scholarly journals COMPARISON BETWEEN RESULTS OF SEISMIC REFRACTION AND STANDARD PENETRATION TEST (SPT) TO STUDY SHALLOW GEOLOGICAL SUBSURFACE IN AN URBAN AREA OF BRASÍLIA, BRAZIL

2014 ◽  
Vol 32 (4) ◽  
pp. 673
Author(s):  
Pedro Vencovsky Nogueira ◽  
Marcelo Peres Rocha ◽  
Welitom Rodrigues Borges ◽  
Eduardo Xavier Seimetz ◽  
Márcio Maciel Cavalcanti
Keyword(s):  
Low Cost ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Standard Penetration Test ◽  
P Wave ◽  
Penetration Test ◽  
Engineering Project ◽  
Common Procedure ◽  
Shallow Seismic ◽  
Investigation Methods

ABSTRACT. The most common procedure for an engineering project/construction is the use of direct survey, borehole and Standard Penetration Test (SPT). Thisprovides punctual information of the geology at the site, and many boreholes are necessary along the construction site, representing a significant amount of the budgetfor the construction and to help develop a better geological understand/map of the site. The use of geophysical methods allows to study the subsurface by indirectmeans, with low cost, and enable to cover large areas if compared to direct surveys. Geophysical methods are increasingly being used in engineering works, however, inBrazil the use in engineering projects is still scarce. In this work was used shallow seismic refraction method to study the shallow subsurface in an area along the futuretrack of the subway system of Bras´ılia, Brazil. The refraction results (P-wave) were compared with previous existing data from Standard Penetration Test (SPT), and soilprofile description. The seismic was used to study the subsurface geology, and SPT data were used to compare the seismic results. We observed a good correlationfor the depths obtained through each method, mostly in the north portion of the line, when the SPT was near the line, indicating that its results are influenced by thesame mechanical parameters, related to soil strength. Our results motivate the use of seismic refraction as a tool to optimize the direct investigation methods for bettergeotechnical characterization of the medium.Keywords: shallow seismic refraction, standard penetration test (SPT), geotechnical study. RESUMO. O procedimento inicial mais comum em um projeto de engenharia é o uso de pesquisa direta, por meio de sondagens e Índice de Resistência à Penetração (SPT, em inglês). Estas ferramentas fornecem informações pontuais acerca da geologia local, sendo necessárias diversas sondagens para desenvolver um bom entendimento geológico/geotécnico da região, fazendo com que as sondagens representem uma quantidade significativa do orçamento da obra de engenharia. O usode métodos geofísicos permite estudar a subsuperfície por meio indireto, com baixo custo, e possibilita cobrir grandes áreas, quando comparado ao uso exclusivo desondagens diretas. Métodos geofísicos estão sendo cada vez mais utilizados em obras de engenharia, no entanto, o seu uso em projetos de engenharia no Brasil aindaé escasso. Neste trabalho foi utilizado o método de sísmica de refração rasa para estudar a subsuperfície em uma área ao longo do futuro trecho do sistema de metrô de Brasília, Brasil. Os resultados de refração (onda P) foram comparados com os dados pré-existentes de SPT e descrição do solo. A sísmica foi empregada para estudara geologia da subsuperfície, os dados SPT foram utilizados para comparar com os resultados sísmicos. Observou-se uma boa correlação para as profundezas obtidas através de cada método, principalmente na porção norte da linha, região em que o SPT está mais próximo da linha, indicando que os seus resultados são influenciados pelos mesmos parâmetros mecânicos, relacionados com a resistência do solo. Nossos resultados motivam o uso de refração sísmica como uma ferramenta para aperfeiçoar os métodos de investigação direta, com objetivo de gerar uma melhor caracterização geotécnica do meio.Palavras-chave: sísmica de refração rasa, índice de resistência à penetração, estudo geotécnico.

GEOTECHNICAL PARAMETERS STUDY USING SEISMIC REFRACTION TOMOGRAPHY

2016 ◽  
Vol 78 (8-6) ◽  
Author(s):  
Rose Nadia ◽  
Rosli Saad ◽  
Nordiana Muztaza ◽  
Nur Azwin Ismail ◽  
Mohd Mokhtar Saidin
Keyword(s):  
Parameter Estimation ◽  
Seismic Refraction ◽  
Standard Penetration Test ◽  
P Wave ◽  
Cohesive Soils ◽  
Penetration Test ◽  
Geotechnical Parameters ◽  
Wave Velocities ◽  
Refraction Tomography ◽  
Loose Medium

In this study, correlation is made between seismic P-wave velocities (Vp) with standard penetration test (SPT-N) values to produce soil parameter estimation for engineering site applications. A seismic refraction tomography (SRT) line of 69 m length was spread across two boreholes with 3 m geophones spacing. The acquired data were processed using Firstpix, SeisOpt2D and surfer8 software. The Vp at particular depths were pinpointed and correlated with geotechnical parameters (SPT-N values) from the borehole records. The correlation between Vp and SPT-N values has been established. For cohesive soils, it is grouped into three categories according to consistencies; stiff, very stiff and hard, having velocity rangesof 575-314 m/s, 808-1483 m/s and 1735-2974 m/s, respectively. For non-cohesive soils, it is also divided into three categories based on the denseness as loose, medium dense and dense with Vp ranges of 528-622 m/s, 900-2846 m/s and 2876-2951 m/s, respectively

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.

