Lake Texcoco Research Articles

Culture, traditions and natural resources of Mexican lakes under the onslaught of anthropic pressures and climate change

Indigenous people and local communities play a vital role in conserving inland water ecosystems and their resources through their cultural and spiritual values embedded in the geographic, socio-political, and economic contexts. The Central Mexico lakes along the Trans-Mexican Volcanic Belt harbored important prehispanic cultures that hybridized during the Spanish conquest, evolving into modern Mexico and changing how lakes were valued. The terrestrial Spanish ways of life were inimical to the prehispanic indigenous lacustrine culture. After the conquest, various actions were carried out to drain the lakes for urban growth and to provide agricultural land. The result has been a decline (e.g., Lake Cuitzeo, Michoacán) and, in some extreme cases, the near disappearance (e.g., Lake Texcoco, Mexico City) of what were once extensive water bodies. Unsustainable use of resources, unsympathetic spatial planning (anthropic impacts), and climate change to warmer/drier conditions have all placed additional pressure on the inland ecosystems. Nonetheless, as herein presented, the prehispanic lacustrine cultural knowledge and traditions persist locally in some locations, having been perpetuated by indigenous people's traditions and habits.

Kinetics of ammonium volatilization in the form of ammonia in soils through a textural gradient

Objective: To estimate the ammonia volatilization rate, using a texture gradient with increasing doses of ammonium in alkaline soils. Design/Methodology/Approach: The experiment took place in the Análisis Químico de Suelos lab of the Soil Department of the Universidad Autónoma Chapingo. The incubations consisted of 25 g of soil from the former Texcoco lake, with 12.5% clay. The soil was air-dried and sieved with a no. 10 mesh. The soil was mixed with three different concentrations (17.5%, 22.5%, and 32.5%) of bentonite, in order to increase clay content. The mixtures were placed in plastic containers with airtight seals. Twelve-point five mL of an ammonium sulfate solution (with 150, 300, 450, 600, and 750 mg of nitrogen kg soil-1) was added. The ammonia was recovered in a container with a boric acid solution. Volumetry was used to quantify ammonium. A completely randomized design with two factors (clay content and ammonium dose) was used. Data were analyzed with a regression analysis, analysis of variance, and Tukey Multiple Comparison Test, using the SAS OnDemand for Academics software. Results: The ammonia volatilization has a linear trend, with the concentration of the applied nitrogen. The volatilization rate ranged from 0.02 to 0.03 mg of ammonium per milligram of the nitrogen applied per kg soil-1. Significant statistical differences were recorded between the effect of the N dose and the clay content on the ammonia volatilization rate. Study Limitations/Implications: Clay content in the soil and ammonia volatilization rate can be used as an indicator to estimate ammonia losses and the ammonia adsorption capacity of the soil. Findings/Conclusions: Ammonia volatilization is independent from clay content and takes place immediately after its application. It has a linear trend regarding the ammonia dose applied. Ammonia volatilization rate decreases (asymptotic trend) as the clay content increases in the soil.

Evaluation of the functional properties of a protein isolate from Arthrospira maxima and its application in a meat sausage

Arthrospira maxima is a microalga that has been collected in Lake Texcoco in the Valley of Mexico since pre-Hispanic times and has been a traditional food source due to its high biomass production and protein content (50–60 %), making it promising for protein extraction. In this context, a protein isolate was obtained from powdered biomass of Arthrospira maxima (PbAm) by alkaline solubilization (pH 11) and isoelectric precipitation (pH 4.2). Arthrospira maxima protein isolate (AmPI) presented higher protein content (82.58 %) and total amino acids compared to PbAm. Functional properties of AmPI were evaluated in comparison with PbAm and soy protein isolate (SPI). Protein extraction resulted in a significant increase in protein solubility (PS) and foaming capacity (FC) of up to 87.78 % and 238.10 %, respectively. Emulsifying capacity (EC) of AmPI was superior to that of PbAm and SPI in pH range 5–7. Inclusion of AmPI as a partial substitute for SPI in the formulation of meat sausages was evaluated by implementing four treatments: T1 (15 % AmPI, 85 % SPI), T2 (10 % AmPI, 90 % SPI), T3 (5 % AmPI, 95 % SPI) and T4 (0 % AmPI, 100 % SPI). Although the texture attributes remained unchanged, a significant reduction in color parameters was observed as the concentration of AmPI increased. An inclusion of 15 % AmPI significantly enhanced the nutritional quality of meat sausages. Results highlight the excellent properties of AmPI, confirming Arthrospira maxima as a promising protein source in the food industry.

