The coronavirus disease 2019 pandemic has posed severe threats to humans and the geoenvironment. The findings of severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) traces in waste water and the practice of disinfecting outdoor spaces in several cities in the world, which can result into the entry of disinfectants and their by-products into storm drainage systems and their subsequent discharge into rivers and coastal waters, raise the issue of environmental, ecological and public health effects. The aims of the current paper are to investigate the potential of water and waste water to operate as transmission routes for Sars-CoV-2 and the risks of this to public health and the geoenvironment. Additionally, several developing countries are characterised by low water-related disaster resilience and low household water security, with measures for protection of water resources and technologies for clean water and sanitation being substandard or not in place. To mitigate the impact of the pandemic in such cases, practical recommendations are provided herein. The paper calls for the enhancement of research into the migration mechanisms of viruses in various media, as well as in the formation of trihalomethanes and other disinfectant by-products in the geoenvironment, in order to develop robust solutions to combat the effects of the current and future pandemics.

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This paper presents a critical review of the grading entropy approach of permeability-coefficient predictions (k P) for coarse-grained soils. The approach applies the grading entropy theory to particle-size distributions (PSDs), such that the entirety of each gradation curve can be interpreted as a single point on a grading entropy chart, plotting its normalised entropy increment (B) against relative base grading entropy (A) values. Published data sets of measured permeability-coefficient (k M) values for saturated compacted silty sand, sand and gravel materials are examined to understand the dependence of A and B on various gradation parameters and the void ratio (e). In particular, log k M negatively correlates with log B and positively correlates with log A and e (log e). As such, power functions of the form

kP=C1AC2BC3eC4 prove statistically superior, noting that the fitting coefficient C 1 to C 4 values are specific to the PSD range and densification (compaction) states investigated for the permeability tests. Recommendations are given for increasing the predictive power, including separate models for well-graded and poorly graded materials and the addition of a particle shape factor and specific surface parameters in the regression correlation.@en

Offshore wind turbines are typically founded on driven steel pipe piles, using either a single large monopile or multiple piles anchoring a tripod or jacket-type structure. Recent design methods for offshore driven piles have been developed based on the results of field tests using instrumented closedended model piles that allowed the measurement of the radial effective stress at a number of locations along the pile shaft. These measured radial stresses were then directly related to in-situ soil properties such as CPT cone resistance. This paper investigates the use of in-situ site investigation techniques, in particular the CPT, for the design of open-ended piles. A recent CPT-based design method, the UCD-11 (Igoe et al. 2011), which is based on field tests using an instrumented open-ended model pile, is applied in the present study to predict the axial tension capacity of two open-ended piles driven into a medium dense sand deposit. The accuracy of this recent method is compared with both traditional earth-pressure and other CPT based methods in order to assess its predictive performance.

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This paper presents the results of a field test performed to study the effects of installation method on the load-displacement response of piles used to support the offshore wind turbines. An instrumented open-ended model pile was installed by jacking in a deposit of medium-dense sand. Pile jacking has environmental benefits over the traditional method of pile driving which can cause noise and vibration damage to the marine mammals. Pile installation by jacking was shown to enhance the pile-soil stiffness response during compression loading. Residual stresses, generated during the installation process, caused the pile to exhibit a relatively soft stiffness response during tension loading. Environmental loading caused by wind and waves which causes piles that support jacket structure to experience tension loading and the serviceability limit state of the foundation to these loads governs the design.

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This paper presents the results from an experimental investigation designed to examine the effect of soil-core development and cyclic loading on the shaft resistance developed by open-ended piles in sand. An instrumented open-ended model pile was installed either by driving or jacking into an artificially-created loose sand deposit in Blessington, Ireland. The tests provided continuous measurements of the soil-core development and the radial effective stresses during installation and subsequent load tests. The equalized radial effective stresses developed at the pile-soil interface were seen to be dependent on the degree of soil displacement (plugging) experienced during installation, the distance from the pile toe, and the number of load cycles experienced by a soil element adjacent to the pile shaft. A new design method for estimating the shaft capacity of piles in sand is proposed and compared with measurements made on prototype field-scale piles.

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Recent design methods for displacement piles have been developed based on the results of field tests using highly instrumented, closed-ended model piles which were able to measure the radial effective stress at a number of locations along the pile shaft. The measured σ' _r were then directly related to in-situ soil properties such as CPT cone resistance. Many design methods have been extended to consider the shaft resistance developed along open-ended (pipe) piles by adopting various assumptions with regard to differences between the radial stress regimes set up by closed and open-ended piles. However, no comparable measurements of σ'r from pipe piles were available to assess the validity of these assumptions. This paper presents the results of radial stress measurements made on an instrumented open-ended pile during installation into loose sand. These measurements are used to investigate the validity of some of the assumptions underlying a number of popular design methods.

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This paper presents the results from an experimental programme that studied the factors affecting the bearing resistance of shallow footings in sand. In particular, the tests considered the effects of the footing width and embedment depth on the pressure-settlement response. By comparing the results with field tests on full-scale footings, simple correlations between the bearing pressure mobilised at normalized settlement levels of 5% and 10% of the footing width and the cone penetration test q_c value were studied. These correlations were found to be independent of footing size, embedment depth and sand state, although they were affected by creep. The rate of mobilisation of the footing resistance at low settlements was found to be strongly dependent on the initial soil state and the previous loading history. A simple non-linear elastic soil model was found to adequately predict this response.

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The paper presents the results of a series of field tests performed to study the causes of friction fatigue experienced by displacement piles. Four instrumented model piles were installed at a dense sand test-bed site. The test series was designed to impose different levels of cyclic loading during pile installation. Static and cyclic load tests were subsequently performed to study the differences in the axial capacities developed for ostensibly monotonic and cyclic installations. The test results indicated that the mobilized horizontal effective stress regime that controls pile side friction primarily depends on the in situ sand state, as reflected by the cone penetration test (CPT) qc resistance. A zone of highly stressed sand that produced a concentration of high shear resistance was mobilized in the vicinity of the pile base. The horizontal effective stress that acted on the pile shaft reduced in response to cyclic loading, with the largest reductions occurring for high-intensity cyclic loading or when the pile had experienced only a few load cycles during installation. Although cyclic loading caused a reduction in the horizontal effective stress that acted on the pile shaft, the elevated stress built up in the vicinity of the pile base during installation remained higher than that remote from the base. The elevated stress in the vicinity of the pile base only dissipated after cyclic tension loading had been applied.

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This paper presents field measurements of the shaft shear stress and the horizontal stress made during the installation of a 73mm diameter instrumented pile in a heavily over-consolidated dense sand deposit. The measurements are compared with Cone Penetration Test (CPT) measurements to investigate the causes of friction fatigue on displacement piles in sand. Copyright ASCE 2006.@en