Geophysical mapping of gypsum for exploration of reserves in the Nong Bua area of Thailand

2020 ◽  
pp. qjegh2019-180
Author(s):  
Rungroj Arjwech ◽  
Mark E. Everett ◽  
Sakhon Saengchomphu ◽  
Kittipong Somchat ◽  
Potpreecha Pondthai
Keyword(s):  
Electrical Resistivity ◽  
Construction Projects ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Raw Material ◽  
P Wave ◽  
The Core ◽  
Micro Cracks ◽  
P Wave Velocity ◽  
Increasing Demand

The increasing demand for gypsum as a raw material for construction projects motivates exploration for additional reserves. Electrical resistivity tomography (ERT) and seismic refraction geophysical methods, augmented with borehole and laboratory measurements on core samples, are used here to delineate the top, bottom and lateral boundaries of an important gypsum ore deposit in Thailand, an economically developing region. The gypsum-bearing formation is found throughout the study area to have an irregular upper boundary on account of karstic dissolution processes. The deeper transition from gypsum to anhydrite, however, is not constrained by the measurements. The P-wave velocity measured in the field is consistent with the core specimen measurements. The electrical resistivity of the core specimens, however, is substantially higher than the values measured in the field. The specimen measurements may depend on the presence of micro cracks, whereas electrical resistivity in the field may be affected by the enclosing clay-rich materials.

scholarly journals Detection of Cover Collapse Doline and Other Epikarst Features by Multiple Geophysical Techniques, Case Study of Tarimba Cave, Brazil

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2835
Author(s):  
Yawar Hussain ◽  
Rogerio Uagoda ◽  
Welitom Borges ◽  
Renato Prado ◽  
Omar Hamza ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Least Square ◽  
P Wave ◽  
Positive Anomaly ◽  
Refraction Tomography ◽  
Collapse Doline

Reliable characterization of the karst system is essential for risk assessment where many associated hazards (e.g., cover-collapse dolines and groundwater pollution) can affect natural and built environments, threatening public safety. The use of multiple geophysical approaches may offer an improved way to investigate such cover-collapse sinkholes and aid in geohazard risk assessments. In this paper, covered karst, which has two types of shallow caves (vadose and fluvial) located in Tarimba (Goias, Brazil), was investigated using various geophysical methods to evaluate their efficiency in the delineation of the geometry of sediments filled sinkhole. The methods used for the investigation were Electrical Resistivity Tomography (ERT), Seismic Refraction Survey (SRS), Seismic Refraction Tomography (SRT) and the Very Low Frequency Electromagnetic (VLF-EM) method. The study developed several (2D) sections of the measured physical properties, including P-wave velocity and electrical resistivity, as well as the induced current (because of local bodies). For the analysis and processing of the data obtained from these methods, the following approaches were adopted: ERT inversion using a least-square scheme, Karous-Hjelt filter for VLF-EM data and time-distance curves and Vp cross-sections for the SRS. The refraction data analysis showed three-layered stratigraphy topsoil, claystone and carbonate bedrock, respectively. The findings obtained from ERT (three-layered stratigraphy and sediment-filled doline), as well as VLF-EM (fractured or filled caves as a positive anomaly), were found to be consistent with the actual field conditions. However, the SRS and SRT methods did not show the collapsed material and reached the limited the depth because of shorter profile lengths. The study provides a reasonable basis for the development of an integrated geophysical approach for site characterization of karst systems, particularly the perched tank and collapse doline.

scholarly journals Evaluating the Geotechnical and Geophysical Characteristics of Expanding Districts in Tehran Using Field Experiments

2018 ◽  
Vol 4 (2) ◽  
pp. 363
Author(s):  
Arash Razmyar ◽  
Abolfazl Eslami
Keyword(s):  
Urban Areas ◽  
Field Experiments ◽  
Geophysical Methods ◽  
Field Tests ◽  
Young Modulus ◽  
Friction Angle ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Engineering Structures ◽  
Geotechnical Characteristics

Considering the increasing population growth and the rapid growth of urbanization and pollution in the environment, providing zoning maps and urban engineering geology seem to be important. The rapid construction growth of cities, as well as the confrontation with events such as earthquakes and failure to observe the geological and geotechnical issues, has caused many engineering problems. The use of geophysical methods not only cannot lonely provide us a complete and comprehensive information on the geotechnical conditions of the earth but also has many disturbances in urban areas, and its use in urban centers is almost impractical. Therefore, it seems that the best way of examining and interpreting the geotechnical characteristics of a site, especially in urban areas, is the use of suspicious data. Therefore, performing geotechnical studies and geotechnical zoning can be useful for retrofitting buildings and engineering structures and reducing their risks. Hence, zoning studies are conducted in this research in order to better recognize the technical soil status for safe construction due to rising the population of Tehran in recent decades and the concentration of population in certain areas of Tehran, especially in the eastern and western regions (districts 4 and 22). In this study, different geotechnical field tests such as standard penetration test (SPT), cone penetration test (CPT) were used to estimate parameters such as adhesion coefficient (C), internal friction angle ( ), Young modulus (E). Other common experiments with conventional geophysical experiments, such as in good experiments, refractive and CSSW were applied to estimate geophysical parameters of bedrock depth and shear wave velocity for zoning these areas.

