The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform
Jian Peng - One of the best experts on this subject based on the ideXlab platform.
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bathynotus a key trilobite taxon for global Stratigraphic Boundary correlation between cambrian series 2 and cambrian series 3
Progress in Natural Science, 2009Co-Authors: Jian Peng, Yuanlong Zhao, Jinliang Yuan, Hong YangAbstract:Abstract The Cambrian trilobite Bathynotus is a special morphology of Redlichiid, which is characterized by a wider thorax axis and an 11th macropleural segment bearing a long, backwardly directed spine. Additionally, its 12th and 13th pleural segments are narrow and they terminate at a fulcrum where they fuse together and to the posterior edge of the long macropleural spine. The genus is widely distributed, occurring in North America, Siberia, the Altay-Sayan fold belt of Russia, South China, the Tarim Basin of China, and Australia. It occurs primarily in deposits of the upper part of the continental slope, at the transition between stable platform settings and subsiding margins of the late Early Cambrian. Here, we recognize three species of Bathynotus from China, including B. holopygus which is widespread around the world. Although six species of Bathynotus have been reported from Siberia and the Altay-Sayan fold belt area of Russia, data presented here suggest that only three of these species are valid. Bathynotus exhibits a short geological range, with its first occurrence late in the unnamed Cambrian Series 2 and the last appearance datum of Bathynotus at the Boundary of Cambrian Series 2 and Cambrian Series 3. The late appearance datum (LAD) of Bathynotus provides an important global Stratigraphic marker of the Boundary between Cambrian Series 2 and Cambrian Series 3.
Y M Cheng - One of the best experts on this subject based on the ideXlab platform.
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incorporating Stratigraphic Boundary uncertainty into reliability analysis of slopes in spatially variable soils using one dimensional conditional markov chain model
Computers and Geotechnics, 2020Co-Authors: Y M Cheng, Daniel DiasAbstract:Abstract Slope stability analysis based on different Stratigraphic Boundary conditions may have significant differences in terms of factor of safety (FS) and the location of the critical slip surface. Therefore, traditional reliability analysis of layered slopes that assumes the Stratigraphic Boundary between two soil layers being a deterministic line or surface can be misleading. This study aims to investigate the influence of the Stratigraphic Boundary uncertainty (SBU) arising from limited site investigation data on slope stability analysis with the consideration of soil spatial variability. A modified one-dimensional conditional Markov chain model is proposed to model the SBU. Cholesky decomposition technique is subsequently utilized to simulate the inherent spatial variability of soil properties based on the simulated Stratigraphic Boundary within the framework of Monte Carlo simulation. A sample example on a two-layered soil slope with limited number of boreholes shows that the proposed method can well simulate the Stratigraphic Boundary based on limited borehole information. The statistics of FS and probability of failure are found not to increase or decrease monotonically with the number of boreholes, but can converge to the correct results if the number of boreholes increases. Moreover, the conventional reliability analysis with an implicit assumption of deterministic Stratigraphic Boundary condition can significantly overestimate the reliability of the slope, but this overestimation decreases with the increase in the scale of fluctuation.
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system reliability analysis and risk assessment of a layered slope in spatially variable soils considering Stratigraphic Boundary uncertainty
Computers and Geotechnics, 2017Co-Authors: Y M Cheng, Xiaomi Wang, Shaohe Zhang, Zhonghu WuAbstract:Abstract Due to complex geological deposition, post-deposition processes and limited site investigation data in engineering practice, soil properties are often spatially variable and the Stratigraphic Boundary in layered soils is generally characterized by uncertainty. The spatial variability of soil properties has been well investigated in past years, whereas the question of how the Stratigraphic Boundary uncertainty affects the slope stability remains unanswered. This paper attempts to investigate the effects of the Stratigraphic Boundary uncertainty on the system reliability and risk of a layered slope in spatially variable soils. In this paper, the spatial variability of soil properties is simulated by non-stationary random fields that are generated by an extended Cholesky decomposition technique, while the stochastic nature of the Stratigraphic Boundary location is simulated by a discrete random variable. Monte Carlo simulation (MCS) is suggested for evaluating the system failure probability and risk. Various comparisons between probabilistic analysis results obtained from considering and neglecting the Stratigraphic Boundary uncertainty have been made for different statistics of soil properties. Results show that the Stratigraphic Boundary uncertainty plays an important role in identifying the slope failure mechanism. Moreover, neglecting the Stratigraphic Boundary uncertainty would generally overestimate the slope failure risk for different statistics, except at small coefficients of variation of the friction angle, where the results are underestimated.
