Near-surface soil stabilization by enzyme-induced carbonate precipitation for fugitive dust suppression     

Song  Jun Young  Sim  Youngjong  Jang  Jaewon  Hong  Won-Taek  Yun  Tae Sup 《Acta Geotechnica》2020,15(7):1967-1980

Acta Geotechnica - To resolve the environmental and sustainability issues from fugitive dust emission and conventional mitigation methods, multiple experiments were conducted to evaluate the...  相似文献   

Differentiated payments for environmental services schemes: Amethodology proposal     

Carlos R.AGUILAR-GóMEZ  Sergio FRANCO-MAASS  Tizbe T.ARTEAGA-REYES 《山地科学学报》2018,15(8):1693-1710

Payment schemes for environmental services face serious budget constraints in Mexico. Payments are equally distributed among forest owners, and the governmental agencies that make payments to beneficiaries do not evaluate the amount of environmental services produced by forested areas. This lack of evaluation could lead to economic and environmental deficiencies that restrict the possible benefits of such programmes. In general, these programmes do not achieve their conservation objectives, and local beneficiaries are not involved in the design or application of these programmes. Similarly, the Payments for Hydrological Environmental Services (PHES) programme of the State of Mexico, Mexico, makes equal payments to beneficiaries of forested areas considering tree density. The objective of the present work was to create a methodology for determining differentiated payments schemes for hydrological environmental services, prioritising areas that contribute the most to groundwater recharge and promote the participation of society. In the Nevado de Toluca Natural Protected Area, the environmental criteria of forest type, tree density and aquifer overexploitation as well as social participation were considered in a multi-criteria analysis implemented in a Geographic Information System. A methodology was developed to determine differentiated payments based on specific forest characteristics that influence the potential capacity of forests to recharge groundwater reserves in addition to the level of social participation. In particular, social participation is key as it could ensure the viability of PHES programmes as conservation alternatives in forested areas with high groundwater recharge potential.  相似文献   

Magnitude of latent heat in thermally loaded clays     

Sergio Samat  Laurent Brochard  Ioannis Stefanou 《国际地质力学数值与分析法杂志》2020,44(14):1926-1957

Temperature changes are known to induce specific couplings in clay, in particular, an anomalously high thermal pressurization in undrained conditions or a thermal compaction in drained conditions, both of which are potential threats for the mechanical stability and sealing capacity of the geomaterials. Thermodynamical analysis of those peculiar thermomechanical couplings points to a potentially important latent energy, which in turn could limit the temperature change upon heating or cooling. The direct measurement of latent energy developed during a laboratory geomechanical test is challenging. Instead, proper identification of thermal hardening in conventional experiments with temperature changes provides an alternative route to estimate latent energy. In this work, existing laboratory thermomechanical tests of clays are analyzed with a rigorous thermodynamic framework to quantify the magnitude of latent energy in thermomechanically loaded clays. A thermodynamically consistent constitutive model for fully saturated clays that combines two key features, (a) the temperature dependence of the blocked energy and (b) the framework of bounding plasticity, is proposed. The performance of the model is validated by reproducing results obtained in laboratory tests for Boom and Opalinus clays. The thermomechanical loads considered to validate the model performance were then used to estimate the percentage of work that remains latent in the clayey material during plastic yielding. We find that the magnitude of latent energy is quite significant, typically a few tens of percent of the total dissipated energy, and increases significantly with temperature. Accordingly, it is expected to play an important role in the thermomechanical response of clays.  相似文献   

An extreme wave event in eastern Yucatán,Mexico: Evidence of a palaeotsunami event during the Mayan times     

Javier Lario  Chris Spencer  Teresa Bardají  Ángel Marchante  Victor H. Garduño-monroy  Jorge Macias  Sergio Ortega 《Sedimentology》2020,67(3):1481-1504

The Yucatán Peninsula, Mexico, has typically been considered a tectonically stable region with little significant seismic activity. The region though, is one that is regularly affected by hurricanes. A detailed survey of ca 100 km of the eastern Yucatán and Cozumel coast identified the presence of ridges containing individual boulders measuring >1 m in length. The boulder ridges reach 5 m in height and their origin is associated with extreme wave event activity. Previously modelled tsunami waves from known seismically active zones in the region (Muertos Thrust Belt and South Caribbean Deformed Belt) are not of sufficient scale in the area of the Yucatán Peninsula to have produced the boulder ridges recorded in this study. The occurrence of hurricanes in this region is more common, but two of the most destructive (Hurricane Gilbert 1988 and Hurricane Wilma 2005) produced coastal waves too small to have created the ridges recorded here. In this paper, a new tsunami model with a source area located on the Motagua/Swan Island Fault System has been generated that indicates a tsunami event may have caused the extreme wave events that resulted in the deposition of the boulder ridges.  相似文献   

