What Lies Beneath: Geophysical Approaches for Assessing Trenchless Water Crossings

2018 ◽  
Author(s):  
Alastair McClymont ◽  
Paul Bauman ◽  
Erin Ernst ◽  
Dan Parker
Keyword(s):  
British Columbia ◽  
Granular Material ◽  
Engineering Design ◽  
Case Studies ◽  
Seismic Refraction ◽  
Geophysical Data ◽  
Water Bodies ◽  
Geophysical Surveys ◽  
Data Gaps ◽  
Different Types

When tied to drilling results, geophysical surveys of trenchless water crossings provide important information on subsurface geotechnical conditions, including bedrock elevation and the locations of zones of granular material within overburden. Because the terrain can change quite dramatically at water crossings, it is difficult to acquire geophysical data that is continuous between the geotechnical boreholes. The resulting data gaps can decrease confidence in understanding the site geotechnical conditions, which increases uncertainties in the detailed engineering design of the trenchless water crossing (e.g., HDD, or MTBM method). We demonstrate here how some of the technical challenges associated with acquiring continuous geophysical data at water crossings can be overcome. These include the use of suspended ERT cables, and complementary waterborne ERT and seismic refraction surveys. To illustrate the efficacy of these techniques, we present case-studies from proposed HDD crossings of three different types of water bodies at sites in British Columbia and Alberta.

Pipeline Route Assessment at River Crossings and in Steep Terrain: Geophysical, Hydrologic and Geotechnical Characterization

2002 ◽  
Author(s):  
Gilein J. Steensma ◽  
Mark A. Kappelhoff ◽  
Duncan A. McInnis ◽  
Eric Gilson
Keyword(s):  
Seismic Refraction ◽  
Geophysical Data ◽  
River Channels ◽  
Refraction Tomography ◽  
Geological Conditions ◽  
Geophysical Surveys ◽  
The Face ◽  
Steep Terrain ◽  
Difficult Terrain ◽  
Lateral Variations

Pipeline river crossings and sections of pipeline routes where steep terrain requires directionally drilled borings have the highest chance of being successfully designed and constructed if subsurface geological conditions are understood. In this paper we present results of geophysical surveys conducted to characterize the subsurface at two pipeline river crossings and at a site where steep topography would likely require directional boring below the face of a steep hillside. The objective is to help assess and minimize the risk in engineering design in difficult terrain by analyzing subsurface geology from geophysical data and vertical geotechnical borings, and evaluating the dynamic behavior of the river itself through hydrologic analysis. Risk factors can be assigned on the basis of lithology and environmental considerations relating to the level of potential impact in different parts of the crossing. The laterally heterogeneous nature of river channels, consisting of stacked paleochannels and floodplains could require a significant number of vertical geotechnical borings for adequate characterization of the entire crossing. We find that a combination of electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and ground penetrating radar (GPR) data can efficiently provide us with an understanding of electrical and mechanical properties from which lateral variations and depth extent of lithology along the proposed boring can be inferred. Confirmatory vertical geotechnical borings allow us to verify our interpretation at two locations. Geophysical data are used to laterally extrapolate the lithologic interpretation and define, in conjunction with surface water hydrologic considerations, the minimum depth of directionally drilled borings and optimum locations of ingress/egress points. The investment in a geological assessment study to understand subsurface conditions prior to beginning horizontal boring operations is essential to mitigate risk and ultimately may save money. In the case of steep terrain, geophysical data can provide valuable information on the vertical and lateral variations in subsurface properties in areas where it would be impossible to safely drill vertical borings. Our last case history is an example of the geological information that can be efficiently inferred from geophysical surveys conducted in steep terrain.

An integrated methodological approach for the three-dimensional modeling of the subsurface structures: the case of Borgo Montello, in Latina, Italy.

