Geotechnical and geophysical characterization of the Bouira-Algiers Highway (Ain Turck,Algeria) landslide

The Ain Turck (Bouira) landslide, in north-center Algeria, is one of the numerous instabilities recorded along the Lakhdaria-Bouira section of the 1200-km-long east-west Algerian highway. The locality of Ain Turck is known for its unstable slopes characterized by a very rough morphology with steep slopes (20 to 25%). This slide threatens the inhabitants of the Ibournanen village, located down the unstable slope, where parts of some houses have fallen into ruin, while others are cracked. It is characterized by an active movement extending over a more or less important slope, of the order of a hundred meters. The land mobilized by this movement corresponds to the layer of shale clays and clays overlaid by a backfill, placed there following the east-west highway works. Geological, geomorphologic, and geotechnical analysis allows determining the soil instability probably related to earthworks during the construction of the highway section a few years earlier, followed by a particularly rainy season in 2012. Acquisitions of ambient seismic noise and H/V ratio processing, as well as the acquisition of an electrical resistivity profile at the instability site, have reinforced our preliminary interpretations of depth and geometry of the sliding surface.     

Vulnerability assessment of coastal areas to sea level rise from the physical and socioeconomic parameters: case of the Gulf Coast of Bejaia,Algeria

The study area (the Gulf of Bejaia) is a coastal zone of about 70 km long in the eastern-central part of the Algerian coast. The coastline characterized by sandy beaches, hotels and tourist facilities, airport, port, villages and towns has known during these last decades several threats like storms, floods and erosion. The present work concerns the mapping of the physical and socioeconomic vulnerability of the Gulf Coast of Bejaia to sea level rise, using Coastal Vulnerability Index (CVI) and geospatial tools. The Physical CVI (CVI_Phys) is calculated from seven physical variables: geomorphology, coastal slope, coastal regional elevation, sea level rise rate, shoreline erosion/accretion rates, tidal range and significant wave height. On the other hand, the parameters population, cultural heritage, roads, railways, land use and conservation designation constitute, for their part, the socioeconomic CVI (CVI_eco). The values obtained from the calculation of CVI_Phys vary between 3.53 and 81.83. These results revealed that 22.42 km of the studied coastline has a low physical vulnerability, 21.68 km a high vulnerability and 15.83 km a very high vulnerability, indicating that the most part of the coastline (53.59%) is vulnerable to sea level rise. According to the obtained values of CVI_eco, the most vulnerable areas of high and very high risk represent 31.81 km of the total coastline. They were found along the western (Bejaia and Tichy) and eastern (Aokas, Souk El Tenine and Melbou) coast, while the least vulnerable stretches, covering 38.19 km of the total length of the coast, occupy the rest of the area. This study highlighted areas that will be most affected by future sea level rise (SLR) and storm events. It revealed that several development projects of Bejaia Gulf Coast, including tourist expansion areas, are planned in sites identified as very vulnerable. The results obtained from this assessment could guide local planners and decision-makers in developing coastal management plans in the most vulnerable areas.     

Geotechnical characterization of marine sediments in the Ulleung Basin,East Sea

The geotechnical characteristics of Ulleung Basin sediments are explored using depressurized samples obtained at 2100 m water depth and 110 m below the sea floor. Geotechnical index tests, X-ray diffraction, and SEM images were obtained to identify the governing sediment parameters, chemical composition and mineralogy. We use an instrumented multi-sensor oedometer cell to determine the small-strain stiffness, zero-lateral strain compressibility and electromagnetic properties, and a triaxial device to measure shear strength. SEM images show a sediment structure dominated by microfossils, with some clay minerals that include kaolinite, illite, and chlorite. The preponderant presence of microfossils determines the high porosity of these sediments, defines their microstructure, and governs all macroscale properties. The shear wave velocity increases as the vertical effective stress increases; on the other hand, porosity, permittivity, electrical conductivity, and hydraulic conductivity decrease with increasing confinement. All these parameters exhibit a bi-linear response with effective vertical stress due to the crushable nature of microfossils. Well-established empirical correlations used to evaluate engineering parameters do not apply for these diatomaceous sediments which exhibit higher compressibility than anticipated based on correlations with index properties. Settlements will be particularly important if gas production is attempted using depressurization because this approach will cause both hydrate dissociation and increase in effective stress.     

