Dynamic Stress Concentration of Surrounding Rock of a Circular Tunnel Subjected to Blasting Cylindrical P-Waves

2018 ◽  
Vol 37 (4) ◽  
pp. 2363-2371 ◽  
Author(s):  
Shiwei Lu ◽  
Chuanbo Zhou ◽  
Zhen Zhang ◽  
Nan Jiang
2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Xiaojie Zhou ◽  
Qinghua Liang ◽  
Zhongxian Liu ◽  
Ying He

A viscous-slip interface model is proposed to simulate the contact state between a tunnel lining structure and the surrounding rock. The boundary integral equation method is adopted to solve the scattering of the plane SV wave by a tunnel lining in an elastic half-space. We place special emphasis on the dynamic stress concentration of the lining and the amplification effect on the surface displacement near the tunnel. Scattered waves in the lining and half-space are constructed using the fictitious wave sources close to the lining surfaces based on Green’s functions of cylindrical expansion and the shear wave source. The magnitudes of the fictitious wave sources are determined by viscous-slip boundary conditions, and then the total response is obtained by superposition of the free and scattered fields. The slip stiffness and viscosity coefficients at the lining-surrounding rock interface have a significant influence on the dynamic stress distribution and the nearby surface displacement response in the tunnel lining. Their influence is controlled by the incident wave frequency and angle. The hoop stress increases gradually in the inner wall of the lining as sliding stiffness increases under a low-frequency incident wave. In the high-frequency resonance frequency band, where incident wave frequency is consistent with the natural frequency of the soil column above the tunnel, the dynamic stress concentration effect is more significant when it is smaller. The dynamic stress concentration factor inside the lining decreases gradually as the viscosity coefficient increases. The spatial distribution and the displacement amplitudes of surface displacement near the tunnel change as incident wave frequency and angle increase. The effective dynamic analysis of the underground structure under an actual strong dynamic load should consider the slip effect at the lining-surrounding rock interface.


2011 ◽  
Vol 99-100 ◽  
pp. 181-189 ◽  
Author(s):  
Hua Xu ◽  
Tian Bin Li ◽  
Long Qi Li

Dynamic stress concentration of tunnels and underground engineers under the action of earthquake waves is a fundamental problem. Selecting circular lining tunnel in semi-infinite space under the action of P waves as prototype, based on the assumption of large circular arc, a set of dynamic stress series solution in semi-infinite space and lining is deduced by wave function expansion method. With specific examples, the influences on shallow-buried depth rock tunnels of different factors which include incident frequency, incident angle, buried depth, rock conditions and lining rigidity are studied. The results show that low-frequency P waves are more dangerous to tunnel lining than high-frequency P waves; When P waves is incident from the bottom of the vertical tunnel or small angle (θα = 0° ~ 30°), the damage of tunnel lining is more seriously; Under the hard rock conditions, when the tunnel buried depth reaches more than 100m, the thickness of overlying rock is not a major factor effecting the dynamic stress and earthquake damages of tunnel structure lining; Under the soft surrounding rock condition, the value of dynamic stress concentration coefficient of lining is still up to 6.5 when the buried depth of tunnels is more than 100m, and what’s more the tunnel lining may still be caused seriously earthquake damage; With the increasing of lining stiffness, the dynamic stress concentration of lining is more uneven, and the value span is greater; so under the premise of meeting bearing capacity and deformation of lining, soft lining is recommended to adapt in the tunnel structure to decrease earthquake damage of tunnels.


2011 ◽  
Vol 323 ◽  
pp. 18-22 ◽  
Author(s):  
Yi Guang Zhang ◽  
Chuan Lu Zhou ◽  
Yi Xian Liu

Based on the scattering theory of elastic waves, employing the wave function expansion method, the scattering and the dynamic stresses concentration of SH wave by circular tunnel with lining are investigated. The analytical solution of the problem is derived, and the numerical solution of the dynamic stress concentration factors around the lining is presented. The effects of the shear elasticity of the surrounding rock and the lining, the wave number on the dynamic stress concentration factors are analyzed. Analysis has shown that the shear elasticity of the surrounding rock and the wave number are factors that influence dynamic stress concentration factor, and provide important theoretical foundation for the earthquake evaluation of lining.


1995 ◽  
Vol 111 (1-2) ◽  
pp. 1-12 ◽  
Author(s):  
H. G. Georgiadis ◽  
A. P. Rigatos ◽  
N. C. Charalambakis

Author(s):  
Tianshu Song ◽  
Tamman Merhej ◽  
Qingna Shang ◽  
Dong Li

In the present work, dynamic interaction is investigated theoretically between several circular cavities near the surface in a semi-infinite piezoelectric medium subjected to time-harmonic incident anti-plane shearing. The analyses are based upon the use of complex variable and multi coordinates. Dynamic stress concentration factors at the edges of the subsurface circular cavities are obtained by solving boundary value problems with the method of orthogonal function expansion. Some numerical solutions about two interacting subsurface circular cavities in a semi-infinite piezoelectric medium are plotted so as to show how the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the structural geometries influence on the dynamic stress concentration factors.


1997 ◽  
Vol 63 (616) ◽  
pp. 2532-2537
Author(s):  
Noboru NAKAYAMA ◽  
Masahiko OHASHI ◽  
Hiroyuku TAKEISHI

Author(s):  
Tianshu Song ◽  
Dong Li ◽  
Lili Sun

In this article, dynamic interaction is investigated theoretically between several circular cavities in an infinite piezoelectric medium under time-harmonic incident anti-plane shear wave load. The theoretical formulations are based upon the use of complex variable and multi-coordinates. Dynamic stress concentration factors at the edges of the circular cavities are obtained by solving boundary value problems with the method of orthogonal function expansion. As examples, some calculating results of two interacting circular cavities in an infinite piezoelectric medium are plotted to show how the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the structural geometries influence on the dynamic stress concentration factors.


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