Hydrogeochemical and isotopic assessment of the origin of NO3− and N–NH3 contents in the aquifer located in a closed lacustrine volcano-sedimentary basin in the metropolitan area of Mexico City

To explain the presence and spatial distribution of NO3− and N–NH3 in the Aquifer of the Metropolitan Area of Mexico City (AMAMC), a hydrogeochemical and isotopic analysis using 13CDIC (as well as the stable isotopes 18O and 2H) in groundwater was conducted. This aquifer is located in an old closed lacustrine volcano-sedimentary basin; some wells hosted in the semi-confined zone contain high N–NH3 concentrations, while others present NO3− contents in the recharge zones (hosted in an oxidizing environment). In this study, a change in the isotopic signature (primarily in 18O and 2H) was observed from the recharge zones to the basin center in some of the wells with high NO3− concentrations, this behavior can be attributed to evaporation during the incorporation of recently infiltrated water. In addition, the results for 13C (along with 2H) in wells with the highest N–NH3 concentrations exhibited an atypically broad range of values. Results indicated the occurrence of hydrogeochemical and/or biochemical processes in the aquifer (in an oxidizing or reducing environment), such as organic degradation, bacterial decomposition (primarily in the ancient Lake Texcoco and which acts as a natural sink for carbon, nitrogen, sulfur, and phosphorus), besides rock weathering and dissolution, which may be responsible for a very marked isotopic modification of the 13C (and, to a lesser extent, 2H). Methanotrophic bacterial activity and methanogenic activity may be related to N–NH3 removal processes by oxidation and residual water incorporation respectively, whereas the increase in the NO3− content in some wells is due to the recent contribution of poor-quality water due to contamination.

Reconstruction of fluvio‐lacustrine landscapes and settlement history in the Texcoco region, Mexico, using a modern geomorphic analog

AbstractLocated in the Basin of Mexico, the eastern shore of former Lake Texcoco sustained a variety of human occupations throughout the Holocene, including preceramic hunter‐gatherers, incipient agriculturalists, and a variety of settlements in the ceramic periods. Nonetheless, the environmental dynamics of occupations on the lakeshore have not been fully addressed. The Archaic preagricultural Texcoco Man site (>5000 B.C.E.) and the Late Formative TX‐LF‐14 site (c. 550‐200 B.C.E.), among others, occupy this fluvio‐lacustrine transitional environment. Few stratigraphic works in and around the sites have been performed. Consequently, it is difficult to understand the dynamics of the sedimentary system in space and time. This work highlights and describes the fluvio‐lacustrine sedimentary dynamics and the resulting landscape that past societies inhabited on the eastern shore of Texcoco Lake. Because the study area has been altered by historic and modern draining, our work employs Lake Santiaguillo and its main tributary, the Tejamen River in the Durango state, as a modern analog to study their sedimentary dynamics. The analyses of surface geomorphology in the Texcoco study area were employed to corroborate the modern analog interpretation. To achieve these goals, we conducted a GIS‐based morphometric analysis and LANDSAT‐8 imagery to study the variations in landforms through wet and dry events. The results indicate an increase in the lake volume, low bifurcation in the active fluvial channels, few inundated surfaces, and the presence of bird‐foot deltaic channels during high precipitation events. In contrast, low precipitation events are characterized by reduced lake volume, increased fluvial channel bifurcation, and expanded floodplains. This heterogeneous landscape thus provided a rich source of diverse natural resources of saline and freshwater aquatic habitats. Simultaneously, constant or recurring flooding events generated a challenging landscape for prehistoric settlers who implemented diverse technologies, such as the construction of tlateles, on the levees of deltaic channels to reduce the risk and impact of flooding events.

Putative 14th Century Outbreak of Foodborne Chagas Disease, Mexico.

A severe epidemic erupted in Coyoacán at the southern end of Lake Texcoco, in Central Mexico, around 1330. Chroniclers of the 16th century reported that after disrupted fish supply, the inhabitants of Coyoacán had suffered high morbidity and mortality. They developed edema of their eyelids, face, and feet, and hemorrhagic diarrhea. Many died, mainly the young and the old. Pregnant women miscarried. The disease is classically considered an illness of nutritional origin. However, its clinical picture and the circumstances of its emergence are remarkably consistent with an outbreak of foodborne Chagas disease, possibly acquired upon the hunting and consumption of alternative food sources, such as infected opossums (Didelphis spp.), unique reservoirs of Trypanosoma cruzi.

