Dynamic deformation characteristics of undisturbed riverbed gravels

1996 ◽  
Vol 33 (2) ◽  
pp. 237-249 ◽  
Author(s):  
N Yasuda ◽  
N Ohta ◽  
A Nakamura
Keyword(s):  
Large Scale ◽  
Sampling Method ◽  
Dynamic Deformation ◽  
Damping Ratio ◽  
Triaxial Tests ◽  
Deformation Characteristics ◽  
S Wave ◽  
Embankment Dam ◽  
Strength And Deformation ◽  
Ps Logging

The strength and deformation characteristics of undisturbed specimens measured by large-scale triaxial tests were compared with those of reconstituted specimens to evaluate the stiffness of natural ground. The undisturbed specimens were sampled from the riverbed gravel foundation of an embankment dam using the freezing sampling method with liquid nitrogen. The validity of the results from the undisturbed specimens was evaluated by comparing the stiffness of the natural ground using P- and S-wave logging (PS logging). The dynamic deformation characteristics (stiffness) of undisturbed specimens are larger than those of reconstitued specimens. Key words: shear modulus, damping ratio, gravel, laboratory test.

Dynamic deformation characteristics of sands and rockfill materials

1993 ◽  
Vol 30 (5) ◽  
pp. 747-757 ◽  
Author(s):  
Nario Yasuda ◽  
Norihisa Matsumoto
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Simple Shear ◽  
Void Ratio ◽  
Dynamic Deformation ◽  
Damping Ratio ◽  
Intermediate Principal Stress ◽  
Deformation Characteristics ◽  
Confining Stress ◽  
Rockfill Materials

Cyclic torsional simple shear (CTSS) tests and cyclic triaxial (CTX) tests were carried out to investigate the dynamic deformation characteristics of sands and rockfill materials. It was found that the shear modulus and damping ratio can be expressed as a function of shear strain, void ratio, and confining stress. Also the shear modulus in CTSS tests is larger than in CTX tests because of the influence of the intermediate principal stress. When the shear strain is increased, the shear modulus (G) and damping ratio (h) of the rockfill materials were altered at smaller strains than in sands. Key words : sands, rockfill materials, torsional simple shear, shear modulus, damping ratio.

Strength and deformation characteristics of shredded rubber tire – sand mixtures

2003 ◽  
Vol 40 (2) ◽  
pp. 254-264 ◽  
Author(s):  
Sompote Youwai ◽  
Dennes T Bergado
Keyword(s):  
Constitutive Model ◽  
Unit Weight ◽  
Triaxial Tests ◽  
Triaxial Testing ◽  
Deformation Characteristics ◽  
Scrap Tires ◽  
Sand Mixture ◽  
Mixing Ratios ◽  
Rubber Tire ◽  
Strength And Deformation

The volume of scrap tires, an undesired urban waste, is increasing every year. One of the possible alternatives for this waste is to use shredded tires alone or mixed with soil as a lightweight backfill. This paper presents the results of triaxial tests on compacted shredded rubber tire – sand mixtures. The tests were carried out with different mixing ratios of shredded rubber tires and sand. With an increasing proportion of sand in the mixture, the density, unit weight, and shear strength of the mixture increased, but the compressibility decreased. The dilatancy characteristics of shredded rubber tires mixed sand were relatively similar to a cohesionless material and can be explained within a critical state framework. A proposed constitutive model broadly captures the strength and deformation characteristics of a shredded rubber tire – sand mixture at different mixing ratios.Key words: shredded rubber tires, triaxial testing, constitutive model.

