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Your search keyword '"Zhou, Shunhua"' showing total 612 results
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612 results on '"Zhou, Shunhua"'

1. How to identify earth pressures on in-service tunnel linings: Insights from Bayesian inversion to address non-uniqueness

Author

Tian, Zhiyao, Zhou, Shunhua, Lee, Anthony, Shan, Yao, and Detmann, Bettina

Subjects
Statistics - Applications
Abstract

Identifying earth pressures on in-service transportation tunnel linings is essential for their health monitoring and performance prediction, particularly in structures that exhibit poor performance. Due to the high costs associated with pressure gauges, pressure inversion based on easily observed structural responses, such as deformations, is preferred. A significant challenge lies in the non-uniqueness of inversion results, where various pressures can yield similar structural responses. Existing approaches often overlook detailed discussions on this critical issue. In addressing this gap, this study introduces a Bayesian approach. The proposed statistical framework effectively quantifies the uncertainty induced by non-uniqueness. Further analysis identifies the uniform component in distributed pressures as the primary source of non-uniqueness. Insights into mitigation strategies are provided, including increasing the quantity of deformation data or incorporating an observation of internal normal force within the tunnel lining -- the latter proving to be notably more effective. A practical application in a numerical case study demonstrates the effectiveness of this approach. In addition, our investigation recommends maintaining deformation measurement accuracy within the range of [-1, 1] mm to ensure satisfactory outcomes. Finally, deficiencies and potential future extensions of this approach are discussed., Comment: This paper has been accepted for publication in Transportation Geotechnics. Please find the published version at https://doi.org/10.1016/j.trgeo.2024.101344

Published
2024
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2. Adaptive tempered reversible jump algorithm for Bayesian curve fitting

Author

Tian, Zhiyao, Lee, Anthony, and Zhou, Shunhua

Subjects
Statistics - Computation, Statistics - Applications
Abstract

Bayesian curve fitting plays an important role in inverse problems, and is often addressed using the Reversible Jump Markov Chain Monte Carlo (RJMCMC) algorithm. However, this algorithm can be computationally inefficient without appropriately tuned proposals. As a remedy, we present an adaptive RJMCMC algorithm for the curve fitting problems by extending the Adaptive Metropolis sampler from a fixed-dimensional to a trans-dimensional case. In this presented algorithm, both the size and orientation of the proposal function can be automatically adjusted in the sampling process. Specifically, the curve fitting setting allows for the approximation of the posterior covariance of the a priori unknown function on a representative grid of points. This approximation facilitates the definition of efficient proposals. In addition, we introduce an auxiliary-tempered version of this algorithm via non-reversible parallel tempering. To evaluate the algorithms, we conduct numerical tests involving a series of controlled experiments. The results demonstrate that the adaptive algorithms exhibit significantly higher efficiency compared to the conventional ones. Even in cases where the posterior distribution is highly complex, leading to ineffective convergence in the auxiliary-tempered conventional RJMCMC, the proposed auxiliary-tempered adaptive RJMCMC performs satisfactorily. Furthermore, we present a realistic inverse example to test the algorithms. The successful application of the adaptive algorithm distinguishes it again from the conventional one that fails to converge effectively even after millions of iterations., Comment: This paper has been accepted for publication in Inverse Problems. Please find the published version at https://doi.org/10.1088/1361-6420/ad2cf7

Published
2024
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30. The Influence of Variation in Groundwater Table on Ground Vibrations from Underground Tunnels

Author

He, Chao, Zhou, Shunhua, Di, Honggui, Zhang, Xiaohui, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Tutumluer, Erol, editor, Nazarian, Soheil, editor, Al-Qadi, Imad, editor, and Qamhia, Issam I.A., editor

Published
2022
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31. Influence of Shield Slurry Property on Filter Cake Quality in Sand Stratum

Author

Ye, Weitao, Fu, Longlong, Zhou, Shunhua, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Tutumluer, Erol, editor, Nazarian, Soheil, editor, Al-Qadi, Imad, editor, and Qamhia, Issam I.A., editor

Published
2022
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48. Vibro-fluidization of sand under coupled static loading and high-frequency cyclic loading

Author

Dai, Ning, Shan, Yao, Fu, Longlong, Ye, Weitao, Guo, Peijun, Zhou, Shunhua, Rackwitz, Frank, and Stolle, Dieter

Subjects
Sand -- Mechanical properties -- Testing, High speed trains -- Environmental aspects, Soils -- Density, Soil structure -- Analysis, Vibration -- Analysis, Earth sciences
Abstract

An increase in the operation speed of high-speed trains often leads to an increase in the loading frequency on subgrade soil. Hence, the long-term dynamic behavior of the subgrade and the service performance of high-speed tracks are affected. To determine the stress-strain characteristics of granular soil under high-frequency loading, a triaxial test setup was modified to investigate the effects of loading acceleration and duration, water content, vibration frequency, cell pressure, and initial soil density. The experimental results indicate that there are reductions in axial stress and volumetric strain during high-frequency loading. The reduction in axial stress is as high as 40%, and that of volumetric strain, which is permanent, could approach 0.1%. The stress reduction, strain compression, and excess pore pressure are found to vary linearly with vibration acceleration when a/g > 0.02, where a is vertical vibration acceleration and g is gravitational acceleration. The reduction in strength and strains are found to depend on the loading acceleration and effective cell pressure, but independent of the loading duration, water content, frequency, and initial density. A threshold acceleration a = 0.02g is observed, below which the changes in the shear strength and volumetric strain induced by vibration are negligible. At high vibration acceleration, the strain amplitude could increase, eventually leading to a collapse of the specimen. Key words: granular soil, critical state, fluidization, deviatoric stress, volumetric strain. L'augmentation de la vitesse d'exploitation des trains a grande vitesse entraine souvent une augmentation de la frequence de chargement du sol de la plate-forme. Le comportement dynamique a long terme de la plate-forme et les performances de service des voies a grande vitesse sont donc affectes. Afin de determiner les caracteristiques de contraintedeformation du sol granulaire sous un chargement a haute frequence, un montage d'essai triaxial a ete modifie pour etudier les effets de l'acceleration et de la duree du chargement, de la teneur en eau, de la frequence de vibration, de la pression des cellules et de la densite initiale du sol. Les resultats experimentaux indiquent qu'il y a des reductions de la contrainte axiale et de la deformation volumetrique pendant le chargement a haute frequence. La reduction de la contrainte axiale peut atteindre 40% et celle de la deformation volumetrique, qui est permanente, peut approcher 0,1%. La reduction des contraintes, la compression des deformations et l'exces de pression interstitielle varient lineairement avec l'acceleration des vibrations lorsque a/g > 0,02 ou a est l'acceleration de vibration verticale et g est l'acceleration gravitationnelle. La reduction de la resistance et des deformations depend de l'acceleration de la charge et de la pression effective des cellules, mais est independante de la duree de la charge, de la teneur en eau, de la frequence et de la densite initiale. Un seuil d'acceleration a = 0.02g est observe, en dessous duquel les changements de la resistance au cisaillement et de la deformation volumetrique induits par la vibration sont negligeables. En cas d'acceleration elevee, l'amplitude de la deformation peut augmenter et conduire a l'effondrement du specimen. [Traduit par la Redaction] Mots-cles: sol granulaire, etat critique, fluidization, contrainte deviatorique, deformation volumetrique., 1. Introduction Vibrations induced by high-speed trains frequently lead to long-term settlement of the track owing to the permanent compression of the subgrade. When the speed of a high-speed train [...]

Published
2022
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