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Prof. Dr. Haitao Yu
Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China

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Journal article
Published: 23 June 2021 in Tunnelling and Underground Space Technology
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A 1 g shaking table test is conducted to investigate seismic responses of a segmental tunnel in sand under near-fault motions. The tunnel model is assembled with segments, bolts and rubber strips and embedded in a shallow sand ground. The test facility, design and preparation of the tunnel model and the sand ground, as well as selected earthquake motions, are presented in detail. Dynamic responses obtained from the experiment include accelerations of the sand ground and the tunnel model, strains of segments, diametric deformations of the tunnel section, as well as bolt tensions and rotation of radial joints. Results show that the ground fundamental frequency changes with different input motions due to sand nonlinearities, and the deformation of the segmental tunnel is concentrated on radial joints. Moreover, near-fault motions would significantly aggravate the seismic response of both the sand ground and the segmental tunnel compared to far-field motions. Physical mechanisms contributed to the observation that near-fault motions would lead to larger shear strains of ground, especially when the ground fundamental frequency decreases, are also discussed.

ACS Style

Yusheng Yang; Haitao Yu; Yong Yuan; Jun Sun. 1 g Shaking table test of segmental tunnel in sand under near-fault motions. Tunnelling and Underground Space Technology 2021, 115, 104080 .

AMA Style

Yusheng Yang, Haitao Yu, Yong Yuan, Jun Sun. 1 g Shaking table test of segmental tunnel in sand under near-fault motions. Tunnelling and Underground Space Technology. 2021; 115 ():104080.

Chicago/Turabian Style

Yusheng Yang; Haitao Yu; Yong Yuan; Jun Sun. 2021. "1 g Shaking table test of segmental tunnel in sand under near-fault motions." Tunnelling and Underground Space Technology 115, no. : 104080.

Journal article
Published: 20 June 2021 in Computers and Geotechnics
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Tunnels located in seismic active areas must support not only static loads exerted by the ground under gravity but also seismic loads from earthquake events. Current analytical solutions for seismic analysis of tunnel structures are limited to circular or rectangular tunnels but not available for tunnels with other complex cross-section shapes, such as straight-wall-arch-shaped or semi-rectangular-shaped tunnels. This paper presents a unified simplified analytical solution for deep tunnels with arbitrary cross-section shapes subjected to seismic loading. Since the cross-section dimension of tunnels is normally much smaller than the wavelength of ground peak velocities, the structure can be designed using the pseudo-static approach. The ground and the tunnel liner are assumed to be elastic, homogeneous, and isotropic in plane strain condition. Two different contact conditions, no-slip and full-slip conditions, are considered at the liner-ground interface. The complex variable theory combined with the conformal mapping technique are employed to obtain closed-form solutions for tunnel deformation and stresses. The proposed solution is verified by providing comparisons between its results and those from the finite element program ABAQUS. Furthermore, parametric analyses are carried out to investigate the influence of soil-structure relative stiffness ratio, cross-section shape, height-span ratio and thickness of middle wall on tunnel responses.

ACS Style

Haitao Yu; Gong Chen. Pseudo-static simplified analytical solution for seismic response of deep tunnels with arbitrary cross-section shapes. Computers and Geotechnics 2021, 137, 104306 .

AMA Style

Haitao Yu, Gong Chen. Pseudo-static simplified analytical solution for seismic response of deep tunnels with arbitrary cross-section shapes. Computers and Geotechnics. 2021; 137 ():104306.

Chicago/Turabian Style

Haitao Yu; Gong Chen. 2021. "Pseudo-static simplified analytical solution for seismic response of deep tunnels with arbitrary cross-section shapes." Computers and Geotechnics 137, no. : 104306.

Journal article
Published: 19 June 2021 in Tunnelling and Underground Space Technology
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Tunnels built in areas subject to earthquake activity must withstand seismic loadings. Covering tunnel liners with a coating layer will be a possible way to mitigate seismic damage to tunnels. In this paper, an analytical solution is developed for the seismic response of deep circular tunnels covered by an isolation layer. Since the cross-section dimension of tunnels is normally much smaller than the wavelength of ground peak velocities, the inertial forces can be neglected, and the structure can be designed using the pseudo-static approach, where the seismic-induced loads or deformations can be approximated by far-field shear stresses. The ground and the isolation layer are assumed to be elastic, homogeneous, and isotropic in plane strain conditions, and the tunnel lining is represented as an elastic shell. Both the full-slip and no-slip conditions are considered for the contact between the tunnel and the isolation layer, while the interface between the isolation layer and the ground is assumed to be continuous. The relative stiffness method, proposed by Einstein and Schwartz (1979), is employed to obtain the closed-form solutions for tunnel distortion and internal forces, including axial force, bending moment, and shear force. The proposed solution is verified by providing comparisons between its results and those from the known results in literature and the Finite Element program. Parametric analyses are presented where the seismic mitigation effects of the isolation layer with different properties such as thickness, elastic modulus, and Poisson’s ratio. Results show that the elastic modulus and thickness of the isolation layer, as well as the tunnel-isolation layer interface conditions (i.e., full-slip and no-slip), have significant influences on the seismic mitigation effect, except for the Poisson’s ratio of the isolation layer. The proposed solution can be used as an effective tool for the design optimization of tunnel structures with an isolation layer.

