Jeoloji Mühendisliği Dergisi

ABSTRACT: The neccesity of natural resource gradually increases with engineering projects which are currently beingcarried out at the present time. For meeting the requirements, basaltic rocks are preferred due to their high strengthand durability. In this context, it is important to know the mineralogical and petrographic characteristics of basalts,which used in engineering applications and when required different sectors, that affect their crack initiating, failurethreshold and as well as the behavior under load. This study aimed to reveal the mechanical behavior of basaltic rockswhich have different mineralogical and petrographic features. Research was carried out on samples that have beencollected from the basalt quarries within Marmara Region and its surroundings. After mineralogical and chemicalcomposition analysis, petrographic properties of basalts were digitized with the help of the image processing. Atthe end of the laboratory studies, mechanic properties were obtained and load values of crack initiation and failurethreshold were determined with acoustic emission method. Obtained result show that load values of crack initiationvalue were found between 0.33σc and 0.54σc and the failure threshold value between 0.83σc and 0.98σc

ABSTRACT: The most important soil behaviour in order to consider in foundation designs of specially light structures builton clay soils is swelling properties of the soil and accordingly soils heave which occurs on soil surface. For thisreason, in surveys related to this kind of soils, it is quite important to determine the swelling properties of soils andappropriate stabilisation methods. Literature contains a vast number of stabilising techniques such as; lime, cement,fly ash, bitume and resin for treatment of expansive soils. Financial perspective of these techniques is very important.Therefore, the primary purpose is low cost for the best treatment. In this study, a laboratory model study wasconducted in order to determine the performance of gypsum column technique on treatment of clay soils. For thispurpose, gypsum column was built in a field model which built in the laboratory and the changes on swelling of thesoil was determined depending on the distance from the column. By using the obtained model data, the performanceof gypsum column technique was analyzed and discussed

ABSTRACT: Soil liquefaction is one of the ground deformations occurred during an earthquake which may cause serious damages such as settlement and tilting of structures due to loss of bearing capacity of foundations. Düzce and its surrounding settle on a plain which consists of silty and sandy layers with shallow groundwater level. Besides, the North Anatolian Fault Zone is a major seismic source which is capable of producing large magnitude earthquakes. All these data point out that the ground deformations like liquefaction and lateral spreading may occur during a probable large earthquake around Düzce and its close vicinity. In this study, the geotechnical data of 40 boreholes drilled to determine the local ground conditions and the groundwater level in Düzce were considered. Based on the field studies, it was aimed to evaluate the liquefaction potential considering the fact that the groundwater level is shallow as well as the subsurface soil is composed of loose alluvium. Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI) methods were taken in to account and the liquefaction potential of Düzce province was determined and mapped with respect to various earthquake scenarios in GIS environment. These maps are compared on the basis of different scenarios. Accordingly, it is concluded that the liquefaction potential is high-very high in the south and south-eastern sections of the study area where the construction of new residential buildings progressively continues.

ABSTRACT: A plant will be constructed between the Alipasa and Sarıkısık feldspar open-pit mines in Karpuzlu-Çine(Aydın) to conduct the works of crushing-grinding and flotation. An investigation was carried out to determineengineering geological conditions at and below the plant-site using scan-lines, geophysical measurements, and threeinclined borehole data. Geological structure and ground conditions including geotechnical data such as discontinuityfrequency and spacing, RQD% and CR% acquired from the drill hole exploration and geophysical survey aredetermined. Along the inclined drill holes, true discontinuity spacing values computed for each core run representthe most intersected discontinuities. In these calculations, determination of the acute angles between the axes ofdrill holes and strikes of the discontinuity sets are important as much as the investigation of fracture distributions inthe subsurface. For this reason, the stereographic projection techniques were used to determine the true acute anglein this work. The purpose of the investigation is to identify and mitigate difficulties caused by ground conditions.The rock conditions comprise heavily jointed and weathered metamorphic rocks and the ability of these to supportthe foundations is considered. It was determined that the bearing capacity values obtained from the geotechnicalcomputations considering RQD values agree with the ones acquired from the geophysical measurements, except theweakness zones (sheared zones). It was also determined that the values of allowable bearing pressure based on thegeotechnical works are more conservative than the ones from the geophysical measurements. When all results areconsidered, the ratio between the allowable bearing capacity (qa) values acquired from geotechnical and geophysicalmeasurements is close to 0.65. 

ABSTRACT: Geothermal reservoirs are renewable energy resources and they are treated as very valuable due to their highpressure and high enthalpy contents. Geothermal fluid stored in the reservoir is used for electricity production,central heating, greenhouse heating and for balyneological purposes. Fluid production from such reservoirs triggershydrodynamic and hydrothermal mechanisms and causes fluid movement and heat transfer in the reservoirs. Modelingstudies start with defining these mechanisms by differential equations and help investigating response of reservoirsto alternative production scenarios and hence obtain sustainable management of such systems. Fundamental studiesfor geothermal reservoir simulation require formulation of the mechanisms and application of boundary and initialconditions and the physical parameters obtained from conceptual model of the geothermal system. Geothermalreservoir modeling studies date back to 1970s and several geothermal reservoirs in the world have been simulated todetermine optimum and sustainable production policies. This paper summarizes the basic principles of geothermal reservoir modeling and introduces basic differential equations and explains mysteries of the reservoir simulatorsnowadays widely used in the geothermal industry. The numerically simulated geothermal fields and the relatedcountries are also summarized together with the references.  

ABSTRACT: In this study research methods are assessed to determine the spatial distribution of petroleum hydrocarboncontamination in the coastal aquifers and to develop a groundwater flow and transport model that can be usedto evaluate the level of natural attenuation that has occurred. The stages of this study include: 1) preliminaryassessment and conceptual model including hydrogeologic characteristics of the site, the history of the site, and anypast or current remedial activities, 2) field and laboratory investigations including soil and groundwater samplingtechniques such as soil borings, multi-level monitoring well installation, aquifer tests and water quality sampling.Parameters to be measured, their measurement methods and use of these data should be explained in detail, 3)physical and geochemical characterization of the study area with the results of the field and laboratory investigations,4) development of the groundwater model with selected software, 5) evaluation of monitored natural attenuationaccording to primary and secondary lines of evidence established during the investigation. The primary linesof evidence, which is a stable or shrinking plume rather than an expanding plume, will be the benzene, toluene,ethylbenzene and xylene (BTEX) contour maps prepared as a result of the groundwater sampling. Secondary linesof evidence, which include geochemical data that serve as indicators of naturally occurring biodegradation andestimates of natural attenuation rates, will be based on electron acceptor/reduction product concentrations measuredwithin the BTEX plume. The results of the groundwater modeling are used to help decide whether the monitorednatural attenuation process results in BTEX contaminant levels declining to acceptable levels within a specified time.If projections of contaminated levels indicate that natural attenuation is not enough for remediation, then additionalremedial alternatives can be recommended for further investigation