Static liquefaction of sands under multiaxial loading

1998 ◽  
Vol 35 (2) ◽  
pp. 273-283 ◽  
Author(s):  
M Uthayakumar ◽  
Y P Vaid
Keyword(s):  
Steady State ◽  
Hollow Cylinder ◽  
Void Ratio ◽  
Friction Angle ◽  
Stress Path ◽  
Shear Loading ◽  
Multiaxial Loading ◽  
Fundamental Study ◽  
Torsional Shear ◽  
Loading Direction

A fundamental study of the undrained behaviour of sands under multiaxial loading is presented. The investigation was carried out using Fraser River and Syncrude sands in a hollow cylinder torsional shear device. Shear loading was carried out under strain control to capture the postpeak strain-softening characteristics of loose sands. It is shown that the undrained response of loose sands is highly dependent on the loading direction. The friction angle mobilized at phase transformation and steady state is a unique material property, independent of the mode of loading, direction of principal stress and initial consolidation stress, and void ratio state. There is no unique relationship between steady state strength and void ratio which is independent of stress path and the level of initial confining stress.Key words: anisotropy, hollow cylinder torsional shear, liquefaction, sand, simple shear, triaxial.

The strength and dilatancy of sand

1992 ◽  
Vol 29 (3) ◽  
pp. 522-526 ◽  
Author(s):  
Y. P. Vaid ◽  
S. Sasitharan
Keyword(s):  
Relative Density ◽  
Triaxial Test ◽  
Friction Angle ◽  
Stress Path ◽  
Triaxial Tests ◽  
Confining Stress ◽  
Peak Friction Angle ◽  
Loading Direction ◽  
Dilation Rate ◽  
Unique Relationship

The effects of stress path and loading direction in the triaxial test on strength and dilatancy of sand are investigated. It is shown that the unique relationship observed between peak friction angle and dilation rate at peak in conventional triaxial tests is followed regardless of stress path, confining stress at failure, relative density, and the mode of loading (compression or extension). Key words : sand, peak friction angle, dilatancy, stress path, triaxial test.

Effect of intermediate principal stress on the deformation response of sand

1996 ◽  
Vol 33 (5) ◽  
pp. 822-828 ◽  
Author(s):  
A Sãyao ◽  
Y P Vaid
Keyword(s):  
Principal Stress ◽  
Hollow Cylinder ◽  
Stress Path ◽  
B Value ◽  
Shear Loading ◽  
Intermediate Principal Stress ◽  
Experimental Program ◽  
Stress Strain ◽  
Deformation Response ◽  
Strain Behaviour

An experimental investigation of the relevance of the intermediate principal stress (σ2) on the deformation response of a sand is presented. The effects of σ2 are conveniently studied through the nondimensional stress parameter b = (σ2 – σ3)/(σ1 – σ3). A series of stress path tests was performed on Ottawa sand specimens in a hollow cylinder torsional shear device. The experimental program includes shear loading at different values of b, and special b tests, in which b was continuously varied at different stress directions. It is shown that the b value may have a significant influence on the stress–strain response of sand, depending on the loading conditions. Key words: hollow cylinder tests, generalized stress paths, sand, stress–strain behaviour, intermediate principal stress.

Collapse behavior of sand

1993 ◽  
Vol 30 (4) ◽  
pp. 569-577 ◽  
Author(s):  
S. Sasitharan ◽  
P.K. Robertson ◽  
D.C. Sego ◽  
N.R. Morgenstern
Keyword(s):  
Steady State ◽  
Void Ratio ◽  
Boundary Surface ◽  
Stress Path ◽  
Published Data ◽  
Stress Deviator ◽  
State Strength ◽  
Flow Slides ◽  
State Boundary ◽  
Collapse Behavior

Loose cohesionless materials can collapse during either static or dynamic loading, resulting in a rapid buildup of pore pressure and associated reduction in shear resistance. As the cohesionless material collapses, it rapidly looses resistance until the acting shear stress decreases to the available residual or steady-state strength. Specially designed stress-path testing has been performed on sand to investigate this collapse process. Results from this test program and previously published data show that a state boundary can be defined when a cohesionless material moves from peak to steady state along a constant void ratio stress path regardless of whether it is loaded drained or undrained. Further, it is demonstrated that the state boundary represents a surface in the effective mean normal stress–deviator stress–void ratio space. Hence, flow slides and liquefaction can be initiated when the stress path followed during either drained or undrained loading attempts to cross this state boundary surface. Key wordy : sand, collapse, liquefaction, stress path, state boundary, triaxial test.

