The performance of mechanical characteristics and failure mode for tunnel concrete lining structure in water-rich layer

Abstract The results based on 2-year long measurements 01 Jan. 2016–2031 Dec. 2017 have been used for discussing the influence of tunnel lining on the size of 222Rn activity concentration and the impact of the employed rock mass insulation on natural convective air exchange. In April, air movement started when the temperature was at least 7 °C lower than the mean inside. Between May and October, an increase to 9 °C above the underground temperature resulted in an increase of radon concentration. An unconstrained convection process did not start until November and it continued until the end of March. The reinforced concrete lining insulated the fractured and absorptive rock mass. The roof and the sidewall lining had little impact on air movement process.

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Intelligent Classification Method for Tunnel Lining Cracks Based on PFC-BP Neural Network

Mathematical Problems in Engineering ◽

10.1155/2020/8838216 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Hao Ding ◽

Xinghong Jiang ◽

Ke Li ◽

Hongyan Guo ◽

Wenfeng Li

Keyword(s):

Neural Network ◽

Bp Neural Network ◽

Structural Parameters ◽

Crack Depth ◽

Tunnel Lining ◽

Parameter Analysis ◽

Training Data ◽

Concrete Lining ◽

Common Disease ◽

Lining Structure

Tunnel lining crack is the most common disease and also the manifestation of other diseases, which widely exists in plain concrete lining structure. Proper evaluation and classification of engineering conditions directly relate to operation safety. Particle flow code (PFC) calculation software is applied in this study, and the simulation reliability is verified by using the laboratory axial compression test and 1 : 10 model experiment to calibrate the calculation parameters. Parameter analysis is carried out focusing on the load parameters, structural parameters, dimension, and direction which affect the crack diseases. Based on that, an evaluation index system represented by tunnel buried depth (H), crack position (P), crack length (L), crack width (W), crack depth (D), and crack direction (A) is put forward. The training data of the back propagation (BP) neural network which takes load-bearing safety and crack stability as the evaluation criteria are obtained. An expert system is introduced into the BP neural network for correction of prediction results, realizing classified dynamic optimization of complex engineering conditions. The results of this study can be used to judge the safety state of cracked lining structure and provide guidance to the prevention and control of crack diseases, which is significant to ensure the safety of tunnel operation.

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Seismic Response Analysis of Concrete Lining Structure in Large Underground Powerhouse

Mathematical Problems in Engineering ◽

10.1155/2017/4106970 ◽

2017 ◽

Vol 2017 ◽

pp. 1-14 ◽

Cited By ~ 2

Author(s):

Xiaowei Wang ◽

Juntao Chen ◽

Ming Xiao ◽

Danqi Wu

Keyword(s):

Constitutive Model ◽

Seismic Response ◽

Surrounding Rock ◽

Concrete Lining ◽

Response Analysis ◽

Analysis Method ◽

Stability Calculation ◽

Concrete Material ◽

Underground Powerhouse ◽

Lining Structure

Based on the dynamic damage constitutive model of concrete material and seismic rock-lining structure interaction analysis method, the seismic response of lining structure in large underground powerhouse is studied in this paper. In order to describe strain rate dependence and fatigue damage of concrete material under cyclic loading, a dynamic constitutive model for concrete lining considering tension and shear anisotropic damage is presented, and the evolution equations of damage variables are derived. The proposed model is of simple form and can be programmed into finite element procedure easily. In order to describe seismic interaction characteristics of the surrounding rock and lining, an explicit dynamic contact analysis method considering bond and damage characteristics of contact face between the surrounding rock and lining is proposed, and this method can integrate directly without iteration. The proposed method is applied to seismic stability calculation of Yingxiuwan Underground Powerhouse, results reveal that the amplitude and duration of input seismic wave determine the damage degree of lining structure, the damage zone of lining structure is mainly distributed in its arch, and the contact face damage has great influence on the stability of the lining structure.