ACS Style

Haitao Yu; Qi Wang. Analytical solution for deep circular tunnels covered by an isolation coating layer subjected to far-field shear stresses. Tunnelling and Underground Space Technology 2021, 115, 104026 .

AMA Style

Haitao Yu, Qi Wang. Analytical solution for deep circular tunnels covered by an isolation coating layer subjected to far-field shear stresses. Tunnelling and Underground Space Technology. 2021; 115 ():104026.

Chicago/Turabian Style

Haitao Yu; Qi Wang. 2021. "Analytical solution for deep circular tunnels covered by an isolation coating layer subjected to far-field shear stresses." Tunnelling and Underground Space Technology 115, no. : 104026.

Journal article
Published: 10 June 2021 in Computer Methods in Applied Mechanics and Engineering
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The paper aims to develop a unified variational framework to bridge the gap between the non-ordinary state-based peridynamics (NOSB-PD) and the classical continuum mechanics (CCM). First, a new force state vector is proposed by introducing the first Piola–Kirchhoff stress. This new force state vector enables the stress divergence of each material point to be expressed by averaging all the force state vectors in its support domain. The new force state vector also ensures the mathematical consistency between the strong form of PD and CCM when the horizon of a material point approaches to zero. Second, the displacement and traction boundaries in CCM are transformed into the non-local fictious boundary layers in PD, and a non-local Gauss’s formulation is presented by transforming the displacement and traction boundaries in CCM into the non-local fictious boundary layers in PD, and this formulation unifies the variational framework and boundary conditions of PD and CCM. Third, a fully implicit algorithm is developed to obtain the general nonlinear problems such as fracture and large deformation of solid materials. Further, a penalty method is employed to eliminate the zero-energy mode oscillation inherently observed in NOSB-PD, and the penalty force and penalty stiffness matrix are derived for the proposed implicit algorithm and numerical implementation. Numerical results demonstrate that the proposed method is accurate and can well capture the fracture and large deformation of solid materials. Results also indicate that the method can effectively prevent the zero-mode oscillations inherently observed in the original NOSB-PD, and thus ensures the computational stability.

ACS Style

Haitao Yu; Yuqi Sun. Bridging the gap between local and nonlocal numerical methods—A unified variational framework for non-ordinary state-based peridynamics. Computer Methods in Applied Mechanics and Engineering 2021, 384, 113962 .

AMA Style

Haitao Yu, Yuqi Sun. Bridging the gap between local and nonlocal numerical methods—A unified variational framework for non-ordinary state-based peridynamics. Computer Methods in Applied Mechanics and Engineering. 2021; 384 ():113962.

Chicago/Turabian Style

Haitao Yu; Yuqi Sun. 2021. "Bridging the gap between local and nonlocal numerical methods—A unified variational framework for non-ordinary state-based peridynamics." Computer Methods in Applied Mechanics and Engineering 384, no. : 113962.

Journal article
Published: 14 May 2021 in Computer Methods in Applied Mechanics and Engineering
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A viscoelastic micropolar peridynamic (VMPD) model is proposed to describe the nonlinear deformation and fracture behaviors of quasi-brittle materials considering loading-rate effects. The governing equations of bonds connecting material points are reformulated by introducing the definition of bond deformation rates. Two peridynamic parameters, corresponding to the normal stiffness and the tangential stiffness of the bond, respectively, are introduced to ensure that the strain energy obtained from the proposed peridynamic model is consistent to that from the continuum viscoelastic mechanics. A novel failure criterion is developed to describe the dynamic progressive fracture of quasi-brittle materials. Damage functions and dynamic strengths of the bond are introduced to capture loading-rate effects for solid materials. The proposed model is verified by comparing its predictions with those from experimental observations. Numerical examples demonstrate that the nonlinear viscoelastic behaviors of quasi-brittle materials such as relaxation, softening–hardening behaviors as well as mix-mode fractures under dynamic loads with different loading rates are well captured by the proposed model.

ACS Style

Haitao Yu; Xizhuo Chen. A viscoelastic micropolar peridynamic model for quasi-brittle materials incorporating loading-rate effects. Computer Methods in Applied Mechanics and Engineering 2021, 383, 113897 .

AMA Style

Haitao Yu, Xizhuo Chen. A viscoelastic micropolar peridynamic model for quasi-brittle materials incorporating loading-rate effects. Computer Methods in Applied Mechanics and Engineering. 2021; 383 ():113897.

