مقاله انگلیسی رایگان در مورد راه حل ساده برای تعامل تونل-خاک-شمع در مدل پی پاسترناک – الزویر 2018

The rapidly increasing demand for public transport construction in congested urban areas will promote tunnel excavation adjacent to existing buildings and services due to the lack of surface space. Adverse effects on nearby pile foundations may be appeared due to changes in ground stress and, hence, building movements. Accurate predicting of effects of tunnelling on pile foundations poses a major challenge during civil engineering design and construction. Increasing attention has been paid to evaluating the effects of shield tunnelling on adjacent piles. The methods used for analyzing this problem may be broadly classified into three categories: numerical analyses, simplified analytical methods and laboratory tests. A variety of research has been conducted on this subject based on the numerical approaches (Surjadinata et al., 2006; Jongpradist et al., 2013; Hong et al., 2015; Fu et al., 2016). The most common method is finite element (FE) method and the simulation results are obtained with the condition on the tunnel, pile and soil as a whole. Several researchers investigated the effects of tunnelling on the bearing capacity and deflection of the piles by the centrifuge model tests (Loganathan et al., 2000; Jacobsz et al., 2004; Lee and Chiang, 2007; Marshall and Mair, 2011; Ng and Lu, 2013; Ng et al., 2013, 2014; Franza and Marshall, 2018). In addition, some researchers performed experimental tests in laboratory to study the effects of tunnelling on pile foundations (Lee and Bassett, 2007; Meguid and Mattar, 2009; Bel et al., 2016). Researchers have been studying different analytical approaches to predict the pile responses during tunnel excavation (Chen et al., 1999; Huang et al., 2009; Mu et al., 2012; Xiang and Feng, 2013; Basile, 2014; Marshall, 2012; Marshall and Haji, 2015; Franza et al., 2017). In order to obtain a better mechanical understanding of the effects of tunnelling on adjacent piles and provide a rapid predication of the response characteristics of existing structures, a simplified two-stage approach is presented in their study. The simplified method to analyze such a problem is carried out in two steps: first, the estimation of green-field ground movements induced by tunnelling, which would occur if the existing piles were not present; second, the calculation of the response of the existing piles to green-field ground movements. Recent studies (Huang et al., 2009; Mu et al., 2012) have investigated the effects of tunnelling on existing piles and evaluated the complex pile-soil interaction, which usually relies on Winkler’s foundation model. According to Winkler’s foundation model, the soil is modelled as a series of closely spaced, mutually independent, linear elastic lateral springs, which provide resistance in direct proportion to the deflection of the pile.