Identifying fatigue damage of mudded intercalations based on dynamic triaxial test

Yan, Changbin; Wang, Hejian; Xu, Xiaowen; Zhang, Yanchang

doi:10.1016/j.enggeo.2020.105933

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…Hence, the confining pressure and dynamic deviator stress have significant impacts on the development of ε p of the UGM. The values of ε p are generally greater than those reported in the existing literature [46][47][48][49]. One possible reason is that the tested confining pressures are relatively small comparing with existing studies.…”

Section: Results and Discussion Of Accumulative Plastic Strain Curvesmentioning

confidence: 62%

“…According to the ASTM D7181-20 standard [ 45 ], the diameter of specimens is required to be no less than six times the d max of the soil for reducing the size effects of specimens on the test data. Currently, a large proportion of triaxial devices are manufactured for conducting tests with soil specimen diameters less than 150 mm (e.g., 39.1, 50, 100 and 150 mm) [ 46 , 47 , 48 , 49 ]. However, the d max of UGMs used as railway subgrade fillings is generally within the range of 50–60 mm as specified by a railway standard of China [ 42 ].…”

Section: Test Materials and Methodsmentioning

confidence: 99%

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Evaluation of Critical Dynamic Stress and Accumulative Plastic Strain of an Unbound Granular Material Based on Cyclic Triaxial Tests

et al. 2021

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Critical dynamic stress (σcri) and accumulative plastic strain (εp) are primary indicators regarding the dynamic stability of unbound granular materials (UGMs). This study aims to seek an effective method to evaluate the dynamic stability of UGMs used in railway subgrades. First, the dynamic characteristics of an UGM used in railway subgrade bed construction were investigated by performing a series of large-scale cyclic triaxial tests, with the results showing that εp versus cycle number (N) curves can be categorized into stable, failure, and critical patterns. Grey relational analyses were then established, where the analyzed results demonstrated that the εp–N curve pattern and final accumulative plastic strain (εs) of the stable curves are strongly correlated with the moisture content (w), confining pressure (σ3), and dynamic deviator stress (σd). The analyzed grey relational grades distributed in a narrow range of 0.72 to 0.81, indicating that w, σ3, and σd have similar degrees of importance on determining the εp–N curve patterns and the values of εs of the UGM. Finally, a data processing method using a back-propagation (BP) neural network is introduced to analyze the test data, and an empirical approach is developed to evaluate the σcri (considering the effects of σ3 and w) and εs (considering the effects of σ3, w, and σd) of the UGM. The analyzed results illustrated that the developed method can effectively reflect the linear/non-linear relationships of σcri and εs with respect to σ3 and/or σd. The σcri approximately increases linearly with increasing σ3, and a simple empirical formula is proposed for the σcri. In addition, εs and its variation rate increase non-linearly with increasing σd but decrease non-linearly as σ3 increases.

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Section: Results and Discussion Of Accumulative Plastic Strain Curvesmentioning

confidence: 62%

Section: Test Materials and Methodsmentioning

confidence: 99%

Evaluation of Critical Dynamic Stress and Accumulative Plastic Strain of an Unbound Granular Material Based on Cyclic Triaxial Tests

et al. 2021

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“…In order to develop the material with similar density index and determine the curing time of the material, the preliminary preparation was carried out first. On the basis of previous research experience [ 25 , 26 , 27 , 28 , 29 , 30 ], the selected materials are as follows: iron powder (fine aggregate, 150 mesh, density ∼5.12 g/cm

); barite powder (fine aggregate, 100 mesh, density ∼4.2 g/cm

); and quartz sand (coarse aggregate, 16–26 mesh, density ∼2.65 g/cm

). Gypsum was used as the cementitious material.…”

Section: Test Processmentioning

confidence: 99%

An Experimental Study on the Preparation of Soft Rock Similar Materials Using Redispersible Latex Powder as a Modifier