Chicago/Turabian Style

Haitao Yu; Xizhuo Chen. 2021. "A viscoelastic micropolar peridynamic model for quasi-brittle materials incorporating loading-rate effects." Computer Methods in Applied Mechanics and Engineering 383, no. : 113897.

Journal article
Published: 22 January 2021 in Tunnelling and Underground Space Technology
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Current knowledge on seismic analysis of underground structures is limited to analytical solutions, numerical methods and scaled model tests. Virtual hybrid simulation (VHS) is an efficient and economical analysis method that combines numerical approaches and experiment methods while taking the advantages of both. In this study, a VHS method employing a multi-axial experimental setup for seismic analysis of soil-structure systems is proposed and the corresponding VHS framework was developed using OpenFresco and OpenSees. To demonstrate the ability of the VHS method in accurately and efficiently capturing seismic behavior of underground structures, the proposed VHS method was applied to evaluate seismic response of the Daikai subway station, during which a good agreement was achieved when comparing the VHS results with those of the complete numerical simulation (CNS). Moreover, the advantages of the expanded multi-axial experimental setup in the proposed VHS method over the simplified single-DOF experimental setup are evaluated and discussed.

ACS Style

Haitao Yu; Yanxi Li; Xiaoyun Shao; Xuesong Cai. Virtual hybrid simulation method for underground structures subjected to seismic loadings. Tunnelling and Underground Space Technology 2021, 110, 103831 .

AMA Style

Haitao Yu, Yanxi Li, Xiaoyun Shao, Xuesong Cai. Virtual hybrid simulation method for underground structures subjected to seismic loadings. Tunnelling and Underground Space Technology. 2021; 110 ():103831.

Chicago/Turabian Style

Haitao Yu; Yanxi Li; Xiaoyun Shao; Xuesong Cai. 2021. "Virtual hybrid simulation method for underground structures subjected to seismic loadings." Tunnelling and Underground Space Technology 110, no. : 103831.

Conference paper
Published: 12 November 2020 in IOP Conference Series: Earth and Environmental Science
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A transition tunnel is generally built to connect a TBM tunnel and a mining tunnel, given the different cross sections associated with each construction method. The transition tunnel may be sensitive to earthquake damage since the tunnel cross-section and stiffness change along the tunnel axis. Studying the seismic performance of the transition tunnel structure, a subtle 3D finite element model is carried out. Comparing with the calculation results of SHAKE91, a reasonable non-reflective boundary condition is used. The concrete adopts an elastoplastic damage constitutive model, and the surrounding rock mass uses an elastoplastic constitutive model based on the Drucker-Prager yield criterion. The effects of different ground motion magnitudes and different types of seismic waves are calculated and analyzed through dynamic time-history method. The calculation results show that the impact range of the construction method butted composite lining section on the tunnel structure of the mine tunnel and the TBM tunnel is about 10m, and the reinforcement of the inner lining will cause a sudden change in the stress of the outside TBM tunnel structure. Moreover, the compressive stress of the surrounding rock and tunnel structure is small, and the structural damage mainly occurs in the area of the arch shoulder and arch foot.

ACS Style

Song Yang; Ruozhou Li; Pengyuan Li; Chao Wang; Fei Yu; Yong Yuan; Haitao Yu. Seismic analysis of a transition tunnel constructed with TBM and mining method. IOP Conference Series: Earth and Environmental Science 2020, 570, 042031 .

AMA Style

Song Yang, Ruozhou Li, Pengyuan Li, Chao Wang, Fei Yu, Yong Yuan, Haitao Yu. Seismic analysis of a transition tunnel constructed with TBM and mining method. IOP Conference Series: Earth and Environmental Science. 2020; 570 (4):042031.

Chicago/Turabian Style

Song Yang; Ruozhou Li; Pengyuan Li; Chao Wang; Fei Yu; Yong Yuan; Haitao Yu. 2020. "Seismic analysis of a transition tunnel constructed with TBM and mining method." IOP Conference Series: Earth and Environmental Science 570, no. 4: 042031.

Review
Published: 12 November 2020 in IOP Conference Series: Earth and Environmental Science
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Several earthquakes have challenged the traditional view that the seismic performance of tunnels is excellent. The seismic damage of these tunnels has led scholars and engineers to study the seismic response of tunnels and underground facilities. Many earthquake damage investigations of mountain tunnels reveal that fault or fracture zone is one of the most critical factors leading to tunnel damage. In this paper, the mechanisms of seismic damages and the main factors that influencing the seismic response of fault-crossing tunnels have been explained. Based on two different aseismic philosophies, different aseismic measures of fault-crossing tunnels including buffer layer, fiber concrete, flexible joint, grouting and enlarging tunnel across have been review, and the advantages and disadvantages of different aseismic measures as well as their application scope have been assessed. The ideal aseismic design of fault-crossing tunnels is as follows: verify the fault activity, accurately estimate the possible displacement and the earthquake intensity of the fault area, and then combine the advantages of different aseismic measures, set up composite aseismic measures at the place where the tunnel crosses the fault zone. It is believed that the present study will help in a better understanding of the seismic response of fault-crossing tunnels and have some guidance of aseismic design of fault-crossing tunnels in engineering practice.

