Comparison of Shear Strength Properties for Undisturbed and Reconstituted Parit Nipah Peat, Johor

Azhar, A T S; Norhaliza, W; Bakar, Ismail; Abdullah, Mohd Ezree; Zakaria, Muhammad Nizam

doi:10.1088/1757-899x/160/1/012058

Cited by 9 publications

(6 citation statements)

References 10 publications

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“…When loading started, the deviator stress almost vertically increased to 0.7, 0.5, and 0.7 MPa under a confining pressure of 0.5, 1.0, and 1.5 MPa, respectively, and then the sand‐silt‐bentonite clay grains were compacted so that the deviator stress gradually increased. Similar stress‐strain behavior was also observed by other workers (Azhar et al, ; Della et al, ). The maximum deviator stress resulted in a collapse of the compacted sediment grains, leading to relatively open structure like micro fractures and the grains were forced to move downward into the void spaces.…”

Section: Resultssupporting

confidence: 90%

Gas Hydrates in Permafrost: Distinctive Effect of Gas Hydrates and Ice on the Geomechanical Properties of Simulated Hydrate‐Bearing Permafrost Sediments

et al. 2019

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The geomechanical stability of the permafrost formations containing gas hydrates in the Arctic is extremely vulnerable to global warming and the drilling of wells for oil and gas exploration purposes. In this work the effect of gas hydrate and ice on the geomechanical properties of sediments was compared by triaxial compression tests for typical sediment conditions: unfrozen hydrate‐free sediments at 0.3 °C, hydrate‐free sediments frozen at −10 °C, unfrozen sediments containing about 22 vol% methane hydrate at 0.3 °C, and hydrate‐bearing sediments frozen at −10 °C. The effect of hydrate saturation on the geomechanical properties of simulated permafrost sediments was also investigated at predefined temperatures and confining pressures. Results show that ice and gas hydrates distinctively influence the shearing characteristics and deformation behavior. The presence of around 22 vol% methane hydrate in the unfrozen sediments led to a shear strength as strong as those of the frozen hydrate‐free specimens with 85 vol% of ice in the pores. The frozen hydrate‐free sediments experienced brittle‐like failure, while the hydrate‐bearing sediments showed large dilatation without rapid failure. Hydrate formation in the sediments resulted in a measurable reduction in the internal friction, while freezing did not. In contrast to ice, gas hydrate plays a dominant role in reinforcement of the simulated permafrost sediments. Finally, a new physical model was developed, based on formation of hydrate networks or frame structures to interpret the observed strengthening in the shear strength and the ductile deformation.

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Section: Resultssupporting

confidence: 90%

Gas Hydrates in Permafrost: Distinctive Effect of Gas Hydrates and Ice on the Geomechanical Properties of Simulated Hydrate‐Bearing Permafrost Sediments

et al. 2019

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“…Fibrous peat dominion a considerable volume of water as its organic coarse particles are usually very loose and the organic particles full with voids and it is occupied with water. In Parit Nipah Johor, the range of water content was from 330 to 650% [15,16]. In these circumstances, the high water content may affect the properties of the peat.…”

Section: Fiber Contentmentioning

confidence: 99%

Segregation Peat Fiber and Pre- Consolidation Pressure Effect on the Physical Properties of Reconstituted Peat Soil

Wahab,

Basri,

Talib

et al. 2019

IJEAT

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The preparation of the undisturbed peat sample at the site must be conducted to understand its characteristics. However, the sampling process becoming difficult due to the condition of peat soils itself. Due to the limitation in gaining undisturbed sample, a study on reconstitution sample becoming more popular in term of investigating the properties of soil that represent the real site condition. The main purpose of this paper was to investigate the physical properties of undisturbed and reconstituted peat RS3.350, RS2.360, RS1.000 and RS0.425. In this study, the segregation of peat and expulsion water with the aids pre-consolidation pressure was applied to the reconstituted sample. The range value of the physical properties of reconstituted peat was varied from each type of peat classification which affected by the segregation fiber and pre-consolidation pressure effect method. The entire reconstituted peat samples were recons passing the opening sieve size 3.350mm, 2.360mm, 1.000mm and 0.425 mm and were subjected with the 50 kPa, 80 kPa and 100 kPa pre-consolidation pressures. As a result, the natural Parit Nipah peat soil was classified as hemic peat (H5). The percentage of water content, liquid limit, organic content and fiber content for the reconstituted sample is lower compared to the undisturbed peat sample; but differed from specific gravity where the percentage for the reconstituted sample was higher than the undisturbed sample. Conclusively, the segregation of peat fiber and pre-consolidation pressure methods greatly affect and change the physical properties of peat samples.

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“…This is because the chemical reactions (hydration and pozzolanic reactions) between peat and FA produces long chain of stabilized peat molecules and it decreases initial void ratio, pre -consolidation pressure and physical properties. Therefore, peat molecules are packed well with the addition of FA which in turns increase c and reduces Φ value of the stabilized peat [3,8].…”

Section: Direct Shear Test Resultsmentioning

confidence: 99%

Compressibility Behaviour of Peat Stabilized with Fly Ash Using DMM: An Experimental and Numerical Study

Nithurshan¹,

Nitharshan²,

Nasvi³

2019

IJTSRD

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Peat is a type of soil made up of partially decomposed plant matters and contains high amount of pores. Therefore, it has high compressibility and low shear strength, which makes it as a geotechnically problematic soil. Two main methods of ground improvement include mechanical and chemical methods. In this research, chemical stabilization was used as ground improvement techniques and this method stabilizes the soil through the addition of chemical admixtures such as ordinary Portland cement (OPC), fly ash, lime etc. Major aim of this research was to study the compressibility characteristics of peat stabilized with ASTM class F fly ash (FA) using deep mixing method (DMM), and an experimental and numerical based study was adapted to achieve the aim. As part of the experimental study, testing including index properties test, direct shear test and consolidation test using Rowe cell apparatus were conducted, while PLAXIS 2D numerical package was used to simulate the laboratory Row Cell consolidation test to predict the consolidation characteristics of peat and FA stabilized peat. A FA dosage of 10% (by weight) was used to prepare the stabilized peat sample. Based on the experimental findings, peat used was classified as sapric amorphous peat. Addition of 10% FA increases the cohesion (c) and decreases angle of friction (Φ). Further compressibility parameters [coefficient of consolidation (Cv), coefficient of secondary compression (Cα) and compression index (Cc)] decrease with the addition of 10% FA and it is due to the chemical reaction between FA and water in the peat, producing a stiffer peat-FA stabilized matrix. Percentage reduction in Cv and Cα are 12.7% -33.4% and 7.1% -25.93% depending on the normal stress, while the percentage reduction in Cc is 10.5%. In addition, it was observed that PLAXIS can predict the consolidation behaviour of peat reasonably well.

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Comparison of Shear Strength Properties for Undisturbed and Reconstituted Parit Nipah Peat, Johor

Cited by 9 publications

References 10 publications

Gas Hydrates in Permafrost: Distinctive Effect of Gas Hydrates and Ice on the Geomechanical Properties of Simulated Hydrate‐Bearing Permafrost Sediments

Gas Hydrates in Permafrost: Distinctive Effect of Gas Hydrates and Ice on the Geomechanical Properties of Simulated Hydrate‐Bearing Permafrost Sediments

Segregation Peat Fiber and Pre- Consolidation Pressure Effect on the Physical Properties of Reconstituted Peat Soil

Compressibility Behaviour of Peat Stabilized with Fly Ash Using DMM: An Experimental and Numerical Study

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