2021 ◽  
Author(s):  
Klodian Skrame ◽  
Diego Albini ◽  
Carlo Moriconi ◽  
Christian Comotti ◽  
Redi Muci ◽  
...  
Keyword(s):  
Seismic Refraction ◽  
Three Dimensional ◽  
Geophysical Data ◽  
Electrical Tomography ◽  
Subsurface Structures ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Stratigraphic Model ◽  
Local Seismic Response ◽  
Geophysical Surveys

<p>In this work, it is intended to highlight the indispensable significance of the geophysical surveys on the hydrogeological research and on the seismic risk mitigation.</p><p>This paper describes the acquisition methodologies, the instrumentation used, the techniques and methods of inversion / interpretation and the results of a hybrid geophysical survey carried out for the reconstruction of the 3-D geological modeling of the Borgo Montello case study, in the Province of Latina, in Italy.</p><p>The aim of the study was to test the use of hybrid geophysical surveys in order to obtain a detailed geological-stratigraphic and hydrogeological modeling of the subsoil, its interpretation in terms of flow model and to identify the relationships between the parameters that define the geological-hydrogeological-stratigraphic model with the local seismic ground motion amplification of the site.</p><p>From a geological point of view, the study area in composed by two main geological formations. The most superficial one is characterized by sedimentary deposits linked to the filling of the Pontine depression: composed by alternations of clays, silty clays and silts, with a subordinate component of silty sands. The second lithological type is linked to the deposition of pyroclastic deposits from the Lazio volcano and in particular from the deposits of reddish pozzolane alternating with thickened tuff, the so-called "Tufo lionato".</p><p>A research approach that integrated different geophysical methods, as: resistivity, induced polarization electrical tomography and seismic refraction and high resolution reflection methods were carried out to reproduce the thickness and the extension of the over mentioned deposits.</p><p>Afterwards, having obtained 5 independent models (seismic reflection section, seismic refraction section, electrical resistivity tomography, electrical tomography and local seismic amplification section) the authors proceeded, through the k-means algorithm methods, for the analysis of the bivariate dataset cluster, in order to identify the relationships between the 5 sets of variables. The proposed methodology was focuses on characterizing the aquifer potential by using simultaneously all the geophysical parameters obtained together with the stratigraphic data, in order to reduce the uncertainties and ambiguity in the interpretation of the geophysical data for a better modeling of the subsoil.</p><p>The obtained results were compared with a collection of existing boreholes, well logs, geotechnical and geophysical data. The 3-D geological models match quite well with the information determined from these previous works.</p><p>Lastly, based on the three-dimensional modeling of the subsurface structures, a Local Seismic Response study was carried out.</p>

scholarly journals Towards an Evaluation-Based Framework of Collaborative Archaeology

2015 ◽  
Vol 3 (2) ◽  
pp. 107-123 ◽  
Author(s):  
David R. Guilfoyle ◽  
Erin A. Hogg
Keyword(s):  
British Columbia ◽  
Community Engagement ◽  
Case Studies ◽  
Project Evaluation ◽  
Methodological Framework ◽  
Community Members ◽  
Analysis And Evaluation ◽  
Archaeological Practice ◽  
Collaborative Archaeology ◽  
Different Types

AbstractCollaborative archaeology is a growing field within the discipline, albeit one that is rarely analyzed. Although collaborative approaches are varied and diverse, we argue that they can all share a single methodological framework. Moreover, we suggest that collaborative archaeology projects can be evaluated to determine the variety among projects and to identify the elements of engaged research. We provide two case studies emphasizing project evaluation: (1) inter-project evaluation of community-engagement in British Columbia archaeology and (2) intra-project evaluation of co-management archaeology projects in Western Australia. The two case studies highlight that project evaluation is possible and that a single framework can be applied to many different types of projects. Collaborative archaeology requires analysis and evaluation to determine what facilitates engagement to further the discipline and to create better connections between archaeologists and community members. The discussed case studies illustrate two shared methods for accomplishing this. The paper argues that collaborative approaches are necessary for advancing archaeological practice.