ACS Style

L F Zhang; R H Li; H Liu; Z B Fang; H B Wang; Yuan Y; H T Yu. A Review on Seismic Response and Aseismic Measures of Fault-crossing Tunnels. IOP Conference Series: Earth and Environmental Science 2020, 570, 052046 .

AMA Style

L F Zhang, R H Li, H Liu, Z B Fang, H B Wang, Yuan Y, H T Yu. A Review on Seismic Response and Aseismic Measures of Fault-crossing Tunnels. IOP Conference Series: Earth and Environmental Science. 2020; 570 (5):052046.

Chicago/Turabian Style

L F Zhang; R H Li; H Liu; Z B Fang; H B Wang; Yuan Y; H T Yu. 2020. "A Review on Seismic Response and Aseismic Measures of Fault-crossing Tunnels." IOP Conference Series: Earth and Environmental Science 570, no. 5: 052046.

Journal article
Published: 31 October 2020 in Soil Dynamics and Earthquake Engineering
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Dynamic responses of a long tunnel in a horizontally layered viscoelastic ground subjected to inclined SH waves are analyzed by Fourier transform in this paper. The tunnel is assumed to be a beam. The free field displacement of the horizontally layered viscoelastic ground is imposed on the long tunnel through the viscoelastic foundation model. The analytical solution is verified through comparison with numerical solutions and other solutions in the literature. Based on the solution, the difference between rigid bases and elastic bases is clarified, and the influence of pressure-dependent effect is discussed. Parametric analyses on the incident angle and the flexibility ratio are also performed. The solution can be easily used in the preliminary seismic analysis and design of tunnels.

ACS Style

Yusheng Yang; Jinghua Zhang; Yong Yuan; Haitao Yu. Dynamic responses of long tunnels in layered viscoelastic ground subjected to inclined SH waves. Soil Dynamics and Earthquake Engineering 2020, 141, 106469 .

AMA Style

Yusheng Yang, Jinghua Zhang, Yong Yuan, Haitao Yu. Dynamic responses of long tunnels in layered viscoelastic ground subjected to inclined SH waves. Soil Dynamics and Earthquake Engineering. 2020; 141 ():106469.

Chicago/Turabian Style

Yusheng Yang; Jinghua Zhang; Yong Yuan; Haitao Yu. 2020. "Dynamic responses of long tunnels in layered viscoelastic ground subjected to inclined SH waves." Soil Dynamics and Earthquake Engineering 141, no. : 106469.

Journal article
Published: 08 September 2020 in Computer Methods in Applied Mechanics and Engineering
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A generalized bond-based micropolar peridynamic model is proposed to simulate the nonlinear deformation and mixed-mode crack propagation of quasi-brittle materials under arbitrary dynamic loads. The mechanical behaviors of the material points are reformulated by incorporating the bond tension–rotation–shear coupling effects, which makes the model suitable for complex discontinuous problems in both three-dimensional spatial and two-dimensional plane conditions. The governing equations of the bond are established by employing the Timoshenko beam theory to simulate the interaction between material points as well as the bond coupling effect. Three kinds of peridynamic parameters, corresponding to the compressive, shear and bending stiffness of the bond, are introduced to keep the consistence of the strain energy obtained from the proposed peridynamic model and from the continuum mechanics under arbitrary deformation fields. Moreover, a novel energy-based failure criterion, involving the maximum stretch, shear strain and rotation angle limits of the bond, is proposed to describe the nonlinear behaviors and progressive failure for general quasi-brittle materials. The proposed model is verified by providing comparisons between its results and those from known analytical solutions and experimental observations. The influences of the bond tension–rotation–shear coupling effect as well as the applicability of the proposed model for the wave propagation, complex deformation and mix-mode fracture problems are also investigated. Results show that the proposed model with the bond coupling effect will greatly improve the simulation accuracy for dynamic problems of quasi-brittle materials under complex loading conditions. Results also indicate that the proposed model can well capture the nonlinear deformation, crack propagation, as well as progressive failure of materials with variable Poisson’s ratios under complex combined loads

ACS Style

Haitao Yu; Xizhuo Chen; Yuqi Sun. A generalized bond-based peridynamic model for quasi-brittle materials enriched with bond tension–rotation–shear coupling effects. Computer Methods in Applied Mechanics and Engineering 2020, 372, 113405 .

AMA Style

Haitao Yu, Xizhuo Chen, Yuqi Sun. A generalized bond-based peridynamic model for quasi-brittle materials enriched with bond tension–rotation–shear coupling effects. Computer Methods in Applied Mechanics and Engineering. 2020; 372 ():113405.

