Buried Structures Research Articles

Tritium Autrigonum (Monasterio de Rodilla, BURGOS): an urban approach to a Hispano-Roman agglomeration based on recent aerial surveys

The ancient town located at Alto de Rodilla (Monasterio de Rodilla, Burgos, Spain), identified as Tritium Autrigonum, has never been the subject of an archeological excavation, although the site has been known for a long time. However, the aerial survey campaigns conducted between 2001 and 2015 made it possible to take a large number of photographs that expose the urban form of the city. They reveal, on an unprecedented scale, a significant portion of the buried structures throughout the agglomeration. After a brief presentation of the site and the extent of our current knowledge, this work details the exploitation of the rectified and georeferenced aerial views, making it possible to obtain an unedited planimetry of the remains. It also provides an exceptionally detailed description of the site. This expanding documentary base was used in 2016 to study the remains identified as monuments. Since then, the analysis of the analysis of the aerial photographs has made it possible to obtain a general plan of the city, the various facets of its urbanism in its various aspects and to situate the city within the urban spaces of the northern Hispanic area.

Dynamic measurements to assess stress levels on buried hydraulic structures

ABSTRACT Old masonry structures have a very special nature that require periodical inspection and evaluation programs. The problem becomes more sophisticated when dealing with vital buried hydraulic structures under continuous functional operation while bearing additional loads from running public services such as railways. This could add extra challenges for determining their structural performance and engineering characteristics if conventional methods are used. Moreover, traditional methods are sometimes costly, time consuming, and can lead to some damage to the structure. The importance of the current research is therefore providing a rapid methodology for evaluating these structures to confirm their current ability to resist operating loads safely, especially when subjected to aging. In this study, the evaluation depends mainly on analyzing the vibration acceleration response of a structure under dynamic loads. Insight into system identification using formal modal analysis was also conducted. Simultaneously, calibrated numerical model was then adopted to predict the expected level of internal stresses. An old masonry irrigation intake buried culvert underneath the main railway lines was selected for examination. The structure was firstly plugged from both sides and emptied, site inspection as well as core sampling of construction materials were conducted. Vibration time history was recorded due to train passage with different speeds. The filed measurements along with mathematical model were used to estimate the level of stresses among the structure. The results showed the ability of the proposed method to evaluate structures in an easy and rapid fashion compared to traditional methods without stopping serviceability of the structure.

3‐D geophysical modeling of a buried, simple impact crater: Holleford impact structure, Ontario, Canada

AbstractHolleford Crater is a deeply buried, 2.35 km diameter late Proterozoic‐early Cambrian (550 ± 50 Ma) simple impact crater located in southeastern Ontario, Canada. Exploration drilling in the 1950–60s indicated a >450 m deep, simple impact structure with an infill stratigraphy of Cambro‐Ordovician clastic and carbonate sediments and a −2.2 mGal gravity anomaly. We conducted new ground‐based geophysical surveys (magnetics, gravity) and potential field modeling to better resolve the buried impact structure depth, subsurface geometry, and postimpact modification. Geophysical surveys reveal a well‐defined ~3 mGal Bouguer gravity low and <20 nT residual magnetic anomaly over the crater basin. The lack of a well‐defined magnetic anomaly is due to the low magnetic contrast between Mesoproterozoic metasedimentary target rocks and Paleozoic infill sediments. The modeled basement surface shows a deeply buried (>400 m), eroded simple impact structure with a rim‐to‐rim diameter (D) of 1.8–2 km, a residual rim height of about 30 m and a true depth (dt) >400 m. The modeled diameter is smaller than the previous estimate (2.35 km) based on the surface outcrop pattern of Paleozoic strata, which overestimates the buried impact structure dimensions. The modeled basement surface identifies a rim breach and a possible fluvial outflow channel in the southeast impact structure rim. The channel is up to 150 m deep and 400 m in width and has morphology similar to outlet channels produced by fluvial rim dissection of terrestrial impact structures and “tadpole craters” on Mars.

