Geotechnical evaluations and deterministic design considerations for pitwall slopes at Eskihisar (Yatağan-Muğla) strip coal mine

Ph.D. - Doctoral Progra

Deformation modulus of heavily jointed-sheared and blocky greywackes by pressuremeter tests: Numerical, experimental and empirical assessments

Deformability of rock masses influencing their behavior is an important geomechanical property for the design of rock structures. Due to the difficulties in determining the deformability of jointed rock masses at the laboratory-scale, various in-situ test methods such as pressuremeter, dilatometer, plate loading tests etc. have been developed. Although these techniques are currently the best and direct methods, they are time-consuming and expensive, and present operational difficulties. In addition, the influence of the test volume on deformation modulus depending on the method employed is also important. For these reasons empirical equations to indirectly estimate the deformation modulus have also been recommended by several investigators as an alternative approach. In this study; the geomechanical quality of weak, heavily jointed, sheared and/or blocky greywacke rock masses, on which very concentrated civil works are continuing at the southern and southwestern parts of Ankara (Turkey), was assessed. The deformation modulus was determined by pressuremeter tests, the possible effects of variables on the derived deformation modulus from the pressuremeter test were evaluated by numerical methods, and the comparisons between the deformation modulus of the greywackes obtained from the pressuremeter tests and their geomechanical quality (GSI and RMR) were made. Numerical simulations revealed that the presence of a disturbed annulus around the borehole causes underestimation of the deformation modulus, while the effect of length to diameter ratio of the pressuremeter probe on the deformation modulus is minor. Based on the geoengineering characterization assessments, mainly two greywacke rock masses with different geomechanical qualities were identified. Geotechnical quality of one of these rock masses was verified by the back analysis of two slope failures. The empirical equations to indirectly estimate the deformation modulus of the greywackes using their GSI and RMR values yielded high coefficients of correlation

A New Empirical Method to Predict Liquefaction-Induced Lateral Spread

Liquefaction-induced lateral spreading affects large areas and causes considerable damages to overlying structures and buried lifelines at shallow depths. In this study, the world-wide lateral spreading case studies compiled from literature and available records of some institutions were re-evaluated to assess the performance of the current empirical methods and to develop a new empirical method for predicting the magnitude of lateral spreading. The probability-based four empirical models were developed using the maximum likelihood methodology for predicting displacements of (a) a sloping ground, (b) a free face, of a ground (c) with and (d) without slope and free face, and their prediction performances were compared with those of the existing models

Assessment of deformation modulus of weak rock masses from pressuremeter tests and seismic surveys

The deformation modulus of intact rock can be determined through standardized laboratory tests for heavily jointed rock masses but this is very difficult, while in situ tests are time-consuming and expensive. In this study, the deformation modulus of selected heavily jointed, sheared and/or blocky, weathered, weak greywacke, andesite and claystone were assessed, based on pressuremeter tests, geo-engineering characterization and seismic surveys. Empirical equations based on GSI and RMR values are proposed to indirectly estimate the deformation modulus of the greywackes. For the andesites, the spacing of the discontinuities is greater than the length of the pressuremeter probe hence the intact rather than rock mass deformation modulus is obtained. The pressuremeter test results from the claystones could not be correlated with the field data; the relationship between the ratio of rock mass modulus to intact rock modulus and RQD appears to give a better estimation of the deformation modulus

Development of geotechnical microzonation model for Yenisehir (Bursa, Turkey) located at a seismically active region

Earthquake hazard zonation for urban areas, mostly referred to as seismic microzonation, is the first and important step towards a seismic risk analysis and mitigation strategy in populated regions. Proper understanding of the local subsurface ground conditions is essential for a realistic assessment. Turkey is one of the earthquake prone countries in the World and the lessons particularly drawn from the devastating 17 August 1999 and 12 November 1999 earthquakes of Turkey revealed the importance of microzonation studies. The purpose of this study is to further develop a geotechnical microzonation model regarding the suitability of the residential areas in Yenisehir (Bursa), a rapidly developing settlement area in a seismically active region of Turkey. For this purpose, properties and dynamic behavior of the Quaternary alluvial soils in study area were assessed. Soil classification, soil amplification, natural soil predominant period, resonance phenomena and liquefaction potential of the study area were evaluated using borehole data and microtremor measurements. The raw data obtained from previous studies carried out at Yenisehir were used for these assessments. Geotechnical microzonation map of Yenisehir was produced according to the surface damage due to liquefaction, soil amplification and distance to streams maps; by using Geographical Information Systems (GIS) based Multi-Criteria Decision Analysis. The weight values were assigned to the layers using Analytical Hierarchical Process method by pairwise comparisons. The produced geotechnical microzonation map indicated that the most critical areas are located in the densely populated middle and the southeastern parts of the study area

Comparison of undrained shear strength by pressuremeter and other tests, and numerical assessment of the effect of finite probe length in pressuremeter tests