Chicago/Turabian Style

Haitao Yu; Xizhuo Chen; Yuqi Sun. 2020. "A generalized bond-based peridynamic model for quasi-brittle materials enriched with bond tension–rotation–shear coupling effects." Computer Methods in Applied Mechanics and Engineering 372, no. : 113405.

Journal article
Published: 01 August 2020 in Journal of Engineering Mechanics
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In this paper, the dynamic response of underground rectangular fluid tank resting on an elastic foundation and subjected to arbitrary dynamic loads is developed in the form of analytical solution. The dynamic responses investigated are deflection, bending moment, and shear force of the tank. The underground rectangular tank is assumed to be a frame composed of horizontal and vertical beams resting on an elastic foundation. The mechanical resistance of elastic foundation is modeled using spring elements that account for soil resistance due to compressive strains in the soil. The fluid in the tank is assumed as inviscid and irrotational, and the influence of free-surface wave is ignored. An analytical solution of free vibration modes of empty tank (dry modes) is derived at first, and then the free vibration modes of fluid tank infilled with water (wet modes) can be obtained by the dry modes. Based on the wet modes, the explicit formulations of dynamic responses of the tank are finally obtained by the modal superposition method. The solutions for several cases, such as empty tank and fully filled fluid tank subjected to harmonic loads, are also discussed. Further parametric analysis is carried out to investigate the influence of the soil–structure relative stiffness ratio on dynamic responses of the fully filled fluid tank.

ACS Style

Haitao Yu; Yuqi Sun; Pan Li; Mi Zhao. Analytical Solution for Dynamic Response of Underground Rectangular Fluid Tank Subjected to Arbitrary Dynamic Loads. Journal of Engineering Mechanics 2020, 146, 04020077 .

AMA Style

Haitao Yu, Yuqi Sun, Pan Li, Mi Zhao. Analytical Solution for Dynamic Response of Underground Rectangular Fluid Tank Subjected to Arbitrary Dynamic Loads. Journal of Engineering Mechanics. 2020; 146 (8):04020077.

Chicago/Turabian Style

Haitao Yu; Yuqi Sun; Pan Li; Mi Zhao. 2020. "Analytical Solution for Dynamic Response of Underground Rectangular Fluid Tank Subjected to Arbitrary Dynamic Loads." Journal of Engineering Mechanics 146, no. 8: 04020077.

Original research
Published: 22 July 2020 in Bulletin of Earthquake Engineering
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A 1 g shaking table test of a shallow segmental mini-tunnel in sand is performed to investigate its dynamic responses. The properties of sand, the materials and design of the segmental tunnel, the construction process of testing models and the instrumentation scheme are introduced in full detail. Two levels of intensity and three typical central frequencies of idealized Ricker wavelets, making six cases of excitations, are applied to both the free-field model and the soil-tunnel model. Two white noise cases before and after the design-level cases are also performed to verify the dynamic characteristics of the models. Comprehensive results, including the acceleration responses of the two models, deformations at radial joints and in the diametral directions of the tunnel, bolt tensions between segments as well as strains of segments, are presented. The minutiae of the test are clarified to reduce uncertainties, and experimental results are carefully verified. It could be a benchmark test of segmental tunnels in dry sand ground by means of 1 g shaking table.

ACS Style

Yong Yuan; Yusheng Yang; Shaohua Zhang; Haitao Yu; Jun Sun. A benchmark 1 g shaking table test of shallow segmental mini-tunnel in sand. Bulletin of Earthquake Engineering 2020, 18, 5383 -5412.

AMA Style

Yong Yuan, Yusheng Yang, Shaohua Zhang, Haitao Yu, Jun Sun. A benchmark 1 g shaking table test of shallow segmental mini-tunnel in sand. Bulletin of Earthquake Engineering. 2020; 18 (11):5383-5412.

Chicago/Turabian Style

Yong Yuan; Yusheng Yang; Shaohua Zhang; Haitao Yu; Jun Sun. 2020. "A benchmark 1 g shaking table test of shallow segmental mini-tunnel in sand." Bulletin of Earthquake Engineering 18, no. 11: 5383-5412.

Research article
Published: 02 March 2020 in International Journal for Numerical and Analytical Methods in Geomechanics
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The longitudinal seismic response of a long tunnel subjected to Rayleigh waves is investigated in this paper. The tunnel is assumed to be infinitely long, has a uniform cross section, and rests on a viscoelastic foundation. The free‐field deformation under Rayleigh waves traveling parallel to the tunnel axis is decomposed into two directions, namely, the axial motion and the vertical motion, and transformed into dynamic loads imposed on the tunnel. Based on the Fourier and Laplace integral transform techniques, the governing equations of tunnels are simplified into algebraic equations, and the analytical solutions are obtained with the convolution theorem. The final solutions of the tunnel responses in terms of deflection, velocity, acceleration, axial force, bending moment, and shear force are investigated. The proposed solution is verified by comparison of its results and those from the finite element program ABAQUS. Further parametric analysis is carried out to investigate the influence of soil‐structure relative stiffness ratio and wave frequency on dynamic longitudinal responses of the tunnel.