Metallogenesis of the late Pan-African gold-bearing East Ouzzal shear zone (Hoggar, Algeria)

In the W Hoggar (Algeria), the major transcurrent N–S East Ouzzal shear zone (EOSZ) hosts several world-class gold deposits over a 100-km length. The late Pan-African EOSZ separates two contrasting Precambrian domains: the Archaean In Ouzzal block to the west (orthogneisses with subordinate metasediments, reworked and granulitized in the c. 2 Ga Eburnean event) and a Middle Proterozoic block to the east (again orthogneisses and metasediments, involved in the c. 600 Ma Pan-African event). The EOSZ is a mylonite belt, 1–3 km wide, with a 50-m-wide ultramylonite belt hosting numerous quartz veins and lenses (giant hydrothermal quartz system) associated with a quartz-sericite-pyrite-carbonate (beresite) alteration. These hydrothermal events occurred under ductile (evolving towards brittle) conditions, between 500 and 300 MPa, at 500–300°C, with aqueous-carbonic fluids derived both from underlying devolatilized metamorphic rocks and a mantle source, as recorded by stable (C, O) isotope data. No gold mineralization was associated with these typical mesothermal events. Following a pressure drop (to 130 MPa), related to the inception of extensional tectonics, the EOSZ was later percolated by a new set of hydrothermal fluids, evolved from basinal waters that deeply penetrated into the In Ouzzal basement. These fluids were Ca-bearing brines (up to 25% wt. eq. NaCl), characterized by high δD (-9 to + 18‰ range), mobilized by the thermal energy released by the late Pan-African granite magmatism (Taourirt granites). As demonstrated by Pb isotope data, the brines leached Au from the In Ouzzal granulites (which contain 3 ppb Au). Fluid inclusion studies indicate that gold was deposited from these brines in the EOSZ at a depth of c. 5 km, due to mixing and cooling with descending diluted fluids.     

Estimation of uniaxial compressive strength of North Algeria sedimentary rocks using density,porosity, and Schmidt hardness

This study aims to establish new correlations to assess uniaxial compressive strength (UCS) of northern Algeria sedimentary rocks. This estimation is based on the measurements of density, porosity, and Schmidt hammer hardness. To achieve this goal, a geological and geotechnical characterization campaign was conducted on 19 types of sandstone and carbonate rocks which have been collected from different geological areas of the Maghrebides chain. Petrographic analyses were conducted to identify the geological characteristics of each kind of rock. Subsequently, physico-mechanical tests (i.e., density, porosity, hardness, and uniaxial compressive strength) were carried out for all the sampled rocks. The results were then used to develop correlations between UCS values and the other parameter values determined. Finally, the UCS predictive equations which have the best predictive powers (coefficient of determination R ² of 0.75 to 0.94) were discussed taking into account the geological specificities of the rocks, and then compared to similar studies developed by other authors in different areas of the world.     

Geotechnical site investigations for possible urban extensions at Suez City, Egypt using GIS

With the development of economic activities in the world, the construction activities have also increased. A proper surface and subsurface investigation is made to assess the general suitability of the site and to prepare an adequate and economic safe design for the proposed work. The main purpose of the current study is to create a spatial model of the geotechnical conditions and considerations by using geographic information systems (GIS) techniques to develop and analyze a site model and to plan site activities at the new extension of Suez City (SC). In the geotechnical site evaluations, GIS can be used in four ways, data integration, data visualization and analysis, planning and summarizing site activities, and data presentation. The integrated data can be displayed; manipulated and analyzed using tools build into the GIS programs, thus creating the geotechnical site model of the study area. Decisions can be made for further site activities and the results of the site activities can be integrated into the GIS site model. Interpretation of geotechnical data frequently involves assimilating information from many sites each with a unique geographical location. Interpretation of these data requires the spatial location to incorporate into the analysis. Weights are assigned to different of mechanical, physical soil properties, geological, hydrogeological, and other ancillary data. Finally, the weighted maps are integrated using a GIS based on the construction purposes for the new extension of SC for significant cost savings in design, construction and longevity. The ideal and good zones’ highest regime has been observed towards central and western regions with sporadic pockets. The marginal zones to average zones are moderately suited for shallow foundation.     