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Experimental Study of the Mechanical Characteristics of a Rock-Like Material Containing a Preexisting Fissure under Loading and Unloading Triaxial Compression

Advances in Civil Engineering ◽

10.1155/2020/9374352 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Taoli Xiao ◽

Mei Huang ◽

Min Gao

Keyword(s):

Experimental Study ◽

Failure Mode ◽

Mechanical Characteristics ◽

Failure Modes ◽

Shear Failure ◽

Triaxial Compression ◽

Tensile Failure ◽

Underground Engineering ◽

Inclination Angles ◽

Loading And Unloading

An experimental study of a rock-like material containing a preexisting fissure subjected to loading and unloading triaxial compression is carried out, and the results show that the mechanical characteristics of the rock-like specimen depend heavily on the loading paths and the inclination of the fissure. The triaxial loading experiment results show that the failure strength linearly increases, while the residual strength linearly decreases with increasing inclination. Furthermore, specimens subjected to triaxial compression show an “X”-type shear failure mode. The triaxial unloading compression experimental results show that specimens with different inclination angles have various failure modes. Specimens with gentle inclinations show a tensile-shear mix failure mode, specimens with middle inclinations show a shear-sliding failure mode, and specimens with steep inclinations show a tensile failure mode. These findings can be used to forecast excavation-induced instabilities in deep underground engineering rock structures.

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Modelling and Characterizing the Adhesion of Parallel-Grooved Interface between Concrete Lining Structure and Geopolymer by Wedge Splitting Method

Mathematical Problems in Engineering ◽

10.1155/2020/2507062 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15

Author(s):

Zhaopeng Yang ◽

Ya Wei ◽

Linbing Wang

Keyword(s):

Fracture Toughness ◽

Fracture Mode ◽

Splitting Method ◽

Average Energy ◽

Concrete Block ◽

Interface Fracture ◽

Concrete Lining ◽

Crack Mouth ◽

Lining Structure ◽

Wedge Splitting

A new method for increasing the interface resistance between geopolymer coating and concrete lining structure without applying the organic binder was suggested in this study. Parallel grooves with different depths and orientations were milled on the top surface of concrete block, and well-blended geopolymer mixture (Na-PSS type geopolymer: Sodium poly-sialate-siloxo) was coated upon the grooved interface. The wedge splitting (WS) experiments were conducted to compare the interface adhesion capacity of specimens with different groove width/depth ratios and groove orientations. The average energy release rate (ERR) was calculated by integrating the Pv-CMOD diagram to quantify the interfacial fracture toughness. To understand the interface strength mechanisms and the fracture mode at the front crack mouth, franc 3D simulation was carried out to segregate the mixed fracture mode to determine the initial pure stress intensity factors K I , K II , K III at the crack mouth. Both the experiments and simulation results indicated that the highest interface fracture toughness was reached by the double diagonal parallel grooves with 0.375 width/depth ratio. These findings put forward a promising attaching method for efficient and reliable passive fire protection coating, with the aim of decreasing the risk of layer delamination in highway tunnels.

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Experimental Study of Deep Alluvium Boring Shaft Lining Used Super Strength Steel Fiber Concrete and Double Steel Plate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.1101 ◽

2011 ◽

Vol 243-249 ◽

pp. 1101-1110

Author(s):

Xiao Jian Wang ◽

Hua Cheng ◽

Zhi Shu Yao ◽

Hai Bin Cai

Keyword(s):

Mechanical Characteristics ◽

Steel Fiber ◽

Engineering Application ◽

High Strength ◽

Steel Cylinder ◽

Fiber Concrete ◽

Lining Structure ◽

Steel Fiber Concrete ◽

New Type ◽

Shaft Lining

The article proposes boring shaft lining used super strength steel fiber concrete and double steel cylinder to solve the problem of the construction of shaft lining in deep alluvium of 700~800m, and studies the mechanical characteristics and failure of the shaft lining structure based on the model testing. The studies indicates that boring shaft lining structure used super strength steel fiber concrete and double steel cylinder may greatly improve the capacity of the shaft lining, the ductility of common high strength concrete shaft lining, obtains good plastic characteristics and upgrades the reliability of the shaft lining structure. In addition, strengthening coefficient of super strength steel fiber concrete based on theoretical analysis and experimental results, providing the design references for the engineering application of the new type shaft lining structure.

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