scholarly journals Undrained shear strength of glacial till soils and its determining factors

Baltica ◽  
2021 ◽  
pp. 246-252
Author(s):  
Domas Gribulis ◽  
Kastytis Dundulis ◽  
Saulius Gadeikis ◽  
Sonata Gadeikienė
Keyword(s):  
Shear Strength ◽  
Triaxial Compression ◽  
Undrained Shear Strength ◽  
Test Results ◽  
Fine Silt ◽  
Determining Factors ◽  
Undrained Strength ◽  
Soil Components ◽  
Undrained Shear

This article presents results of the test conducted on the undrained shear strength of till clayey soils of Eastern Lithuania, which are characterized by rigid and very stiff consistency and low plasticity. According to the classification of soils presented in LST EN ISO 14688–2:2018 Geotechnical Investigation and Testing – Identification and Classification of Soil − Part 2: Principles for a Classification, the tested soils are classified as sandy low plasticity clays. The undrained shear strength was tested using the triaxial compression (unconsolidated undrained) method. The test results showed that peculiarities of the particle size distribution had a crucial impact on the undrained strength of these soils, i.e. on the correlation of clay and fine silt fractions with the rest of soil components.

Profiling of overconsolidation ratio in clays by field vane

1988 ◽  
Vol 25 (1) ◽  
pp. 150-157 ◽  
Author(s):  
Paul W. Mayne ◽  
James K. Mitchell
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Undrained Shear Strength ◽  
Correction Factors ◽  
Test Results ◽  
Overconsolidation Ratio ◽  
Empirical Correction ◽  
Preconsolidation Pressure ◽  
Undrained Strength ◽  
Undrained Shear

The field vane (FV) has traditionally been utilized to obtain profiles of undrained shear strength in soft to medium clays. After some 40 years of experience with FV results, it has been suggested that empirical correction factors be applied to the FV data to account for the effects of strain rate, anisotropy, and disturbance on measured shear strengths. As an additional use of the device, the FV may be calibrated at each site to develop profiles of overconsolidation ratio (OCR) with depth. A data base of oedometer test results and FV strengths from 96 different clays has been compiled to use as a basis for this calibration. Key words: field vane, undrained strength, clay, overconsolidation ratio, preconsolidation pressure, shear strength, vane shear.

Determination of the consistency limits of soils by the fall cone test

1986 ◽  
Vol 23 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Y. Wasti ◽  
M. H. Bezirci
Keyword(s):  
Shear Strength ◽  
Key Words ◽  
Water Content ◽  
Strength Criterion ◽  
Undrained Shear Strength ◽  
Wide Range ◽  
Undrained Strength ◽  
Content Range ◽  
Undrained Shear

The liquid and plastic limits for a variety of natural and artificial soils covering a wide range of plasticity, as determined by the Casagrande method and the fall cone test and based on a strength criterion, were compared. To check the validity of the strength criterion, the undrained shear strength of these soils has been determined with a laboratory vane over the water content range between these limits. A limited comparison of the undrained strength values obtained from the vane test and fall cone test is also given. Key words: Atterberg limits, consistency, fall cone, laboratory vane, shear strength.

scholarly journals Interpretation of undrained shear strength observed in confined triaxial compression tests on compacted clay

2021 ◽  
Author(s):  
Chee K. Wong ◽  
Martin Lun ◽  
Ron C.K. Wong
Keyword(s):  
Shear Strength ◽  
Unsaturated Soil ◽  
Water Pressure ◽  
Triaxial Compression ◽  
Undrained Shear Strength ◽  
Compacted Clay ◽  
Compression Tests ◽  
Basic Model ◽  
Triaxial Compression Tests ◽  
Undrained Shear

This paper presents an interpretation technique to quantify the effects of compaction state and matric suction on the undrained shear strength of compacted clay under confined undrained triaxial compression. This novel technique is based on the mathematical frameworks of SHANSEP (Stress History and Normalized Soil Engineering Property) method for saturated soil and BBM (Barcelona Basic model) for unsaturated soil. Test data of compacted Calgary till were analyzed and interpreted using the proposed technique. The interpretation technique is very useful in delineating the relative impacts of the factors on the behavioral trends in measured undrained shear strength. It was found that in addition to the initial compacted void ratio and suction, soil structure and failure mode exert significant influence on the undrained shear strength of compacted clay. This technique is attractive to engineering practitioners because the confined undrained compression tests (with no pore air and water pressure measurement) are much simpler and less time consuming compared to rigorous laboratory tests on unsaturated soil.

