scholarly journals Influence of the rotation of principal stress directions on undrained shear strength

2013 ◽  
Vol 45 (2) ◽  
pp. 183-192 ◽  
Author(s):  
Grzegorz Wrzesiński ◽  
Zbigniew Lechowicz
Keyword(s):  
Shear Strength ◽  
Principal Stress ◽  
Laboratory Tests ◽  
Cohesive Soil ◽  
Undrained Shear Strength ◽  
Hollow Cylinder Apparatus ◽  
Stress Directions ◽  
Anisotropic Consolidation ◽  
Undrained Conditions ◽  
Undrained Shear

Abstract Influence of the rotation of principal stress directions on undrained shear strength. The paper presents the results of research on natural cohesive soil carried out in the Hollow Cylinder Apparatus (HCA). The main goal of this study was to determine the values of undrained shear strength at different angle of the rotation of principal stress directions. The research were carried out with anisotropic consolidation and shearing in undrained conditions (CAU) on cohesive soil with overconsolidation ratio (OCR) equals 4 and plasticity index (Ip) about 77%. The results of laboratory tests allow to assess the influence of the rotation of principal stress directions on undrained shear strength

scholarly journals Testing of Undrained Shear Strength in a Hollow Cylinder Apparatus

2015 ◽  
Vol 37 (2) ◽  
pp. 69-73 ◽  
Author(s):  
Grzegorz Wrzesiński ◽  
Zbigniew Lechowicz
Keyword(s):  
Shear Strength ◽  
Principal Stress ◽  
Hollow Cylinder ◽  
Laboratory Tests ◽  
Undrained Shear Strength ◽  
Cohesive Soils ◽  
Silty Clay ◽  
Hollow Cylinder Apparatus ◽  
Stress Directions ◽  
Undrained Shear

Abstract The paper presents the results of tests performed in a Torsional Shear Hollow Cylinder Apparatus on undisturbed cohesive soils. The tests were performed on lightly overconsolidated clay (Cl) and sandy silty clay (sasiCl). The main objective of the tests was to determine the undrained shear strength at different angles of rotation of the principal stress directions. The results of laboratory tests allow assessing the influence of rotation of the principal stress directions on the value of undrained shear strength that should be used during designing structure foundations

Mechanisms controlling the undrained shear strength behaviour of clays

1999 ◽  
Vol 36 (6) ◽  
pp. 1030-1038 ◽  
Author(s):  
A Sridharan ◽  
K Prakash
Keyword(s):  
Shear Strength ◽  
Double Layer ◽  
Clay Mineralogy ◽  
Shear Resistance ◽  
Undrained Shear Strength ◽  
Interparticle Forces ◽  
Physico Chemical ◽  
Viscous Shear ◽  
Undrained Conditions ◽  
Undrained Shear

The undrained shear strength behaviour of kaolinitic soils is shown to be quite opposite to that observed for montmorillonitic soils under different physico-chemical environments. The mechanism controlling the undrained shear strength behaviour of soils is a function of clay mineralogy of the soils. The present investigation proposes two mechanisms to explain the contradictory behaviour of kaolinitic and montmorillonitic soils under undrained conditions. The undrained shear strength of kaolinitic soils is a result of the net attractive forces and the mode of particle arrangement as governed by the interparticle forces, whereas that of montmorillonitic soils can be attributed to the viscous shear resistance of the double-layer water. The validity of the proposed mechanisms is confirmed by the results of the present investigation and those in the literature.

Variability of undrained shear strength cu within one organic soli layer

2017 ◽  
Vol 32 (1) ◽  
pp. 8-13
Author(s):  
Krzysztof Załęski ◽  
Patryk Juszkiewicz ◽  
Paweł Szypulski
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Organic Soil ◽  
Undrained Shear Strength ◽  
Test Results ◽  
Geotechnical Parameters ◽  
Soil Layers ◽  
Undisturbed Samples ◽  
Strength Tests ◽  
Undrained Shear

For the purpose of this article a program of geotechnical laboratory tests was performed on organic soil (mud) samples from one geological layer. All undisturbed samples were taken within the same excavation in square grid with a side about 30 cm. Differences between specimen parameters were found both at basic test results and at shear strength tests results. Based on all performed tests authors suggest carefulness in assuming geotechnical parameters of organic soil layers because of theirs spatial variability even in very close vicinity.

