Bored piles in tropical soils and rocks: shaft and base resistances, t–z and q–w models

Abstract

Analyses of load tests on 100 instrumented bored piles in different weathering grades of different tropical geological formations of peninsular Malaysia enabled correlations of ultimate shaft and base resistance with standard penetration test (SPT) results and unconfined compression strengths. The data also enabled development of shaft resistance (t–z) and base resistance (q–w) models that are related to SPT, unconfined compressive strength and rock types. The t–z models can be used for strain softening and strain hardening while the q–w models are for strain hardening and stiffening behaviour. The models thus developed were applied for analysis of 35 piles in the database that were loaded until the load–settlement curves were significantly non-linear. Most of the analyses resulted in a reasonable match with the measured load–settlement and load-transfer curves up to 1.5 times the pile working load, regardless of whether the q–w function was strain hardening or stiffening. Accurate matching with measured load–settlement and load-transfer curves for 1.5–3 times working load was conditional on the correct choice of the q–w function. The models were further tested against 27 published load test results from across the world.

Innovations in Micropile Testing Using Distributed Optical Fibre Sensors

“…43.5 kN/m at three times WL. Further analysis can be correlated from DOFS data for shaft and base resistances [20].…”

Editorial

“…The work aims in part to determine ultimate shaft and base resistance parameters. Ong et al (2021) found that shaft resistance parameter reduces with increasing SPT N value (see Figure 2).…”

“…Torrez-Cruz (2019) presented correlations linking void ratio to the slope and vertical location of the steady-state line in 'e-log(p′) space'. This themed issue contains nine papers (Barnes, 2021; Thaimo and Ekolu, 2021; Ahmed and Agaiby, 2021a; Ahmed and Agaiby , 2021b;Wong, 2021;Shivaprakash and Sridharan, 2021;Lin et al, 2021;Ong et al, 2021;Rout and Singh, 2021) which we now outline.…”

“…The authors reported that the back-calculated β value is generally larger than the conventional design method (see Lin et al, 2021). Ong et al (2021) presents data from 100 instrumented test piles. The dataset contains piles installed across a range of geological formations and weathering profiles.…”

The DINGO database of axial pile load tests for the UK: settlement prediction in fine-grained soils

“…The significance of such online tools has been recognised by various investigators from different countries who have compiled databases with pile data. These include databases from North America (Paikowsky et al 2004), Western Europe (Galbraith, Farrell, andByrne 2014), North Africa (AbdelSalam, Baligh, andEl-Naggar 2015) and South-East Asia (Ong et al 2021). Global databases have also been recently compiled for tests in sands by a Chinese-UK-Australian consortium (Yang et al 2015(Yang et al , 2016 and the Deep Foundation Institute and UC-Irvine (Find A Pile.com, Lemnitzer and Favaretti 2013) for lateral-load tests.…”