Reconsideration of case histories for estimating undrained shear strength in sandy soils

1999 ◽  
Vol 36 (5) ◽  
pp. 907-933 ◽  
Author(s):  
C E (Fear) Wride ◽  
E C McRoberts ◽  
P K Robertson
Keyword(s):  
Shear Strength ◽  
Sandy Soils ◽  
Standard Penetration Test ◽  
Undrained Shear Strength ◽  
Soil Liquefaction ◽  
Penetration Test ◽  
Case Histories ◽  
Original Case ◽  
Undrained Strength ◽  
Undrained Shear

When sandy soils respond in a strain-softening manner to undrained loading, an estimation of the resulting undrained shear strength (Su) is required to determine the potential for flow liquefaction at a given site. One of the most commonly used methods for estimating the undrained strength of liquefied sand is an empirical standard penetration test (SPT) based chart (originally proposed by H.B. Seed), which was developed using a number of case histories. The original interpretations of these case histories are viewed by many workers and regulatory agencies as the most authoritative measure of the liquefied strength of sand. Consequently, in comparison, other less conservative methods are generally held in an unfavourable light. This paper reexamines the original database of case histories in view of some more recent concepts regarding soil liquefaction. The objectives of this paper are to explore and reassess the issues involved in the original assessment and to offer alternative views of the case records. The conclusions presented here indicate that alternative explanations of the liquefied strength of sand are not inconsistent with the original case histories. Key words: sandy soils, soil liquefaction, undrained strength, standard penetration test (SPT).

Landslide history in a Tertiary sedimentary basin in the Quaternary in Japan

1991 ◽  
Vol 7 (1) ◽  
pp. 671-677
Author(s):  
S. Okusa ◽  
N. Takahama ◽  
Y. Fujita
Keyword(s):  
Shear Strength ◽  
Sedimentary Basin ◽  
Undrained Shear Strength ◽  
Climatic Conditions ◽  
History Of ◽  
Undrained Strength ◽  
Japanese Islands ◽  
Undrained Shear ◽  
Present Activity ◽  
Drained Shear Strength

AbstractThe landslide activities in the Quaternary of the Japanese Islands have been controlled by active neotectonic movements and humid climatic conditions. Most of the present active landslides in Cenozoic muddy sediment in the Japanese Islands occur in the ancient landslides site. In the Musigame landslides site in the Cenozoic Niigata sedimentary basin, the present active landslides are concentrated along the fissures and cracks in the ancient primary landslide blocks. The initial failure of the primary Musigame landslides might have occurred in the mudstone with the intact undrained shear strength and the retrogressive failures with a combination of the intact undrained shear strength and residual undrained strength. Secondary and presently active landslides have occurred in the previously disturbed mudstone in accordance with the residual drained shear strength. The analysis of the occurrence, movement and history of the primary and secondary landslides is essential to understand the present activity of landslide.

Performance of clay samples reinforced with vertical granular columns

2007 ◽  
Vol 44 (1) ◽  
pp. 89-95 ◽  
Author(s):  
J Black ◽  
V Sivakumar ◽  
J D McKinley
Keyword(s):  
Shear Strength ◽  
Ground Improvement ◽  
Stress Path ◽  
Undrained Shear Strength ◽  
Replacement Ratio ◽  
Replacement Method ◽  
Single Column ◽  
Undrained Strength ◽  
Area Replacement Ratio ◽  
Undrained Shear

This paper reports an experimental study in which samples of soft kaolin clay (100 mm in diameter and 200 mm in height) were reinforced with vertical columns of sand and tested under triaxial conditions. Samples were reinforced with either a single column of sand of 32 mm diameter or three columns of sand, each of 20 mm diameter. The replacement method was used to form the columns. The columns were installed in the clay to depths of 120 and 200 mm. Tests were also carried out on samples that were not reinforced with sand columns. The samples were compressed under both drained and undrained conditions. It was found that the undrained shear strength of samples containing full-depth columns was greatly improved compared with that of the unreinforced samples. In the fully drained tests, the sample installed with a single column of 32 mm diameter exhibited better performance than the sample with three columns of 20 mm diameter, although the area replacement ratio in the case of the three 20 mm diameter columns was higher than that of the single 32 mm diameter column. However, the undrained strength of the composite material was not particularly affected by the number of columns.Key words: Ground improvement, undrained shear strength, consolidation, stress path, settlement.

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.

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