ACS Style

Yusheng Yang; Haitao Yu; Yong Yuan; Mi Zhao. Analytical solution for longitudinal seismic response of long tunnels subjected to Rayleigh waves. International Journal for Numerical and Analytical Methods in Geomechanics 2020, 44, 1371 -1385.

AMA Style

Yusheng Yang, Haitao Yu, Yong Yuan, Mi Zhao. Analytical solution for longitudinal seismic response of long tunnels subjected to Rayleigh waves. International Journal for Numerical and Analytical Methods in Geomechanics. 2020; 44 (10):1371-1385.

Chicago/Turabian Style

Yusheng Yang; Haitao Yu; Yong Yuan; Mi Zhao. 2020. "Analytical solution for longitudinal seismic response of long tunnels subjected to Rayleigh waves." International Journal for Numerical and Analytical Methods in Geomechanics 44, no. 10: 1371-1385.

Journal article
Published: 01 February 2020 in Soil Dynamics and Earthquake Engineering
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Shaking table tests are conducted to study the discrepant responses of shaft-tunnel junction. The cases with transverse excitations are introduced in a previous paper, while the current paper mainly addresses the responses under longitudinal excitations. A brief introduction is provided on the design of the tests. Data of accelerations, dynamic strains, and circumferential-joint extensions are presented in four cases. Two white-noise cases are conducted to evaluate dynamic characters of the model system as well as examine repeatability of the test results. Two synthetic-earthquake-motion cases are conducted to study the seismic responses of the shaft-tunnel junction under natural earthquakes of different intensities. As revealed by the acceleration data, the shaft and the tunnel have exhibited quite different dynamic characters under longitudinal excitations. The extent of shaft-tunnel discrepancy is statistically quantified by correlational method. Although transverse strains of the tunnel are slightly elevated at the shaft-tunnel junction, absolute values of the strains remain in a lower range which is below 65 με. However, the discrepant responses have caused tensile deformations of the tunnel, which eventually lead to significant circumferential-joint extensions near the shaft. A simplified analytical model is proposed to establish the relationship between the discrepant responses and the longitudinal deformations of the tunnel. At the end, testing data from the transverse-excitation and the longitudinal-excitation cases are compared. In both cases, the shaft-tunnel relative displacement and the soil-tunnel relative stiffness are considered as the two key factors.

ACS Style

Jinghua Zhang; Yong Yuan; Zhen Bao; Haitao Yu; Emilio Bilotta. Shaking table tests on shaft-tunnel junction under longitudinal excitations. Soil Dynamics and Earthquake Engineering 2020, 132, 106055 .

AMA Style

Jinghua Zhang, Yong Yuan, Zhen Bao, Haitao Yu, Emilio Bilotta. Shaking table tests on shaft-tunnel junction under longitudinal excitations. Soil Dynamics and Earthquake Engineering. 2020; 132 ():106055.

Chicago/Turabian Style

Jinghua Zhang; Yong Yuan; Zhen Bao; Haitao Yu; Emilio Bilotta. 2020. "Shaking table tests on shaft-tunnel junction under longitudinal excitations." Soil Dynamics and Earthquake Engineering 132, no. : 106055.

Journal article
Published: 21 January 2020 in Soil Dynamics and Earthquake Engineering
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Analytical solutions are deduced for seismic responses of shaft-tunnel junction under longitudinal excitations. The influence of the tunnel is incorporated by introducing terms of shaft-tunnel and soil-tunnel interactions into equations originally developed for rigid caissons. The shaft is simplified into a rigid body. The tunnel is represented by a continuous beam perpendicularly fixed onto the shaft. Firstly, solutions for displacements of the shaft are given. Then, solutions for the three major internal forces of the tunnel are proposed. Validity of the proposed solutions is examined by finite element method in respect of the shaft and the tunnel separately. The comparisons confirm that the proposed solutions could successfully predict the displacements of the shaft and the three major internal forces of the tunnel at the vicinity of the shaft-tunnel junction. However, they become less accurate with increasing distance to the shaft. Interactions among the shaft, the tunnel, and the soil are discussed based on the proposed solutions. A special emphasis is placed on the mutual influences between the shaft and the tunnel. Displacements of the shaft, especially the rotational displacements, are likely to decrease under longitudinal excitations when connected to tunnels. Shaft-soil relative displacement and soil-tunnel relative stiffness are the two key factors affecting the seismic responses of the tunnel. The former determines the amplitudes of the internal forces, while the latter governs how the internal forces distribute along the tunnel axis. A conceptual aseismic measure is studied by setting a pin joint at the shaft-tunnel junction. Theoretically, it could eliminate the influence imposed on the tunnel by the rotational displacement of the shaft.

ACS Style

Jinghua Zhang; Yong Yuan; Emilio Bilotta; Haitao Yu. Analytical solutions for seismic responses of shaft-tunnel junction under longitudinal excitations. Soil Dynamics and Earthquake Engineering 2020, 131, 106033 .

