scholarly journals Analysis on the Seismic Performance of Shock Absorption Layer Applied in Tunnel Lining Structure Using Shaking Table Model Tests

2021 ◽  
Author(s):  
Y. M. Wen ◽  
C. L. Xin ◽  
Z. H. Yin ◽  
Z. M. Huang ◽  
X. M. Li ◽  
...  
Keyword(s):  
Surrounding Rock ◽  
Tunnel Lining ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Vibration Frequencies ◽  
Shock Absorption ◽  
Absorption Layer ◽  
Acceleration Amplitude ◽  
Lining Structure ◽  
Table Model

Abstract Shock absorption layer is a relatively simple and effective aseismic measure, which can bear the adverse effects of surrounding rock deformations and buffer the forces acting on lining structure with seismic action. This paper conducts a series of shaking table model tests to analyze and compare the aseismic performances of tunnel lining structure with and without shock absorption layer in different grades of surrounding rocks, in which the superior thickness of shock absorption layer is determined. Therein, it is concluded that the shock absorption layer has prominent influence on reducing the acceleration responses of surrounding rock and lining structure with seismic excitation. The setting of the shock absorption layer can reduce the acceleration amplitude of tunnel lining with seismic excitation by about half. Furthermore, the setting of 1 cm shock absorption layer will increase the Fourier amplitudes and change the vibration frequencies of surrounding rock and lining structure with seismic excitation, while the setting of 2 cm shock absorption layer can significantly decrease the Fourier amplitudes and keep the vibration frequencies of surrounding rock and lining structure with seismic excitation. Therefore, the aseismic effect of 2 cm shock absorption layer is better than the aseismic effect of 1 cm shock absorption layer, which can both reduce the acceleration amplitude and Fourier amplitude of tunnel lining with seismic excitation while keep its characteristics in frequency domain. This research on the aseismic performance of shock absorption layer can contribute to the construction of tunnel engineering and improve the safety of tunnel lining structure.

Reliability Analysis of Hydraulic Tunnel Lining Structure with Stochastic Finite Elements Method

2010 ◽  
Vol 163-167 ◽  
pp. 3267-3273
Author(s):  
Dong Hai Liu ◽  
Jiang Zheng ◽  
Zi Long Li
Keyword(s):  
Finite Elements ◽  
Failure Probability ◽  
Surrounding Rock ◽  
Tunnel Lining ◽  
Finite Elements Method ◽  
Geological Conditions ◽  
Lining Structure ◽  
Stochastic Finite Elements ◽  
Construction Condition ◽  
Physical And Mechanical Characteristics

Many uncertain factors, e.g. surrounding rock physical and mechanical characteristics, are important influence effecting on lining structure safety. By comprehensively considering uncertainties of surrounding rock conditions (lining structure and initial stress), we put forward a new method used to quantitative analysis on the lining structure safety. Analyzing the uncertainties and their distribution characteristics of hydraulic tunnels, we adopted stochastic finite elements method to calculate failure probability of lining structures corresponding to various geological conditions, and then the reliability and sensitivity were achieved. Applying the presented method to a practical project, we got the failure probability of the tunnel lining structure under the construction condition, which provided great support for structure optimal design and tunnel construction safety protection.

scholarly journals Influence of Loose Contact between Tunnel Lining and Surrounding Rock on the Safety of the Tunnel Structure

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1733
Author(s):  
Zijian Ye ◽  
Chengping Zhang
Keyword(s):  
Contact Area ◽  
Three Dimensional ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Tunnel Lining ◽  
Point Of View ◽  
Railway Tunnel ◽  
Contact State ◽  
Lining Structure ◽  
The Stability

