Preprints
Filtering by Subject: Civil and Environmental Engineering
The interplay between clay fabric and mechanical response of deep-seated landslides
Published: 2019-12-05
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geology, Geotechnical Engineering, Physical Sciences and Mathematics
Deep-seated landslides are amongst the most devastating natural hazards on earth, typically involving a rigid rock mass sliding over a weak, clayey shear-band. The mechanical response of this shear-band to the loading of the overburden is therefore critical for the stability of a landslide. We hereby show that this mechanical response is strongly linked to the mineralogy and microstructure of the [...]
Optical wave gauging using deep neural networks
Published: 2019-12-04
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geomorphology, Physical Sciences and Mathematics
We develop a remote wave gauging technique to estimate wave height and period from imagery of waves in the surf zone. In this proof-of-concept study, we apply the same framework to three datasets: the first, a set of close-range monochrome infrared (IR) images of individual nearshore waves at Duck, NC, USA; the second, a set of visible (i.e. RGB) band orthomosaics of a larger nearshore area near [...]
Urban Near-surface Seismic Monitoring using Distributed Acoustic Sensing
Published: 2019-11-27
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics
Urban subsurface monitoring requires high temporal-spatial resolution, low maintenance cost, and minimal intrusion to nearby life. Distributed acoustic sensing (DAS), in contrast to conventional station-based sensing technology, has the potential to provide a passive seismic solution to urban monitoring requirements. Based on data recorded by the Stanford Fiber Optic Seismic Observatory, we [...]
Effects of off-fault inelasticity on near-fault directivity pulses
Published: 2019-11-27
Subjects: Civil and Environmental Engineering, Engineering, Geotechnical Engineering
Near-fault motion is often dominated by long-period, pulse-like particle velocities with fault-normal polarization that, when enhanced by directivity, may strongly excite mid- to high-rise structures. We assess the extent to which plastic yielding may affect amplitude, frequency content, and distance scaling of near-fault directivity pulses. Dynamic simulations of 3D strike-slip ruptures reveal [...]
Simulating Electropulse Fracture of Granitic Rock
Published: 2019-11-22
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geology, Geotechnical Engineering, Mining Engineering, Physical Sciences and Mathematics
Electropulse treatments employ a series of high-voltage discharges to break rock into small fragments. As these methods are particularly suited to fracturing hard brittle rocks, electropulse treatments can serve to enhance or substitute for more traditional mechanical approaches to drilling and processing of these materials. Nevertheless, while these treatments have the potential to improve [...]
Dynamic modelling of overprinted impermeable fault gouges and surrounding damage zones as lower dimensional interfaces
Published: 2019-11-14
Subjects: Chemical Engineering, Civil and Environmental Engineering, Computational Engineering, Engineering, Petroleum Engineering
In the modelling of subsurface fluid flow, faults are dominant features since they can act as fluid pathways or barriers. Special emphasis is therefore placed in representing them in a numerically efficient manner and the use of lower dimensional domains has become prevalent to simulate higher permeability features like fractures. Such features, however, only represent some of the components of [...]
A note on the instability and pattern formation of shrinkage cracks in viscoplastic soils
Published: 2019-11-08
Subjects: Civil and Environmental Engineering, Engineering, Materials Science and Engineering
In this note we present a theoretical study on the conditions for the onset of cracks, as well as the corresponding pattern formation, in saturated viscoplastic soils under isotropic loading (extension). The type of stress applied is left unspecified, to cover a variety of loadings including shrinkage due to dessication, isotropic thermal expansion, mechanical loading and so forth. By treating [...]
Over 1000 rivers accountable for 80% of global riverine plastic emissions into the ocean
Published: 2019-10-24
Subjects: Civil and Environmental Engineering, Engineering, Environmental Engineering
Plastic waste increasingly accumulates in the marine environment, but data on the distribution and quantification of riverine sources, required for development of effective mitigation, are limited. Our new model approach includes geographical distributed data on plastic waste, landuse, wind, precipitation and rivers and calculates the probability for plastic waste to reach a river and [...]
