An analytical solution for sectional estimation of stress and displacement fields around a shallow tunnel

Lin, Luo-bin; Chen, Fuquan; Huang, Zeng

doi:10.1016/j.apm.2018.12.012

Cited by 15 publications

(2 citation statements)

References 31 publications

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“…For a two‐layer chamber, Wang and Li 26 obtained an analytical solution of stress through the liner–rock interaction with complex variable function. Lin et al 27 used a complex variable approach and discrete Fourier transform theory to investigate the shallow buried chambers supported by segment linings. Zhou et al 28 developed an axisymmetric model for multilayer chambers under internal loads and calculated the hydraulic–mechanical interaction in hydraulic chambers using the equivalent coupling method.…”

Section: Introductionmentioning

confidence: 99%

Stress redistribution in a multilayer chamber for compressed air energy storage in abandoned coalmine: Elastic analytical insights and material choice

Sun,

Wang,

Zhang

et al. 2023

Energy Science & Engineering

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Compressed air energy storage (CAES) is attracting attention as one of large‐scale renewable energy storage systems. Its gas storage chamber is one of key components for its success. A successful utilization of an abandoned coalmine roadway depends on the stability of the gas storage chamber. The chamber is a multilayer structure and the redistribution of the stress and displacement in each layer is critical to the chamber stability. So far, this redistribution mechanism under any lateral pressure coefficient and internal air pressure has been unclear and thus a quick and easy evaluation on the CAES chamber stability becomes difficult. In this study, the redistributions of stress and displacement in each layer are analytically solved based on complex variable function theory. First, the stress and displacement in three CAES multilayer structures are obtained under any lateral pressure coefficient and internal air pressure. Then, a comprehensive parameter b1 is obtained to describe the redistribution of stress and displacement in rock mass, lining layer, and grout layer. Its linkage with lateral pressure coefficient, internal air pressure, and material properties is analytically expressed. Thirdly, an analytical expression is obtained for the influence range of internal air pressure on chamber stress. Finally, the role and selection of lining and grouting layers are explored at different lateral pressure coefficient and internal air pressure. It is found that the CAES chamber stability can be effectively and quickly evaluated by these analytical solutions and comprehensive parameters and enhanced by a material with low bulk modulus but high shear modulus.

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Section: Introductionmentioning

confidence: 99%

Stress redistribution in a multilayer chamber for compressed air energy storage in abandoned coalmine: Elastic analytical insights and material choice

Sun,

Wang,

Zhang

et al. 2023

Energy Science & Engineering

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“…Therefore, a comprehensive analysis of the entire process of multi-stage excavation incorporating time-dependent plastic behaviour of geomaterials and the coupled solid-fluid interaction is crucial to perform a proper numerical simulation of underground excavation problems. Empirical, analytical or numerical methods has been widely used in tunnelling design (Alejano et al, 2012;Bobet, 2009;Cai, 2008;Chen et al, 2019;Debernardi and Barla, 2009;Do et al, 2020;Galli et al, 2004;Kargar and Haghgouei, 2020;Lin et al, 2019;Lin et al, 2020;Sakurai, 2010;Shin et al, 2002;Song and Rodriguez-Dono, 2021;Song et al, 2020;Song et al, 2018a andUnlu and Gercek, 2003;Vlachopoulos and Diederichs, 2009;Vu et al, 2013;Wang et al, 2019;Wang and Nie, 2010;Wang et al, 2018e;Zareifard, 2018). Among all these methods, the convergence-confinement method (CCM) provides an efficient way to determine support forces by considering the groundstructure interaction (Alejano et al, 2010;Alejano et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Modelling time-dependent plastic behaviour of geomaterials