Cathodic protection shielding of coated buried pipeline

AbstractDuring the 2000s, the concept of cathodic protection (CP) shielding was first raised in open literature and remains debated between coatings professionals. The mechanism of CP shielding, and its understanding continue to be studied for different coatings with different approaches and using various techniques. From the CP shielding factors to the assessment methods, the published literature merits a deep analysis to capture the established knowledge and identify the research gaps to further tackle the issue for reliable coated buried structures. A holistic approach to this topic seems necessary where coatings ageing, cathodic protection, electrochemistry, and transport processes should be considered. In the first part of the present review, the recent works related to the understanding of CP shielding, coatings properties were considered before discussing the mechanisms involved underneath coatings. Transport phenomena and their relationship with cathodic protection performance in the presence of chemical and microbiological processes are discussed in the second part. Finally, CP shielding assessment methods and modeling works are presented and discussed from different perspectives.

Shocked quartz in sandstone from the buried Ilkurlka impact structure, Officer Basin, Western Australia

AbstractThe Ilkurlka structure is an ~12 km diameter buried circular aeromagnetic anomaly within the Officer Basin in Western Australia. Prior studies postulated a range of origins, including meteorite impact. We report the presence of pervasive deformation in the first drill cores from the structure. Brecciated sandstone and siltstone contain arrays of quartz grains with concussion fractures and rare shocked quartz grains with planar deformation features (PDF). Universal stage measurements of two quartz grains reveal one grain with PDF parallel to (0001) orientation and three PDF sets parallel to . A second grain contains three PDF sets parallel to and one set parallel to . The shocked grains are interpreted to have formed in situ, rather than representing transported detrital shocked grains. These results suggest local shock compression of at least 10 GPa; however, preservation of primary porosity and overall paucity of shocked grains may indicate lower mean shock pressures. (U‐Th)/He dating of 58 apatite grains from four samples across both cores shows a dominant age population at ~265 Ma and a minor age population at ~135 Ma. These dates overlap with regional events and thus do not provide an unambiguous impact age. An upper Carboniferous to lower Permian maximum impact age is provisionally proposed based on inferred missing target rock stratigraphy.

Optical Fiber Sensing-Aided 3D-Printed Replacement Parts for Enhancing the Sensing Ability of Architectural Heritage.

This study discussed the application of optical fibers in addressing the problem of insufficient light harvesting and sensing health monitoring in ancient buildings. Based on three-dimensional (3D) printing technology to fix the light-harvesting lens and conducting optical fiber, develop the replacement parts that can be buried into the optical fiber of ancient buildings. By introducing the experimental application to improve the experimental quality of research and teaching. Firstly, it highlights the advantage that the optical fiber plus lens structure design can make the natural light introduced for a long time; secondly, it points out that the buried optical fiber structure design does not affect the warmth and sound insulation of the building; finally, the health monitoring of the building is realized through the proposed method of buried optical fiber sensing. The design scheme adopts a fiber optic light transmission and sensing system, which can realize the whole system's corrosion resistance, after laying buried and low-cost operation.

Research on seismic fragility of subway station based on incremental dynamic analysis method

Seismic intensity measure is an significant parameter that affects the accuracy of structural seismic risk assessment, and plays an important role in the performance-based earthquake engineering research framework. Taking a two story, three span, and shallow buried subway station as the research object, a two-dimensional finite element analysis model of soil structure underground in a typical engineering site was established using ANSYS. Ten earthquake records were selected from PEER as input, and the structural seismic fragility analysis method based on incremental dynamic analysis (IDA) method was introduced into the subway station structure. The maximum story drift angle was used as the structural damage index, and three typical seismic intensity measures were selected, the exploration is conducted on the seismic intensity measures applicable to shallow buried subway stations and the variation pattern of seismic response of subway stations with increasing seismic amplitude. The seismic fragility curve of shallow buried subway station structures is established to obtain the failure probability of the structure at different seismic intensity levels. The analysis results indicate that for shallow buried subway stations, PGA is the most suitable seismic intensity measure, and the comparison with existing empirical fragility curves shows that the vulnerability analysis method is feasible and can quantitatively provide the failure probability of structures at different performance levels, providing reference for seismic design of underground structures.