Historical Political Ecology in the Former Lake Texcoco: Hydrological Regulation

Lake Texcoco in Mexico is a remarkable place for observing how human and natural relationships evolve through time in a landscape. Since the opening of the watershed and the draining of the lake, there have been various attempts to exploit the area, although few have succeeded. This study highlights the importance of historical analysis in identifying socio-natural processes that have historically influenced lake use, degradation, management, and conservation. The novelty of this study lies in its application of a historical political ecology approach to understand the evolving dynamics between power relations and the ecology of the former Lake Texcoco in Mexico Valley. By examining both the ecological and political-economic history of the lake, this study reveals how conflicts related to natural resource management in the past have influenced the ecological dynamics of the present. Overall, this study presents a unique perspective on the socio-natural history of Lake Texcoco, demonstrating the potential of using historical political ecology to understand the long-term effects of environmental change.

Screening of Spirulina Components for Anti-Parkinson's and Anti-Alzheimer's Activity byin Silico Methods and Docking Studies.

Spirulina platensis was first isolated from Lake Texcoco by Aztecs in the sixteenth century. In 2012, spirulina was considered to be safe dietary supplement by the Food and Drug Administration (FDA). Spirulina is a cyanophytic microalgae that is often considered as single cell protein. It contains many essential amino acids, proteins, fatty acids, antioxidant pigments, carotenoids, and cyanogenic pigments, that is, phycocyanobilins and phycocyanins (Eriksen, Appl Microbiol Biotechnol, 80(1):1-4, 2008). Components of spirulina are investigated for many health benefits and for pharmaceutical uses (Karkos et al., Spirulina in clinical practice: evidence-based human applications). Spirulina has been found to have a role in growth, immunity (Wu et al., Arch Toxicol, 90(8):1817-40, 2016), antioxidant (Wu et al., Arch Toxicol, 90(8):1817-40, 2016), antiviral (Ayehunie et al., J Acquir Immune Defic Syndr Hum Retrovirol, 18(1):7-12, 1998), antitoxicologic, anti-cancerogenic (Hirahashi et al., Int Immunopharmacol, 2(4):423-34, 2002), antidiabetic (Layam and Reddy, Diabetol Croat, 35(2):29-33, 2006), and neuroprotective properties. In this study, we focused on spirulina components in anti-Parkinson's and anti-Alzheimer's activity. Four potential targets, two for each activity, that is, structure of parkinE3 ligase (PDB ID:4I1H) and structure of BACE bound to 5-(3-(5-chloropyridin-3-yl)phenyl)-5-cyclopropyl-2-imino-3-methylimidazolidin-4one (PDBI D:4DJx) for anti-Parkinson's activity and structure of human MAO B in complex with selective inhibitor safinamide (PDB ID:2V5Z) and crystal structure of human BACE-1 in complex with CNP520(PDB ID:6EQM) for anti-Alzheimer's activity, have been selected. The in silico results and scoring of virtual screening, that is, molecular docking, were compared with commonly used marketed drugs such as levodopa for Parkinson's disease (PD) and rivastigmine (Rösler et al., BMJ, 318(7184):633-40, 1999) for Alzheimer's disease.

Lime Treatment of Lake Texcoco Clays with Some Insights on the Application of Deep Mixing Columns

The soils across Lake Texcoco (LT) basin are notorious for the presence of highly compressible salt-affected lacustrine clays. The geological formation of the area accompanied by the unmonitored flow of water from Mexico City region has resulted in a unique sodium-rich clay that is highly plastic (plasticity index~200), and impermeable ( k~1.5 × 10−9 m/s) and possesses low compressive strength (unconfined compressive strength < 10 kPa). Over the last few decades, the entire basin has settled at an average of 13.2 cm per year and will continue further with increased loads as a result of rapid urbanization. In planning a solid foundation for the airport, as well as developing the surrounding area, trial sections were built to analyze the effect of quicklime (CaO) on the natural clay s physical, chemical, and engineering properties through laboratory testing. The lab-scale investigations were accompanied with field measurements using the variable energy dynamic cone penetrometer (DCP) and plate load tests. Additionally, a numerical analysis of the effect of deep mixed columns (DMC) to reduce consolidation settlement was performed. The numerical analysis comprised of various DMC stabilizers, loading pressures, column lengths, and area replacement ratios. DMC lengths were observed to be the most dominant parameter to reduce consolidation settlements. Settlement reduction was more sensitive to the area replacement ratio for end-bearing columns, and to the loading pressures for floating columns. Based on the stabilizers evaluated, a combination lime and Portland cement performed the best across all loading pressures and column lengths. Other stabilizer combinations also had a remarkable effect on limiting the consolidation settlement.