The use of Artificial Neural Networks in the modeling of socioeconomic category of Integrated Water Resources Management (Case study: Saf-Saf River Basin, North East of Algeria)

This research work has an objective to determine the effective variables in socioeconomic category of Integrated Water Resources Management for Saf-Saf river basin characterized by fast growing demand of urban and rural populations and the demand of economic sectors including industry and agriculture. In this paper, the artificial neural network models were used to model and predict the relationship between water resources mobilization and socioeconomic variables in the Saf-Saf river basin. The study area chosen is Saf-Saf river basin and real data were collected from 30 municipalities for reference year 2010. The results indicate that the feed-forward multilayer perceptron models with back-propagation are useful tools to define and prioritize the most effective variable on water resources mobilization and use. The model evaluation shows that the correlation coefficients are more than 94 % for training, verification, and testing data. The model aims to link the water resources mobilization and driving forces variables with the objective to strengthen the Integrated Water Resources Management approach.     

Lessons Learned from the Landslides in Shengli East Open-Pit Mine and North Open-Pit Mine in Xilinhot City,Inner Mongolia Province,China

The locations of the 2013 eastern ShengLi open pit mine landslide and the 2010 northern ShengLi open pit mine landslide were both in the XilinHot city of Inner Mongolia province, in areas with similar geographical, regional geological, geomorphic conditions and excavation depth. There are so many similar characteristics, such as landslides triggered by the rain storms, landslides occurred many times, landslides with long time deformation, but there are also some differences between the two landslides, such as the scale and failure mode. Field investigations showed that the two landslides were both occurred several days after the rain storms, the eastern ShengLi open pit mine landslide body with the volume of 85 million m³ has been in persistent deformation with an observed maximum horizontal displacement of 58 m in August 2013, Furthermore the implemented check dams at east open pit mine had not formed an efficacious blocking system to resist the flow because of incorrect judgment regarding the landslide style. The northern ShengLi open pit mine landslide body with 0.5–1 million m³ occurred several times after each rain storm. In the whole, the time of persistent deformation about the eastern ShengLi open pit mine was much longer than that of the northern ShengLi open pit mine because of the difference of the filling material of fault and space combination between the faults and the slope. Field investigation, physical model experiments, real-time displacement monitoring and numerical simulation were implemented to investigate the characteristics, mechanism, and retaining measures of the two landslides. The insights gleaned herein may be valuable for the understanding of the mechanisms of landslides and improving preventative measures against these types of events in north China in the future.     

Campanian Climatic Change: Isotopic Evidence from Far East, North America, North Atlantic and Western Europe

Paleoclimatic settings have been reconstructed for the Campanian using original oxygen-isotopic analyses of well-preserved molluskan and foraminifera shells from Russian Far East, Hokkaido, USA, Belgium and some DSDP holes (95, 98, 102, 390A, and 392A) in North Atlantic. Early Early Campanian climatic optimum has been recognized from data on high bottom shelf water paleotemperatures in middle latitudes of both the western circum-Pacific (to 24.2°C) and the eastern circum-Pacific (to 26.4°C) areas and high bottom shallow water paleotemperatures in high latitudes of the Koryak Upland (22.4–25.5°C), which agrees with the data on the Campanian Barykovskaya flora in high latitudes (Golovneva and Herman, 1998) and Jonker flora and its equivalents in middle latitudes. Judging from the data on comparatively high bottom shallow water paleotemperature values in high latitudes, South Alaska (19.4°C) and the Koryak Upland (22.4–25.5°C), we also expect Latest Campanian temperature maximum, which has not been confirmed, however, for low and middle latitudes by neither of isotopic nor paleobotanic data now. Main climatic tendency during the Campanian (with the exception of Latest Campanian) has been learned from isotopic composition of Campanian aragonitic ammonoid shells from the Hokkaido-South Sakhalin (Krilyon) marine basin. In contrary to Huber’s et al. (2002) assumption, we expect warm greenhouse conditions during the most part of the Campanian.     

