Experimental study of a naturally weathered stiff clay

2016 ◽  
Vol 53 (12) ◽  
pp. 2047-2057 ◽  
Author(s):  
Maria Clorinda Mandaglio ◽  
Nicola Moraci ◽  
Marco Rosone ◽  
Camillo Airò Farulla
Keyword(s):  
Shear Strength ◽  
Mechanical Behaviour ◽  
Triaxial Compression ◽  
Experimental Studies ◽  
Water Retention Curve ◽  
Compression Tests ◽  
Weathered Soils ◽  
Wide Range ◽  
Stiff Clay ◽  
Triaxial Compression Tests

Studying the shear strength of a naturally weathered clay is important to understand rain-induced slope failures in weathered soils. However, experimental studies on naturally weathered soils are limited. The paper focuses on the laboratory experimental investigation carried out to analyse the shear strength of a naturally weathered stiff clay that can be found in unsaturated conditions in situ. This has an important practical relevance in the evaluation of the stability conditions of natural slopes at clay outcrops. Different experimental techniques of suction measurement were used to obtain the soil-water retention curve of the clay over a wide range of suctions. Scanning electronic microscope (SEM) observations and results of mercury intrusion porosimetry (MIP) tests are also presented to highlight the considerable fabric arrangement modifications at the microstructural level induced by wetting–drying processes. Moreover, isotropic consolidated drained triaxial compression tests on undisturbed and reconstituted saturated specimens and controlled-suction triaxial compression tests on unsaturated undisturbed specimens were carried out. The test results allowed examination of the saturated mechanical behaviour of clay and comparison of the mechanical behaviour of the saturated material with that in an unsaturated condition.

An Elastoplastic Model for Granular Materials Exhibiting Particle Crushing

2007 ◽  
Vol 340-341 ◽  
pp. 1273-1278 ◽  
Author(s):  
De An Sun ◽  
Wen Xiong Huang ◽  
Dai Chao Sheng ◽  
Haruyuki Yamamoto
Keyword(s):  
Shear Strength ◽  
Granular Materials ◽  
Triaxial Compression ◽  
Model Performance ◽  
Confining Pressure ◽  
Model Parameters ◽  
Compression Tests ◽  
Particle Crushing ◽  
Wide Range ◽  
Triaxial Compression Tests

A practical elastoplastic constitutive model for granular materials is presented. And the model is suitable for description of the material behaviour for a wide range of stresses, including those sufficient to cause particle crushing. With a limited number of model parameters, the model can predict the confining-pressure dependent stress-strain relation and shear strength of granular materials in three-dimensional stresses, especially of variation of shear strength and dilatancy characteristics due to particle crushing under high confining pressure. The model parameters, which have clear physical meanings, can be determined from the results of isotropic compression test and conventional triaxial compression tests. The model performance is demonstrated for triaxial compression tests of a sand for a wide range of the confining-pressure from 0.2MPa to 8.0MPa.

Influence of mineralogy and moisture content on plasticity and induced anisotropic damage of a claystone; application to nuclear waste disposals

2000 ◽  
Vol 171 (6) ◽  
pp. 621-627 ◽  
Author(s):  
Anne-Sophie Chiarelli ◽  
Beatrice Ledesert ◽  
Malek Sibai ◽  
Mohammed Karami ◽  
Nasser Hoteit
Keyword(s):  
Moisture Content ◽  
Nuclear Waste ◽  
Mechanical Behaviour ◽  
Triaxial Compression ◽  
Anisotropic Damage ◽  
Compression Tests ◽  
Two Factors ◽  
Triaxial Compression Tests ◽  
The Way

Abstract The influence of mineralogy and moisture content on mechanical behaviour of a claystone rock is studied by the way of uniaxial and triaxial compression tests and microscopic observations. Some parameters characteristic of phenomena like plasticity and induced anisotropic damage are discussed as a function of these two factors. Rock behaviour becomes more brittle when calcite content grows or when clay or moisture content decreases. At the microlevel, plasticity is induced by slip of clay sheets and induced anisotropic damage appears by growth of oriented microcracks at the interface between grains and matrix.

Mechanical Properties of Bentonite-Sand Mixtures Under Triaxial Stress Condition

1994 ◽  
Vol 353 ◽  
Author(s):  
M. Umedera ◽  
A. Fujiwara ◽  
N. Yasufuku ◽  
M. Hyodo ◽  
H. Murata
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Water Content ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Strength Properties ◽  
Compression Tests ◽  
Optimum Water Content ◽  
Triaxial Compression Tests ◽  
Optimum Water

AbstractA series of triaxial compression tests is being conducted under the drained condition on bentonite and sand mixtures, known as buffer, in saturated and optimum water content states to clarify the mechanical properties of the buffer.It was found that the mechanical properties of bentonite and sand mixtures are strongly influenced by water and bentonite contents: shear strength in a saturated state is less than that in an optimum water content state; shear strength decreases rapidly with increasing bentonite content. Strength properties are much dependent on confining pressure.

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.