Integration of Multi-geophysical Approaches to Identify Potential Pathways of Heavy Metals Contamination - A Case Study in Zeida, Morocco

2020 ◽  
Vol 25 (3) ◽  
pp. 415-423
Author(s):  
Ahmed Lachhab ◽  
El Mehdi Benyassine ◽  
Mohamed Rouai ◽  
Abdelilah Dekayir ◽  
Jean C. Parisot ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Electrical Current ◽  
P Wave ◽  
Low Resistivity ◽  
Refraction Tomography ◽  
Geophysical Surveys

The tailings of Zeida's abandoned mine are found near the city of Midelt, in the middle of the high Moulouya watershed between the Middle and the High Atlas of Morocco. The tailings occupy an area of about 100 ha and are stored either in large mining pit lakes with clay-marl substratum or directly on a heavily fractured granite bedrock. The high contents of lead and arsenic in these tailings have transformed them into sources of pollution that disperse by wind, runoff, and seepage to the aquifer through faults and fractures. In this work, the main goal is to identify the pathways of contaminated water with heavy metals and arsenic to the local aquifers, water ponds, and Moulouya River. For this reason, geophysical surveys including electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and very low-frequency electromagnetic (VLF-EM) methods were carried out over the tailings, and directly on the substratum outside the tailings. The result obtained from combining these methods has shown that pollutants were funneled through fractures, faults, and subsurface paleochannels and contaminated the hydrological system connecting groundwater, ponds, and the river. The ERT profiles have successfully shown the location of fractures, some of which extend throughout the upper formation to depths reaching the granite. The ERT was not successful in identifying fractures directly beneath the tailings due to their low resistivity which inhibits electrical current from propagating deeper. The seismic refraction surveys have provided valuable details on the local geology, and clearly identified the thickness of the tailings and explicitly marked the boundary between the Triassic formation and the granite. It also aided in the identification of paleochannels. The tailings materials were easily identified by both their low resistivity and low P-wave velocity values. Also, both resistivity and seismic velocity values rapidly increased beneath the tailings due to the compaction of the material and lack of moisture and have proven to be effective in identifying the upper limit of the granite. Faults were found to lie along the bottom of paleochannels, which suggest that the locations of these channels were caused by these same faults. The VLF-EM surveys have shown tilt angle anomalies over fractured areas which were also evinced by low resistivity area in ERT profiles. Finally, this study showed that the three geophysical methods were complementary and in good agreement in revealing the pathways of contamination from the tailings to the local aquifer, nearby ponds and Moulouya River.

التفسير الموضوعي للقرآن الكريم: مجالاته ومنهجية البحث فيه (Thematic Interpretation of the Qur’Én: Its Scopes & Methodology), (TafsÊr MauÌË‘Ê: Aspek-aspek dan Metodologi Kajian)

2010 ◽  
Vol 7 (2) ◽  
pp. 51
Author(s):  
فتحي بن جمعة أحمد
Keyword(s):  
Key Words ◽  
Case Studies ◽  
Research Methodology ◽  
Real Life ◽  
Systematic Investigation ◽  
Research Topic ◽  
Research Projects ◽  
Thematic Unity ◽  
Different Types ◽  
Significant Area

