An analysis method for the influence of tunneling on adjacent loaded pile groups with rigid elevated caps

Abstract

SUMMARYTunnel excavation could influence the working performance of adjacent pile foundations. How to accurately predict the tunneling-induced pile responses is becoming an important issue in urban areas. Previous methods tend to neglect the influence of working loads on the tunneling-induced pile responses. In this paper, a two-stage analysis method is proposed to study the behavior of pile groups with rigid elevated caps subjected to tunneling-induced ground movements, in which the pile-pile interaction, coupling of longitudinal and lateral deformation, and influence of working loads are considered. This method is validated by comparing the results with those from a general pile analysis program, GEPAN, centrifuge test data and field measured data. Thereafter, a series of parametric studies is carried out. The results show that the influence of working load on tunneling-induced pile responses is significant. Three different features of the pile responses will take place for different depth ratios. With the increase in soil stiffness, the tunneling-induced axial force increases linearly, whereas the bending moment increases nonlinearly. For soils with high stiffness, the maximum bending moment increases linearly with the ground loss ratio within the range of 0-5%; but for soils with low stiffness, this tendency becomes obviously nonlinear.

Open-face tunnelling effects on non-displacement piles in clay – part 2: tunnelling beneath loaded piles and analytical modelling

“…Analytical works have generally taken the form of the two-step approach method (TSAM) (Chen et al, 1999), in which the assumed 'greenfield' settlements are used as input to either a boundary-element analysis or t-z load-transfer analysis. More recent analyses, such as those reported by Kitiyodom et al (2005), Huang et al (2009), Zhang et al (2011), Zhang et al (2013) and Basile (2014), have focused on pile groups and how to best model interaction factors between adjacent piles for linear elastic and non-linear elastic load-transfer curves. Such methods have proved to be reasonably successful for the back-analysis of centrifuge and field data associated with tunnelling adjacent to piles (using centrifuge and field data reported by Loganathan et al (2000) and Pang et al (2005), respectively).…”

Analytical Method for Evaluation of Coupled Responses of a Multidirectionally Loaded Pile-Raft Foundation Induced by Tunnelling in Layered Soils

“…The analytical method proposed by [22] is widely recognized as one of the most important solutions for the problem [23,27,28]. And the empirical method proposed by [27] based on the analytical method [22] is proved to be the most useful method employed in practice [11,13,14,20]. Thus, the closed form of the empirical solution of free-field soil deformation induced by tunnelling is employed in this study for its easy application in layered soils:…”

“…However, according to some experimental studies [19], the influence of the working load is not negligible. Reference [20] presented a method to calculate the response of loaded pile groups induced by tunnelling that considered the influence of working loads; however raft-soil interaction, pile-soil surface interaction, and the coupled effect of vertical and horizontal responses were not considered in their method, where only the vertical working load was considered. However, pile-raft foundations are always subjected to horizontal loads, either a moment or load combined with a vertical load.…”

Multiple Criteria Selection of Pile-Column Construction Technology

“…The model is based on ARAS method and AHP technique. Zhang et al (2011a) proposed a two-stage analysis method to study the behaviour of pile groups with rigid elevated caps. A single pile foundation utilizes a single, generally a large-diameter structural element to support all of the loads (weight, wind, etc.)…”