Experimental Investigation of the Liquefaction Properties and Post-Liquefaction Volumetric Strain of Calcareous Sand in Dredger Fill Site

In this study, dynamic triaxial cyclic tests were conducted to examine the liquefaction properties and post-liquefaction volumetric strain of calcareous sand from a dredger fill site in the midst of the islands and reefs of the South China Sea. The test results indicated that there were some differences in micromorphology and composition between the calcareous sand obtained via dredging and natural calcareous sand. Axial cyclic stress attenuation can lead to higher cyclic vibration than actual liquefaction vibration, and the modified method can eliminate the effect of axial cyclic stress attenuation. Saturated calcareous sand liquefies under undrained and cyclic loading conditions, and the liquefaction resistance of the calcareous sand decreases with an increase of the effective confining pressure in the dense state. Calcareous sand obtained via dredging exhibited a higher liquefaction resistance compared with other types of calcareous sand. Furthermore, the proposed pore pressure development modified model better describes the pore pressure growth of the calcareous sand from the filling site. The fitting parameters of this model exhibited a high correlation with the relative density. Moreover, the post-liquefaction volumetric strain of the calcareous sand is larger than that of quartz sand, exhibiting a linear relationship with relative density.

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Experimental investigation of the effect of compliant pores on reservoir rocks under hydrostatic and triaxial compression stress states

Canadian Geotechnical Journal ◽

10.1139/cgj-2018-0133 ◽

2019 ◽

Vol 56 (7) ◽

pp. 983-991

Author(s):

Hua Yu ◽

Kam Ng ◽

Dario Grana ◽

John Kaszuba ◽

Vladimir Alvarado ◽

...

Keyword(s):

Pore Pressure ◽

Triaxial Compression ◽

Matrix Material ◽

Volumetric Strain ◽

Confining Pressure ◽

Differential Pressure ◽

Sandstone Sample ◽

Stress States ◽

Rock Springs ◽

Stage 1

The presence of compliant pores in rocks is important for understanding the stress–strain behaviors under different stress conditions. This paper describes findings on the effect of compliant pores on the mechanical behavior of a reservoir sandstone under hydrostatic and triaxial compression. Laboratory experiments were conducted at reservoir temperature on Weber Sandstone samples from the Rock Springs Uplift, Wyoming. Each experiment was conducted at three sequential stages: (stage 1) increase in the confining pressure while maintaining the pore pressure, (stage 2) increase in the pore pressure while maintaining the confining pressure, and (stage 3) application of the deviatoric load to failure. The nonlinear pore pressure – volumetric strain relationship governed by compliant pores under low confining pressure changes to a linear behavior governed by stiff pores under higher confining pressure. The estimated compressibilities of the matrix material in sandstone samples are close to the typical compressibility of quartz. Because of the change in pore structures during stage 1 and stage 2 loadings, the estimated bulk compressibilities of the sandstone sample under the lowest confining pressure decrease with increasing differential pressure. The increase in crack initiation stress is limited with increasing differential pressure because of similar total crack length governed by initial compliant porosity in sandstone samples.

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The effect of confinement in liquefaction tests carried out in a cyclic simple shear apparatus

E3S Web of Conferences ◽

10.1051/e3sconf/20199208002 ◽

2019 ◽

Vol 92 ◽

pp. 08002 ◽

Cited By ~ 3

Author(s):

Lucia Mele ◽

Stefania Lirer ◽

Alessandro Flora

Keyword(s):

Simple Shear ◽

Initial Conditions ◽

Confining Pressure ◽

Cyclic Stress ◽

Shear Tests ◽

Liquefaction Resistance ◽

Pressurized Water ◽

Cyclic Stress Ratio ◽

Complex Behaviour ◽

Continuous Rotation

The cyclic simple shear tests can be used to reproduce in laboratory the complex behaviour of the soil during an earthquake, simulating the continuous rotation of the principal stress axes. In this research a comparison of results between cyclic simple shear tests carried out with confining pressure or confining rings is reported. A cyclic simple shear apparatus is used to carry out tests with confining rings (the conventional way to carry out cyclic simple shear tests) and with a confining pressure applied to the specimen through pressurized water, where the K0 condition during consolidation is guaranteed by a sophisticated control system. The apparatus, in both the configurations, is described in detail. All tests were carried out on reconstituted specimens of an Italian sand with similar initial conditions, such as low relative density and confining pressure. All experimental results are reported in the plane cyclic stress ratio (CSR) and number of cycles where liquefaction occurs (Nliq) in order to evaluate the effect of confinement on the liquefaction resistance of the studied sand.

