Effect of Tunneling on Adjacent Piled Foundation in Clay

C F, Leung,C W Ong,K Y Yong

doi:10.32732/jcec.2019.8.1.19

Abstract

Soil movements arising from tunnel excavation may induce severe stresses on adjacent piled foundations. This paper investigates the behavior of piles due to nearby tunneling in soft clay using centrifuge modeling technique. Centrifuge modeling has an advantage that the consolidation time of the clay under forced gravity field can be expedited significantly to study the long term performance of a pile due to tunneling. The types of piles investigated in the present study include floating pile, socketed pile and end bearing piles with different pile head conditions. The test results on the induced axial and lateral pile responses due to tunneling are presented in this paper and the implications of the findings to engineering practice are highlighted.

Highlights

Tunnel excavations are often carried out for subway construction and utilities in many urban cities worldwide
Centrifuge modeling technique is employed as the prototype stresses can be correctly simulated and the consolidation of the clay can be expedited under a forced gravitational field to study the long term behavior of the pile due to tunneling
The results reveal that the magnitude of induced moment on a pile can be large if there is adjacent tunnel excavation

Summary

Introduction

Tunnel excavations are often carried out for subway construction and utilities in many urban cities worldwide. In such very close proximity, tunneling may induce severe stresses on the piles due to soil movements arising from the tunnel excavation. Centrifuge modeling technique is employed as the prototype stresses can be correctly simulated and the consolidation of the clay can be expedited under a forced gravitational field to study the long term behavior of the pile due to tunneling. Long term refers to the state that all the pile and soil movements have stabilized. The practical implications of the findings will be discussed

Centrifuge model setup and procedure

Test configuration

Lateral pile behavior

Axial pile behavior

Conclusions