Stress path and steady state

1990 ◽  
Vol 27 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Y. P. Vaid ◽  
E. K. F. Chung ◽  
R. H. Kuerbis
Keyword(s):  
Steady State ◽  
Effective Stress ◽  
Void Ratio ◽  
Triaxial Compression ◽  
Stress Path ◽  
Stress Space ◽  
Sand Liquefaction ◽  
State Strength ◽  
The Difference ◽  
State Stress

The effect of stress path on the steady state line of a liquefiable sand is investigated. Results from undrained triaxial compression and extension tests on water-deposited sands show that the steady state line of a given sand, though unique in the effective stress space, is not so in the void ratio – effective stress space. The sand is contractive over a much larger range of void ratios in extension than in compression. While a single steady state line emerges for compression loading, extension loading yields several lines, each characteristic to a given deposition void ratio. All these extension lines lie to the left of the compression line in void ratio – effective stress space. Thus at a given void ratio, steady state strength is smaller in extension than in compression, the difference increasing as the sand becomes looser. The implications of the results are discussed in relation to practical design. Key words: sand, liquefaction, steady state, stress path.

Loading Direction Versus Crack Propagation Path in a Lead-Free Single Solder Joint Sample

2008 ◽  
Author(s):  
Feng Gao ◽  
Jianping Jing ◽  
Janine Johnson ◽  
Frank Z. Liang ◽  
Richard L. Williams ◽  
...  
Keyword(s):  
Solder Alloy ◽  
Mixed Mode ◽  
Shear Fracture ◽  
Pure Shear ◽  
Shear Loading ◽  
Propagation Path ◽  
Mixed Mode Loading ◽  
Cohesive Failure ◽  
Loading Direction ◽  
Shear Component

In this paper, single solder joints (SSJs) were subjected to moderate speed loading (5mm/sec) in different directions, from pure tensile, mixed mode to pure shear. Fracture surfaces from different loading directions were examined both experimentally and numerically. It is observed that intermetallic compound (IMC) is formed between the solder alloy and the Cu pad, and failure typically occurs at or near the solder/IMC/Cu interfaces on the board side. Pure tensile loading typically leads to interfacial fracture along the IMC/Cu interface. Mixed mode loading usually results in a mixture of interfacial and cohesive failure with crack propagating in a zigzag fashion between the solder/IMC interface and the solder alloy. Loading with higher shear component tends to result in more cohesive failure of the solder alloy near the solder/IMC interface. Under pure shear loading, failure is almost always cohesive within the solder alloy near the solder/IMC interface.

scholarly journals Evolution Rules of Fractures for Mudstone under Compression Shear Load and the Fractal Characteristics of Broken Blocks

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Zhaoyun Chai ◽  
Jinbo Bai ◽  
Haiyang Zhang ◽  
Pan Yang
Keyword(s):  
Fractal Dimension ◽  
Compression Test ◽  
Shear Fracture ◽  
Fractal Theory ◽  
Friction Angle ◽  
Shear Loading ◽  
Shear Load ◽  
Deformation And Failure ◽  
Fractal Characteristics ◽  
Logarithmic Relationship

Failure of rocks is commonly induced by compressive and shear coupling loading. Knowledge of the mechanism and process of deformation and failure of rocks under compressive shear loading condition is an important basis for the study of stability in rock engineering. Based on the nonlinear fractal theory, it is possible to examine the evolution rules of fractures in mudstone under compression shear load and the fractal characteristics of broken blocks using the shear compression test with variable angles of mudstone specimens in natural conditions. This research shows that the cohesion and friction angle parameters of rock samples are achieved by draw Mohr’s strength envelope according to the test date of variable-angle shear compression test. It also shows that the shape of load-displacement curves of rocks can be divided into four stages: compaction, elastic, plastic, and fracture, and the curve can accurately represent the transformation and breakage characteristics of rock during shear fracture. And the distribution of broken blocks shows a strong statistical resemblance to the fractal distribution, and the fractal dimension is able to reflect the distribution characteristics of broken blocks. With increasing the shear angle, the fractal dimension of broken blocks decreases in a logarithmic relationship.

Test Methods for Measuring Mechanical Parameter of Simulated Lunar Dust

2013 ◽  
Vol 333-335 ◽  
pp. 389-393
Author(s):  
Man Li ◽  
Dong Bo Tian ◽  
Zhi Hao Wang ◽  
Yu Bai ◽  
Hui Qi Zheng ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Void Ratio ◽  
Friction Angle ◽  
Test Methods ◽  
Experimental Investigations ◽  
The Moon ◽  
Engineering Property ◽  
Lunar Dust ◽  
Large Numbers ◽  
Moon Exploration

Due to the preciousness of real lunar dust, the lunar dust simulant is usually employed to replace the real one in the large numbers of experimental investigations about its mechanical property and engineering property. Therefore, the investigation on mechanical property of lunar dust simulant is also extremely significant. This research has put forward several methods for measuring mechanical property, which are used to measure the parameters including particle size distribution, particle proportion, relative density, void ratio, cohesion, internal friction angle, etc. of lunar dust simulant. The lunar dust simulant is determined to be suitable for application in the moon exploration project experiment after comparing these parameters with relevant typical mechanical parameters of foreign lunar dust simulant.

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