Application of artificial intelligence techniques for rolling dynamic compaction

Rolling dynamic compaction (RDC), involving non-circular modules towed behind a tractor, is now widespread and accepted among many other soil compaction methods. However, to date, there is no accurate method to reliably predict the increase in soil strength after the application of a given number of passes of RDC. This paper presents the application of artificial intelligence (AI) techniques in the form of artificial neural networks (ANNs) and genetic programming (GP) for a priori prediction of the density improvement by means of RDC in a range of ground conditions. These AI-based models are developed by using in situ soil test data, specifically cone penetration test (CPT) and dynamic cone penetration (DCP) test data obtained from several ground improvement projects that employed the 4- sided, 8-tonne ‘impact roller’. The predictions of ANN- and GP-based models are compared with the corresponding actual values and they show strong correlations (r > 0.8). Additionally, the robustness of the optimal models is investigated in a parametric study and it is observed that the model predictions are in a good agreement with the expected behaviour of RDC.R. A. T. M. Ranasinghe and M. B. Jaks

Liquefaction Assessment Using the CPT and Accounting for Soil Ageing

Due to its continuous data recording capability, excellent repeatability and accuracy, relatively low cost and simplicity of operation, the cone penetration test (CPT) offers enhanced liquefaction assessment over its predecessor the standard penetration test (SPT). However, soil ageing, which influences the cyclic resistance ratio (CRR), is difficult, if not impossible, to be detected by the CPT due to disturbance during the test. This situation may lead to excessively conservative estimation of CRR values which result in conservative assessment of liquefaction potential. This paper presents and discusses liquefaction assessment using the CPT and methods for accounting for soil ageing. A field study, conducted at Gillman, South Australia, is presented and the study site is assessed for liquefaction potential. This paper also explores the influence of soil ageing on the subsequent liquefaction assessment

Assessment of the luck associated with settlement predictions that are based on elastic theory

This paper deals with quantifying the uncertainty associated with settlement predictions that are based on elastic theory. Because of spatial soil variability, deterministic solutions cannot provide information about the likely error of the prediction. Accordingly, it is only through luck that a particular deterministic prediction coincides with the observed settlement.William S. Kaggwa, Mei T. Cheong, and Mark B. Jaks

Recent advances and future challenges for artificial neural systems in geotechnical engineering applications

Published as Open Access article.Artificial neural networks (ANNs) are a form of artificial intelligence that has proved to provide a high level of competency in solving many complex engineering problems that are beyond the computational capability of classical mathematics and traditional procedures. In particular, ANNs have been applied successfully to almost all aspects of geotechnical engineering problems. Despite the increasing number and diversity of ANN applications in geotechnical engineering, the contents of reported applications indicate that the progress in ANN development and procedures is marginal and not moving forward since the mid-1990s. This paper presents a brief overview of ANN applications in geotechnical engineering, briefly provides an overview of the operation of ANN modeling, investigates the current research directions of ANNs in geotechnical engineering, and discusses some ANN modeling issues that need further attention in the future, including model robustness; transparency and knowledge extraction; extrapolation; uncertainty.Mohamed A. Shahin, Mark B. Jaksa and Holger R. Maie

Quality assessment of local and franchise beef and chicken burgers

Six brands of local beef and chicken burgers, three brands of franchise beef and two brands of franchise chicken burgers were evaluated for proximate composition, myoglobin and meat content, colour (L, a, b values) and microbiology composition i.e. Total Plate Count (CFU/gm), Coliform and Escherichia coli Counts (MPN/gm), Staphylococus aureus Count (CFU/gm) and presence of Salmonella sp. All franchise beef burgers had higher protein and moisture contents (except burger C) and lower carbohydrate content than the local brands. No significant differences (p > 0.05) in fat, ash and crude fibre contents were observed between local brands and franchise beef burgers. Most local brands of chicken burgers had lower levels of protein and moisture and higher levels of fat, fibre and carbohydrate than the franchises. No significant differences (p > 0.05) in ash content was observed between the local brands and franchise chicken burgers. All beef burgers had low myoglobin and meat contents «65%) with the exception of AI, FI and GI burgers. Chicken burgers, EI, FI and franchise burger B had higher meat content (>65%) than the others. All beef and chicken burgers had higher 'L' values which ranged between 45.13 % to 53.68% and 62.75 % to 72.48% respectively except FI which was darker. Local brands of beef burgers had a higher 'a' value compared to the franchises and all chicken burgers had a low 'a" value except FI which was redder. Low Total Plate Count, Coliform and E. coli counts were detected in all burger samples. S. aureus counts in most local brands of beefand chicken burger samples were higher than the franchises which ranged from 2 to 11 CFU/gm sample and 6 to 22 CFU/gm sample respectively. Salmonella sp was not present in all burger samples