scholarly journals Applications of Shallow Seismic Refraction Measurements in the Western Carpathians (Slovakia): Case Studies

2018 ◽  
Vol 48 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Bibiana Brixová ◽  
Andrea Mosná ◽  
René Putiška
Keyword(s):  
Thermal Power ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Waste Storage ◽  
Shallow Seismic ◽  
First Case ◽  
Refraction Tomography ◽  
Storage Area ◽  
Station Waste

Abstract Shallow seismic measurement, specifically seismic refraction tomography, is an effective geophysical method that has applications in various sectors. It enables the search for and determination of the course of the interfaces, thus helping to resolve geological, environmental, hydrogeological, engineering, geotechnical and other problems. The paper demonstrates the possibilities of using these methods through examples of shallow seismic measurements that have been performed at various four locations in the Western Carpathian Mountains. The first case study describes Monastery Pond at Katarínka. It was found that, the basement of the Monastery pond is at a depth of 2-3 m below the surface and the results were also confirmed by electrical resistivity tomography (ERT). The next measurement through the thermal power station waste storage showed that the storage area base runs at a depth of about 20 m under the measured profile. The third case study addresses the depth of groundwater depth in the area of Borská nízina. The measurement confirmed the assumed depth of ground water level at 3.35 m below the surface. In the last case study, border fault between the Turiec Basin and the Malá Fatra Mts. was mapped by application of shallow refraction methods. The results show that shallow seismic methods shed light on the problem and in combination with other geophysical methods are an effective tool with great potential. They provide very useful data for shallow mapping applications.

scholarly journals Subsurface Soil Evaluation using Seismic Refraction Tomography and Standard Penetration Test at Bukit Bunuh Impact Crater Area

2019 ◽  
Vol 4 (1) ◽  
pp. 1-10
Author(s):  
Mustapha Adejo Mohammed ◽  
Rosli Saad ◽  
Nur Azwin Ismail ◽  
Sabiu Bala Muhammad ◽  
Amsir Taib ◽  
...  
Keyword(s):  
Impact Crater ◽  
Seismic Refraction ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Soil Evaluation ◽  
Refraction Tomography ◽  
Subsurface Soil

An Evaluation of the Level of Liquefaction in an Iron Mine in the Central Henan Transit Railway Line Project

2011 ◽  
Vol 99-100 ◽  
pp. 282-285
Author(s):  
Shi Jie Qu ◽  
Ji Fei Liu ◽  
Hong Xing Liu
Keyword(s):  
Clay Content ◽  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Preliminary Design ◽  
Penetration Test ◽  
Engineering Project ◽  
Protective Measures ◽  
Railway Line ◽  
Transport Project ◽  
Iron Mine

Soil liquefaction is extremely detrimental to the Central Henan transit railway line project. The present study proposes a preliminary design to evaluate the effects of liquefaction and to determine the parameters and protective measures that need to be implemented. The geological properties, clay content, groundwater level, and the thickness of the overlying non-liquefied soil were initially determined. Then, a standard penetration test was employed to analyse the soil liquefaction potential in an iron mine in the Central Henan rail transport project. The evaluation of similar engineering project sites with middle-class areas vulnerable to liquefaction is important to determine the necessary anti-liquefaction measures.

scholarly journals Liquefaction Assessment Using the CPT and Accounting for Soil Ageing

2018 ◽  
Vol 7 (3) ◽  
pp. 162-168
Author(s):  
Bambang Setiawan ◽  
Mark Jaksa
Keyword(s):  
Low Cost ◽  
South Australia ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Liquefaction Potential ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio ◽  
Conservative Estimation ◽  
Liquefaction Assessment ◽  
Soil Ageing

Due to its continuous data recording capability, excellent repeatability and accuracy, relatively low cost and simplicity of operation, the cone penetration test (CPT) offers enhanced liquefaction assessment over its predecessor the standard penetration test (SPT). However, soil ageing, which influences the cyclic resistance ratio (CRR), is difficult, if not impossible, to be detected by the CPT due to disturbance during the test. This situation may lead to excessively conservative estimation of CRR values which result in conservative assessment of liquefaction potential. This paper presents and discusses liquefaction assessment using the CPT and methods for accounting for soil ageing. A field study, conducted at Gillman, South Australia, is presented and the study site is assessed for liquefaction potential. This paper also explores the influence of soil ageing on the subsequent liquefaction assessment.

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