New geophysical and zircon data support an impact hypothesis for the Velingara structure (Senegal)

On Earth, impact structures are rare in intertropical zones. Here we evaluate the 35–40 km diameter Velingara depression in Senegal as a candidate impact structure. The depression has a topographic relief of only 50 m and is essentially buried under modern sediments. For the first time, potential-field ground observations and a microstructural survey of detrital zircons for shock features were conducted at Velingara. A 15 mGal gravity low in a 10 km diameter central anomaly was found, while significant (100 nT) amplitude magnetic field anomalies were observed in the depression. Forward modeling was used to explain the crustal sources of the anomalies, arguing in favor of the presence of a buried impact structure. An electron backscatter diffraction survey of circa 5,000 detrital zircons from a sample of modern alluvium identified a single granular zircon; orientation data for the grain does not record the former presence of reidite, but does closely resemble grains with highly dispersed neoblast orientations that have only been reported from impact settings. Age determination by LA-ICP-MS indicates the unusual granular zircon recorded an age of ca. 550 Ma. Results of the geophysical data and zircon microstructural survey reported here are consistent with, but do not yet prove, an impact origin hypothesis for the Velingara structure. The difference in amplitude between the diameter of the depression, and that of the gravity anomaly remains puzzling. Several impact scenarios are considered, which include the subsequent evolution via surface processes of a 10-km crater into a larger depression, or a large-scale (d = 40 km) complex impact crater with a peculiar geophysical anomaly limited to its central region.

Modular polymer stormwater collection structure response to one-week design-truck load

Full-scale physical modelling was used to evaluate the response of modular polymer stormwater collection structures when subjected to design-truck loading that was sustained for 1 week (i.e. a parked vehicle) and when buried with minimum soil cover. Surface loading was applied on a steel load pad that simulates one-half of the AASHTO design-truck single-axle that was held constant for 1 week to assess the stability of the buried system and demand on the platen and column components of the modules to allow independent load rating of the buried structure. No collapse or limiting state occurred. The 1-week creep buckling resistance was found to be nearly four times the factored column demand to 1-week loading for both module types. New insight into the time-dependent behaviour of the soil–structure system was gained by comparing the buried response to creep tests conducted on isolated columns and platens. The response of the buried soil–structure system was less severe than unconstrained creep. Column loads were found to not increase with time. Bending deflections increased by 1.04 to 1.26 times when buried rather than by 3.0 to 3.4 times for unconstrained creep as platen creep when buried was greatly restrained by the soil.

Ground penetrating radar investigations of buried remnants at ancient capital cities of Panchala and Vatsa kingdoms spread along Ganga-Yamuna doab of India from 600 BCE to 1100 CE

Ahichhatra and Kaushambi, ancient settlements located in Uttar Pradesh, comprise differential cultural deposits and architectural remnants from 2500 BCE to 1200 CE. These settlements flourished as the capital cities of once-prosperous urban kingdoms known as Panchala and Vatsa Mahajanapadas but remain abandoned in the present day. To provide ancillary data for the simplification of traditional archaeological explorational practices, a few portions located in and around the fortified areas of both settlements were considered for subsurface investigations using Ground Penetrating Radar (GPR). In Ahichhatra and Kaushambi, 2D and 3D GPR survey was carried out in the open areas devoid of vegetation for the understanding of the spatial alignment of the buried features within the fortified walls. The subsurface investigations at Ahichhatra have shown high amplitude reflections referring to buried wall structures, residential complexes, raised platforms, past-used surfaces and structural continuity. Also, the partial excavation carried out at Ahichhatra has revealed walls and compacted floors validating our findings. From Kaushambi, the findings include wall structures and interconnected chambered structures. The anomalies obtained in the data collected from considered survey sites located in Ahichhatra are 1–2 m wide and 2–4 m deep whereas in Kaushambi they are 0.5–1 m wide and 2–4 m deep. These findings helped us to determine the progressive urban relics of the ancient kingdoms which were known for their second phase of urbanism in Ganga Valley that prevailed until their abandonment. For a better understanding of the cultural history, detailed mapping of the contemporary sites can be carried out using integrated survey methods.