CPT sounding and the scale of variability of Auckland residual soil

The cone penetration test (CPT) provides a huge amount of data in comparison with other in situ test procedures - complete sets of readings every 10 mm or so of penetration. Some years ago a site in Albany was investigated with 30 closely spaced CPT soundings to a depth of 10 m. The intention of this paper is to take the analysis of the data gathered further in order to understand better the scale of the variability of the properties of the residual soil common around the Auckland region. We have data at two scales: vertical and horizontal. In the vertical direction, there are one thousand readings over the 10 m depth of each sounding. In the horizontal direction, there are 30 CPT soundings within a square of 8 m side, the closest being at 1 m spacing. We will present our explorations of the properties in terms of an autocorrelation function and by determining the average distance between zero crossings of the de-trended qc data.M. J. Pender, M. B. Jaksa and Andrew Hollan

Passive arching in rubberized sand backfills

The deformation and stress profiles of passive arching in a coarse sand and two rubberized sand backfills were investigated using a trapdoor apparatus. The trapdoor apparatus was instrumented with high-speed imaging equipment and a series of pressure sensors. The images of the deformation process in the backfills were analysed using the digital image correlation technique. The effect of a local surcharge on the deformation and stress profiles was also examined. It was observed that the rubber inclusions helped reduce the deformation of the backfills. Passive arching moduli and stress variations between the backfills examined are compared.Hamidreza Khatami, An Deng, and Mark Jaks

Three-dimensional modeling of geocell-reinforced straight and curved ballast embankments

Available online 15 June 2018This paper outlines a three-dimensional modeling study conducted on straight and curved geocell-reinforced embankments. The study uses the discrete element method to represent varying angularities of ballast infill and models their mechanical response under monotonic and cyclic loading conditions. The simulation results show good agreement with test results and the case studies indicate that the geocell enhances embankment stiffness under monotonic loading and improves its resilience when subjected to cyclic loading. The geocell more evenly distributes stresses within the ballast embankments. The reinforced ballast embankments also exhibit less vertical displacement and lateral spreading than the unreinforced ballast embankments do.Yang Liu, An Deng, Mark Jaks

Three-dimensional discrete-element modeling of geocell-reinforced ballast considering breakage

This paper presents a three-dimensional discrete-element method (DEM) study examining the settlement and breakage behavior of geocell-reinforced ballast. The reinforced ballast chamber reproduced the geocell in configuration and the ballast particles in shape and breakage characteristics. The reinforced ballast chamber was subjected to monotonic and cyclic loads. Parametric studies were conducted on the geocell embedment depth and ballast shape. For each case, ballast settlement, geocell responses, and ballast breakage behavior were evaluated. This study demonstrates that the geocell can effectively reduce settlement and ballast breakage. The geocell stiffens its embedded layer and reduces stress propagation into the underlying layer.Yang Liu, An Deng, and Mark Jaks

Passive noise datasets at regolith sites

The data presented in this article contain datasets of passive noise measurements at regolith sites in Adelaide, South Australia. The data were acquired using three component (3C) LE-3Dlite Lennartz seismometers with an eigenfrequency of 1 Hz. The data were acquired at eight sites across Adelaide׳s regolith in a hexagonal array layout. Four tests, each with a duration of 30 min, were conducted at different times. The ambient noise data can be used for both horizontal to vertical spectral ratio (HVSR) analysis and array analyses, which are essential to obtain the site fundamental frequency and the ellipticity of the fundamental mode Rayleigh waves at the measured site. The array analyses are useful to obtain the dispersion curves, which are needed to estimate the shear wave velocity profile.Bambang Setiawan, Mark Jaksa, Michael Griffith, David Lov