Effect of imperfect interfaces on dynamic response of a composite lining tunnel with an isolation layer under plane P and SV waves

The single scattering of P- and SV-waves by a cylindrical fiber with a partially imperfect bonding to the surrounding matrix is investigated, which benefits the characterization of the behavior of elastic waves in composite materials. The imperfect interface is modelled by the spring model. To solve the corresponding single scattering problem, a collocation point (CP) method is introduced. Based on this method, influence of various aspects of the imperfect interface on the scattering of P- and SV-waves is studied. Results indicate that (i) the total scattering cross section (SCS) is almost symmetric about the axis α=π/2 with respect to the location (α) of the imperfect interface, (ii) imperfect interfaces located at α=0 and α=π highly reduce the total SCS under a P-wave incidence and imperfect interfaces located at α=π/2 reduce the total SCS most significantly under SV-incidence, and (iii) under a P-wave incidence the SCS has a high sensitivity to the bonding level of imperfect interfaces when α is small, while it becomes more sensitive to the bonding level when α is larger under SV-wave incidence.

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Field Test for a Base Isolation Structure on Condition of Horizontal and Initial Displacement

Applied Sciences ◽

10.3390/app12010232 ◽

2021 ◽

Vol 12 (1) ◽

pp. 232

Author(s):

Ying-Xiong Wu ◽

Xin-Jun Dong ◽

You-Qin Lin ◽

Hao-De Cheng

Keyword(s):

Dynamic Response ◽

Dynamic Characteristics ◽

Natural Vibration ◽

Base Isolation ◽

Seismic Structure ◽

Control Effect ◽

Initial Displacement ◽

Pump System ◽

Vibration Period ◽

Isolation Layer

There are a few isolated structures that have been subjected to seismic testing. An isolated structure is incapable of tracking, adjusting, and controlling its dynamic characteristics. As a result, field evaluations of solitary structures’ dynamic characteristics are important. The horizontal initial displacement of a base isolation kindergarten made of 46 isolation bearings is 75 mm. The method for creating the horizontal initial displacement condition is illustrated, as are the primary test findings. Horizontal initial displacement is accomplished with the assistance of a reaction wall, rods, and hydraulic pump system. To begin, we removed the building using hydraulic jacks to produce horizontal displacement of the isolation layer and then attached rods to support the building. The rods were then shot and unloaded, causing the building to shake freely, and its dynamic response and other parameters were tested. The results indicate that the natural vibration period of an isolated structure is much greater than the natural vibration period of a seismic structure. The isolation layer’s hysteretic curve as completely filled; upon unloading, the isolation layer as promptly reset; the dynamic response control effect of each was visible, but the top floor’s acceleration was magnified by approximately 1.27 times.

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