Steel Buildings' Seismic and Interaction Behavior, Under Different Shapes of Tunnel Drilling

Introduction

Due to population growth in cities and urgent needs to transport facilities, there are some decades that constructing tunnels has been considered as a key strategy in reducing the volume of traffic and making the transportation as easy as possible. In this regard, extensive studies have been done by different researchers on the effects of tunneling, tunnels stability and major interactions of tunnel constructions. Major research studies were about predicting the movements of the earth around the tunnels and have been completed by experimental methods or by analytical and numerical strategies. Peck did a field study on the number of circular tunnels drilled in different soil profiles and indicated that the ground level subsidence has a Gaussian curve (Peck, 1969). Similarly, other studies have been done on the basis of empirical and analytical methods. Analytical methods which are based on the elasticity theories, predicted surface subsidence profiles, using the balanced equations. (Other available empirical studies about basis of Peck relations have been done by many researchers, which mostly all of obtained results were the same as original relation but with small changes of used parameters, these studies could be found in following references (Atkinson & Potts, 1977; Atewell & Farmer, 1974; Clough & Schmidt, 1981; Leach, 1985; Mair et al., 1982; Oteo & Sagaseta, 1996). One of the important factors for seismic division of different zones is acceleration of earth's surface; thus, underground structures affects are very important in the surface acceleration. The Effects of underground structures on seismic responses of structures above the ground is under investigation and the conclusion is that the underground structures have direct effects on above structures seismic responses (Yiouta-Mitra et al., 2007). Several ways have been investigated to describe the effects of underground cavity structures on the above structures which are under surface waves and volume waves, but the investigated methods are based on some simple assumptions (Dravinski, 1983; Lee, 1988; Mow & Pao, 1971; Smerzini et al., 2009; Wong et al., 1985). Sun and Wang studied the acceleration of the ground in the with-tunnel case and non-tunnel case and stated that there will be a change in the velocity of the earth's surface in presence of a tunnel (Sun & Wang, 2012).