江苏徐州市区地基土工程地质分区及岩土工程问题

通过对徐州市区多年实际勘测资料的分析,依据地形、地貌、地基土沉积年代、成因类型等组合特征将徐州市区划分为四个工程地质区;研究了不同工程地质区域内不同地基土的物理、力学等工程地质特征;阐述了四个区存在的主要岩土工程地质问题,据此对该区勘察设计及地基处理方案提出建议。     

Classification and Potential Utilization of Eocene Coals of Meghalaya,North East India

In the present study, petrographic and geochemical investigation of Meghalayan coal deposits have been carried out to classify these coals in terms of rank, type and grade, using Indian and International classification schemes. Based on petrographic and geochemical characteristics, an attempt has also been made to identify the potential utilization of Meghalayan coals for various industrial applications. According to the study, these coals have been classified as sub-bituminous C to high volatile bituminous in rank, vitric in type and clean to ashy in grade. Considering their hydrocarbon potential, these coals are suitable for liquefaction and gasification.     

中铁青岛世界博览城项目岩土工程勘察钻探实践

结合中铁世界博览城会展及配套项目岩土工程详细勘察钻孔实践,针对地层复杂,钻孔过程中发生的泥浆严重漏失、卡钻、埋钻等现象,采取了优质泥浆护壁、注浆、下套管、优化钻进参数等行之有效的技术措施,提高了施工效率,降低了成本,取得了非常明显的技术效果。     

建立常州市工程地质数据库智能系统框架的探讨

基于ArcGIS信息集成平台和Oracle数据库,构建了常州市工程地质数据库智能系统框架,对长期分散积累的工程地质数据进行收集整理、挖掘利用,开发了工程地质数据科学管理和辅助决策功能,集工程地质数据管理与发布、工程地质数据处理、工程地质数据分析、地下空间规划分析、地下工程可视化与分析子系统于一体,可为城市规划、城市建设和决策,提供工程地质依据。     

Interpretation of aeromagnetic and gravity data in East Qattara Depression, North Western Desert, Egypt

The study area lies to the east of Qattara Depression at the north of the Western Desert, Egypt. It is bounded by latitudes 29°00?? and 30°00?? N and longitudes 28°00?? and 29°30?? E, including Abu Gharadig basin, which is the most petroliferous basin in the Egyptian Western Desert. Numerous exploratory wells show that the area is characterized by a thick sedimentary section, unconformably overlying the basement rocks. The main objective of the present study is to outline the structural parameters controlling the area under consideration. Aeromagnetic and gravity data were subjected to the analytic signal, 3D Euler deconvolution and edge enhancement techniques. The Analytic signal and 3D Euler deconvolution were utilized mainly to locate the main subsurface contact zones and to determine the depth and structural indices of the expected causative subsurface structural elements. However, the edge enhancement technique was used with various windows to enhance the edges of subsurface structures. The structural indices were estimated to be ranging between 0.16 and 0.26, indicating that the area is mainly controlled by faults. The depth of these structural elements was also estimated to be ranging between <1.37 and 5.29?km. It has been shown that the structural elements of the study area have different directions, trending E-W, ENE, NW, and N-S.     

南京市危险废弃物处置中心填埋区岩土工程特征及对策

介绍了南京市危险废弃物处置中心填埋库区岩土工程地质特征，并介绍了国内外填埋材料方面的研究成果。就南京市危险废弃物处置中心填埋库区填埋坑的稳定、沉降、防渗等问题展开讨论，提出了较为合理的解决方案。     

Groundwater geochemistry of Ain Azel area,Algeria

Hydrogeochemical data for 18 groundwater samples and 11 hydrochemical parameters were subjected to Q- and R-mode cluster analysis and inverse geochemical modeling. Q-mode cluster analysis resulted in three distinct water types (brackish water type, saline water type and highly saline water type). R-mode cluster analysis led to the conclusion that the water–rock interaction is the major source of contamination for the groundwater in the area. Geochemical modeling results show that carbonates, gypsum, halite, carbon dioxide (gas), and chlorite are dissolving, whereas Ca-montmorillonite, gibbsite, illite, K-mica, kaolinite, and quartz are mostly precipitating along different flow paths in the groundwater system of the area.     

