Lateral response of single piles in cemented sand and weak rock

Fengju Guo

    Research output: ThesisDoctoral Thesis

    1589 Downloads (Pure)

    Abstract

    Competent deposits of cemented sands distribute extensively along the coastline areas of Western Australia and many other coastline areas worldwide. These soils do not conveniently fall into any specific soil types of sand or clay and there are not yet generally accepted procedures for the design and analysis of piled foundations where lateral loads are comprised predominantly in these soils. In-situ cone penetration test (CPT) provides continuous profile data of the soils in question. Utilizing the cone data for design parameters for the lateral piled foundations has increasingly attracted interests.

    This thesis investigates the lateral response of single piles in cemented sand and weak rock. The geotechnical behavior of the soils across a wide range from very weakly-cemented sands to well-cemented sands has been studied through a series of laboratory testing programs and in-situ testing programs. Full-scale lateral load experiments were performed with fully instrumented drilled and grout piles in a weak calcareous sandstone deposit at Pinjar, North West Perth in Western Australia. Centrifuge-scale load tests were also carried out on model piles preinstalled in very weakly-cemented sands artificially prepared with varying cement contents.

    The results of the field test were used to develop the load transfer P-y relationships as well as the limiting transverse pressures Pu on piles for the well-cemented soils. The results of centrifuge model test in conjunction with finite element modelling were used to develop the lateral pressure-displacement P-y relationships and the limiting transverse pressures Pu for the very weakly-cemented soils. The field and centrifuge tests were modelled well using a hyperbolic P-y relationship and the obtained ultimate lateral resistance. Existing methods to estimate Pu and the formulations of P-y curves were also evaluated and conclusive comments made to the comparisons.

    The thesis then explores the potential of using CPT qc data directly for the design and analysis of laterally loaded piles. A simple CPT-based bi-linear p-y approximation for the lateral response is proposed. This formulation is shown to provide good predictions for lateral pile response in a variety of cemented deposits.
    Original languageEnglish
    QualificationDoctor of Philosophy
    Supervisors/Advisors
    • Hu, Yuxia, Supervisor
    • Fourie, Andy, Supervisor
    • Lehane, Barry, Supervisor
    Publication statusUnpublished - 2015

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