AMA Style

Jinghua Zhang, Yong Yuan, Emilio Bilotta, Haitao Yu. Analytical solutions for seismic responses of shaft-tunnel junction under longitudinal excitations. Soil Dynamics and Earthquake Engineering. 2020; 131 ():106033.

Chicago/Turabian Style

Jinghua Zhang; Yong Yuan; Emilio Bilotta; Haitao Yu. 2020. "Analytical solutions for seismic responses of shaft-tunnel junction under longitudinal excitations." Soil Dynamics and Earthquake Engineering 131, no. : 106033.

Journal article
Published: 29 November 2019 in Applied Sciences
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This paper presents experimental assessment of the effect of the ratio of vertical to horizontal peak ground acceleration (RVH) on underground metro station. An atrium-style metro station embedded in artificial soil subjected to earthquake loading is examined through shaking table tests. The experimental results for three different RVH, including soil acceleration, soil-structure acceleration difference, dynamic soil normal stress (DSNS), and structural dynamic strain, are presented and the results are compared with the case of horizontal-only excitation. It is found that for an atrium-style metro station, the differences in horizontal acceleration amplitude between the structure and the adjacent soil rise with increasing RVH, which are different at different depths. The most significant differences occur at the depth of the ceiling slab. It is also observed that both the amplitude and distribution of peak DSNS have obvious differences between the left and right side walls at all levels. It is therefore concluded that the RVH has a significant influence on dynamic soil-structure interaction. It is believed that under extreme earthquake loading, such as near fault zones, RVH is a parameter of paramount importance and should be accounted for in the seismic analyses and seismic performance assessments of underground structures, especially for those with zero or near-zero buried depth, such as atrium-style metro stations.

ACS Style

Zhiming Zhang; Emilio Bilotta; Yong Yuan; Haitao Yu; Huiling Zhao. Experimental Assessment of the Effect of Vertical Earthquake Motion on Underground Metro Station. Applied Sciences 2019, 9, 5182 .

AMA Style

Zhiming Zhang, Emilio Bilotta, Yong Yuan, Haitao Yu, Huiling Zhao. Experimental Assessment of the Effect of Vertical Earthquake Motion on Underground Metro Station. Applied Sciences. 2019; 9 (23):5182.

Chicago/Turabian Style

Zhiming Zhang; Emilio Bilotta; Yong Yuan; Haitao Yu; Huiling Zhao. 2019. "Experimental Assessment of the Effect of Vertical Earthquake Motion on Underground Metro Station." Applied Sciences 9, no. 23: 5182.

Journal article
Published: 23 November 2019 in Applied Sciences
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The vertical shear behaviors of an immersion joint with steel shear keys subjected to multidirectional loads are investigated in this paper. An experiment of an immersion joint model is carried out. Two kinds of compression–shear tests of the joint are considered in this experiment. The first kind of compression–shear test applies a specific vertical shear load and five different levels of longitudinal compressive loads on the joint. An additional compression–vertical shear destruction test is also conducted under the minimum longitudinal compressive load, wherein the vertical shear load is incrementally increased until failure of the joint. The other kind of compression–shear test is a bidirectional shear test, in which both the longitudinal compressive load and the transverse shear load are fixed, and the vertical shear load is gradually increased until reaching a target value. The results show that the shear force–displacement curves of the joint in any loading case can be divided into two stages: a non-linear development stage and a quasi-linear development stage. The vertical shear stiffness of the joint is found to increase with increasing longitudinal compressive load, and the existence of a transverse shear load enhances this effect. The ultimate shear capacity of the joint is smaller than the sum of the shear capacities of all vertical steel keys. In addition, the failure of the joint appears at the shear key on one sidewall of the joint.

ACS Style

Yong Yuan; Jianhui Luo; Haitao Yu. Experimental Study on Vertical Shear Behaviors of an Immersion Joint with Steel Shear Keys. Applied Sciences 2019, 9, 5056 .

AMA Style

Yong Yuan, Jianhui Luo, Haitao Yu. Experimental Study on Vertical Shear Behaviors of an Immersion Joint with Steel Shear Keys. Applied Sciences. 2019; 9 (23):5056.

Chicago/Turabian Style

Yong Yuan; Jianhui Luo; Haitao Yu. 2019. "Experimental Study on Vertical Shear Behaviors of an Immersion Joint with Steel Shear Keys." Applied Sciences 9, no. 23: 5056.

