Remediation of the geotechnical problems of the Hasankeyf historical area, southeastern Turkey

The castle, palaces and man-made historical and recent cave dwellings of Hasankeyf will be partly flooded by the reservoir of the Ilisu dam which is planned to be constructed over the Tigris River. Hasankeyf is entirely within the Germik formation which is composed of whitish to light gray and/or beige, medium strong, fresh to slightly weathered, thick to very thick bedded, locally massive, almost horizontal or gently dipping silty, sandy limestone. The major geotechnical concerns in the area consist of the possibility of kinematic failure of the foundation of "Little Palace" and the collapse of some of the roofs of the adjacent man-made cave dwellings carved in rock due to insufficient pillar (wall) thicknesses to carry the overburden load. A limit equilibrium analysis of the kinematically unstable planar rock block underlying the foundation of 'Little Palace' was performed as a function of the water level in the reservoir. The maximum required anchor force was calculated as approximately 3,000 kN/m which led to a total anchor force of about 42,000 kN for the 14-m-wide slope face of the unstable planar block. The results of the finite element analysis to determine the minimum stable pillar (wall) thickness required between adjacent caves led to a recommendation to apply a steel arch support to one of the adjacent caves at Hasankeyf in case the wall thickness was less than or equal to 0.60 m

A Comparison of Local Site Conditions with Passive and Active Surface Wave Methods

This study encompasses dynamic soil characterization and seismic hazard mapping of the Plio-Quaternary and especially Quaternary alluvial sediments of the Çubuk district and its close vicinity that is situated towards the north of Ankara. The project site is located at a region which has a potential of being seriously affected by a possible earthquake occurring along the Çubuk Fault Zone that is thought to be a continuation of the Dodurga Fault Zone and a sub-fault belt of the North Anatolian Fault System that is one of the most prominent fault systems in Turkey with significant earthquake potential. Non-invasive seismic methods were used to obtain a 1-D shear wave velocity profile of the subsurface at 41 sites and two measurements were taken at each site for passive and active surface wave methods. The Multichannel Analysis of Surface Wave Method (MASW) and the Microtremor Array Method (MAM) were used as active and passive surface wave methods, respectively. By combining these two techniques, the shear wave velocity profiles of the sites were obtained. Based on the results, site classes were assigned for seismic hazard assessment studies followed by a preparation of a seismic zonation map of the site utilizing GIS software

EVALUATION OF SITE CHARACTERIZATIONS AND SITE EFFECTS OF THE ANKARA BASIN, TURKEY

ABSTRACT The purpose of this study is to assess the in-situ site characteristics and to perform seismic hazard studies of the Upper Pliocene to Pleistocene fluvial and Quaternary alluvial and terrace deposits located towards the west of Ankara. Based on a general engineering geological, geotechnical and seismic characterization of the site, site classification systems were assigned for seismic hazard evaluations. Then, short-period noise recordings of the microtremor measurements at the ground surface have been used to estimate the site response of the site. This research mainly focuses on the development of a methodology to integrate the various components necessary for a regional multihazard seismic risk assessment that includes consideration of hazards due to local site effects. These tasks have been fulfilled through the development of an engineering database that was obtained from invasive and non-invasive explorations at the study area. Hence, the engineering geological and geotechnical site characterization studies have been compiled; and geophysical site characterization studies have been performed, particularly in the Quaternary sediments of the Ankara basin. By using all of these studies, hazard assessment maps (i.e., site classification map and site period map) and a seismic zonation map of Ankara basin, Turkey were developed along with discussing the consequences of the seismic hazards

Assessment of kinematic rock slope failures in Mudurnu Valley, Turkey

Slope instabilities are one of the most frequent natural hazards capable of causing severe failures both at regional and large scales. Mudurnu, which is settled on a steep valley, is affected by regional rock slope instabilities. These instabilities constitute a hazard and create an important risk to the community since they threaten human lives, settlement areas, and historically-important structures. In order to minimize the hazard and risk associated with slope instabilities, rock masses along the valley were characterized and the potential failure mechanisms were defined. The west side of the valley, which is the focus of the research, is characterized by Cretaceous pelagic discontinuous limestone, and is prone to complex failures. The aim of the study is to characterize the rock mass along the valley, divide the area into geomechanically-uniform sectors, define possible modes of failure (kinematics) and ultimately quantify the potential failure (kinetics) and the associated risk. For the study, in addition to the field work and scan-line survey measurements, an Unmanned Aerial Vehicle (UAV) was utilized to collect high-resolution images from problematic locations that were not accessible. Then, a point cloud of the area was generated. The images were interpreted and the resulting structural representation of the rock mass was compared with information gathered from the scan-line survey in the field. Afterwards, it was used to identify the possible modes of failure along the valley. Since seismic activity in the area is significant due to the proximity of the North Anatolian Fault Zone (NAFZ), which is the most active fault system in Turkey, dynamic loading was also considered for the stability analyses

