Experimental Investigation of Dynamic Characteristics of Subsea Sand‐Silt Mixtures

Feng, Tian; Tang, Yuting; Wang, Qiyenan; Zhang, Jian; Song, Jing

doi:10.1155/2019/5619039

“…The results proposed that the compaction procedure caused an overconsolidation state dependent on the moisture content during compaction effort [15]. Feng et al used the resonance column test to evaluate the influence of confining pressure, mix ratio, curing age, and cement content on the dynamic characteristics of subsea sand-silt mixtures [16]. Khosravi et al developed a new methodology to extend an existing small-strain shear modulus G max model to determine G max of unsaturated silty soils along different paths of the soil water retention curve including the scanning loops [17].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Dynamic Shear Modulus Ratio and Damping Ratio of the Quaternary Sedimentary Soils in the Offshore Areas of the Yellow Sea

Fang

¹

,

Lv

²

,

Xu³

et al. 2021

Geofluids

0

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The effects of marine and continental sedimentary environments and geological ages on the dynamic shear modulus ratio and damping ratio of the Quaternary sedimentary soils in the offshore areas of the Yellow Sea were analyzed by using a resonant column device (GCTS, USA). The results show the following: (1) The G max of various marine soils increases with the depth and shows a typical linear relationship. (2) The marine transgression has significantly different effects on the dynamic shear modulus ratio versus the shear strain amplitude curves (i.e., G / G max ~ γ a curves) and the damping ratio versus the shear strain amplitude curves (i.e., λ ~ γ a curves) of the different soil types in the offshore areas of the Yellow Sea. The effects of marine transgression were strong on clays, moderate on silty clays, and minor on silts. (3) The geological ages have noticeable effects on the G / G max ~ γ a curves of the tested marine silty clays, marine silts, and continental silty clays, but the effects of geological ages on the λ ~ γ a curves are minimal. The fitting parameters and recommended empirical equations of the G / G max ~ γ a and λ ~ γ a curves for each type of the tested soils (silty clay, clay, and silt) were obtained mirroring the effects of sedimentary environments and geological ages.

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“…e dynamic modulus and damping ratio are the basis of foundation engineering seismic design, seismic stability evaluation, settlement prediction, and other works. Researchers also attach great importance to this research work and carry out a series of studies on various types of soil through field tests, indoor resonant column tests, dynamic triaxial tests, and dynamic torsional shear tests [1][2][3][4]. In actual engineering, dynamic loads such as earthquakes, traffic, waves, and other dynamic loads produce vertical dynamic stress and horizontal dynamic stress in foundation soil.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Dynamic Modulus and Damping Ratio of Compacted Loess under Circular Dynamic Stress Paths

Yang

¹

,

Shao

²

,

Zhi

³

2021

Advances in Civil Engineering

2

0

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Dynamic loads such as earthquakes and traffic will simultaneously generate vertical dynamic stress and horizontal shear stress in the foundation soil. When the vertical dynamic stress amplitude is twice the horizontal shear dynamic stress amplitude, and the phase difference between them is 90°, a circular dynamic stress path is formed in the τ z θ d ∼ σ zd − σ θ d / 2 stress coordinate system. To simulate the stress state of soil in the area of the circular dynamic stress path caused by bidirectional dynamic stress coupling, a series of tests of compacted loess under the action of a circular dynamic stress path were carried out using a hollow cylindrical torsion shear apparatus. The effects of the mean principal stress, dry density, and deviatoric stress ratio (the ratio of deviator stress to average principal stress) on the dynamic modulus and damping ratio of compacted loess were mainly studied. The test results show that, under the action of the circular dynamic stress path, the larger the mean principal stress is, the larger the dynamic compression modulus and dynamic shear modulus are. The dynamic compression modulus increases obviously with increasing dry density, but the dynamic shear modulus increases only slightly. When the deviator stress ratio increases from 0 to 0.4, the dynamic compression modulus and dynamic shear modulus increase to a certain extent. In addition, the greater the dry density and deviatoric stress ratio are, the greater the initial dynamic compression modulus and initial dynamic shear modulus of the compacted loess. The dynamic compression damping ratio of compacted loess increases with increasing mean principal stress, but the dynamic shear damping ratio decreases with increasing mean principal stress. Dry density basically has no effect on the dynamic compression damping ratio and dynamic shear damping ratio of compacted loess. When the dynamic strain exceeds 1%, the greater the deviatoric stress ratio is, the smaller the dynamic compression damping ratio and the dynamic shear damping ratio are. The research results can provide reference for the study of dynamic modulus and damping ratio of loess under special stress paths.

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“…It has been widely used in the construction on islands and reefs. On the one hand, calcareous sand is the main material for marine reclamation land and protective engineering [11][12][13][14][15][16][17][18]. On the other hand, calcareous sand is also an important raw material for fine concrete aggregate [19,20].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Mathematical Modeling of Monotonic Behavior of Calcareous Sand

Zhang

¹

,

Luo

²

,

Qiu

³

et al. 2020

Advances in Civil Engineering

1

0

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The prominent performance of wave elimination and energy absorption makes calcareous sand important and useful in infrastructure construction and protection engineering. Due to the high compressibility induced by remarkable intragranular void and irregular shape, calcareous sand presents different mechanical behaviors from common terrestrial sands. Considerable efforts have been made to explore the static and dynamic mechanical properties of calcareous sand. In this paper, a series of monotonous experiments have been performed on calcareous sand utilizing the electrohydraulic servo-controlled test apparatus designed by the Global Digital Systems Ltd (GDS). The effects of confining pressure and relative density on the mechanical properties of dry, drained, and undrained saturated sand were studied, and the underlying micromechanism of deformation and failure was discussed. It can be found that the residual stress of dry calcareous sand is independent of the relative density, while the peak stress and residual stress of drainage saturated sand have a positive correlation with the relative density. The increase of confining pressure makes the strain softening more remarkable and heightens the peak stress and residual stress. The stress-strain curve of calcareous sand can be divided into two portions: prepeak portion and postpeak softening portion. For the dry sand and drainage saturated sand, the softened part can be partitioned into three phases, i.e., accelerated phase, steady phase, and degradation phase, while the undrained saturated sand tends to hyperbolic softening. A mathematical model composed of a hyperbolic function and an inverted S-shaped function was formulated to describe the multiphase characteristic, in which the setting of parameter p expands its applicability. The experimental result validated the model, showing that the model can better describe the monotonic stress-strain relationship of calcareous sand. Besides, the physical meanings of model parameters were discussed.

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Experimental Investigation of Dynamic Characteristics of Subsea Sand‐Silt Mixtures

Cited by 4 publications

References 39 publications

Experimental Study of the Dynamic Shear Modulus Ratio and Damping Ratio of the Quaternary Sedimentary Soils in the Offshore Areas of the Yellow Sea

Experimental Study of the Dynamic Shear Modulus Ratio and Damping Ratio of the Quaternary Sedimentary Soils in the Offshore Areas of the Yellow Sea

Experimental Study on the Dynamic Modulus and Damping Ratio of Compacted Loess under Circular Dynamic Stress Paths

Experimental and Mathematical Modeling of Monotonic Behavior of Calcareous Sand

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