关键词: 砂土, 隧道开挖, 桩-土-隧道相互作用, 桩基础

Abstract: Based on traditional empirical equations for calculating vertical displacements of sands during tunneling in sands, effect of tunneling on nearby pile foundation in respect of axial force in sands is investigated. According to ground and subsurface settlement troughs induced by tunneling in sand, a simplified calculating method for evaluating effect of tunneling in sands on axial force of nearby piles is firstly proposed by considering nonlinear pile-soil interaction. Meanwhile, the two-step method was adopted and the nearby piles were taken as vertical passive piles. The results calculated using the simplified method is then compared with experimental results obtained from geotechnical centrifuge tests, which validate the rationality of the proposed method. In addition, many influence factors, including tunnel cover, tunnel diameter, distance between tunnel and pile, tunnel volume loss, pile length and pile diameter are also investigated during the study. It has been found that the axial force of pile decreases with the increase of tunnel cover thickness, while increasing with the increase of tunnel diameter and soil volume loss ratio. The axial force reaches to the maximum value when the distance between tunnel and pile is approximately 2.5 times of the tunnel diameter. The axial force of pile increases with the increase of pile length and pile diameter.

Key words: sand, tunneling, pile-soil-tunnel interaction, pile foundation