Dynamic Stress Concentration Around Shallow-Buried Circle Cavity Under Transient P Wave Loads in Different Conditions

Author(s):  
Ming Tao ◽  
Linqi Huang ◽  
Xibing Li ◽  
Shaofeng Wang

<p>Based on the large-arc assumption, an analytical model is established and solved by using the complex variable function method to illustrate the dynamic stress concentration around a shallow-buried cavity under transient loads. The jump points in the dynamic stress concentration factor (DSCF) curve that do not in line with the overall trend is filtered out to obtain more reasonable results. The convergence speed of the Graf addition formula is examined, as well as the effects of the incidence angle, frequency, and burial depth on the DSCF around the cavity. Examples show that a larger arc radius and a higher incident frequency correspond to slower convergence of the Graf addition formula. There are differences between the DSCF distributions of high-frequency incidents (such as blasting waves) and low-frequency incidents (such as seismic waves). There are three tensile-stress zones and three compressive-stress zones approximately equally spaced around the cavity in the low-frequency case, and there are two tensile-stress zones and two compressive-stress zones in the high-frequency case. Regarding the variation of the DSCFs with respect to the cavity depth, incidence angle and position of wave peak there are significant differences between the high- and low-frequency cases.</p>

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.


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.


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