SlugIn 1.0: A Free Tool for Automated Slug Test Analysis          下载免费PDF全文

Sergio Martos‐Rosillo  Carolina Guardiola‐Albert  Alberto Padilla Benítez  Joaquín Delgado Pastor  Antonio Azcón González  Juan José Durán Valsero 《Ground water》2018,56(3):362-365

The correct characterization of aquifer parameters is essential for water‐supply and water‐quality investigations. Slug tests are widely used for these purposes. While free software is available to interpret slug tests, some codes are not user‐friendly, or do not include a wide range of methods to interpret the results, or do not include automatic, inverse solutions to the test data. The private sector has also generated several good programs to interpret slug test data, but they are not free of charge. The computer program SlugIn 1.0 is available online for free download, and is demonstrated to aid in the analysis of slug tests to estimate hydraulic parameters. The program provides an easy‐to‐use Graphical User Interface. SlugIn 1.0 incorporates automated parameter estimation and facilitates the visualization of several interpretations of the same test. It incorporates solutions for confined and unconfined aquifers, partially penetrating wells, skin effects, shape factor, anisotropy, high hydraulic conductivity formations and the Mace test for large‐diameter wells. It is available in English and Spanish and can be downloaded from the web site of the Geological Survey of Spain. Two field examples are presented to illustrate how the software operates.  相似文献   

Rapid shoreline flooding enhances water turbidity by sediment resuspension: An example in a large Tibetan lake     

Huan Mi  Cédric G. Fichot  Karin R. Bryan  Gang Qiao  Sergio Fagherazzi 《地球表面变化过程与地形》2020,45(15):3780-3790

Rapid water level rise due to climate change has the potential to remobilize loose sediments along shorelines and increase the turbidity of nearshore waters, thereby impacting water quality and aquatic ecosystem health. Siling Lake is one of the largest and most rapidly expanding lakes on the Tibetan Plateau. Between 2000 and 2017, this lake experienced an increase in water level of about 8 m and a doubling in water turbidity. Here, using this lake as a study site, we used a wave model and high-resolution remote sensing of turbidity (Landsat-8) to assess the potential connection between water-level rise, enhanced wind-driven sediment resuspension and water turbidity. Our analysis revealed that strong bottom shear stresses triggered by wind-generated waves over newly flooded areas were related to an increase in water turbidity. The spatial variability of Siling Lake turbidity showed a strong dependence on local wind characteristics and fetch. Two factors combined to drive the increase in turbidity: (1) high wave energy leading to high bottom shear stresses, and (2) flooding of unvegetated shallow areas. Using a new relationship between wave energy and turbidity developed here, we expect the increase in turbidity of Siling Lake to taper off in the near future due to the steep landscape surrounding the lake that will prevent further flooding. Our results imply that rising water levels along the coast are not only expected to influence terrestrial ecosystems but could also change water quality. The methodology presented herein could be applied to other shorelines affected by a rapid increase in water level. © 2020 John Wiley & Sons, Ltd.  相似文献   

On the morphology of radial sand ridges     

Weina Zhang  Xiaohe Zhang  Huiming Huang  Yigang Wang  Sergio Fagherazzi 《地球表面变化过程与地形》2020,45(11):2613-2630

We use a hydrodynamic model applied to an idealized fan-shaped basin to explore the morphology and dynamics of radial sand ridges in a convergent coastal system. A positive morphological feedback between channel incision and flow redistribution is responsible for the formation of the channel-ridge pattern. The selection mechanism of bottom wavelength is associated with flow concentration in the deeper part of the channels. Our results are compared to sediment and hydraulic dynamics in the radial sand ridges (RSRs) in China. In a convergent, sloping basin the tangentially averaged tidal velocity peaks at 47 km from the apex. This distance is similar to the arc distance, 62 km, where the RSRs are most incised. An offshore shift in tidal phase results in stronger flows near the north coastline, explaining the presence of asymmetric channel patterns. A numerical stability analysis indicates that small radial oscillations with a wavelength of 10° to 15° maximize the velocity in the troughs. This oscillation wavelength also emerges in the RSRs, which display a peak in spectral energy at a radial wavelength between 25° to 37.5°. High-resolution numerical simulations in the RSRs confirm that flow concentration occurs in the deeper part of the channels, keeping them flushed. We therefore conclude that the RSRs display morphometric characteristics similar to other tidal incisions, like tidal inlets and intertidal channels. This result further supports the dominant role of tidal prism and related peak velocities in incising coastal landscapes. © 2020 John Wiley & Sons, Ltd.  相似文献   