Song¹

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Representing the time-dependent plastic behaviour of geomaterials is a critical issue in the correct application of tunnelling design techniques such as the convergence-confinement method or numerical modelling. Furthermore, during underground excavations below the water table, the effect of seepage flow cannot be ignored, and the behaviour of the tunnel must be analysed in a coupled hydro-mechanical framework. The main objective of this thesis is to analyse the response of tunnels excavated in saturated time-dependent plastic rock masses. For this purpose, a time-dependent plastic constitutive model has been developed and implemented in the software CODE_BRIGHT to simulate the time-dependent, strain-softening and creep-induced failure behaviour of geomaterials. Moreover, a coupled hydro-mechanical model is utilised to simulate the interaction between solid deformations and fluid flows. The obtained results provide relevant insights into the response of tunnels excavated in saturated time-dependent plastic rock masses. However, numerical difficulties might occur when modelling multi-stage excavations problems, when considering multi-physics coupled processes or non-linear mechanical material models, especially if the layers or pieces of excavated material are relatively coarse. In order to mitigate these numerical difficulties, a smoothed excavation (SE) method has been proposed and implemented in the software CODE_BRIGHT, which can improve numerical efficiency and mitigate non-convergence issues. Subsequently, to analyse the stability of tunnels with a combined support system, numerical solutions have been developed for tunnels excavated in strain-softening rock masses, considering the whole process of tunnel advancement, and the sequential installation of primary and secondary support systems. For this purpose, the actual compatibility conditions at both the rock-support interface and the support-support interface are considered. This method provides a convenient alternative method for the preliminary design of supported tunnels. La adecuada representación del comportamiento plástico y dependiente del tiempo de los geomateriales es una cuestión crítica en la correcta aplicación de técnicas de diseño de túneles como el método de convergencia-confinamiento o el modelado numérico. Por otro lado, durante las excavaciones subterráneas por debajo del nivel freático no se puede ignorar el efecto del flujo de filtración y, por tanto, el comportamiento del túnel debe analizarse en un marco hidromecánico acoplado. El principal objetivo de esta tesis es analizar la respuesta de túneles excavados en macizos rocosos plásticos saturados y dependientes del tiempo. Para este propósito, se ha desarrollado e implementado un modelo constitutivo plástico dependiente del tiempo en el software CODE_BRIGHT, que permite simular el comportamiento dependiente del tiempo, el de reblandecimiento por deformación y el inducido por fluencia de los geomateriales. Además, se ha utilizado un modelo hidromecánico acoplado para simular la interacción entre la deformación del sólidas y el flujo de fluido. Los resultados obtenidos proporcionan información relevante sobre la respuesta de los túneles excavados en macizos rocosos plásticos, saturados y dependientes del tiempo. Sin embargo, pueden surgir dificultades numéricas al modelar problemas de excavaciones en varias etapas, al considerar procesos multifísicos acoplados o modelos de materiales mecánicos no lineales, especialmente si las capas o piezas de material excavado son relativamente gruesas. Para mitigar estas dificultades numéricas, se ha propuesto e implementado un método de excavación suavizada (SE) en el software CODE_BRIGHT, que puede mejorar la eficiencia numérica y mitigar los problemas de no convergencia. Posteriormente, para analizar la estabilidad de túneles con sistemas de sostenimiento combinado, se han desarrollado soluciones numéricas para túneles excavados en macizos con reblandecimiento por deformación, considerando todo el proceso de avance del túnel y la instalación secuencial de los sistemas de sostenimiento primario y secundario. Con este propósito, se han considerado las condiciones reales de compatibilidad tanto en la interfaz roca- sostenimiento como en la interfaz sostenimiento-sostenimiento. Este método proporciona un método alternativo conveniente para el diseño preliminar de túneles con sostenimiento.

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Analytical Method for Predicting Tunnel Deformation Caused by Overlying Excavation Considering the Dewatering

Li,

Wang,

Luo

et al. 2024

Num Anal Meth Geomechanics

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Predicting the tunnel deformation caused by overlying excavation is a crucial catch in current rail transit construction. Most theoretical studies overlook the effect of dewatering on tunnel response. This study utilized Mindlin's stress solution and an improved incremental method to calculate the additional load resulting from excavation. The load increment due to dewatering was determined based on the effective stress principle and a modified Dupuit infiltration curve. Treating the tunnel as a series of segment rings on a Vlazov foundation, the energy variance method and a collaborative deformation model were employed to develop a tunnel deformation prediction model. The proposed model's validity was confirmed by examining two traceable cases. Based on this, further discussion addressed the impact of dewatering depth, tunnel burial depth, tunnel‐pit relative distance, and intersection angle on existing tunnel deformation. Finally, combining the proposed model with multiple regression analysis, a semi‐empirical method was established to determine the tunnel's maximum vertical displacement. The study found that dewatering extends the tunnel force range, and the tunnel subsidence was positively correlated with groundwater level drop depth. The increase in the tunnel burial depth and distance from the excavation center led to a longer soil unloading transfer path, resulting in reduced disturbance to the tunnel. A smaller intersection angle between the excavation's short edge and the tunnel led to less disturbance of the underlying tunnel, which should be avoided in practical engineering. The developed semi‐empirical formulae have sufficient engineering accuracy, guiding the reinforcement of the underlying tunnel.

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An analytical solution for sectional estimation of stress and displacement fields around a shallow tunnel

Cited by 15 publications

References 31 publications

Stress redistribution in a multilayer chamber for compressed air energy storage in abandoned coalmine: Elastic analytical insights and material choice

Stress redistribution in a multilayer chamber for compressed air energy storage in abandoned coalmine: Elastic analytical insights and material choice

Modelling time-dependent plastic behaviour of geomaterials

Analytical Method for Predicting Tunnel Deformation Caused by Overlying Excavation Considering the Dewatering

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