Effect of pulsed current cathodic protection on pipeline steel API 5L X65 corrosion mitigation: An investigation and machine learning-assisted modeling

Pulsed current cathodic protection (PCCP) could be more effective than direct current cathodic protection (DCCP) for mitigating corrosion in buried structures in the oil and gas industries if appropriate pulsed parameters are chosen. The purpose of this research is to present the corrosion prevention mechanism of the PCCP technique by taking into account the effects of duty cycle as well as frequency, modeling the relationships between pulse parameters (frequency and duty cycle) and system outputs (corrosion rate, protective current and pipe-to-soil potential) and finally identifying the most effective protection conditions over a wide range of frequency (2–10 kHz) and duty cycle (25%-75%). For this, pipe-to-soil potential, pH, current and power consumption, corrosion rate, surface deposits and investigation of pitting corrosion were taken into account. To model the input-output relationship in the PCCP method, a data-driven machine learning approach was used by training an artificial neural network (ANN). The results revealed that the PCCP system could yield the best protection conditions at 10 kHz frequency and 50% duty cycle, resulting in the longest protection length with the lowest corrosion rate at a consumption current 0.3 time that of the DCCP method. In the frequency range of 6–10 kHz and duty cycles of 50%-75%, SEM images indicated a uniform distribution of calcite deposits and no pits on cathode surface.

Remotely Sensing the Invisible—Thermal and Magnetic Survey Data Integration for Landscape Archaeology

Archaeological landscapes can be obscured by environmental factors, rendering conventional visual interpretation of optical data problematic. The absence of evidence can lead to seemingly empty locations and isolated monuments. This, in turn, influences the cultural–historical interpretation of archaeological sites. Here, we assess the potential of integrating thermal and magnetic remote sensing methods in the detection and mapping of buried archaeological structures. The area of interest in an alluvial plain in Tuva Republic makes the application of standard methods like optical remote sensing and field walking impractical, as natural vegetation features effectively hide anthropogenic structures. We combined drone-based aerial thermography and airborne and ground-based magnetometry to establish an approach to reliably identifying stone structures concealed within alluvial soils. The data integration led to the discovery of nine buried archaeological structures in proximity to an Early Iron Age royal tomb, shedding light on ritual land use continuity patterns.

MODELING OF THE LITHOSPHERE IN THE WHITE SEA REGION USING DECOMPOSITION OF ANOMALOUS GRAVITATIONAL AND MAGNETIC FIELDS

The research area includes the White Sea and adjacent land located in the junction zone of the eastern part of the Fennoscandian Shield and the Russian Plate. The purpose of the study is to construct a model of the lithospheric structure of the region using decomposition of anomalous gravitational and magnetic fields and inverse problem solving for components of gravity and magnetic fields, respectively. The decompositions of the fields were provided by the singular spectral method in the software package "R 4.3.1". The inverse problems were solved using the programs of the "Integro" complex. The components of the fields help to identify and analyze buried geological structures. The rift system of the White Sea is most clearly represented by the fourth component of the gravitational and magnetic fields. The positions of density and magnetic inhomogeneities of the Earth’s crust corresponding the components of the fields have been determined. The component model is compared with the seismic density and magnetic models of the lithosphere along the 3-AР geotraverse (Kem – White Sea Throat).

Unveiling the past: Utilizing satellite imagery archives to study archaeological landscapes in the northeastern Nile Delta, Egypt

This paper investigates the utilization of satellite imagery archives in the northeastern Nile Delta to examine and explore the evolution of archaeological landscapes. The study incorporates optical satellite imagery from multiple sensors, including Landsat, ASTER, and CORONA, in addition to historical topographic maps, and digital elevation data. The methodology involves employing Support Vector Machine (SVM) algorithm, spatial analysis, and analyzing vegetation indices. The findings reveal significant landscape changes during the period from the prehistoric to the Byzantine era, influenced by natural factors such as sea level changes and land subsidence. Moreover, the landscape changed after the construction of the Aswan High Dam, influenced by human activities such as agriculture and urbanization. The study was successful in detecting the remains of the Tanitic branch, an ancient branch of the Nile River. Additionally, the analysis of vegetation indices showed crop anomalies, which may be indicative of buried structures. However, further investigations, including ground surveys and excavations, are needed for validation. The research contributes to the understanding of the region's historical and cultural significance, highlights the impact of human activities on archaeological sites, and underscores the importance of preserving cultural heritage in the face of environmental changes and urban development.