The improvement of the contact state between the surrounding rock and tunnel lining, such as the effect of back-fill grouting behind lining, was important for maintaining the stability of the lining structure. To explore the influence of loose contact states behind lining on the safety of tunnel lining, a case of field investigation in a railway tunnel with a symmetrical lining structure was presented in this paper. A model test was conducted to prove the accuracy of the numerical simulation in the condition of dense contact state between the lining and surrounding rocks. Based on this, the three-dimensional (3-D) impact of loose contact states on the mechanic behavior of the lining structure under different compactness and different loose contact areas behind lining was investigated and summarized. Furthermore, the influence of the percentage of the insufficient strength behind lining was explored. Finally, the grade of the influence of the loose contact state on the safety of the lining structure was classified. The results revealed that: (1) in order to maintain the stability of lining structure, the compactness of the back-fill grouting behind lining was recommended to be above 80%, and the range of the loose contact area should be no more than 60 degree; (2) the strength of the back-fill grouting behind lining should be above 50% strength of the surrounding rock, the loose contact state behind lining should be improved in time to avoid expansion of the loose contact area; and (3) the classification of the influence grade on the safety of the lining structure provides a basic reference for controlling the quality of the back-fill grouting. This research gives a new point of view for the evaluation of the contact state between lining and surrounding rock.

Experiment and Simulation Study on Vibration Control of an Ancient Pagoda with Damping Devices

2018 ◽  
Vol 18 (10) ◽  
pp. 1850120 ◽  
Author(s):  
Tao Li ◽  
Sheliang Wang ◽  
Tao Yang
Keyword(s):  
Shaking Table Test ◽  
Shaking Table ◽  
Damping Force ◽  
Shock Absorption ◽  
Restoring Force ◽  
Equivalent Damping ◽  
Acceleration Amplitude ◽  
Displacement Angle ◽  
Wild Goose ◽  
Better Than

In order to choose an effective method for improving the seismic performance of an ancient pagoda called the Small Wild Goose Pagoda, 12 damping devices of varying properties are developed. They are made of shape memory alloy-suspension pendulum damping systems (SMA-SPDSs) based on the restoring force of the SMA wires. By means of the shaking table test, the frequency, equivalent damping and equivalent damping force of the SMA-SPDS are analyzed first to acquire their respective trend of influence. Then, four shock absorption plans (one without SMA-SPDS) are analyzed numerically, and the frequency, displacement and acceleration amplitude, inter-story displacement angle and inter-story shear force calculated are compared with those of the experiment. The results show that the shock absorption rate of Plan 3 is better than all the others, and the simulation results are in agreement with the corresponding experimental results, which also prove that the simulation presented in this paper is feasible, which can be used to verify the rationality and applicability of the device (SMA-SPDS). Therefore, it provides a theoretical means for conducting the strengthening and repairing work of the pagoda concerned.

Shaking Table Model Test of Loess Tunnel Structure under Rainfall

2021 ◽  
Author(s):  
Xinhai Zhou ◽  
Xuansheng Cheng ◽  
Lei Qi ◽  
Ping Wang ◽  
Shaofeng Chai ◽  
...  
Keyword(s):  
Model Test ◽  
Shaking Table ◽  
Tunnel Structure ◽  
Table Model ◽  
Shaking Table Model Test

Structural Analysis of an Offshore Jacket Model Under Seismic Excitation

2008 ◽  
Author(s):  
Helder J. D. Correia ◽  
Anto´nio C. Mendes ◽  
Carlos A. F. S. Oliveira
Keyword(s):  
Point Of View ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Model Structure ◽  
Structural Members ◽  
Jacket Structures ◽  
Reaction Forces ◽  
Nodal Displacements ◽  
Good Agreement

In the present work the action of earthquakes upon offshore jacket structures is analysed by means of ADINA software. Our case-study refers to an existing model structure, previously constructed at the Laboratory of Fluid Mechanics of UBI, which has been analysed from the hydrodynamic point of view — Mendes et al. [1, 2]. The seismic excitation will be imposed at the base of this model structure, with frequencies and amplitudes corresponding to actual earthquake conditions transposed to the model scale of 1:45. The FEM software is utilised to calculate the natural frequencies of the model and to obtain stresses at selected members, as well as their nodal displacements. Our purpose is to quantify maximum stresses occurring in critical structural members and to verify the survivability criterion. The predictions of the numerical model, in terms of the reaction forces at the base and acceleration at the top of the structure, are then correlated with the experimental measurements performed when the model structure is excited in an especially designed shaking table (Correia [3]), revealing a good agreement between both results.