Zhang

Xiang

et al. 2022

Molecules

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The engineering geological problems of soft rock are common in large slope engineering and underground engineering surrounding rock. In order to study the change in mechanical properties of soft rock under the action of loading, excavation and rainfall, this paper carried out experimental research on similar materials of soft rock. The similar material of soft rock is prepared by using iron fine powder, barite powder and quartz sand as aggregate, gypsum as binder and redispersible latex powder as regulator. A single-factor influence test was designed with the content of redispersible latex powder as variation parameter. Analysis the influence of redispersible latex powder from the perspectives of physical and mechanical indexes, failure forms, stress–strain states and changes after water seepage. In addition, evaluate the feasibility of this similar material in geomechanical model test. Experimental results show that the density, compressive strength and Poisson’s ratio of similar materials can be improved to a certain extent by the redispersible latex powder with low dosage. However, the above indexes show a significant downward trend with the increase in dosage when the dosage exceeds 2%. The deformation modulus always shows a downward trend, and this trend becomes more significant especially when the dosage exceeds 2%. With the increase in the redispersible latex powder, the stress–strain curves of similar materials show obvious elastic and plastic stages. The failure mode gradually changes to X-shaped conjugate failure, which is common in soft rock, and the material changes from brittle failure to plastic failure. In addition, this type of similar material with gypsum as cementing agent will cause serious damage and loss of bearing capacity after seepage. These methods produce similar materials with low strength, low deformation modulus and plastic failure form, which can be used to simulate the stability of soft rock engineering caused by loading or excavation. At the same time, it also sheds lights on preparing similar materials of hard rock.

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“…Yan et al examined the dynamic behaviour of mudded interlayers under the influence of cyclic dynamic loading. The results indicated that the strength parameters of mudded interlayers exhibited a significant decline in response to repeated dynamic loading 5 . Ma et al explored the effect of water content and normal stress in remodeling samples on the shear strength of weak interlayers 6 ; Zhang et al carried out the rheological test of muddy interlayers under the combined action of static shear and discontinuous dynamic shear.…”

Section: Introductionmentioning

confidence: 95%

The effects of dry density and moisture content on the shear characteristics of clay-type muddy interlayer

Chen,

Zhang,

Qiu

et al. 2024

Preprint

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Shear strength parameter is one of the important indexes of soil, which is the key factor to determine the stability of the project. In order to study the shear characteristics of clay-type muddy interlayer, an improved direct shear apparatus was used to carry out indoor direct shear tests under different dry density and moisture content conditions. The results show that the shear stress increases with the increase of dry density and decreases with the increase of moisture content. When the moisture content is 20%, the shear stress-shear displacement of the muddy interlayer shows obvious strain-softening phenomenon. When the moisture content is 23% and 25%, the sample shows hardening characteristics at low normal stress level. With the increase of stress level, the curve transits from softening type to hardening type. When the moisture content is 28%, the curves show slight strain softening. Under the condition of low moisture content, the internal friction angle decreases with the increase of dry density, while the cohesion increases with the increase of dry density. At medium moisture content, both of them fluctuated with dry density, but the amplitude was not large. At high water content, the response effects of internal friction angle, cohesion and dry density are not obvious. The research results can provide a reference for the research on disaster prevention and early warning of related projects of clay-type muddy interlayer.

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Identifying fatigue damage of mudded intercalations based on dynamic triaxial test

Cited by 5 publications

References 15 publications

Evaluation of Critical Dynamic Stress and Accumulative Plastic Strain of an Unbound Granular Material Based on Cyclic Triaxial Tests

Evaluation of Critical Dynamic Stress and Accumulative Plastic Strain of an Unbound Granular Material Based on Cyclic Triaxial Tests

An Experimental Study on the Preparation of Soft Rock Similar Materials Using Redispersible Latex Powder as a Modifier

The effects of dry density and moisture content on the shear characteristics of clay-type muddy interlayer

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