Analysis and mapping of lunar wrinkle ridges (LWRs) using automated LWRs detection process with LROC-WAC and LOLA data

Maps of lunar wrinkle ridges (LWRs) were created from 70°N to 70°S and 140°E to 140°W (extracted and highlighted the major LWRs area) using automated LWRs detection process with Lunar Reconnaissance Orbiter Camera wide range angle camera and Lunar Orbiter Laser Altimeter data. Automatic detection of LWRs is challenging because the ridges are of irregular shapes and many ridges have been eroded and/or degraded over time. It’s a preliminary study of automated ridge detection from DEM data. Statistics and measurements of the extracted LWRs, including orientation, extent, length, height, and elevation offset, were performed based on the mapping of lunar ridges. The identified ridges were classified based on their orientation, distribution, direction, and each class were further divided over basalts, and nearby highlands. According to the findings, 3,375 segments with a total length of 26,455.01 km were identified, and the average elevation offset, width, and height of all the wrinkle ridges were 40.39 m, 3.47 km, and 0.29 km respectively after weighting by length. The LWRs were divided into three morphologies and distributions: parallel ridges, isolated ridges, and concentric ridges. The vast majority of LWRs were found in basalts area, with an extension into neighboring highland. The relations between the morphological parameters were further quantitatively analyzed, and a similar linear correlation between the width and height was found in each class of lunar ridges, implying that small and large ridges were formed as a continuum and that the three classes of ridges were probably formed by some common processes. Finally, the relations between the lunar wrinkle ridges and other geomorphic phenomena were analyzed, indicating that purely volcanic origin or buried premare structures are difficult to reconcile with the investigation. In addition, the consistency between the occurrence of the lunar wrinkle ridges and the thickness of lunar maria indicates that the formation of lunar wrinkle ridges is closely related to the lunar maria; nevertheless, the statistical NW direction of individual classes of LWRs also proposes the presence of an appropriate stress field during the process of their formation.

Design-truck ultimate limit states of buried modular polymer stormwater collection structures

Modular polymer stormwater structures are a relatively new class of buried structure with two horizontal platens supported by vertical columns. While structural demand at design truck loads has been quantified, the ultimate limit state to design truck loading is unknown. Full-scale physical experiments were conducted to quantify the applied load and identify the mode(s) of failure at the ultimate limit state of three types of modular structures when buried (with 0.6 m soil cover) and subject to static design truck loading. All three module types tested reached an ultimate limit state at applied loads around three times the nominal design load but had different modes of failure. The ultimate resistance for the module with columns having the lowest moment of inertia relative to length squared was caused by column buckling and top platen rupture, while the two modules with nearly twice the moment of inertia relative to length squared failed by top platen rupture and their column forces at most were 70%–75% of their short-term single column buckling resistance. The results provide new data to allow independent load rating of the buried structure, support continued assessment of column buckling, and identify the need to limit platen bending deflections.

The Impact Of Carbon Fiber on the surface properties of the 3D Printed PEGT Product

