmin. The soil structure has no apparent influence on the critical-state friction angle (ϕ′c = 27.5°), which suggests that the critical stress ratio does not depend on interparticle forces. The undrained shear strength of kaolinite is controlled by its initial packing density rather than by any interparticle attractive forces, and yet the influence of the structure on the effective stress path is obvious.Key words: interparticle forces, shear modulus, damping ratio, stress–strain behavior, undrained shear strength, critical state.

scholarly journals Undrained Shear and Pore Space Characteristics of Treated Loose Sands with Lime-Activated Zeolite in Saturated Settings

2020 ◽  
Vol 30 (2) ◽  
pp. 105-132
Author(s):  
Babak Jamhiri ◽  
Mohammad Siroos Pakbaz
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Void Ratio ◽  
Pore Space ◽  
Water Pressure ◽  
Undrained Shear Strength ◽  
Alkali Activation ◽  
Unconfined Compression ◽  
Overburden Pressure ◽  
Undrained Shear

AbstractThis research investigates the mechanical behavior of artificially cemented sandy soils formed by lime alkali activation of natural zeolite under saturation settings. In order to verify the bar capability of cemented sands with this new method, an analysis of the undrained shear strength of the soil with pore water pressure ratio measurements was performed from the interpretation of the results of unconfined compression tests. The effect of zeolite-lime blend on treated sands was also visualized by scanning electron microscopy. For the studied soils, it was concluded from the unconfined compression stress values that the soil is fully capable of withstanding compressions due to overburden pressure. Additionally, this study seeks to evaluate the effect of the void ratio on the pore space and undrained shear strength. The results showed that pore water B-ratio increases with the decrease of the void ratio. Moreover, with the increase of zeolite content, confining pressure, and curing age, the peak failure strength increases. The results indicated a promising consistency of treated samples with lime and zeolite under various values of undrained shearing and B-ratios, making this method an ideal treatment for loose sand deposits.

scholarly journals Comparison of the Use of Cement, Gypsum, and Limestone on the Improvement of Clay through Unconfined Compression Test

2019 ◽  
Vol 5 (2) ◽  
pp. 131
Author(s):  
Ika Puji Hastuty
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Soil Properties ◽  
Compression Test ◽  
Unconfined Compressive Strength ◽  
Soil Stabilization ◽  
Unconfined Compression ◽  
Unconfined Compression Test ◽  
Limestone Soil ◽  
Materials Used

Soil stabilization is an effort to improve soil properties by adding additives in the soil to increase the soil strength and maintain the shear strength of the soil. There are many materials which can be used as stabilizers. The materials used in this study were cement, gypsum, and limestone, then the compressive strength values were compared by using the Unconfined Compression Test (UCT). The mixture combinations used in this study were 1% to 10% of cement, gypsum, and limestone on clay by curing for 14 days. The compressive strength value resulted from the unconfined compression test on the original soil sample was 1.4 kg/cm2. The original soil was classified as moderately sensitive soil because the sensitivity value of the original soil was 2. After being stabilized with various mixtures of cement, gypsum, and limestone, soil stabilization using cement obtained the maximum unconfined compressive strength value is 3.681 kg/cm2 in the mixture of 10%. Similarly, the soil stabilization using limestone and gypsum also obtained its maximum unconfined compressive strength value in the mixture of 10% is 3.307 kg/cm2 and 2.975 kg/cm2, respectively.

scholarly journals Site Investigations of the Lacustrine Clay in Taihu Lake, China, Using Self-Boring Pressuremeter Test

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6026
Author(s):  
Bin Wang ◽  
Kang Liu ◽  
Yong Wang ◽  
Quan Jiang
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Normal Distribution ◽  
Taihu Lake ◽  
Undrained Shear Strength ◽  
Plasticity Index ◽  
Lake Area ◽  
Site Investigations ◽  
Lacustrine Clay ◽  
Undrained Shear

Site investigations of the soils are considered very important for evaluation of the site conditions, as well as the design and construction for the project built in it. Taihu tunnel is thus far the longest tunnel constructed in the lake in China, with an entire length of over 10 km. However, due to the very insufficient site data obtained for the lacustrine clay in the Taihu lake area, a series of self-boring pressuremeter (SBPM) field tests was therefore carried out. Undrained shear strengths were deduced from the SBPM test, with the results showing generally higher than those obtained from the laboratory tests, which may be attributed to the disturbance to the soil mass during the sampling process. Degradation characteristics of the soil shear modulus (Gs) were mainly investigated, via a thorough comparison between different soil layers, and generally, the shear modulus would cease its decreasing trends and become stable when the shear strain reaches over 1%. Meanwhile, it was found that a linear relationship between the plasticity index and the shear modulus, and between the decay rate of the shear modulus and the plasticity index as well, could be developed. Further statistical analysis over the undrained shear strength and shear modulus distribution of the soils shows that the undrained shear strength of the soils follows a normal distribution, while the shear modulus follows a log-normal distribution. More importantly, the spatial correlation length of the shear modulus is found much smaller than that of the undrained strength.

The influence of constitutive models on self-boring pressuremeter interpretation in clay

1995 ◽  
Vol 32 (3) ◽  
pp. 420-427 ◽  
Author(s):  
Christropher Nigel Pye
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Constitutive Models ◽  
Undrained Shear Strength ◽  
Systematic Difference ◽  
Stiff Clays ◽  
Perfectly Plastic ◽  
Lift Off ◽  
Elastic Perfectly Plastic ◽  
Undrained Shear

A comparison of the elastic-perfectly plastic (EPP) and hyperbolic (HB) theories for interpreting loading and unloading parts of self-boring pressuremeter (SBP) tests in clay is presented. Computer-aided modelling (CAM) is used to analyze 60 SBP tests in clay to obtain shear modulus (G), undrained shear strength (Su), and in situ total horizontal geostatic stress (σHo). It is shown that the technique of CAM is consistent, repeatable, and simple to use. For all tests analyzed by both models the inferred horizontal geostatic stresses are identical and comparable to "lift-off" measurements. A small systematic difference is found between the two models for the undrained shear strength of soft and stiff clays. The shear modulus valves derived from the EPP model are unrelated to the true modulus of the soil. There is, however, a semiempirical relationship between the HB model and pressuremeter unload–reload (UR) shear modulus. Key words : clay, self-boring pressuremeter, elastic-perfectly plastic, hyperbolic.

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