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Strength anisotropy and heterogeneous rotated anisotropy are prevalent phenomena in natural slopes. Previous studies have underscored their significance in slope stability analysis. However, in previous slope stability analyses, the effects of strength anisotropy and heterogeneous rotated anisotropy on slope stability were studied separately, without considering their coupled effect. This paper aims to propose a probabilistic analysis framework of slope stability considering the coupled effect of strength anisotropy and heterogeneous rotated anisotropy. Through an undrained clay slope case, the proposed probabilistic analysis framework is examined. The influence of strength anisotropy and heterogeneous rotated anisotropy on slope stability is investigated. The results show that the proposed probabilistic analysis framework of slope stability considering the coupled effect of strength anisotropy and heterogeneous rotated anisotropy is effective. Both strength anisotropy and heterogeneous rotated anisotropy have an important influence on slope stability. Furthermore, the statistics of safety factor including mean value, coefficient of variation, and reliability index, vary with the strength anisotropy coefficient, the heterogeneous anisotropy coefficient, and the rotational angle. The smaller the strength anisotropy coefficient, the larger the heterogeneous anisotropy coefficient, and the smaller the reliability index. The rotational angle of strata corresponding to the minimum and maximum values of the slope reliability index is sensitive to the strength anisotropy coefficient, but not to the heterogeneous anisotropy coefficient.

期刊论文 2025-04-28 DOI: 10.3389/feart.2025.1581457

This article presents a micro-structure tensor enhanced elasto-plastic finite element (FE) method to address strength anisotropy in three-dimensional (3D) soil slope stability analysis. The gravity increase method (GIM) is employed to analyze the stability of 3D anisotropic soil slopes. The accuracy of the proposed method is first verified against the data in the literature. We then simulate the 3D soil slope with a straight slope surface and the convex and concave slope surfaces with a 90 degrees turning corner to study the 3D effect on slope stability and the failure mechanism under anisotropy conditions. Based on our numerical results, the end effect significantly impacts the failure mechanism and safety factor. Anisotropy degree notably affects the safety factor, with higher degrees leading to deeper landslides. For concave slopes, they can be approximated by straight slopes with suitable boundary conditions to assess their stability. Furthermore, a case study of the Saint-Alban test embankment A in Quebec, Canada, is provided to demonstrate the applicability of the proposed FE model. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

期刊论文 2025-03-01 DOI: 10.1016/j.jrmge.2024.03.038 ISSN: 1674-7755

Although extensive investigations have been performed on soil anisotropy, little information is available regarding its quantification. The quantification of anisotropy reflects the extent to which the inherent anisotropy of soil controls its mechanical behavior and so it is crucial for connecting comprehensive experimental research with soil constitutive models and engineering practices. The present study evaluates the level of shear strength anisotropy in various types of soil. A database is compiled of the variations of shear strength with the direction of major principal stress (alpha) as established via hollow-cylinder torsional shear tests, covering more than 20 types of soil. This study reviews critically the existing methods for strength anisotropy, finding none of them quantifies anisotropy satisfactorily. The present study proposes using the bracketed area by the S(alpha)/S(0)-alpha curve and the line S(alpha)/S(0) = 1 to measure the level of strength anisotropy, where S(alpha) is the soil strength as a function of alpha. The proposed method in this study can measure the strength anisotropy levels of sands, silts, clays, residual soil, calcareous sand, mudstone, and glacial till, among others. Additionally, the anisotropy degree measured using the proposed method appears to be consistent with the results of microstructural anisotropy evaluations. This study enhances the understanding of soil anisotropy by providing a comprehensive database of soil strength anisotropy and proposing a general method for its quantification.

期刊论文 2024-05-01 DOI: 10.1061/IJGNAI.GMENG-8640 ISSN: 1532-3641

Soil is a complex material that exhibits both spatial variability and anisotropy. For simplicity, the traditional approach for analyzing slope stability often assumes that soil is homogeneous or isotropic, which can lead to an overestimation of slope stability and reliability. To address this issue, a novel approach is proposed in this study that uses an anisotropic yield criterion based on the random finite-element method to evaluate the influence of strength anisotropy on slope stability, while accounting for the influence of spatial variability on reliability. The proposed approach is applied to a typical case of slope reliability analysis. It is shown that the results of the proposed approach are consistent with those of previous studies and OPTUM G2 outcomes. The assessment involves determining the safety factors for both homogeneous and anisotropic conditions, while also taking into account the probability of failure in the presence of spatial variability. It is found that strength anisotropy significantly affects slope stability and reliability, as the factor of safety decreases from 1.255 to 1.037 and the probability of failure increases from 3.5% to 52.1% when considering strength anisotropy (n=0.707, xi=11.25 degrees). In addition, a sensitivity analysis is performed to investigate the influence of slope geometric parameters, strength anisotropic parameters, and spatial variability parameters on slope stability and reliability.

期刊论文 2024-05-01 DOI: 10.1061/NHREFO.NHENG-2000 ISSN: 1527-6988

Layered rock mass is a type of engineering rock mass with sound mechanical anisotropy, which is generally unfavorable to the stability of underground works. To investigate the strength anisotropy of layered rock, the Mohr-Coulomb and Hoek-Brown criteria are introduced to establish the two transverse isotropic strength criteria based on Jaeger's single weak plane theory and maximum axial strain theory, and parameter determination methods. Furthermore, the sensitivity of strength parameters (K1, K2, and K3) that are used to characterize the anisotropy strength of non-sliding failure involved in the strength criteria and confining pressure are investigated. The results demonstrate that strength parameters K1 and K2 affect the strength of layered rock samples at all bedding angles except for the bedding angle of 90 degrees and the angle range that can cause the shear sliding failure along the bedding plane. The strength of samples at any bedding angle decreases with increasing K1, whereas the opposite is for K2. Except for bedding angles of 0 degrees and 90 degrees and the bedding angle range that can cause the shear sliding along the bedding plane, K3 has an impact on the strength of rock samples with other bedding angles that the specimens' strength increases with increase of K3. In addition, the strength of the rock sample increases as confining pressure rises. Furthermore, the uniaxial and triaxial tests of chlorite schist samples were carried out to verify and evaluate the strength criteria proposed in the paper. It shows that the predicted strength is in good agreement with the experimental results. To test the applicability of the strength criterion, the strength data of several types of rock in the literature are compared. Finally, a comparison is made between the fitting effects of the two strength criteria and other available criteria for layered rocks. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

期刊论文 2024-04-01 DOI: 10.1016/j.jrmge.2023.06.006 ISSN: 1674-7755
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