City Research Online

Abstract

Tunnelling in densely populated urban areas often induces ground displacements that may affect nearby structures, especially when excavations occur in saturated sandy soils where control of volume loss can be challenging. This paper presents a detailed case study of the response of a 1940s printing workshop, comprising two buildings of single and three-storeys, to tunnel construction by an Earth-Pressure-Balance (EPB) Tunnel Boring Machine (TBM). A comprehensive mon-itoring programme included precise levelling for vertical displacements of the ground surface and building and total station measurements to capture horizontal displacements of the building. The shallower westbound tunnel induced maxi-mum ground surface settlements of 78.8 mm near the building (volume loss ≈ 1.93%), with trough width parameters Ky ranging from 0.31 to 0.37. The build-ing exhibited flexible behaviour overall: its settlements closely followed the greenfield Gaussian settlement trough. Horizontal displacements of the façade towards the tunnel reached 2 to 5 mm in the transverse direction. Pre-existing wall cracks widened noticeably, and new cracks formed in the three-storey block, consistent with hogging deformation beyond the inflection point of the settlement trough. Soil-structure interaction is discussed: the relatively low stiffness of the one-storey building arising from its long-span steel frame, and pre-existing cracks played a key role in its response. Suggestions are made regarding monitor-ing requirements to help detect tunnelling-induced building deformation mecha-nisms.

Publication Type:	Conference or Workshop Item (Paper)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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