Hong Yang - One of the best experts on this subject based on the ideXlab platform.
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bathynotus a key trilobite taxon for global Stratigraphic Boundary correlation between cambrian series 2 and cambrian series 3
Progress in Natural Science, 2009Co-Authors: Jian Peng, Yuanlong Zhao, Jinliang Yuan, Hong YangAbstract:Abstract The Cambrian trilobite Bathynotus is a special morphology of Redlichiid, which is characterized by a wider thorax axis and an 11th macropleural segment bearing a long, backwardly directed spine. Additionally, its 12th and 13th pleural segments are narrow and they terminate at a fulcrum where they fuse together and to the posterior edge of the long macropleural spine. The genus is widely distributed, occurring in North America, Siberia, the Altay-Sayan fold belt of Russia, South China, the Tarim Basin of China, and Australia. It occurs primarily in deposits of the upper part of the continental slope, at the transition between stable platform settings and subsiding margins of the late Early Cambrian. Here, we recognize three species of Bathynotus from China, including B. holopygus which is widespread around the world. Although six species of Bathynotus have been reported from Siberia and the Altay-Sayan fold belt area of Russia, data presented here suggest that only three of these species are valid. Bathynotus exhibits a short geological range, with its first occurrence late in the unnamed Cambrian Series 2 and the last appearance datum of Bathynotus at the Boundary of Cambrian Series 2 and Cambrian Series 3. The late appearance datum (LAD) of Bathynotus provides an important global Stratigraphic marker of the Boundary between Cambrian Series 2 and Cambrian Series 3.
Zhonghu Wu - One of the best experts on this subject based on the ideXlab platform.
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system reliability analysis and risk assessment of a layered slope in spatially variable soils considering Stratigraphic Boundary uncertainty
Computers and Geotechnics, 2017Co-Authors: Y M Cheng, Xiaomi Wang, Shaohe Zhang, Zhonghu WuAbstract:Abstract Due to complex geological deposition, post-deposition processes and limited site investigation data in engineering practice, soil properties are often spatially variable and the Stratigraphic Boundary in layered soils is generally characterized by uncertainty. The spatial variability of soil properties has been well investigated in past years, whereas the question of how the Stratigraphic Boundary uncertainty affects the slope stability remains unanswered. This paper attempts to investigate the effects of the Stratigraphic Boundary uncertainty on the system reliability and risk of a layered slope in spatially variable soils. In this paper, the spatial variability of soil properties is simulated by non-stationary random fields that are generated by an extended Cholesky decomposition technique, while the stochastic nature of the Stratigraphic Boundary location is simulated by a discrete random variable. Monte Carlo simulation (MCS) is suggested for evaluating the system failure probability and risk. Various comparisons between probabilistic analysis results obtained from considering and neglecting the Stratigraphic Boundary uncertainty have been made for different statistics of soil properties. Results show that the Stratigraphic Boundary uncertainty plays an important role in identifying the slope failure mechanism. Moreover, neglecting the Stratigraphic Boundary uncertainty would generally overestimate the slope failure risk for different statistics, except at small coefficients of variation of the friction angle, where the results are underestimated.
Daniel Dias - One of the best experts on this subject based on the ideXlab platform.
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incorporating Stratigraphic Boundary uncertainty into reliability analysis of slopes in spatially variable soils using one dimensional conditional markov chain model
Computers and Geotechnics, 2020Co-Authors: Y M Cheng, Daniel DiasAbstract:Abstract Slope stability analysis based on different Stratigraphic Boundary conditions may have significant differences in terms of factor of safety (FS) and the location of the critical slip surface. Therefore, traditional reliability analysis of layered slopes that assumes the Stratigraphic Boundary between two soil layers being a deterministic line or surface can be misleading. This study aims to investigate the influence of the Stratigraphic Boundary uncertainty (SBU) arising from limited site investigation data on slope stability analysis with the consideration of soil spatial variability. A modified one-dimensional conditional Markov chain model is proposed to model the SBU. Cholesky decomposition technique is subsequently utilized to simulate the inherent spatial variability of soil properties based on the simulated Stratigraphic Boundary within the framework of Monte Carlo simulation. A sample example on a two-layered soil slope with limited number of boreholes shows that the proposed method can well simulate the Stratigraphic Boundary based on limited borehole information. The statistics of FS and probability of failure are found not to increase or decrease monotonically with the number of boreholes, but can converge to the correct results if the number of boreholes increases. Moreover, the conventional reliability analysis with an implicit assumption of deterministic Stratigraphic Boundary condition can significantly overestimate the reliability of the slope, but this overestimation decreases with the increase in the scale of fluctuation.