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Soil Liquefaction Assessment Using Soft Computing Approaches Based on Capacity Energy Concept

Geosciences ◽

10.3390/geosciences10090330 ◽

2020 ◽

Vol 10 (9) ◽

pp. 330

Author(s):

Zhixiong Chen ◽

Hongrui Li ◽

Anthony Teck Chee Goh ◽

Chongzhi Wu ◽

Wengang Zhang

Keyword(s):

Relative Density ◽

Soft Computing ◽

Earthquake Engineering ◽

Textural Properties ◽

Confining Pressure ◽

Soil Liquefaction ◽

Multivariate Adaptive Regression Splines ◽

Soil Parameters ◽

Liquefaction Resistance ◽

Energy Concept

Soil liquefaction is one of the most complicated phenomena to assess in geotechnical earthquake engineering. The conventional procedures developed to determine the liquefaction potential of sandy soil deposits can be categorized into three main groups: Stress-based, strain-based, and energy-based procedures. The main advantage of the energy-based approach over the remaining two methods is the fact that it considers the effects of strain and stress concurrently unlike the stress or strain-based methods. Several liquefaction evaluation procedures and approaches have been developed relating the capacity energy to the initial soil parameters, such as the relative density, initial effective confining pressure, fine contents, and soil textural properties. In this study, based on the capacity energy database by Baziar et al. (2011), analyses have been carried out on a total of 405 previously published tests using soft computing approaches, including Ridge, Lasso & LassoCV, Random Forest, eXtreme Gradient Boost (XGBoost), and Multivariate Adaptive Regression Splines (MARS) approaches, to assess the capacity energy required to trigger liquefaction in sand and silty sands. The results clearly prove the capability of the proposed models and the capacity energy concept to assess liquefaction resistance of soils. It is also proposed that these approaches should be used as cross-validation against each other. The result shows that the capacity energy is most sensitive to the relative density.

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Effect of relative density and biocementation on cyclic response of calcareous sand

Canadian Geotechnical Journal ◽

10.1139/cgj-2018-0573 ◽

2019 ◽

Vol 56 (12) ◽

pp. 1849-1862 ◽

Cited By ~ 24

Author(s):

Peng Xiao ◽

Hanlong Liu ◽

Armin W. Stuedlein ◽

T. Matthew Evans ◽

Yang Xiao

Keyword(s):

Calcium Carbonate ◽

Relative Density ◽

Pore Pressure ◽

Soil Particle ◽

Engineering Properties ◽

Excess Pore Pressure ◽

Calcareous Sand ◽

Sem Images ◽

Cyclic Response ◽

Excess Pore

Microbial-induced calcium carbonate precipitation (MICP) represents a promising approach to improve the geotechnical engineering properties of soils through the precipitation of calcium carbonate (CaCO3) at soil particle contacts and soil particle surfaces. An extensive experimental study was undertaken to investigate the influence of initial relative density on the efficiency of the biocementation process, the reduction of liquefaction susceptibility, and the cyclic response in biocemented calcareous soils. For this purpose, stress-controlled undrained cyclic triaxial shear (CTS) tests were carried out on untreated and MICP-treated calcareous sand specimens for different initial relative densities and magnitudes of biocementation. Improvement in the cyclic response was quantified and compared in terms of excess pore pressure generation, evolution of axial strains, and the number of cycles to liquefaction. The cyclic experiments show that MICP treatment can change the liquefaction failure mechanism from flow failure to cyclic mobility and can significantly change the excess pore pressure generation response of initially loose specimens. Scanning electron microscope (SEM) images indicate the CaCO3 crystals alter the characteristics of the sand particles and confirm the physical change in soil fabric that impacts the dynamic behavior and liquefaction resistance of MICP-treated specimens. Furthermore, the effect of biocementation was contrasted against the effect of relative density alone, and MICP treatment was shown to exhibit greater efficiency in improving the cyclic resistance than densification.

