scholarly journals Effect of drainage and saturation on undrained shear strength for compacted sandy soils

2019 ◽  
Vol 92 ◽  
pp. 07003
Author(s):  
Yukio Nakata ◽  
Tetsuya Tashita ◽  
Hiromu Chibana ◽  
Kenji Matsukata
Keyword(s):  
Triaxial Compression ◽  
Strength Properties ◽  
Undrained Shear Strength ◽  
Degree Of Saturation ◽  
Compression Tests ◽  
Compacted Soils ◽  
Partially Saturated ◽  
Saturated Condition ◽  
Undrained Strength ◽  
Triaxial Compression Tests

Collapses of embankments have occurred due to heavy rainfall. It is very important to understand the strength properties under various unsaturated, partially saturated and fully saturated conditions of compacted materials. So, a series of unsaturated and saturated triaxial compression tests for compacted soils have been conducted to understand the effects of drainage and saturation on undrained strength. Soil samples were collected from several road embankments to carry out the experiments. The undrained (CU) strength of compacted material decreased with increase in the degree of saturation. Especially, the strength decreased from partially saturated condition to fully saturated condition was remarkable. The decrease of the materials with volume contractive behaviour was appeared clearly.

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.

scholarly journals Consolidated Undrained Triaxial Compression Tests and Strength Criterion of Solidified Dredged Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Jianwen Ding ◽  
Xusong Feng ◽  
Yupeng Cao ◽  
Sen Qian ◽  
Feng Ji
Keyword(s):  
Shear Strength ◽  
Water Pressure ◽  
Triaxial Compression ◽  
Strength Criterion ◽  
Undrained Shear Strength ◽  
Compression Tests ◽  
Dredged Materials ◽  
Strength Evolution ◽  
Triaxial Compression Tests ◽  
Undrained Shear

Consolidated undrained triaxial compression tests were performed to investigate the shear strength behavior of the solidified dredged materials (SDM). The variation law of deviator stress and excess pore water pressure with the increase of the applied confining pressure was investigated. It is found that the shear strength envelope is consisted of two lines, and there exists a transitional stress on the intersection point. The undrained shear strength develops slightly with the increase of applied normal stress in the preyield state. However, the undrained shear strength increases significantly in the postyield state, and the strength envelope is nearly a straight line with the extension through the origin. Based on the triaxial test data and the binary medium model, a strength criterion considering strength evolution mechanism is proposed and the relevant parameters of the strength criterion were discussed. Comparisons of the predicted results and experimental data demonstrate that the proposed strength criterion can properly describe the strength evolution rules of the SDM.

Study of Constitutive Model of the Schist under Natural and Saturated Condition

2013 ◽  
Vol 444-445 ◽  
pp. 1326-1334
Author(s):  
Xi Xi Zhu ◽  
Cong Xin Chen ◽  
Yun Zheng ◽  
Guan Wen Cheng ◽  
Yi Chao Zhou
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Rock Slope ◽  
Triaxial Compression ◽  
Guangdong Province ◽  
Strength Properties ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Micro Cracks ◽  
Triaxial Compression Tests

Taking the schist as investigative subject, which is the weak layer widely distributed in Yun Fu pyrite, Guangdong province, the deformation characteristics and strength properties of the schist rock mass are analyzed through laboratory uniaxial and triaxial compression tests. Based on the tests on natural and saturated schist, the elastic constitutive equations of the schist, considering the closing of micro cracks, are established; and the deformation characteristics and strength properties of water-weakening influence is analyzed. Through the tests, the deformation characteristics and strength properties of the schist are further understood, which can give some advices to the design of rock slope containing weak layers of the schist.

A Comparative Study of Hydromechanical Properties in Saturated and Partially Saturated Conditions of Two Soils from the Runway of Oran Airport

2017 ◽  
Vol 21 ◽  
pp. 319-326
Author(s):  
Mohamed Chikhaoui ◽  
Dashnor Hoxha ◽  
Naima Belayachi ◽  
Ammar Nechnech
Keyword(s):  
Triaxial Compression ◽  
Confining Pressure ◽  
Natural Soil ◽  
Compression Tests ◽  
Partially Saturated ◽  
Laboratory Results ◽  
Pressure Meter ◽  
Statistical Representativeness ◽  
Triaxial Compression Tests

This study concerns the ground soils of the second runway of the Es-Sénia airport in Oran (Algeria). This airport was built on a very complex hydro geotechnical site when underground cavities, following the dissolution of gypsum soil, were found during the before-construction geologic studies. Several, techniques are used in laboratory (Permeability, triaxial compression tests at various confining pressure, and hydric tests in saturated and unsaturated conditions) and for in situ it’s used the results of SPT and pressure-meter tests. A comparison of parameters of two soils identified in saturated and partially saturated conditions by in situ and laboratory tests was performed in order to respond to questions of the similarity of hydro mechanical properties of two soils as well as their statistical representativeness of the in-situ reality. It is found that, in respect to the studied parameters, laboratory results are statistically significant and reconstituted soils is statistically representative of natural soil reconstitution.

scholarly journals Triaxial Compression Testing of Multicomponent Geomaterials from Quartz-Poor (Syenitic) Systems