Undrained shear strength in stability calculation of embankments and foundations on soft clays

1980 ◽  
Vol 17 (4) ◽  
pp. 591-602 ◽  
Author(s):  
Rolf Larsson
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Undrained Shear Strength ◽  
Test Results ◽  
Stability Calculation ◽  
Soft Clays ◽  
Empirical Relations ◽  
Undrained Shear

Undrained shear strength of soft clays is usually measured by field vane tests or laboratory tests. The relevance of the test results in stability calculations of embankments and foundations is discussed. Empirical relations for undrained shear strengths obtained from Scandinavian clays are compared with reported failures.

Investigating performance of micropiled raft in foundation of power transmission line towers in cohesive soil: experimental and numerical study

2018 ◽  
Vol 55 (3) ◽  
pp. 312-328 ◽  
Author(s):  
Ali-Asghar Zekavati ◽  
Alireza Khodaverdian ◽  
Mohammad-Ali Jafari ◽  
Ahmad Hosseini
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Transmission Line ◽  
Power Transmission ◽  
Cohesive Soil ◽  
Undrained Shear Strength ◽  
Sensitivity Analyses ◽  
Power Transmission Line ◽  
Efficiency Coefficient ◽  
Undrained Shear

This paper captures the behavior of micropiled rafts in power transmission line tower foundations in cohesive soil, concentrating on their uplift performance whether due to the tower position along the line or under wind loading conditions. In this regard, first a number of micropiles were driven into the ground of a project site at the ParehSar power plant, Gilan, Iran. Compression and uplift loading tests were conducted according to relevant standards. On the basis of the field data, a three-dimensional finite element model was developed and subsequently calibrated and verified. The behavior of micropiled rafts subjected to uplift, which is a typical type of loading in foundations of 230 kV four-circuit lattice towers, was then studied by means of this model in terms of a wide-ranging parametric study. In the sensitivity analyses, the impacts of various parameters, such as micropile spacing-to-diameter (s/d) and length-to-diameter (l/d) ratios along with undrained shear strength of the soil, on the uplift capacity of an individual micropile within and out of the group were investigated. Furthermore, interaction factors were computed based on diverse values for undrained shear strength of the soil, s/d ratio, l/d ratio, and grout–soil adhesion. From design and analysis perspectives, the finite element method (FEM) outputs revealed that the efficiency coefficient of micropiled rafts during uplift can be considered equal to one. Moreover, it was found that not only does the behavior of micropiles affect the neighboring micropiles immediately adjacent to the loaded one, but it also influences those in further rows, the result of which would be considering their significance as well.

scholarly journals Improvement of Geotechnical Properties of Cohesive Soil Using Crushed Concrete

2019 ◽  
Vol 5 (10) ◽  
pp. 2110-2119 ◽  
Author(s):  
Mahdi O. Karkush ◽  
Sarah Yassin
Keyword(s):  
Shear Strength ◽  
Soft Soil ◽  
Deformation Modulus ◽  
Cohesive Soil ◽  
Undrained Shear Strength ◽  
Geotechnical Properties ◽  
Crushed Concrete ◽  
Waste Concrete ◽  
Natural Aggregates ◽  
Undrained Shear

Some natural resources such as gravel are not renewable, therefore, it is necessary to reduce the use of such resources and replace them with other recycled, economic, and environmentally friendly materials. Recycled crushed concrete aggregates demolished from old buildings and blocks of waste concrete can be used to replace the natural aggregates. The present study focused on using recycled crushed concrete in improvement the chemical and geotechnical properties of soft soil having undrained shear strength of 6.78 kPa. The soft soil samples were mixed with 5, 10, and 15% of crushed concrete. The blocks of waste concrete are grinded by mills to get crushed concrete which passing sieve no. 4. Such aggregates are lighter than natural aggregates and provide a good deformation modulus when mixed with soil. In Iraq, there are hundred thousand tons of concrete blocks used as fences and now considered wastes after removing these security fences, so it’s important to interest from recycling of such materials to be used in the improvement wide region of soft soils in Iraq. The results of tests showed increasing the undrained shear strength of soft soil by 175-193.5% and reduced the compressibility of soft by 25-31% measured in terms of compression index.

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