Shear characteristics of calcareous gravelly soil

Wang, Xinzhi; Wang, Xing; Jin, Zong-Chuan; Meng, Qingshan; Zhu, Changqi; Ren, Wang

doi:10.1007/s10064-016-0978-z

Cited by 59 publications

(6 citation statements)

References 15 publications

(12 reference statements)

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“…Calcareous sands can be widely observed in tropical marine environment. The intrinsic properties distinguish calcareous sands from other terrigenous sediments both physically and mechanically, in terms of particle angularity, high crushability, and weakly cemented soil structure (Wang et al 2017). As stated by Coop and Atkinson (1993), calcareous sands tend to have very loose fabric, due to particle interlocking effect and extremely high intra-granular void ratios.…”

Section: Introductionmentioning

confidence: 96%

Effect of particle breakage on the shear strength of calcareous sands

et al. 2021

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The particle breakage of calcareous sands plays a key role in determining the particle shape and shear strength. This process has been analysed in the current study by employing the ring shear tests on calcareous sands sampled from the South China Sea. In this study, a set of parameters, e.g. roundness and aspect ratio, have been employed to quantify the geometrical properties of calcareous sands pre- and after the breakage. These two parameters have been found to correlate well with the vertical loading stress level, shear strain and shear strength. The particle breakage leads to the change of micro-structure during the shear test, as illustrated by the Scanning Electron Microscopy (SEM) images. It is found that during the shearing deformation, particle breakages can effectively reduce, while particle rearrangements can increase the shear strength of the calcareous sands.

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Section: Introductionmentioning

confidence: 96%

Effect of particle breakage on the shear strength of calcareous sands

et al. 2021

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“…The soil at the site was classified as sandy gravels, and so the shear-strength parameter values appear to be on the high side, although they are within the range suggested by Duncan and Christopher (2004) and the friction angle range of 40° to 50° for coarse granular material suggested by Terzaghi et al (1996). Wang et al (2017) performed laboratory investigations on gravelly calcareous soil that were found to exhibit a high cohesion and a larger friction angle than other granular materials. In the present case, the XRD results for the debris material reveal that calcium carbonate and clay minerals are predominant.…”

Section: Stability Analysis Of the Slopementioning

confidence: 99%

“…12 XRD patterns for sand fines of debris material 2.6.2 Effect of gravel content on the angle of internal friction, ϕ In the field, gravel content substantially varies over a wide range, which in turn markedly influences the friction angle, ϕ. Dupla et al (2007) performed triaxial tests on soil-rock mixtures and concluded that the volumetric fractionof gravel is the main cause that affects the shear-strength parameters and elastic properties. Studies have been conducted in the past to establish a correlation between ϕ and gravel content(Irfan and Tang 1993;Lindquist 1994; Modley 1999;Iannacchione and Vallejo 2000;Xu et al 2011;Wang et al 2017;Wang et al 2020). This is helpful for obtaining the field value of ϕ based on the gravel content at a particular location.…”

mentioning

confidence: 99%

An experimental and field investigation study on geotechnical characterisation and stability assessment of Surbhi Resort landslide at Mussoorie, India

Venkateswarlu

Singh

2022

Preprint

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Landslides occur frequently in the Himalayan region, especially during the monsoon season. Stability assessment of any landslide site provides a good understanding of the shear-strength response of the in-situ geomaterials and causative factors. Often the sliding geomaterial is a complex mixture of soil and rock pieces in the form of debris underlain by jointed rock strata (bedrock). Testing of these materials in the undisturbed state is generally not feasible, and hence, the shear-strength parameters are derived through simple field investigation, index testing and classification. In the present study, a methodical procedure involving field investigations and laboratory studies was adopted to carry out stability assessment of a landslide site in the Lesser Himalayan region. The field investigations included a ground-penetrating radar (GPR) study, mapping of joints in the rock mass and collection of debris and rock samples. Apart from it, laboratory studies included an X-ray diffraction (XRD) analysis of the sand-fines matrix, index testing of soil samples, direct shear tests on debris samples and point-load strength-index testing on rock chunks. Laboratory tests were performed using conventional triaxial and a state-of-the art large-sized direct shear experiments. For large-sized direct shear testing, the gravel fraction was varied to quantify the effect of gravel content on the internal friction angle (ϕ). The parameter, cohesion of the debris was derived through back-analysis method. The rock mass rating (RMR), tunnelling quality index (the Q-system) and the geological strength index (GSI) were used to characterise the rock mass whereas, the shear strength parameters of the rock mass were derived through two non-linear strength criteria. Initial estimates of the shear-strength parameters of debris and the rock mass were employed to obtain the factor of safety (FOS) of the slope, which was found to have been underestimated. Back-analysis was then used to adjust the shear-strength parameter for cohesion. These adjusted parameters were then used to assess the stability of the slope and to suggest remedial measures.

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“…Coop et al [19] investigated the particle breakage degree of coral sand under different shear strains through a ring shear test and discovered that coral sand no longer breaks after reaching a certain shear strain; the initial gradation and normal stress of the sample are the main factors that determine the final gradation. Wang et al [20] conducted a direct shear test on calcareous sand in the South China Sea and found that the cohesion of calcareous sand is much higher than that of quartz sand and increases considerably with the average particle size. Rezvani et al [21] compared the triaxial shear behaviors of two kinds of coral sand with different particle sizes under the same conditions and found significant differences in their stress-strain curves.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Experiments and Numerical Simulation on Dynamic Response of Island Reclamation Coral Sand under Aircraft Load

et al. 2023

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The construction of island airports on coral reefs inevitably encounters the impact load of aircraft takeoff and landing. However, previous studies have not presented a detailed description of the dynamic response of the coral sand beneath the runways of island reclamation airports under aircraft load. In the current study, the coral sand of Mischief Reef Airport in the Nansha Islands, China, was selected as the background. The pore water pressure and strain characteristics of reshaped coral sand under aircraft loads with different dynamic stress amplitudes and vibration frequencies were studied using dynamic triaxial tests. Particle discrete element software was employed to study the deformation characteristics of coral sand with different particle sizes and porosities under aircraft loads. Results show that when the dynamic stress amplitude and vibration frequency were small, the pore water pressure and strain of the coral sand samples gradually increased with the number of load cycles, and the growth rate became increasingly small. When the dynamic stress amplitude and vibration frequency were large, the axial strain of the coral sand samples increased with the vibration frequency, and the growth rate exhibited an increasing trend. The deformation of the coral sand samples increased with porosity under aircraft loading. The larger the variation range of the coral sand particle size was, the larger the coral sand deformation caused by aircraft takeoff and landing load was. These results can provide a reference for the treatment and repair of the airstrip foundation of island airports.

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Shear characteristics of calcareous gravelly soil

Cited by 59 publications

References 15 publications

Effect of particle breakage on the shear strength of calcareous sands

Effect of particle breakage on the shear strength of calcareous sands

An experimental and field investigation study on geotechnical characterisation and stability assessment of Surbhi Resort landslide at Mussoorie, India

Laboratory Experiments and Numerical Simulation on Dynamic Response of Island Reclamation Coral Sand under Aircraft Load

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