Journal article
Published: 21 November 2019 in Tunnelling and Underground Space Technology
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A transition tunnel is generally built to connect a TBM tunnel and a drill-and-blast tunnel, given the different cross sections associated with each construction method. The transition tunnel may be sensitive to earthquake damage due to the fact that the tunnel cross-section and stiffness change along the tunnel axis. To study the seismic performance of the transition tunnel structure, a series of shaking table tests are carried out. The transition tunnel model is divided into four regions to consider the change of cross-section. Key technical details of the test setup are presented, with a focus on: layout of the model, cross-sections and stiffness of the four regions, model materials, modeling procedure and sensors’ layout. Based on test results, the acceleration response of the tunnel liner and the dynamic pressure between surrounding rock and tunnel liner are discussed. In addition, the peak acceleration, Arias Intensity, and Fourier spectrum are presented for each of the four tunnel regions, to discuss the influence of the change of the cross-sections and stiffness on the seismic response of the tunnel regions.

ACS Style

Juntao Chen; Haitao Yu; Antonio Bobet; Yong Yuan. Shaking table tests of transition tunnel connecting TBM and drill-and-blast tunnels. Tunnelling and Underground Space Technology 2019, 96, 103197 .

AMA Style

Juntao Chen, Haitao Yu, Antonio Bobet, Yong Yuan. Shaking table tests of transition tunnel connecting TBM and drill-and-blast tunnels. Tunnelling and Underground Space Technology. 2019; 96 ():103197.

Chicago/Turabian Style

Juntao Chen; Haitao Yu; Antonio Bobet; Yong Yuan. 2019. "Shaking table tests of transition tunnel connecting TBM and drill-and-blast tunnels." Tunnelling and Underground Space Technology 96, no. : 103197.

Journal article
Published: 24 August 2019 in Soil Dynamics and Earthquake Engineering
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This paper proposes an analytical solution for dynamic responses of the vertical shaft in a shaft-tunnel junction under transverse loads. The assumption is that the shaft could be regarded as a rigid body under certain circumstances. Based on that premise, equations originally developed for rigid caissons are incorporated with terms of shaft-tunnel and soil-tunnel interactions. Two specific dynamic scenarios are considered. The first one is when the shaft is subject to transverse dynamic loads above the ground surface. The second one is when the shaft-tunnel junction is under transverse seismic excitations. Validity of the proposed solution is examined in both scenarios by finite element method. Then, the proposed solution is used to evaluate influence of the tunnel. In the first scenario, the tunnel has a major influence on dynamic responses of the shaft. Displacements of the shaft are likely to be reduced because the tunnel adds to the stiffness matrix. Yet, in the second scenario, influence of the tunnel is minor enough to be neglected. Seismic responses of the shaft are approximately the same with or without the tunnel.

ACS Style

Jinghua Zhang; Yong Yuan; Emilio Bilotta; Bu Zhang; Haitao Yu. Analytical solution for dynamic responses of the vertical shaft in a shaft-tunnel junction under transverse loads. Soil Dynamics and Earthquake Engineering 2019, 126, 105779 .

AMA Style

Jinghua Zhang, Yong Yuan, Emilio Bilotta, Bu Zhang, Haitao Yu. Analytical solution for dynamic responses of the vertical shaft in a shaft-tunnel junction under transverse loads. Soil Dynamics and Earthquake Engineering. 2019; 126 ():105779.

Chicago/Turabian Style

Jinghua Zhang; Yong Yuan; Emilio Bilotta; Bu Zhang; Haitao Yu. 2019. "Analytical solution for dynamic responses of the vertical shaft in a shaft-tunnel junction under transverse loads." Soil Dynamics and Earthquake Engineering 126, no. : 105779.

Journal article
Published: 05 July 2019 in Soil Dynamics and Earthquake Engineering
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The stiffness distribution of an atrium subway station with zero buried depth spatially varies when columns in the first level underground are removed and lateral beams replace the middle part of the floor slabs. It is pertinent to the mechanism and effects of multidirectional ground shaking on such structures. In this paper, the response characteristics of an atrium subway station subjected to bidirectional ground motions in a shaking table test were presented. Under horizontal seismic shaking, the structure, without a soil cover, showed a non-negligible rocking mode coupled with the well-known racking of the structure. Under vertical seismic shaking, the lateral beams, without supporting columns, demonstrated an obvious bending vibration associated with an overall up and downward movement. Overall, the horizontal component contributed more to dynamic response of the structure than the vertical component.

ACS Style

Huiling Zhao; Yong Yuan; Zhiming Ye; Haitao Yu; Zhiming Zhang. Response characteristics of an atrium subway station subjected to bidirectional ground shaking. Soil Dynamics and Earthquake Engineering 2019, 125, 105737 .

AMA Style

Huiling Zhao, Yong Yuan, Zhiming Ye, Haitao Yu, Zhiming Zhang. Response characteristics of an atrium subway station subjected to bidirectional ground shaking. Soil Dynamics and Earthquake Engineering. 2019; 125 ():105737.

Chicago/Turabian Style

Huiling Zhao; Yong Yuan; Zhiming Ye; Haitao Yu; Zhiming Zhang. 2019. "Response characteristics of an atrium subway station subjected to bidirectional ground shaking." Soil Dynamics and Earthquake Engineering 125, no. : 105737.