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The Effect of Cyclic Loading of Liquefaction on Palu Sands

10.5194/egusphere-egu21-11043 ◽

2021 ◽

Author(s):

Muhammad Firas Andanawarih ◽

Widjojo Adi Prakoso

Keyword(s):

Relative Density ◽

Cyclic Load ◽

Stress Ratio ◽

Cyclic Stress ◽

Cyclic Triaxial ◽

Liquefaction Resistance ◽

Cyclic Stress Ratio ◽

Factors Affecting ◽

Earthquake Load ◽

Central Sulawesi

Liquefaction is a phenomenon where soil loses its strength. The phenomenon of liquefaction occurs on non-cohesive soils with medium to fine grains. The phenomenon of liquefaction occurs during an earthquake, the ground experiences shaking vibrations. Palu, Central Sulawesi, Indonesia is one of the areas affected by the liquefaction phenomenon which causes damage to infrastructure in the area. The Palu earthquake that occurred on September 28, 2018, at 18:02:44 WITA with a magnitude of Mw = 7.4, centered on 26 km north of Donggala, Central Sulawesi. One aspect of the assessment for soil susceptibility to potential liquefaction is laboratory tests. One common laboratory test that can be performed is the cyclic triaxial test. The factors affecting the liquefaction resistance of saturated sand are the relative density and cyclic stress ratio (CSR). The susceptibility of each relative density (30%, 50% and 70%) of the soil experiencing liquefaction and the cyclic stress ratio (0.15, 0.20 and 0.25) will be varied to see the amount of cyclic load needed until the soil experiences liquefaction, the load frequency to represent the earthquake load is 1 Hz with sinusoidal waves. This study will test the fine sands from Palu, Central Sulawesi, Indonesia, to determine their respective behavior when the soil is given a cyclic load.Keywords: Cyclic Triaxial, Liquefaction, Cyclic Stress Ratio, Relative Density, Fine Sands.

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Experimental and Mathematical Modeling of Monotonic Behavior of Calcareous Sand

Advances in Civil Engineering ◽

10.1155/2020/8861605 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Haotian Zhang ◽

Zongmu Luo ◽

Yanyu Qiu ◽

Huachao Liu ◽

Juan Gu ◽

...

Keyword(s):

Mechanical Properties ◽

Residual Stress ◽

Relative Density ◽

Peak Stress ◽

Confining Pressure ◽

Experimental Result ◽

Hyperbolic Function ◽

Saturated Sand ◽

Calcareous Sand ◽

Stress Strain

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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Liquefaction and Reliquefaction Resistance of Saturated Sand Deposits Treated with Sand Compaction Piles

10.21203/rs.3.rs-259542/v1 ◽

2021 ◽

Author(s):

Gowtham Padmanabhan ◽

Ganesh Kumar

Keyword(s):

Relative Density ◽

Ground Improvement ◽

Cyclic Stress ◽

Shaking Table ◽

Repeated Loading ◽

Saturated Sand ◽

Liquefaction Resistance ◽

Cyclic Stress Ratio ◽

Pore Water Pressures ◽

Soil Densification

Abstract To mitigate liquefaction and its associated soil deformations, ground improvement techniques were adopted in field to reinforce saturated sand deposits. Sand Compaction Pile (SCP) is one such popular proven treatment to improve liquefaction resistance of sandy deposits. Installation of sand compaction piles improves soil density and rigidity which further enhance seismic resistance against liquefaction and this was well evident from past field observations. However, studies involving SCP performance during repeated shaking events were not available/limited. In this study, using 1-g uniaxial shaking table a series of shaking experiments were performed on SCP treated and untreated sand deposits having 40% and 60% relative density subjected to repeated incremental acceleration loading conditions(i.e. 0.1g – 0.4g at 5 Hz frequency).Parameters such as improvement in soil resistance and relative density, generation and dissipation of excess pore water pressures, maximum observed foundation settlement and soil displacement and variation in cyclic stress ratio were evaluated and compared. Seismic response of liquefiable sand deposits found to be improved significantly due to SCP installation together with occurrence of continuous soil densification under repeated loading. The experimental observations suggested that SCP can perform better even at repeated shaking events.

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Laboratory measurement of Biot's coefficient and pore pressure influence on poroelastic rock behaviour

The APPEA Journal ◽

10.1071/aj17069 ◽

2018 ◽

Vol 58 (1) ◽

pp. 182 ◽

Cited By ~ 1

Author(s):

Hossein Salemi ◽

Stefan Iglauer ◽

Ali Rezagholilou ◽

Mohammad Sarmadivaleh

Keyword(s):