柴北缘-东昆仑地区的造山型金矿床

柴北缘－东昆仑是中国西部秦祁昆褶皱山系的一部分，它的显生宙造山经历了加里东和晚华力西－印支两个旋回，并以多岛洋／裂陷槽、软碰撞和多旋回造山为特点。该区已发现多个造山型金矿床，它们具有相似的地质－地球化学特征。有两组成矿年龄：一是是加里东期（相当于加里东造山晚期）；二是晚华力西－印支期（处于该造山旋回晚期）。前期为性地中地壳顶部－上地壳底部的金矿化，后期则形成于较浅层次（1．2－5．7km）的金矿体侵位自区域北部向南部，矿床元素组合由Au-As向Au-Sb转化，金矿成矿年龄由老变新，成矿深度相应变浅。研究认为，与碰撞有关的热事件以及逐步升高地热增温率，驱动被加热的建造水和大气降水流体沿碰撞带和大型剪切等长距离地迁移、活动，并淋取围岩的成矿元素，形成含金流体。在进入到矿床或矿体构造后，由于构造性质转换，物理化学条件亦随之改变，含金流体沉淀，形成金矿体。这些金矿形成于造山晚期，是造山作用的产物，后者为前者提供了空间、热－动力条件。     

The copper-silver occurrences of Rahmani,Western Sahara,Algeria

The copper-silver occurrences of Rahmani (Western Sahara, Algeria) are located in paleochannel facies of Cambrian sandstones deposited onPan-African volcanics and intrusives. Sulfur isotope analyses were performed on pyrite and copper sulfides in order to trace the origin of the copper-silver mineralization. S isotopic data preclude that bacterial reduction of Cambrian sulfate could have induced the formation of the sulfides. Non-bacterial reduction of sulfate during burial diagenesis is the most valuable explanation for disseminated pyrite. Isotopic ratios on copper sulfides indicate that they result from the reaction of actual or subactual sulfate-bearing surface water with the disseminated pyrite. The origin of copper and silver remains unclear. They are thought to be brought by the downward migrating surface water but their origin could be either the leaching of the Cambrian sandstones or of the weathered volcanics.     

Geotechnical characterisation of Obudu damsite, Obudu, south-eastern Nigeria

The Obudu dam is being built across Abeb river in Obudu area of the Cross River State (Nigeria). The earthfill dam will be approximately 18 m high with a crest length of 385 m. The dam site is located within part of the Obudu crystalline basement plateau which is a region of low seismicity. The terrain is smoothly undulating and low lying and was known to be composed of unclassified basement and decomposed bedrock (overburden). The present study was carried out to assess the suitability of the chosen dam axis based on the determination of the nature and geotechnical characteristics of the overburden and bedrock. The investigation included geophysical surveys, bearing capacity tests (cone penetrometer and standard penetration), classification and grain size distribution as well as tests for compaction, consolidation and compressive strength. The results show that the bedrock is heterogeneous, including gneisses sillimanite, biotite and granite types), dolerite, quartzite and pegmatite with an overall moderate strength (about 76.04 MN m⁻² average) and fair rock mass rating (RMR). The bedrock along the dam axis is apparently lacking in major fractures which could lead to short circuiting of the future impoundment. The overburden (soil) comprises silt (MH, ML), silty clay (CL) and silty sand (SM) with a combined thickness of about 2–20 m, increasing away from the valley floor towards the shoulders. Generally the overburden is of suitable compressive strength (150–300 KN m⁻²), low to medium plasticity and swelling potential and low permeability (up to 1.41 × 10⁻⁷ ms⁻¹) which would ensure a tight reservoir. The material settlement is expected to be small and slow. Accordingly, excavation of up to 5 m, decreasing towards the valley shoulders has been suggested to expose the recommended bearing medium: fresh/competent bedrock and overburden in the valley floor and flanks, respectively. While a detailed investigation of burrow areas was not part of the present study, a few potential sites in the dam axis and reservoir areas have been suggested based on the evaluation of material properties.