Network topology and rainfall controls on the variability of combined sewer overflows and loads
Published: 2019-10-24
Subjects: Civil and Environmental Engineering, Engineering, Environmental Engineering
Water and pollutant fluxes from combined sewer overflows (CSO) have a significant impact on receiving waters. The random nature of rainfall forcing dominates the variability of sewer discharges, pollutant loads, and concentrations. An analytical model developed here, shows how sewer network topology and rainfall properties variously impact the stochasticity of CSO functioning. Probability [...]
The sensitivity of estimates of multiphase fluid and solid properties of porous rocks to image processing
Published: 2019-10-10
Subjects: Chemical Engineering, Civil and Environmental Engineering, Earth Sciences, Engineering, Hydrology, Petroleum Engineering, Physical Sciences and Mathematics, Transport Phenomena
X-ray microcomputed tomography X-ray microCT) is a rapidly advancing technology that has been successfully employed to study flow phenomena in porous media. It offers an alternative approach to core scale experiments for the estimation of traditional petrophysical properties such as porosity and single-phase flow permeability. It can also be used to investigate properties that control multiphase [...]
Does a damaged fault zone mitigate the near-field landslide risk during supershear earthquakes?—Application to the 2018 magnitude 7.5 Palu earthquake.
Published: 2019-10-03
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geotechnical Engineering, Physical Sciences and Mathematics
The impact of earthquakes can be severely aggravated by cascading secondary hazards. The 2018 Mw 7.5 Palu, Indonesia earthquake led to devastating tsunamis and landslides, while triggered submarine landslides possibly contributed substantially to generate the tsunami. The rupture was supershear over most of its length, but its speed was unexpectedly low, between the S-wave velocity Vs and [...]
Paradoxical impact of sprawling intra-Urban Heat Islets: Reducing mean surface temperatures while enhancing local extremes
Published: 2019-09-09
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Life Sciences, Physical Sciences and Mathematics, Statistics and Probability
Cities are at the forefront of climate change impacts and face a growing burden of adaptation to ensuing natural hazards. Extreme heat is a particularly challenging hazard as persistent heatwaves are locally exacerbated by the Urban Heat Island (UHI) effect. As a result, there is an increasing scientific interest in the influence of diverse urban morphologies on UHI. However, as the temperatures [...]
Hydropower dependency and climate change in sub-Saharan Africa: A nexus framework and evidence-based review
Published: 2019-09-06
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Environmental Studies, International and Area Studies, Physical Sciences and Mathematics, Social and Behavioral Sciences
In sub-Saharan Africa, 160 million grid-connected electricity consumers live in countries where hydropower accounts for over 50% of total power supply. A warmer climate with more frequent and intense extremes could result in supply reliability issues. Here, (i) a robust framework to highlight the interdependencies between hydropower, water availability, and climate change is proposed, (ii) the [...]
Building back bigger in hurricane strike zones
Published: 2019-09-03
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Geomorphology, Physical Sciences and Mathematics, Sustainability
Despite decades of regulatory efforts in the United States to decrease vulnerability in developed coastal zones, exposure of residential assets to hurricane damage is increasing — even in places where hurricanes have struck before. Comparing plan-view footprints of individual residential buildings before and long after major hurricane strikes, we find a systematic pattern of ‘building back [...]
Emergent self-similarity and scaling properties of fractal intra-Urban Heat Islets for diverse global cities
Published: 2019-09-02
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Physical Sciences and Mathematics, Statistics and Probability
Urban areas experience elevated temperatures due to the Urban Heat Island (UHI) effect. However, temperatures within cities vary considerably and their spatial heterogeneity is not well characterized. Here, we use Land Surface Temperature (LST) of 78 global cities to show that the Surface UHI (SUHI) is fractal. We use percentile-based thermal thresholds to identify heat clusters emerging within [...]