Bacillus paralicheniformis isolated from a hypersaline sediment of Lake Texcoco, draft genome sequence of strain TXO7B-1SG6.

ABSTRACTWe present the draft genome sequence of the halotolerant strain Bacillus paralicheniformis TXO7B-1SG6.

Thermal properties of soft clayey soils from the former Lake Texcoco in Mexico

Thermal properties of soils are essential for the design of many engineering projects, such as underground cable systems, thermal ground improvement techniques, and energy geostructures. Although the thermal properties of typical soils have been widely studied, little research has focused on the thermal characterization of soils with unusual properties, such as the soft clays from the former Lake Texcoco in Mexico. These sediments are known for their exceptionally high water content, plasticity index, and porosities. The present study describes a systematic evaluation of the thermal conductivity, specific heat capacity, and thermal diffusivity of Texcoco clays and their inherent variability. Forty laboratory samples from eleven different locations were studied using the dual-probe heat pulse method, X-ray diffractometry, Scanning Electron Microscopy, and standard soil classification tests. The results showed that the studied samples have lower thermal conductivities and higher specific heat capacities than those previously reported for saturated clays. These differences were mainly attributed to the high porosities of the peculiar clays from the former Lake Texcoco. The thermal conductivity did not show a specific trend with depth. From statistical analyses, it was established that the shifted lognormal distribution and the normal distribution accurately describe the natural variability of the thermal conductivity and specific heat capacity, respectively. Finally, the efficacy of eight selected prediction models for the thermal conductivity of saturated clays was assessed. The geometric mean and the weighted series-parallel heat flow (WSP) models delivered the best fit to the experimental data. This study deepens our understanding of ground thermal properties by providing information about soil with unusual characteristics. Furthermore, it gives an initial database for the thermal properties of Mexican soils that can serve as a reference for the development and design of some of the geotechnical applications previously described.

Late Pleistocene and Holocene palaeoecological reconstruction of Lake Texcoco (Basin of Mexico) based on its ostracod record

AbstractWe present a palaeohydrological reconstruction of Lake Texcoco over the last 32.7 cal ka based on ostracod records consisting of two species, Candona patzcuaro and Limnocytherina axalapasco. Overall, the presence of these species suggests that Lake Texcoco was highly saline and experienced occasional desiccation periods. Moreover, this work helps improve our knowledge of L. axalapasco, an endemic species of central Mexico; their eggs could remain dormant‐resting to survive long dry periods. Four ostracod zones reflect the main environmental changes that occurred during the Late Pleistocene and Holocene. From 32.7 to 30 cal ka bp (Zone 4), Lake Texcoco's water levels were stable and alkaline with saline conditions. Zone 3, representing the period from 30 to 18 cal ka bp, includes a period of enhanced precipitation (greatest abundance of C. patzcuaro) from 30 to 26 cal ka bp. From 26 to 18 cal ka bp, an abundance of L. axalapasco reflects shallower and more saline conditions. The Last Glacial Maximum was characterised by cold and humid conditions with enhanced runoff, especially at 25.3, 21.9, and 20.7 cal ka bp. Zone 2 (18–7 cal ka bp) represents the driest period on record. Finally, shallow and saline lake conditions have prevailed over the last 7 cal ka (Zone 1).

Water Diversion in the Valley of Mexico Basin: An Environmental Transformation That Caused the Desiccation of Lake Texcoco

Mexico’s basin is one of the most altered in the country, owing to the presence of the megalopolis of Mexico City. Lake Texcoco, which had the basin’s biggest extension, dried up almost completely. The basin’s evolution over time led in the formation of a megabasin in which water is transported from one source to another to serve the urban region and subsequently drained to prevent flooding. The major hydrotechnical works in Mexico Basin have been interpreted as a solution to the problem of flooding in Mexico City, but they were actually part of a much larger strategy of territorial appropriation by the Spanish colonists. The ecological imbalance that has resulted has sparked a variety of social issues. For the purpose of analyzing the environmental transformation of Lake Texcoco over the last 500 years, actors and processes that influenced specific moments in the country’s history were identified; these elements showed the inexorable relationship between the lake and Mexico City. Subsequently, they were grouped by periods with similar trends in terms of the way in which society relates to and appropriates the natural environment of the lake. It was found that the critical moment for the desiccation of Lake Texcoco occurred during the Spanish colonial historical period as part of the redesign of the city; from then on, the same environmental imaginary prevailed century after century, shaped by social and economic factors. This study contributes to the literature on how urbanization affects natural resources by making an original theoretical contribution through an analysis based on political ecology, and it adds to the literature on how people use the prevailing federal area of the lake.