The primary focus of this work is the development of a hybrid composite material for 3D filaments. Polyethylene phthalate glycol (PETG) and (PETG/Carbon) fiber composite materials have their surface properties (surface roughness, Shore hardness, and micro hardness) tested. A ratio of 15% carbon fiber (in the form of carbon filaments) was used as the reinforcing filler. Using FDM (fused deposition modeling material) technology, the surface properties of PETG material used in 3D printed objects were enhanced. An ENDER 3D printer was used to create three PETG and PETG/Carbon fiber samples, using the printer setting 240°C temperature, 80°C build plate temperature, 55mm/s speed, 0.2mm layer height and speed fan 100mm/s. After that, an optical microscope and FT-IR technologies were used to investigate the samples. Results showed that as compared to PETG, the surface roughness of PETG/Carbon was reduced by 32.7%. This allowed carbon fiber to break doubly bonded in the PETG structure and also enhanced sample flow and adhesion. The PETG/Carbon samples had a Shore hardness D that was 2.16% lower than PETG's, but a slightly higher Micro hardness, making them more comparable to 10.4 HV than to 9.6 HV. However, the carbon fiber was reinforced and showed high compatibility with a PETG polymer matrix at the samples' buried structures, demonstrating that a 3D printer is an effective production tool for producing homogenized composite materials. According to claims, these features enhance the carbon fiber's ability to slide in PETG/Carbon samples.

An LSTM RNN proposal for surrogate modeling the dynamic response of buried structures to earthquake plane waves in soil half-spaces

This paper presents a variant of the long short-term memory (LSTM) recurrent neural network for surrogate modeling and predicting the seismic response of buried structures to in-plane inclined shear waves in heterogeneous soil profiles. The proposed model is designed to accept scalar and time-dependent random variables as input features to facilitate Monte Carlo (MC) based uncertainty quantification tasks where both the earthquake wave field and system properties are sources of uncertainty. To this end, it employs short-duration synthetic time histories for training instead of actual earthquake records to ensure efficiency. We discuss several configurations to evaluate the performance of the proposed methodology in predicting the tunnel response at different locations. We use two application examples concerning forward uncertainty quantification and sensitivity analysis to assess further the efficacy and accuracy of the proposed surrogate modeling approach.

Evaluation of the Earth Pressure Acting on Concrete Box Culverts

Earth pressure on concrete box culverts is a key component of design and load-rating decisions. The American Association of State Highway and Transportation Officials has revised the design guidelines over the years to impose greater design/rating earth pressures for buried structures. Currently, the Iowa Department of Transportation uses the maximum and minimum lateral earth pressure of 36/18 lb/ft3 specified for load factor design (LFD) and allowable stress design (ASD) and 60/30 lb/ft3 for load and resistance factor design (LRFD). The objective of this research is to monitor and evaluate the real earth pressures acting on deep-buried culvert structures. To achieve this objective, two concrete box culverts–one in Ida County and the other in Crawford County–were monitored for more than 2.5 years and 1 year, respectively, to identify the realistic design soil pressure. The captured pressure, strain, and temperature data were analyzed to find the relation between the temperature and earth pressure experienced by the culverts. The measured vertical and lateral pressures were compared with the specified design pressure loading. The monitoring results from both culverts led to the consistent conclusion that the earth pressure experienced by the culverts was two to six times that of the design values with the LRFD and LFD/ASD methods. This paper revealed that the earth pressure acting on the deeply embedded culvert could be higher than the design-specified value. Further research was recommended to investigate the relation between the soil weight and culvert vertical/lateral pressure for Iowa design specifications.

Probing three-dimensional mesoscopic interfacial structures in a single view using multibeam X-ray coherent surface scattering and holography imaging

Visualizing surface-supported and buried planar mesoscale structures, such as nanoelectronics, ultrathin-film quantum dots, photovoltaics, and heterogeneous catalysts, often requires high-resolution X-ray imaging and scattering. Here, we discovered that multibeam scattering in grazing-incident reflection geometry is sensitive to three-dimensional (3D) structures in a single view, which is difficult in conventional scattering or imaging approaches. We developed a 3D finite-element-based multibeam-scattering analysis to decode the heterogeneous electric-field distribution and to faithfully reproduce the complex scattering and surface features. This approach further leads to the demonstration of hard-X-ray Lloyd’s mirror interference of scattering waves, resembling dark-field, high-contrast surface holography under the grazing-angle scattering conditions. A first-principles calculation of the single-view holographic images resolves the surface patterns’ 3D morphology with nanometer resolutions, which is critical for ultrafine nanocircuit metrology. The holographic method and simulations pave the way for single-shot structural characterization for visualizing irreversible and morphology-transforming physical and chemical processes in situ or operando.