Abstract on Application of Geophysics in Solving Environmental and Engineering Problem

APPLICATION OF GEOPHYSICAL METHODS IN SOLVING ENGINEERING AND ENVIRONMENTAL PROBLEMS Lawrence A. Anine, Department of Earth Science, Federal University of Petroleum Resources, Effurun. The use of geophysical methods in solving engineering and environmental problems has increased over the years in most developed countries like Japan. During the 60’s, when Japan was still in their developing era, geophysical methods were used in investigation of new construction such as tunnel, dams, buildings and so on.In the present era, geophysical methods are now used in investigating disaster prevention, maintenance of existing construction and soil and ground water pollutions. As a developing country and continent, various geophysical methods should be employed in solving various engineering and environmental problems because they play a vital role in solving such problems. This vital role played by geophysicists, especially in construction of new roads, railways and high-rise buildings wi ll be reflected in the future because, for instance, during construction, huge amounts of concretes are been used and this requires huge amount of sands.So, if low quality sands are used, the performance or quality of the concretes will decelerate, and as such shortens its durable years. Such concretes can cause accident in the future due to its bad quality. Therefore, it is important to an engineer to investigate the health of these concretes (building materials) and this role becomes much more important in the future. Geophysical methods with non-destructive techniques will be employed in testing the construction.Geophysical investigation is employed not only during construction but also for maintenance of existing constructions. Most concretes construction will reach their durable years after about 15 to 20 years and these durable years needs to be extended in order to use them longer than before since the rate of new construction will reduce in the coming era of low rate of econ omical growth. So, existing constructions needs to be well maintained and these quality control and maintenance of the existing construction becomes much more important in the future.As more industries are being created in Nigeria and in other developing countries of Africa, huge amount of waste will be generated and disposed into the ground in and around the factories, polluting the soil and underground water in that area. Geophysical methods are employed in investigation for remediation of the polluted soil and underground water. It plays an important role in solving this problem resulting from increasing amount of environmental pollutions in this area.In investigation of soil and groundwater pollution, geophysical methods can be used as a tool for Estimation of the total area that has been polluted and the degree of pollution. Investigation and detection of the source of the pollution. Studying and understanding the mechanism of pollution. Monitoring of remediation of the polluti on. Geophysical methods used for shallow subsurface investigation can be used in detecting drum cans containing contaminant buried at shallow depths.Flow of contaminant can also be investigated using techniques like the self potential method which can estimate the distribution of impermeable and permeable layers and the flow characteristic of ground water and as such can be used to monitor the remediation process of the pollution. Pumping-up well Visualization of groundwater flow by streaming potential measurements (after Sato et al. , 1997) Geophysics is also employed in Transportation projects and it’s use in geotechnical projects is increasing among transportation agencies like the US state, Federal (i. DOTs-Department of Transportation) and Canadian transportation agencies. Geophysical Edited with the trial version of Foxit Advanced PDF Editor To remove this notice, visit: www. foxitsoftware. com/shopping APPLICATION OF GEOPHYSICAL METHODS IN SOLVING ENGINEERING AND ENVIR ONMENTAL PROBLEMS methods mostly used in transportation projects are Seismic method, Ground penetrating radar(G. P. R) and vibration monitoring and they have been employed in bedrock mapping, mapping soil deposits(soil characterization) and in investigating roadway subsidence.The purpose of using geophysics in transportation projects is to identify and characterize physical properties of subsurface geomaterials in a manner that benefits highway projects and transportation programs in ways like reducing project cost, achieving better and broader subsurface characterization, increasing speed of acquisition and utilizing a noninvasive approach to evaluate subsurface conditions.Application of borehole geophysical methods as applied to the non-petroleum sector have enjoyed a resurgence of growth in recent years as engineers and environmental scientist are beginning to appreciate and use the added value of borehole geophysical data in solving engineering and environmental problems especia lly in developed countries.Advanced borehole geophysical methods such as gamma, resistivity, fluid temperature and resistivity, electromagnetic induction (EM), magnetic susceptibility, P- and S- wave velocity, flowmeter, optical televiewer, borehole video, and crosshole seismic tomography have been used to characterize fractured-rock ground-water flow, delineate bedrock foliation and fracture orientation, map unconsolidated hydrogeologic units, and delineate saltwater intrusion(Stumm, 2003). Geophysics is also employed in the investigation for disaster prevention in areas prone to disasters like earthquakes, volcanoes, e. . c. Deep seismic reflection and gravity methods are almost always necessary for delineation of active faults and deep subsurface structure in investigation for earthquake disaster prevention. Key Words: Pollutant Remediation, Disaster Prevention, Borehole Geophysical Methods, Self Potential, Ground Penetrating Radar, Seismic method, Gravity method, Electromagnetic Induction, Gamma, Vibration monitoring, soil characterization. ABBREVIATIONS G. P. R :- Ground Penetrating Radar EM:- Electromagnetic Induction P-wave:- Primary waves S-wave:- Secondary waves DOTs:- Department of TransportationREFERENCES Sato, H. , Shima, H. , and Sakurai, K. , 1997, A study on generation of streaming potential due to pumping-up of groundwater: Proc. of the 97th technical conference of SEGJ, 279-282 (in Japanese). Satoru, O. , Application of Geophysical exploration for Environmental Earth Sciences and Engineering: OYO Corporation, 4-2-6 Kudan-kita, Chiyoda-ku, Tokyo, Japan, 1-11. Sirles, P. C. , 2006, Use of Geophysics for Transportation Projects; A synthesis of Highway Practice(NCHRP synthesis): Transportation Research Board,Washington D.C. , 1-12. Stowell, J. R, An overview of Borehole Geophysical methods for solving Engineering and Environmental problems: EG&G Mount Sopris Instrument, Colorado, U. S. A. Stumm, F. , Chu, A. , 2003, Application of Advanced surface and Borehole Geophysical methods to environmental and engineering problems on long Island and Manhattan, New York: US Geological Survey, Coram, NY. Uomoto, T. , 2000, Maintenance of concrete structures in the 21 century: BUTSURI-TANSA, (Geophysical Exploration), 53, 499506 (in Japanese).