ANAMMOX MICROBIAL ACTIVITY IN SODIUM SALINE SOIL OF FORMER LAKE TEXCOCO, MEXICO

The Anammox process, involving transformation of ammonium to dinitrogen, is well known in aquatic ecosystems. However, this anaerobic process in soil has been little explored, even less in extremophile soils. The saline-sodic soil of the former Lake Texcoco exposed to desertification with irrigation projects using wastewater of Mexico City, is a unique environment, yet little is known about its microbial ecology. The objective of this study was to examine the presence of Anammox microorganisms and their microcosm activity after a period of Anammox enrichment (229 days). Microcosm kinetics monitored after the 229 days enrichment experiment, showed a significant removal of ammonium and nitrite, with a significant production of dinitrogen. The stoichiometric conversion of NO2– and NH4+ to N2 gas is complete in the studied soils, based on an Anammox process where 1 mole of NH4+ resulted in 1.02 moles of N2. The presence of the Anammox functional gene hzoA was observed in saline-sodic soils of the former Lake Texcoco. The Anamx1 and Anamx2 operational taxonomic units (OTU) are phylogenetically close to a bacterium of the phylum Planctomycetes from a wastewater treatment reactor and marine environment (AB257585.1 and HE654780.1, respectively). Those two OTU represent indigenous or exogenous Anammox microorganisms phylotypes. The existence of microorganisms with Anammox activity in a saline-sodic alkaline soil is of great interest for the understanding of the nitrogen cycle in extremophile soils.

STUDY OF THE DYNAMIC BEHAVIOR OF FINE SOIL REINFORCED WITH RECYCLED POLYETHYLENE TEREPHTHALATE (PET) FIBER

ABSTRACT: PET occupies a preponderant place in plastic waste in Mexico, in the last six years the post-consumer stockpiling of PET has been the highest in America and during 2017 its recovery increased by 20,000 tons per year, their increase reached 445,000 tons per year [1]. In this way, one of the alternatives to recycling PET is produce fibers to reinforce fine soils of low shear strength and high deformation like Mexico’s city soil. For this particular case, Mexico City’s soil is notorious for its high plasticity, low strength, high compressibility and cracking tendency. Due to these, the strongest earthquakes have shown the brutal amplification and the substantial increase in the duration of the movements. In order to seek new alternatives for soil improvement in the Valley of Mexico, this study investigates the dynamic behavior of a high plasticity silty soil extracted from the former Texcoco Lake, reinforced with different PET fiber contents. The results indicate that there is a significant modification in the dynamic parameters of the soil due to fiber inclusion, an increase in the maximum elastic shear stiffness of the soil and a significant decrease in deformation for a fiber content of 0.3% at all confining pressures, this can be useful in the construction by improving the properties of this type of soil for geotechnical works through the inclusion of synthetic fibers, the large-scale use of stone materials from loan banks for stabilizing soil can be reduced, which will also avoid requiring reinforcement geosynthetics made of new materials. According to the results obtained in this research it was developed some applications and a general construction method for geotechnical works Key Words: Fiber-reinforcement, Soil stabilization, Seismic engineering, Unsaturated soils, Geosynthetics.

The collapse of Álvaro Obregón 286 building in Mexico City during the September 19, 2017 earthquake. A case study

