Small-strain stiffness of Zenoz kaolin in unsaturated conditions

Biglari, Mahnoosh; d’OnofrioAnna,; MancusoClaudio,; Kazem, JafariMohammad; ShafieeAli,; Ashayeri, Iman

doi:10.1139/t11-105

Cited by 27 publications

(15 citation statements)

References 11 publications

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“…In the low suction range before AEV, the shear modulus increases linearly with suction, after which its increase is predominantly non-linear, mainly due to the distinct hydraulic regulation at the particle level (Mancuso et al, 2002). Similar observations were also reported for a range of different soils by Marinho et al (1996); Vinale et al (2001), Inci et al (2003), Sawangsuriya et al (2008), Biglari et al (2012) and Heitor et al (2012). In addition, Mancuso et al (2002) and, more recently, Heitor et al (2013) also reported that the small strain shear modulus depends mainly on the soil fabric derived from compaction, that is, dry and wet of optimum water content particularly in the macroporosity range.…”

Section: Introductionsupporting

confidence: 77%

The role of compaction energy on the small strain properties of a compacted silty sand subjected to drying–wetting cycles

2015

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Heitor, A., Indraratna, B. & Rujikiatkamjorn, C. (2015). The role of compaction energy on the small strain properties of a compacted silty sand subjected to drying -wetting cycles. Geotechnique: international journal of soil mechanics, 65 (9), 717-727.The role of compaction energy on the small strain properties of a compacted silty sand subjected to drying -wetting cycles AbstractThe elastic properties of a soil are usually investigated to describe its engineering behaviour. The results of previous studies indicate that the effect of changes in suction on the elastic response at a small strain level of soils is significant during compaction and post-compaction periods. Limited efforts have been focused on quantifying those post-compacted responses due to the changes in suction induced by wetting and drying cycles. During their service life, most earth structures experience changes in hydraulic behaviour owing to climatic changes. These seasonal fluctuations in turn impact on the geomechanical performance of compacted soil. In this paper the aspects related to the elastic properties of compacted soils subjected to cycles of drying and wetting are described. Particular emphasis is placed on the effect of compaction energy on the hysteric behaviour (i.e. amplitude of the hysteresis loop) and its dependence on the initial stress state conditions and suction history. The results not only confirm the importance of the current suction in governing the shear and compression velocities and associated moduli, but they also suggest that subsequent drying-wetting cycles or suction history can further induce hysteretic changes, particularly along the wetting paths. The elastic properties of a soil are usually investigated to describe its engineering behaviour. The results of previous studies indicate that the effect of changes in suction on the elastic response at a small strain level of soils is significant during compaction and post-compaction periods. Limited efforts have been focused on quantifying those post-compacted responses due to the changes in suction induced by wetting and drying cycles. During their service life, most earth structures experience changes in hydraulic behaviour owing to climatic changes. These seasonal fluctuations in turn impact on the geomechanical performance of compacted soil. In this paper the aspects related to the elastic properties of compacted soils subjected to cycles of drying and wetting are described. Particular emphasis is placed on the effect of compaction energy on the hysteric behaviour (i.e. amplitude of the hysteresis loop) and its dependence on the initial stress state conditions and suction history. The results not only confirm the importance of the current suction in governing the shear and compression velocities and associated moduli, but they also suggest that subsequent drying-wetting cycles or suction history can further induce hysteretic changes, particularly along the wetting paths.

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Section: Introductionsupporting

confidence: 77%

The role of compaction energy on the small strain properties of a compacted silty sand subjected to drying–wetting cycles

2015

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“…Although studies of dynamic soil properties within the laboratory environment, e.g. resonant column testing, have been performed for several decades, the effects of saturation, particle size and shape, gradation and matrix suction were not investigated until the early 1980s (Wu et al 1984;Qian et al 1991;Wheeler et al 2003;Biglari et al 2012). Further, very little research has been performed on anisotropic shear moduli for unsaturated soils (Ng and Yung 2008;Ng et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Partially saturated soil causing significant variability in near surface seismic signals

Taylor

McKenna

Kelley

et al. 2013

Near Surface Geophysics

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The behaviour of dry, moist, and saturated soils has been studied for over a century without ade quately investigating the behaviour associated with transient saturation in the near surface, i.e. the upper 1 m of overburden, including the effects of rapid meteorological changes, dynamic fluid flow, and variability of saturation on shallow seismic sensors. This paper presents observational data wherein the geophysical instrumentation response was significantly influenced by near‐surface post‐precipitation saturation and additional laboratory experimentation on the effects of satu ration on shear wave velocity. The lack of partially‐saturated data is primarily because transient meteorological events have not been critically important to the types of long‐term deployments performed in the past, where sensors were situated in hard‐rock, collecting data under idealized conditions, as opposed to sedimentary settings. Shorter‐duration deployments and smaller system architectures, e.g. persistent monitoring, now necessitate detailed a priori knowledge of meteoro logical impacts to system design and performance. The purpose of this persistent monitoring geophysical instrumentation is to continually monitor the near surface and relate small perturbations to a specific source type(s) and distance(s) from the receiver. As such, the received signal is compared to known sources within a predetermined geo logical/meteorological condition. Presented herein is the calibration signal generated by a 3.63‐kg (8‐lb) sledgehammer prior to and post 36 hours of steady precipitation. The resulting subsurface seismic velocity time‐histories show a significant increase in signal amplitude, change in fre quency content and no change in duration. Thus, the amplification effects of near‐surface moisture variability combined with dynamic pore fluid could be interpreted as false positives of a specific source signature and/or instrument failure.

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“…It means that the compacted specimen has initial suction level higher than 150 kPa and lower than 300 kPa. Initial suction of these ideal samples were measured by [6] at 240 kPa. In Figures 5 and 6 the specific volume changes (dv) of the samples are plotted versus the time in the suction levels of 150 kPa and 300 kPa for the slow and the high rate tests, respectively.…”

Section: Resultsmentioning

confidence: 99%

Effects of loading frequency on cyclic parameters of unsaturated Zenoz kaolin

2016

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Abstract. According to the considerable effects of the loading frequency on the cyclic behaviour of the soils and lack of the sufficient and precise data in this field for the unsaturated soils, more attention needs to be paid to the experimental investigations in various loading paths and frequencies. Meanwhile the unsaturated cyclic tests require advanced equipment and need more precision and time. In this paper, the results of two groups of tests which were performed on an unsaturated fine grained soil in the same initial condition are presented and compared during specific stress paths (pre-cycles of loading and during cycles). The tests are performed using the same suction-controlled cyclic triaxial apparatus in the same stress path before loading cycles, but two conditions of the cyclic loading frequencies (slow cyclic tests with the constant suction condition during the cycles and rapid cyclic tests with the unsteady suction condition during the cyclic path). The results show that increase in the loading frequency leads to the considerable increase in the shear modulus of the samples in the same strain levels.

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Small-strain stiffness of Zenoz kaolin in unsaturated conditions

Cited by 27 publications

References 11 publications

The role of compaction energy on the small strain properties of a compacted silty sand subjected to drying–wetting cycles

The role of compaction energy on the small strain properties of a compacted silty sand subjected to drying–wetting cycles

Partially saturated soil causing significant variability in near surface seismic signals

Effects of loading frequency on cyclic parameters of unsaturated Zenoz kaolin

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