Impact of highly weathered geology on pipejacking forces
Journal Title: Geotechnical Research - Year 2017, Vol 4, Issue 2
Abstract
For the Kuching Wastewater Management System Phase 1 project in Kuching, Malaysia, 7·7 km of trunk sewer lines were constructed in the highly fractured, highly weathered Tuang Formation using a pipe-jacking method. The pipelines were founded at depths of up to 35m below Kuching City, where the majority of the pipe-jacking activities would traverse the Tuang Formation. Jacking forces in highly fractured geology are not well understood as most jacking force models were derived for drives traversing soils. Therefore, a novel method was developed, whereby equivalent rock strength characteristics were interpreted from direct shear testing on reconstituted tunnelling rock spoils. Tangential peak strength parameters, c0t,p and e0t,p, were developed from the nonlinear behaviour of the reconstituted spoils and applied to a wellestablished jacking model to assess arching and development of jacking forces from four documented drives. The backanalysed parameters lavg and rEV were used to demonstrate that geology had significantly affected the development of jacking forces. The back-analysis of the studied drives was successfully validated through finite-element modelling. This research shows that the developed parameters c't,p and et0,p and the back-analysed parameters uavg and EV can be reliably used to predict jacking forces in highly fractured, highly weathered geology.
Authors and Affiliations
Dominic Ong
Keywords
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- EP ID EP292348
- DOI 10.1680/jgere.16.00022
- Views 55
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