There is a wide body of research reported in the literature which compare the undrained shear strength determined from various field and laboratory tests. The pressuremeter testing equipment and the related design techniques have been continuously refined. However, the undrained shear strength (S (u)) determined from the pressuremeter test (PMT) is generally higher than that obtained from other field or laboratory tests. In this study, numerical methods to consider the effects of length to diameter ratio (L/D) of the pressuremeter probe, and the procedural implications of soil disturbance and testing depth on the undrained shear strength determined from the PMT were investigated and possible correction factors depending on L/D ratio were established. In addition, in order to compare the variations in undrained shear strength of a clayey material with depth and testing method, a lightly overconsolidated and highly plastic clay, called "Eymir Lake clay" near Ankara (Turkey), was selected as the material of the study, and its values of undrained shear strength (S (u)), which were determined by PMT, field vane shear (FVT), conic penetration test (CPT), and laboratory tests, were compared. Based on the numerical analysis results, the correction factors depending on the L/D ratio of the conventional probes were suggested. The correction factors ranged from 0.83 to 0.96 for L/D ratios of 5.3 to 11, respectively, and they were determined to be independent of the rigidity values ranging from 25 to 200. It was also shown that overestimation of S (u) is independent of depth. In addition, due to very low permeability values of the Eymir Lake clay, it is concluded that for soils with coefficients of permeability lower than 10(-10) m/s, partial drainage around the pressuremeter probe is unlikely. Based on the comparison among the results from laboratory and different field tests, the values of S (u) determined from the theoretical Palmer's solution are higher than those from CPT, FVT, and CU tests. If the correction for L/D ratio is applied to the values of S (u) determined from the Palmer's solution, S (u) from pressuremeter approaches S (u) obtained from FVT; however, there is still a slight overestimation in S (u) obtained from PMT. This overestimation is probably due to the differences in the mode of failure and the presence of a disturbed zone around the pressuremeter probe. However, S (u) determined from the PMT by empirical methods is close to those determined from CPT, FVT, and CU tests

Yer Mühendislik Terimleri Sözlüğü

Uzmanlık alanlarına hitap eden ve terimlerle birlikte bunların tanımlarının da birlikte verildiği sözlüklerin hazırlanması, Türk dilinin zenginliğinin ortaya çıkarılması, dilimizin dünya dilleri arasında değerine yakışır bir düzeye ulaştırılması ve terminolojide birlikteliğin sağlanması açısından büyük bir öneme sahiptir. Bu çerçevede; maden, jeoloji, inşaat ve jeofizik mühendisliği dallarının yer kürenin yüzeyinde ve sığ derinliklerinde gerçekleştirilen mühendislik işleriyle olan ilgileri ve ortak çalışmaları dikkate alınarak; mühendislik jeolojisi, hidrojeoloji, jeoteknik saha incelemesi, kaya mekaniği ve kaya mühendisliği, maden işletme ve tünelcilik, zemin mekaniği, temel mühendisliği, zemin dinamiği-deprem jeoteknik (yer tekniği) mühendisliği, zemin iyileştirmesi, mühendislik jeofiziği ve sismoloji gibi konuların yanı sıra, adı geçen mesleklerce ortak olarak kullanılan jeoloji terimlerini de içeren bir terimler sözlüğünün hazırlanmasının yararlı olacağı düşünülmüştür. Bu amaçla Reşat Ulusay, Mehmet Ekmekçi, Hasan Gerçek, K. Önder Çetin ve Mustafa Aktar tarafından hazırlanan ve TMMOB Maden Mühendisleri Odası tarafından basılan "Yer Mühendislik Terimleri Sözlüğü"; tanımlarıyla ve İngilizceleriyle birlikte verilmiş 1675 terim ile "bkz." kısaltmasıyla birlikte sunulmuş ve yeni terimlerle aynı anlama gelen 517 terim olmak üzere, toplam 2192 terimi içermektedir. Bu sözlüğün ülkemizde yer mühendisliği konularında çalışan uygulamacı, araştırmacı ve mühendislik eğitimi alan öğrenciler arasında terminolojide birlikteliğin sağlanmasına yardımcı olması ve dilimizin teknik anlamda daha güçlü kılınması yönünde katkı sağlaması beklenmektedir. 262 sayfadan oluşan cilt kapaklı bu sözlüğe, başta Maden Mühendisleri Odası olmak üzere, Jeoloji, İnşaat ve Jeofizik Mühendisleri Odalarından da ulaşılabilir

Assessment of geoengineering and environmental problems for the possible use of abandoned rock hewn settlement area in Ürgüp Cappadocia Turkey

The Cappadocia Region of Central Anatolia having a very distinct culture is one of the attractive touristic sites of Turkey due to its spectacular and unique landforms and historical heritages. In this region, the structures carved into thick to massive tuffs survived and kept their original integrity for a number of centuries. Environmental and anthropological factors at the Cappadocia Region have been the main reasons for extensive subsurface and multi-purpose use in the past and present. In addition, thermal insulation properties of the tuffs make these rocks suitable for use in underground openings. The Kayakapi Neighborhood, located in the town of Urgup, is one of the famous historical sites. This site is situated within the "Goreme National Park and the Rock Sites of Cappadocia" which was inscribed on the World Heritage List in 1985. In order to develop the tourism potential of this abandoned site while preserving its cultural and natural values, a natural environmental conservation and revitalization project was initiated. As an integral part of this project, in this study, environmental and engineering geological problems, including rock fall potential and stability of about 1,200 rock-hewn structures, were investigated and an inventory was prepared for the possible re-use of the underground openings and other structures at the site, and remedial measures were recommended. The assessments based on observations and experimental studies indicated that the tuffs do not show significant changes both perpendicular and parallel to layering, and discontinuities and rock weathering seem to be more important factors controlling the stability of rock-hewn structures. The major stability problems threatening the re-use of the openings are structurally-controlled block instabilities, overbreaks, and erosion and shearing of the pillars made of tuff. On the other hand, the area at the entrance of the site requires some protection measures such as the construction of a retaining wall, systematic bolting of rock slabs and removal of some blocks having rock fall potential. The inventory for the openings suggests that there are a number of openings that can be re-used after necessary remedial measures