Bionic Jump Mechanism Analysis Based on Locust Hind

2013 ◽  
Vol 461 ◽  
pp. 184-190
Author(s):  
Dong Hui Chen ◽  
Heng Xie ◽  
Shao Bo Ye ◽  
Ting Wu ◽  
Xin Lu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Triaxial Compression ◽  
Mechanism Analysis ◽  
Compression Tests ◽  
Fibrous Root ◽  
Factors Affecting ◽  
Complex Shear ◽  
Different Types ◽  
Soil Complex ◽  
Triaxial Compression Tests

The structure of corn stubble was complex and closely combined with the soil, so dig location and root-soil separation are the urgent problem of the manufacturing of corn stubble harvesting machinery. This paper mainly focuses on investigating the interaction principles of corn stubble and soil which by the UU triaxial compression tests. Compared the shear strength of three different types of corn root-soil complexes (vertical root, horizontal root, complex root) and pure soil, and analyzed three important factors affecting the root-soil complex shear strength, it was shown that the presence of corn fibrous root can enhance the soil shear strength and different with their layout types. It will provide a theoretical basis for the design of bionic agricultural tillage components for root- soil separation.

Isothermal modeling of sand–bentonite mixtures at elevated temperatures

1995 ◽  
Vol 32 (1) ◽  
pp. 78-88 ◽  
Author(s):  
B.E. Lingnau ◽  
J. Graham ◽  
N. Tanaka
Keyword(s):  
Shear Strength ◽  
Elevated Temperatures ◽  
Triaxial Compression ◽  
Friction Angle ◽  
Compression Tests ◽  
Strain Behavior ◽  
Bentonite Buffer ◽  
State Boundary ◽  
Increasing Temperature ◽  
Triaxial Compression Tests

Two models are proposed for describing the stress–strain behavior of sand–bentonite (buffer) mixtures at elevated temperatures: (1) isothermal pseudoelasticity and (2) isothermal elastic-plasticity. Data to support the models come from consolidated undrained triaxial compression tests performed on dense saturated buffer specimens at effective confining stresses up to 9.0 MPa and temperatures of 26°, 65°, and 100 °C. Measurements indicate that volumes decrease with increasing temperature if the tests are carried out under drained conditions. These trends can be modelled by a family of hardening lines in semilog compression space. Power law relationships are presented for undrained shear-strength envelopes that increase in size with an increase in temperature. The slopes of unload-reload lines, κ, in semilog compression space vary with temperature and can be related to systematic variation in the friction angle [Formula: see text]. The shear modulus G50 at 50% peak strength also depends on temperature. Several plotting techniques are used to show the existence of different state boundary surfaces for each test temperature. Key words : sand–bentonite, buffer, compression, shear strength, temperature, modelling.

scholarly journals Assessment of strength and deformation of lightweight concrete and its components under triaxial compression, taking into account the macrostructure of the material

2021 ◽  
Vol 264 ◽  
pp. 02015
Author(s):  
Chorikul Raupov ◽  
Ulugbek Shermuxamedov ◽  
Anora Karimova
Keyword(s):  
Lightweight Concrete ◽  
Triaxial Compression ◽  
Experimental Studies ◽  
Confining Pressure ◽  
Hardened Cement ◽  
Compression Tests ◽  
Triaxial Strength ◽  
Pressure Parameter ◽  
Strength And Deformation ◽  
Triaxial Compression Tests

The paper presents the results of experimental studies on the strength and deformations of lightweight concrete, mortar matrix and hardened cement paste under triaxial compression. Tests on samples were carried out using short-term triaxial proportional σ1 > σ2 = σ3 loading (i.e. axial compression + lateral hydrostatic pressure). During the loading, the ratio of the main stresses (both axial and lateral) was kept constant up to the end of tests. The experimental studies were carried out for different low ratios of σ2/σ1. A theoretical estimation has been discussed to approximate experimental results and prediction of triaxial strength values for different types of lightweight concrete. An estimation of the confining pressure parameter K has been done for the used mode of loading.

scholarly journals Change of soil mechanical properties due to triaxial sample size

2019 ◽  
Author(s):  
Šarūnas Skuodis ◽  
Neringa Dirgėlienė ◽  
Ieva Lekstutytė
Keyword(s):  
Shear Strength ◽  
Sample Size ◽  
Triaxial Compression ◽  
Specimen Size ◽  
Compression Tests ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Soil Shear Strength ◽  
Confining Pressures ◽  
Triaxial Compression Tests

Triaxial test is widely used to determine the behaviour and strength parameters of soil. Several consolidated drained triaxial compression tests were performed on two specimen sizes of sand and clay. This article investigate and compares the influence of specimen size and scale effect on the soil shear strength. The tests results show that the shear strength parameters are influenced by the clay specimen size. The results indicate that the effect of triaxial clay sample size is more significant with higher confining pressures. The second type of tests carried out on sand samples shows that sample size doesn‘t influence the results of the shear strength. Author’s show that clay analyses can be significantly affected by the choice of the specimen size used to determine shear strength parameters.

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