ملخص البحث تعدّ هذه المحاولة في دراسة مجالات التفسير الموضوعي ومنهجية البحث فيه  مفتاحا لبعض القضايا المتعلقة بالموضوع، ومدخلا لدراسة التفسير الموضوعي يسهل على طلاب العلم والباحثين فهم كلام الله، وتدبر معانيه، والاهتداء به، والقيام ببحوث تطبيقية في مجالات التفسير الموضوعي. فقد بينت أن مجالات البحث في التفسير الموضوعي أربعة وهي البحث في المصطلح، والموضوع، والمحاور، والوحدة الموضوعيّة في السورة القرآنيّة. وقد أكدت أن البحث في محاور القرآن الكريم من مجالات البحث في التفسير الموضوعي التي لم تحظَ باهتمام الباحثين، ثم توسعت في سوق الأدلة والبراهين الدالة على أن الوحدة الموضوعية للسورة القرآنيّة مجال أساس من مجالات البحث في التفسير الموضوعي الذي لا ينبغي إغفاله، وإهمال شأنه. ثم بحثت في موضوع منهجيّة البحث في التفسير الموضوعي، ونظراً للخلط أوالاضطراب الذي بدا لدى بعض الباحثين في هذا الصدد، وضحت المقدمات المنهجيّة العامة الضرورية للبحث في التفسير الموضوعي ثم حاولت رسم الإطار التصوري والمنهجي العام والضوابط الأساسية التي يجب أن يتبعها الباحث إذا أراد الكتابة في التفسير الموضوعي. ثم بيّنت الخطوات الأساسيّة للبحث في التفسير الموضوعي ومنها حرية الباحث في اختيار موضوع بحثه والاطلاع على أكبر عدد ممكن من التفاسير بمختلف أنواعها مع الاستفادة من التراث البشري في حقول المعرفة المتنوعة على أن تكون الهيمنة للقرآن أولا وأخيرا على الكتب الأخرى والنظريات البشرية. الكلمات الرئيسة: القرآن، تفسير، موضوعي، مجالات، منهج. Abstract This article is an attempt to address the issue of the scopes and research methodology in the thematic commentary of the Holy Qur’Én. It could be considered as an introductory work for students and researchers who are interested in this field of research which will help them develop a good understanding of the meanings and teachings of the Qur’Én and its application to the real life. It may also help them undertake case studies and research in the field of thematic commentary of the Qur’Én. It has been explained in the article that the scope of the thematic commentary of the Qur’Én includes four areas; i.e. the concept, the topic, the central themes and the thematic unity of the SËrah/Chapter. The article gives a special emphasis on the study of the Qur’Énic central themes as it was overlooked by some researchers. It also provides a systematic investigation on the thematic unity of the SËrah/Chapter and considers it a significant area of research in the thematic commentary of the Qur’Én. The article also addresses the issue of the research methodology in the field of the thematic commentary of the Qur’Én. In this regard, the author highlights the principles, conditions and framework for undertaking research projects in this field of study and explains the major steps that should be followed in the execution of the research. These steps include freedom of choosing the research topic, freedom of benefitting from different types of tafsÊr (interpretation of the Qur’Én) works and schools and benefitting from the human heritage in different fields of knowledge, provided that the Qur’Én should have controlling power on other books and human theories.   Key Words: The Qur’Én, TafsÊr, Thematic, Scopes, Methodology. Abstrak Artikel ini ialah satu percubaan menangani isu  skop dan metodologi penyelidikan dalam tafsiran Al-Qur’Én Holy mengikut tema. Ia boleh dianggap sebagai satu kajian permulaan untuk pelajar-pelajar dan sarjana-sarjana yang meminati bidang ini penyelidikan yang akan membantu mereka merangka satu pemahaman yang baik tentang makna-makna dan ajaran-ajaran Qur’Én dan perlaksanaannya dalam kehidupan sebenar. Ia mungkin juga  dapat membantu mereka menjalankan kajian kes dalam bidang penyelidikan tafsiran Al-Qur’Én mengikut tema. Artikel ini akan menjelaskan  skop tafsiran Al-Qur’Én mengikut  tema ini merangkumi empat bidang:  konsep tafsiran mengikut tema, topiknya, tema-tema kecil dan tema umum Surah Al-Qur’Én. Artikel ini memberi satu penekanan khas pada kajian tafsiran Al-Qur’Én mengikut  tema kerana ia agak kurang mendapat perhatian beberapa penyelidik. Ia juga menampilkan satu kajian sistematik pada pemahaman tema Surah dalam Al-Qur’Én dan menganggapnya satu bidang penyelidikan penting dalam kajian tafsiran Al-Qur’Én mengikut tema. Artikel juga memberikan perhatian kepada bidang metodologi penyelidikan terhadap usaha tafsiran Al-Qur’Én secara bertema. Dalam hal ini, pengkaji akan menonjolkan prinsip-prinsip, syarat-syarat dan rangka kerja untuk projek-projek projek penyelidikan dalam lapangan ini dan menerangkan langkah-langkah utama yang harus diikuti dalam pelaksanaan penyelidikan yang berkenaan. Lang-langkah ini termasuk kebebasan memilih tajuk penyelidikan, kebebasan dalam mengambil  manfaat daripada jenis-jenis tafsiran Qur’Én yang berbeza serta sekolah-sekolah pemikiran yang berbeza dalam aliran tafsir serta rangka bagaimana memanfaatkan warisan tamadun manusia berlandaskan ajaran Al-Qur’Én. Kata Kunci: Al-Qur’Én, TafsÊr, Tema, Bidang-bidang, Metodologi.