Pore Pressure ◽

Volumetric Strain ◽

Local Stress ◽

Confining Pressure ◽

Hydrocarbon Reservoirs ◽

Biot’S Coefficient ◽

Geomechanical Analysis ◽

Loading System ◽

Pressure Changes ◽

Stress Variations

Understanding rock behaviour as a function of pore pressure and confining pressure is crucial for petroleum and geomechanical analysis. Indeed, deformation and local stress variations within hydrocarbon reservoirs and their surroundings occur due to pore pressure changes. Theoretically, pore pressure changes coupled with stress variations in hydrocarbon reservoirs are a function of the Biot’s coefficient, the elastic properties of the rock and the reservoir shape. Thus, in this study, the Biot’s coefficient was measured as a function of porosity, permeability, and volumetric strain for five Gosford sandstone samples. A triaxial loading system was used to measure rock volumetric strain while pore pressure and confining pressure were varied. The constant deformation technique was employed for these experiments; i.e. the variation of pore pressure created a volumetric strain, and the confining pressure required to restore the original volumetric strain was measured to calculate Biot’s coefficient. For the investigated samples, measured liquid permeabilities were in the range of 7–10 mD and Biot’s coefficients were 0.84–0.91. This is consistent with similar investigations by other researchers in which measured Biot’s coefficients were in the range of 0.65–0.90. This study thus illustrates how liquid permeability and the Biot’s coefficient decrease as a function of confining pressure.

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Effects of fines content on liquefaction strength and dynamic settlement of reclaimed soil

Canadian Geotechnical Journal ◽

10.1139/t01-083 ◽

2002 ◽

Vol 39 (1) ◽

pp. 254-265 ◽

Cited By ~ 48

Author(s):

Lien-Kwei Chien ◽

Yan-Nam Oh ◽

Chih-Hsin Chang

Keyword(s):

Relative Density ◽

Land Reclamation ◽

Volumetric Strain ◽

Soil Liquefaction ◽

Dry Density ◽

Test Results ◽

Liquefaction Resistance ◽

Fines Content ◽

Reclaimed Soil ◽

Dynamic Settlement

In this study, the reclaimed soils in the Yunlin area of west Taiwan are adopted as test samples. The specimens were prepared by moist tamping at different relative densities and fines contents. Triaxial liquefaction tests were performed to evaluate the liquefaction strength and liquefaction-induced settlement. The test results show that the liquefaction strength of reclaimed soil increases as the relative density increases. In addition, under constant relative density, the liquefaction strength decreases as the fines content increases. Based on the test results and one-dimensional consolidation theory, the volumetric strain and settlement can be evaluated by dry density and fines content of the reclaimed soil. The results show that the settlement ratio decreases as the relative density increases. The figures and results can be references for the evaluation of liquefaction strength and liquefaction-induced settlement. The results are useful for liquefaction strength and settlement analysis for planning, design, and related research on land reclamation engineering.Key words: reclaimed soil, liquefaction resistance, fines content, settlement.

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Liquefaction and Pore Water Pressure Generation in Sand

International Journal of Geotechnical Earthquake Engineering ◽

10.4018/ijgee.2012010104 ◽

2012 ◽

Vol 3 (1) ◽

pp. 57-85 ◽

Cited By ~ 5

Author(s):

T. G. Sitharam ◽

B. V. Ravishankar ◽

S. M. Patil

Keyword(s):

Relative Density ◽

Shear Strain ◽

Pore Pressure ◽

Pore Water Pressure ◽

Water Pressure ◽

Cyclic Strain ◽

Confining Pressure ◽

Triaxial Tests ◽

Before And After ◽

Reconstituted Soil

Cyclic strain controlled laboratory triaxial undrained tests were performed on sand samples collected from earthquake affected Ahmedabad City of Gujarat (India). To study the factors controlling the liquefaction potential and pore pressure generation, cyclic strain controlled triaxial tests were carried out on (a) base sand, (b) pure sand, and (c) pure sand and non plastic silt mixture. All the tests were conducted on reconstituted soil samples and consolidated isotropically to different effective confining pressures. Base sand, clean sand and sand with non-plastic fines were tested using cyclic strain controlled triaxial undrained tests for different combination of shear strain amplitudes, initial effective confining pressure, and relative density (RD). In case of base sand and pure sand both have qualitatively the same liquefaction and pore pressure generation behaviors. For sand with non plastic fines, basic concept of limiting fines content (LFC) is justified and shown that how the behavior of mixture undergoes transition before and after LFC. This transitional behavior is observed both in the liquefaction strength and pore pressure generation. To obtain a mean relationship between liquefaction strength, pore pressure generation on relative density, confining pressure and shear strain amplitude, approaches previously adopted by Talaganov (1996) are used.

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