Discontinuous rock slope stability analysis by limit equilibrium approaches - a review

Slope stability is one of the most important topics of engineering geology with a background of more than 300 years. So far, various stability assessment techniques have been developed which include a range of simple evaluations, planar failure, limit state criteria, limit equilibrium analysis, numerical methods, hybrid and high-order approaches which are implemented in two-dimensional (2D) and three-dimensional (3D) space. In the meantime, limit equilibrium methods due to their simplicity, short analysis time, coupled with probabilistic and statistics functions to estimate the safety factor (F.S), probable slip surface, application on different failure mechanisms, and varied geological conditions has been received special attention from researchers. The presented paper provides a review to limit equilibrium methods used for discontinuous rock slope stability analyses with different failure mechanisms of natural and cut slopes. The article attempted to provide a systematic review for rock slope stability analysis outlook based on limit equilibrium approaches

Discontinuous rock slope stability analysis under blocky structural sliding by fuzzy key-block analysis method

This study presents a fuzzy logical decision-making algorithm based on block theory to effectively determine discontinuous rock slope reliability under various wedge and planar slip scenarios. The algorithm was developed to provide rapid response operations without the need for extensive quantitative stability evaluations based on the rock slope sustainability ratio. The fuzzy key-block analysis method utilises a weighted rational decision (multi-criteria decision-making) function to prepare the 'degree of reliability (degree of stability-instability contingency)' for slopes as implemented through the Mathematica software package. The central and analyst core of the proposed algorithm is provided as based on discontinuity network geometrical uncertainties and hierarchical decision-making. This algorithm uses block theory principles to proceed to rock block classification, movable blocks and key-block identifications under ambiguous terms which investigates the sustainability ratio with accurate, quick and appropriate decisions especially for novice engineers in the context of discontinuous rock slope stability analysis. The method with very high precision and speed has particular matches with the existing procedures and has the potential to be utilised as a continuous decision-making system for discrete parameters and to minimise the need to apply common practises. In order to justify the algorithm, a number of discontinuous rock mass slopes were considered as examples. In addition, the SWedge, RocPlane softwares and expert assignments (25-member specialist team) were utilised for verification of the applied algorithm which led to a conclusion that the algorithm was successful in providing rational decision-making

Application of the modified Q-slope classification system for sedimentary rock slope stability assessment in Iran

Abstract(#br)The Q-slope system is an empirical method for discontinuous rock slope engineering classification and assessment. It has been introduced recently to provide an initial prediction of rock slope stability assessment by applying simple assumptions which tend to reflect different failure mechanisms. This study offers a correlation relationship between Q-slope and slope stability degree using case studies of sedimentary rock slopes from 10 regions of Iran. To this end, we have investigated 200 areas from these regions, gathered the necessary geotechnical data, have classified the slopes from a Q-slope perspective, and have estimated their stability relationships. Based on artificial intelligence techniques including k-nearest neighbours, support vector machine, Gaussian process, Decision tree, Random-forest, Multilayer perceptron, AdaBoost, Naive Bayes and Quadratic discriminant analysis, the relationships and classifications were implemented and revised in the Python high-level programming language. According to the results of the controlled learning models, the Q-slope equation for Iran has indicated that the stability-instability class distributions are limited to two linear states. These limits refer to the B-Line (lower limit) as

Geotechnical Properties and Permeability of Compacted Clay in the Gölbaşı Region Ankara

This study evaluated the geotechnical properties and permeability of compacted clayey foundation soils in the Gölbaşı region of Ankara to determine their suitability as a compacted landfill liner material. The results of the tests showed that the clay was suitable to be used as a compacted clay landfill liner material. Copyright of Journal of Solid Waste Technology & Management is the property of Journal of Solid Waste Technology & Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract

Lined waste containment systems: A method for design and performance evaluation

The objective in designing lining systems for the containment of the leachate generated within a landfill is the prevention of contamination of groundwater and surface waters. The technology involving the design of these systems has progressed to a point that the integrity of the containment can be relied on over the long term. Double-lined systems provide the additional benefit of being able to quantify the performance of the lining system through the detection of leakage through the upper liner. The difficulty, however, lies with the qualitative evaluation of the system. This paper addresses this issue and offers a practical approach for the design and evaluation of double-lined systems and the leakage that is detected