During the September 19, 2017 Puebla-Morelos Earthquake in Mexico City, 46 buildings experienced global or partial collapses. However, perhaps the most emblematic collapsed building during this earthquake was Álvaro Obregón 286 building (AO-286), located at Hipódromo Condesa District in the soft soils of former western Lake Texcoco. Unfortunately, 49 people died there, being the building which claimed more victims in Mexico City during this earthquake. Taking aside this tragedy, the collapse of Alvaro Obregón 286 building is an interesting case study from a structural engineering viewpoint, as it has several angles to explore to try to explain the reasons of its failure. In this paper, the authors report a detailed study that they conducted to try to understand better the collapse of AO-286 building and the observed damage in the neighboring AO-284 building. As no blueprints or lab data were publicly available, the authors did first a forensic study. Information was gathered from sources like press reports, public information and pictures taken at the site by the authors and by many other people. Then, using Google Maps and Google Earth information and tools, the following items were defined and measured: plan geometries and dimensions, story heights, locations of main structural axes, likely cross sections of structural resisting elements and observed tilting. With all this information, the authors estimated the likely steel reinforcement in reinforced concrete members and steel sections that these buildings could have had by designing them according to the recommendations available in the 1957 building code which was used in their design, using also the analytical methods and design practices at the times. Observed tilting before the earthquake, soil-structure interaction effects and the likeliness of structural pounding between AO-286 and AO-284 buildings were considered within the study. The recorded ground motions at nearby CI05 station were used for nonlinear dynamic simulations. From all these studies, it can be concluded that although AO-286 building did not have enough strength and ductility to survive the severity of the ground motions (when studied alone), structural pounding with AO-284 building, favored by the existing tilting in both buildings due to progressive soil settlements and soil-structure interaction effects had an important role in the observed collapse for AO-286 building and the severe damage observed in AO-284 building.

Archaeology of Mexico City: new studies in the study of the history of the ancient Aztecs

The article presents an overview of archaeological discoveries in Mexico City over the past few years. The research, which is carried out primarily by Mexican scientists, is based on both traditional methods of archaeology and the capabilities of modern science, in particular, electroresistive tomography and geophysics. The article uses primary data and their inclusion in the history of archaeological research in Mexico City is still ahead. Despite the preliminary nature of the assessments of these archaeological data, they allow not only to clarify the established ideas based on the many decades of work of archaeologists, but also to take them into account when further studying the past of the Aztecs and their capital Mexico City-Tenochtitlan. The paper presents the materials of recent excavations in the area of the Main Temple (Mexico City proper) and Greater Mexico City (the ancient territory around Lake Texcoco). In the center of Mexico City, archaeologists have discovered the remains of the room in which the Spaniards were, who first found themselves in the Aztec capital, fragments of pre-Hispanic stone basreliefs. It is also a find of the Great (Great) Tsompantli (traditional construction of skulls). The excavations of the Great Cuaushikalco as part of the ritual and sacred space and the ancient objects associated with it can be considered noteworthy. In the Greater Mexico City area, there are ongoing studies of an artificial tunnel, a cave (a symbol of the entrance to the world of the dead) inside the famous pyramid of the Moon in Teotihuacan. Here, on the territory of the ancient valley of Mexico, the study of the Preclassic period of its history continues (archaeological surveys in Zacatenco and Tlalpan with the oldest burials of unusual cone-shaped graves and intentional spiral arrangement of bodies). The post-classical period (the Aztec era) was enriched by excavations of salt mining sites, etc. The article notes that the new archaeological data generally confirm the well-known features of the Aztec society, without justifying, but also without belittling its own importance in world history and culture.

Demography of Hexarthra jenkinae (de Beauchamp) (Rotifera) from ephemeral and permanent habitats of the shallow waterbody Lake Texcoco (Mexico)

Demography of Hexarthra jenkinae (de Beauchamp) (Rotifera) from ephemeral and permanent habitats of the shallow waterbody Lake Texcoco (Mexico)

Amber Brian, Bradley Benton, Peter B. Villella and Pablo García Loaeza, translators and editors. History of the Chichimeca Nation: Don Fernando de Alva Ixtlilxochitl’s Seventeenth-Century Chronicle of Ancient Mexico

Amber Brian, Bradley Benton, Peter B. Villella and Pablo García Loaeza, translators and editors. <i>History of the Chichimeca Nation: Don Fernando de Alva Ixtlilxochitl’s Seventeenth-Century Chronicle of Ancient Mexico</i>

Simulation of the time-dependent behaviour of a test embankment on soft soil

The now-abandoned project for a new international airport for Mexico City was located at a site on the former Texcoco Lake, where extremely difficult subsoil conditions prevail. The behaviour of one of the trial embankments built to test foundation solutions for the runways is analysed in this paper. Observational data were gathered over 50 months at the so-called reference embankment, where no special foundation or soil improvement techniques were adopted. The performance of this embankment was investigated through finite-element simulations in which an elasto-viscoplastic constitutive model was implemented in commercial software. The model incorporates key features such as time dependence, long-term deformation and an anisotropic flow surface. The results provide an assessment of the constitutive description adopted as well as the role of anisotropy in the simulation of the case study.