Airborne geophysical surveys in Greenland in 1998

1999 ◽  
pp. 34-38 ◽  
Author(s):  
Thorkild M. Rasmussen ◽  
Leif Thorning
Keyword(s):  
High Resolution ◽  
Geophysical Data ◽  
Digital Data ◽  
Geological Survey ◽  
Magnetic Data ◽  
Magnetic Survey ◽  
Original Series ◽  
Geophysical Surveys ◽  
The Government

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Rasmussen, T. M., & Thorning, L. (1999). Airborne geophysical surveys in Greenland in 1998. Geology of Greenland Survey Bulletin, 183, 34-38. https://doi.org/10.34194/ggub.v183.5202 _______________ Airborne geophysical surveying in Greenland during 1998 consisted of a magnetic project referred to as ‘Aeromag 1998’ and a combined electromagnetic and magnetic project referred to as ‘AEM Greenland 1998’. The Government of Greenland financed both with administration managed by the Geological Survey of Denmark and Greenland (GEUS). With the completion of the two projects, approximately 305 000 line km of regional high-resolution magnetic data and approximately 75 000 line km of detailed multiparameter data (electromagnetic, magnetic and partly radiometric) are now available from government financed projects. Figure 1 shows the location of the surveyed areas with highresolution geophysical data together with the area selected for a magnetic survey in 1999. Completion of the two projects was marked by the release of data on 1 March, 1999. The data are included in the geoscientific databases at the Survey for public use; digital data and maps may be purchased from the Survey.

Aeromagnetic survey in central West Greenland: project Aeromag 2001

2002 ◽  
pp. 67-72 ◽  
Author(s):  
Thorkild M. Rasmussen
Keyword(s):  
High Resolution ◽  
Magnetic Measurements ◽  
Geophysical Data ◽  
High Quality ◽  
Aeromagnetic Survey ◽  
Original Series ◽  
West Greenland ◽  
Airborne Measurements ◽  
Geophysical Surveys ◽  
Airborne Geophysical Data

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article. Rasmussen, T. M. (1). Aeromagnetic survey in central West Greenland: project Aeromag 2001. Geology of Greenland Survey Bulletin, 191, 67-72. https://doi.org/10.34194/ggub.v191.5130 The series of government-funded geophysical surveys in Greenland was continued during the spring and summer of 2001 with a regional aeromagnetic survey north of Uummannaq, project Aeromag 2001 (Fig. 1). The survey added about 70 000 line kilometres of high-quality magnetic measurements to the existing database of modern airborne geophysical data from Greenland. This database includes both regional high-resolution aeromagnetic surveys and detailed surveys with combined electromagnetic and magnetic airborne measurements.

scholarly journals Withdrawal Properties of Self-Tapping Screws in Japanese larch (Larix kaempferi (Lamb.) Carr.) Cross Laminated Timber

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 524
Author(s):  
Junhua Xu ◽  
Shuangbao Zhang ◽  
Guofang Wu ◽  
Yingchun Gong ◽  
Haiqing Ren
Keyword(s):  
Regression Model ◽  
Engineering Design ◽  
Wood Species ◽  
Japanese Larch ◽  
Effective Length ◽  
Larix Kaempferi ◽  
Cross Laminated Timber ◽  
The World ◽  
Different Types ◽  
Length Increment

With the increasing popularity of cross-laminated timber (CLT) constructions around the world, there have been attempts to produce CLT using local wood species in different countries, such as Japanese larch (Larix kaempferi (Lamb.) Carr.) in China. Thus, the need to investigate the connection performance also increases to support the design and construction of CLT buildings using local wood species. In this study, the withdrawal properties of three different types of self-tapping screws (STS), with a diameter of 6 mm, 8 mm, and 11 mm, were tested with Japanese larch CLT. The results revealed that the withdrawal strength of STS increased with increasing density and effective length, but decreased with an increasing diameter. With a density increment of 0.05 g/cm3, the withdrawal strength increased by an average of 9.4%. With an effective length increment of 24 mm, the withdrawal strength increased by an average of 1.4%. An empirical regression model was adopted to predict the withdrawal strength of Japanese larch CLT based on the results, which can be used for potential engineering design of CLT connections using STS.

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