2017 ◽  
Vol 63 (4) ◽  
pp. 1-7
Author(s):  
Lukáš Krmíček ◽  
Martin Závacký
Keyword(s):  
Triaxial Compression ◽  
Negative Influence ◽  
Strength Properties ◽  
Compression Tests ◽  
The Czech Republic ◽  
Microgranular Enclaves ◽  
Mafic Microgranular Enclaves ◽  
Indirect Tensile ◽  
Host Rocks ◽  
Triaxial Compression Tests

AbstractThis paper focuses on mafic microgranular enclaves enclosed in quartz-poor igneous rocks and their effect on strength properties of the rock massif. The study examines host rock–enclave multicomponent geomaterials from enclave-bearing syenitic rocks from the Třebíč Massif exposed in the Královec quarry near Jaroměřice nad Rokytnou in the Czech Republic. A series of laboratory tests were performed to describe strength properties of individual constituents of the multicomponent geomaterials. We mainly focused on triaxial compression tests, however, rebound hardness, uniaxial compressive strength and indirect tensile strength were determined as well. The obtained results indicate that enclaves and even the contact zones between the enclaves and host rocks do not have any negative influence on the rock strength. In contrast, enclaves represent “stress concentrators” within such multicomponent systems. Strength properties of various multicomponent geomaterials are practically an unexplored topic in the field of rocks mechanics and future studies are needed to establish a robust database describing the behaviour of such geocomposites.

The behavior of loose gassy sand

1999 ◽  
Vol 36 (3) ◽  
pp. 482-492 ◽  
Author(s):  
J L Grozic ◽  
P K Robertson ◽  
N R Morgenstern
Keyword(s):  
Void Ratio ◽  
Triaxial Compression ◽  
Time Domain Reflectometry ◽  
Degree Of Saturation ◽  
Triaxial Testing ◽  
Compression Tests ◽  
Ottawa Sand ◽  
Apparent Dielectric Constant ◽  
Triaxial Compression Tests ◽  
Flow Liquefaction

Methane gas, found in loose deltaic deposits, can contribute to the triggering of flow liquefaction of submarine slopes. The behavior of loose gassy sand is studied in the laboratory using monotonic consolidated undrained triaxial compression tests. Samples consisted of reconstituted Ottawa sand prepared to degrees of saturation ranging from 80 to 100%. Gas contents were determined using a time domain reflectometry miniprobe with a series of calibrations relating apparent dielectric constant to degree of saturation. The results indicate that loose gassy sands can strain soften and experience flow liquefaction. If the degree of saturation is lower than the "cut-off" value, for a specific void ratio, flow liquefaction will not occur.Key words: triaxial testing, liquefaction, Ottawa sand, gassy, unsaturated.

A Simple Unconsolidated Undrained Triaxial Compression Test Emulator

2015 ◽  
Vol 771 ◽  
pp. 104-107
Author(s):  
Riska Ekawita ◽  
Hasbullah Nawir ◽  
Suprijadi ◽  
Khairurrijal
Keyword(s):  
Triaxial Compression ◽  
Measurement Data ◽  
Radial Strain ◽  
Compression Tests ◽  
Viscous Effects ◽  
Axial Pressure ◽  
Strain Stress ◽  
The University ◽  
And Storage ◽  
Triaxial Compression Tests

An unconsolidated undrained (UU) test is one type of triaxial compression tests based on the nature of loading and drainage conditions. In order to imitate the UU triaxial compression tests, a UU triaxial emulator with a graphical user interface (GUI) was developed. It has 5 deformation sensors (4 radial deformations and one vertical deformation) and one axial pressure sensor. In addition, other inputs of the emulator are the cell pressure, the height of sample, and the diameter of sample, which are provided by the user. The emulator also facilitates the analysis and storage of measurement data. Deformation data fed to the emulator were obtained from real measurements [H. Nawir, Viscous effects on yielding characteristics of sand in triaxial compression, Dissertation, Civil Eng. Dept., The University of Tokyo, 2002]. Using the measurement data, the stress vs radial strain, stress vs vertical strain, and Mohr-Coulomb circle curves were obtained and displayed by the emulator.

Strength envelope of granular soil stabilized by multi-axial geogrid in large triaxial tests

2020 ◽  
Vol 57 (3) ◽  
pp. 448-452 ◽  
Author(s):  
A.S. Lees ◽  
J. Clausen
Keyword(s):  
Triaxial Compression ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Failure Envelope ◽  
Element Analysis ◽  
Linear Elastic ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Triaxial Compression Tests ◽  
Properties Of Soil

Conventional methods of characterizing the mechanical properties of soil and geogrid separately are not suited to multi-axial stabilizing geogrid that depends critically on the interaction between soil particles and geogrid. This has been overcome by testing the soil and geogrid product together as one composite material in large specimen triaxial compression tests and fitting a nonlinear failure envelope to the peak failure states. As such, the performance of stabilizing, multi-axial geogrid can be characterized in a measurable way. The failure envelope was adopted in a linear elastic – perfectly plastic constitutive model and implemented into finite element analysis, incorporating a linear variation of enhanced strength with distance from the geogrid plane. This was shown to produce reasonably accurate simulations of triaxial compression tests of both stabilized and nonstabilized specimens at all the confining stresses tested with one set of input parameters for the failure envelope and its variation with distance from the geogrid plane.

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