Experimental Study on Non-Perpendicular Frame Structure of Tall Building

2008 ◽  
Vol 400-402 ◽  
pp. 593-598
Author(s):  
Wei Xing Shi ◽  
Cheng Qing Liu ◽  
Xi Lin Lu ◽  
Song Zhang ◽  
Ying Zhou
Keyword(s):  
Similarity Theory ◽  
Structural Type ◽  
Shaking Table ◽  
Frame Structure ◽  
Scale Model ◽  
Prototype Structure ◽  
Table Model ◽  
Practical Engineering ◽  
Whiplash Effect ◽  
Shaking Table Model Test

A shaking table model test is conducted for Guangzhou West Tower to study its seismic behavior in State Key Laboratory for Disaster Reduction in Civil Engineering at Tongji University. Guangzhou West Tower adopts a new structure system and the significant characteristic of this system is the non-perpendicular frame arranged around the building, acting both as columns and bracings. Based on the similarity theory and member equivalent principle，a 1/80 scale model of this building is made of polymethyl methacrylate(PMMA). The model’s dynamic characteristics, earthquake-resistant behavior, responses of acceleration and deformation under different wave peak values are investigated, then the seismic responses of the prototype structure are deduced and analyzed. The whiplash effect of the prototype structure is studied, and the weak position of the structure is found out. The experiment results demonstrate that it is feasible to apply this structural type to practical engineering. Finally, some suggestions for the engineering design of the prototype structure are put forward.

Seismic Response of Pile Groups Improved with Deep Cement mixing Columns in Liquefiable Sand: Shaking Table Tests

2021 ◽  
Author(s):  
Dingwen Zhang ◽  
Anhui Wang ◽  
Xuanming Ding
Keyword(s):  
Seismic Behavior ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Pile Group ◽  
Shaking Table ◽  
Excess Pore Pressure ◽  
Shaking Table Tests ◽  
Pile Groups ◽  
Acceleration Response ◽  
Table Model

A series of shaking table model tests were performed to examine the effects of deep cement mixing (DCM) columns with different reinforcement depths on the seismic behavior of a pile group in liquefiable sand. Due to the DCM column reinforcement, the fundamental natural frequency of the model ground increases noticeably. The excess pore pressure of soils reduces with the increase of reinforcement depths of the DCM columns. Before liquefaction, the acceleration response of soils in the improved cases is obviously lower than that in the unimproved case, but the acceleration attenuation is greater after liquefaction in the unimproved case. Moreover, the lateral displacement of the superstructure, the settlement of the raft, and the bending moment of the piles in the improved cases are significantly reduced compared to those in the unimproved case, and the reduction ratios rise with the increase of reinforcement depth of the DCM columns. However, reinforcement by the DCM columns may result in the variation of the location of the maximum moment that occurs in the pile.

The Slabbing Mechanics Analysis of the Tunnel Lining

2011 ◽  
Vol 243-249 ◽  
pp. 3530-3537
Author(s):  
Zu Song Wu ◽  
Guang Qi Chen ◽  
Kou Ki Zen ◽  
Xin Rong Liu
Keyword(s):  
Surrounding Rock ◽  
Tunnel Lining ◽  
The Self ◽  
Road Tunnel ◽  
The Road ◽  
Mechanics Analysis ◽  
The Stability

When the road tunnel is excavated, the multi lining is used to being applied. In order to keep the surrounding rock stabilize and arouse the self-stability of the surrounding rock, building the first support is essential. But the slabbing often occurs near the spring line on the surface of the first lining, and because the slabbling is a common failing and not attracted our most attentions, it will develop to the crack and threaten the stability of the structure finally. This paper uses the line elastic method to analyze the mechanics that causes this slabbing phenomenon via the interaction between the surrounding rock and the first lining, and suggests the measure that escape the slabbing.

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