Young’s Modulus of Peat Soil Under Cyclic Loading

Abstract

Peat soil classified as high organic content with diverse range of fibers, distinctive intrinsic properties with low shear strength. The behaviour of peat soils under dynamic loading conditions has been studied. Therefore, a series laboratory of cyclic triaxial test on peat soil carried out to determine the effect of cyclic loading to the peat soil behavior after subjecting to cyclic loading is presented. In this study, the frequencies applied for the dynamic testing on the peat soil samples were focused and simulated on traffic vehicle loading frequencies, earthquakes and machine operations. Peat soil sample used from Parit Nipat, Malaysia (PNpt) with natural moisture content, m = 603% and liquid limit of w l = 231%. A series of undrained cyclic triaxial test were performed on undisturbed peat soil sample under isotropically consolidated specimens. In addition, the strain of amplitude applied is 0.1% to investigate the effectiveness of large strain amplitude response by allowing the generation of cyclic pore pressure and developed stress-strain cycle during cyclic loading. Correspondingly, the undrained Young's modulus of the undrained shear strength subjected to cyclic loading in this study in the range of 60 to 70 for hemic peat soil. The specimen loaded into specific frequency causes in reduction of Young's modulus related to stiffness and more pronounced in softening behaviour. The hysteresis-loops profile with regard to E parameters from 1 st cycle to 100 th cycles of Young's modulus, E (MPa) for PNpt degrades precisely to an applied effective stress, 0.4 MPa (25 kPa) and 0.4 MPa (50 kPa). Cyclic loading frequencies resulted in decreases of the Young's Modulus of peat soil that related to stiffness and more pronounced in softening behaviour. The result indicates that a reduction effect in the stress-strain cycle occurs in a peat soil from the initial stage of cyclic loading towards the end of 100 th cycles due to the repeated loading application.

A Study on Linear Shrinkage Behavior of Peat Soil Stabilized with Eco-Processed Pozzolan (EPP)

“…The reversible and irreversible shrinkage coefficient values were determined using the "saran resin" process. Hamamoto et al [22], Mohamad and Zainorabidin [23], and Wu et al [24] investigates a breakthrough in peat shrinkage that is linked to peat soil heat transport under varying saturation conditions and the impact of volume shrinkage on peat soil thermal properties. Bin Zainorabidin et al [25] used the bar linear shrinkage approach to examine soil volume shifts and shrinkage at four dimensional stages.…”

Stress Path Behaviour and Friction Angle Transition Due to the Cyclic Loading Effects

“…This section is the outcome of the experimental program methodology detailed from previous section, which was done to study the effects of cyclic loading on the post-cyclic effective friction angle. Generally, the dynamic response of a soil is presented in two forms, as (1) shear modulus degradation, and (2) damping curves for a wide range of shear strains [31], but the dynamic properties of Johor and Sabah peat soils were published by the author in several recent works [32,33]. The total parameters to be studied is two (2), both of which are related to Mohr-Coulomb.…”

Maximum Strain Effect and Secant Modulus Variation of Hemic Peat Soil at large Deformation due to Cyclic Loading

“…The term "dynamic loading" consists of a system that exhibits a degree of consistency both in its magnitude and in its frequency [2]. It has been related to explaining nonstatic repetitive soil loading [3,4]. Soil deposits are often subjected to cyclic loading due to wave action, traffic loading or earthquakes, machine operations, wind, and wave actions [5].…”