Shear modulus and damping ratio characteristics of gravelly deposits

2000 ◽  
Vol 37 (3) ◽  
pp. 638-651 ◽  
Author(s):  
Shang-Yuh Lin ◽  
Ping Sien Lin ◽  
Hong-Su Luo ◽  
C Hsein Juang
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Large Scale ◽  
Damping Ratio ◽  
Triaxial Tests ◽  
Equal Weight ◽  
Analysis And Design ◽  
Replacement Method

In this paper, the results of an experimental investigation of dynamic characteristics of gravelly cobble deposits, such as shear modulus (G) and damping ratio (D), are presented. The gravelly cobble deposits are very common in the Taichung metropolitan area of Taiwan where there is an urgent need to determine G and D for dynamic analysis and design of structures. The test program includes measurements of shear wave velocity by the downhole method and large-scale dynamic triaxial tests and resonant-column tests. Special consideration is given to preparing samples of gravelly cobble deposits for laboratory tests. The "equal-weight replacement method" to scale down the real gravelly deposits to cell diameters is used for the preparation of samples. This method is found to be satisfactory, as consistent and reasonable results are obtained. The results of the present study show that the shear modulus - shear strain (G-γ) relationship for this gravelly deposit does not follow exactly those reported in the literature. The deviation of this G-γ relationship from those reported in the literature is investigated and explained.Key words: shear modulus, damping ratio, downhole, shear wave velocity, gravel.

Deformation characteristics of two cemented calcareous soils

2004 ◽  
Vol 41 (6) ◽  
pp. 1139-1151 ◽  
Author(s):  
Shambhu S Sharma ◽  
Martin Fahey
Keyword(s):  
Cyclic Loading ◽  
Damping Ratio ◽  
Calcareous Soils ◽  
Confining Pressure ◽  
Stiffness Degradation ◽  
Triaxial Tests ◽  
Repeated Loading ◽  
Deformation Characteristics ◽  
Initial Stiffness ◽  
Strain Threshold

The effect of cementation on the deformation characteristics of two cemented calcareous soils was investigated through a series of undrained triaxial tests performed under both monotonic and cyclic loading conditions. Increasing the level of cementation significantly increased the initial stiffness, resulting in the stiffness being more independent of the confining pressure. The curves of stiffness degradation with strain obtained from both cemented and uncemented calcareous soils compared with those of other noncalcareous soils revealed that calcareous soil attains a faster rate of modulus reduction with a higher strain threshold. It was also observed that the pattern of stiffness degradation is very similar in both cemented and uncemented samples. The stiffness degradation curves obtained from cyclic tests were found to lie within the range defined by the corresponding monotonic tests. The effect of number of cycles on the stiffness during cyclic loading was also examined and is found to depend on whether the postyield behaviour is controlled by the cohesive or the frictional response. Examination of the variation of damping ratio with strain revealed that the observed difference in the stiffness degradation curves between calcareous and noncalcareous soils was also reflected in the damping ratio, with the damping ratio of calcareous soils being below the range defined for noncalcareous soils.Key words: calcareous soils, triaxial test, shear modulus, damping ratio, repeated loading.

scholarly journals Normalized Shear Modulus and Damping Ratio of Soil–Rock Mixtures With Different Volumetric Block Proportions

2021 ◽  
Vol 9 ◽  
Author(s):  
Shengnian Wang ◽  
Xinqun Gao ◽  
Honglei Hui ◽  
Wei Ma ◽  
Chong Shi ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Large Scale ◽  
Volume Fraction ◽  
Damping Ratio ◽  
Triaxial Tests ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Confining Pressures ◽  
Gravelly Soils ◽  
Shear Behaviors

The volume fraction of rock blocks plays a particularly significant role in static/dynamic shear behaviors of soil–rock mixtures (SRM). Large-scale cyclic triaxial tests for SRM with different volumetric block proportions (VBPs) were performed at different confining pressures to investigate the reduction of dynamic shear modulus (G) and the increase of damping ratio (λ). Results indicate that VBP has a significant effect on the dynamic behaviors of SRM. The higher VBP is more likely to result in a gentler reduction of G and a faster increase of λ. The variations of dynamic shear modulus ratio (G/G0) and normalized damping ratio (λnor) fall within relatively narrow bands but are very different with gravelly soils and sands due to VBP with particle size larger than 2 mm. The G/G0 and λnor can be characterized by empirical functions about normalized shear strain amplitude (γnor).

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