Shock deformation confirms the impact origin for the Cerro do Jarau,Rio Grande do Sul,Brazil, structure     

Wolf Uwe Reimold  Alvaro Penteado Crsta  Maximilian Hasch  Astrid Kowitz  Natalia Hauser  Joana Paula Sanchez  Luiz Sergio Amarante Simes  Grace Juliana de Oliveira  Patrice T. Zaag 《Meteoritics & planetary science》2019,54(10):2384-2397

Cerro do Jarau is a conspicuous, circular morpho‐structural feature in Rio Grande do Sul State (Brazil), with a central elevated core in the otherwise flat “Pampas” terrain typical for the border regions between Brazil and Uruguay. The structure has a diameter of approximately 13.5 km. It is centered at 30^o12′S and 56^o32′W and was formed on basaltic flows of the Cretaceous Serra Geral Formation, which is part of the Paraná‐Etendeka Large Igneous Province (LIP), and in sandstones of the Botucatu and Guará formations. The structure was first spotted on aerial photographs in the 1960s. Ever since, its origin has been debated, sometimes in terms of an endogenous (igneous) origin, sometimes as the result of an exogenous (meteorite impact) event. In recent years, a number of studies have been conducted in order to investigate its nature and origin. Although the results have indicated a possible impact origin, no conclusive evidence could be produced. The interpretation of an impact origin was mostly based on the morphological characteristics of the structure; geophysical data; as well as the occurrence of different breccia types; extensive deformation/silicification of the rocks within the structure, in particular the sandstones; and also on the widespread occurrence of low‐pressure deformation features, including some planar fractures (PFs). A detailed optical microscopic analysis of samples collected during a number of field campaigns since 2007 resulted in the disclosure of a large number of quartz grains from sandstone and monomict arenite breccia from the central part of the structure with PFs and feather features (FFs), as well as a number of quartz grains exhibiting planar deformation features (PDFs). While most of these latter grains only carry a single set of PDFs, we have observed several with two sets, and one grain with three sets of PDFs. Consequently, we here propose Cerro do Jarau as the seventh confirmed impact structure in Brazil. Cerro do Jarau, together with Vargeão Dome (Santa Catalina state) and Vista Alegre (Paraná State), is one of very few impact structures on Earth formed in basaltic rocks.  相似文献   

Built environment and agricultural value at risk from Hurricane Irma flooding in Florida (USA)     

Miller  Alexander J.  Arias  Mauricio E.  Alvarez  Sergio 《Natural Hazards》2021,109(2):1327-1348

Natural Hazards - Flooding is the most costly type of natural disaster, as well as the most frequent. To provide risk-based flood insurance, providers must be able to accurately determine an...  相似文献   

The Flat Dilatometer Test in an Unsaturated Tropical Soil Site     

Rocha  Breno Padovezi  Rodrigues  Roger Augusto  Giacheti  Heraldo Luiz 《Geotechnical and Geological Engineering》2021,39(8):5957-5969

The site characterization of unsaturated soils is well stablished based on laboratory tests, which are expensive and time-consuming. In-situ testing methods, such as the flat dilatometer test (DMT), are an alternative to the traditional approach of drilling, sampling, and laboratory testing. The literature on DMT interpretation is well established on saturated and well-behaved soils. Only few studies deal with DMT interpretation in unusual soils, and little is known about the influence of soil suction on this test. This paper presents and discusses the influence of soil suction on four DMT campaigns carried out in an unsaturated tropical soil site, also incorporating the soil suction influence on the DMT interpretation. Soil suction was estimated by the soil–water characteristic curve (SWCC) and water content profiles. The water content profiles range from 11.3 to 19.7% which corresponds to a suction range estimated by SWCCs mostly between 6 and 200 kPa. Soil suction significantly influenced DMT data up to 5 m depth at the studied site (the unsaturated active zone) increasing the intermediate DMT parameters. The average horizontal stress index (K_D) was equal to about 1.7 and the average dilatometer modulus (E_D) was about 4.7 MPa in the active zone and practically doubled their values due to in situ soil suction. The estimated peak friction angle (?) was 20–30% higher due to soil suction influence on DMT assuming the soil behaves as a sand like material. Soil suction must be considered to assess the behavior of the investigated soil by the DMT. The suction influence should be incorporated in the effective stress and this approach considerably improved the site characterization of the studied site.

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