Influence of weathering on the engineering properties of Harsit granitic rocks (NE Turkey)

Weathering and hydrothermal alteration of the granitic rocks in the Eastern Black Sea Region (NE Turkey) are important phenomena affecting the engineering projects in the region. The study investigated the probable paths of rock-forming mineral transformations due to weathering in the Harsit granitoid rocks, the changes of the major oxides as a consequence of weathering and the effects of weathering on the engineering properties. To identify the changes in the major oxides, the volume concentrations were considered in relation to the dry density. Chemical leaching during weathering was shown to be significant in changing the minerals. It was concluded that the engineering properties of the weathered granitic rocks can be most reliably predicted by P-wave velocity.      

Effect of weathering on the geomechanical properties of the Miocene basalts in Malatya,Eastern Turkey

Miocene volcanic rocks are widely exposed in the eastern Taurids, Turkey. The geomechanical properties and weathering degree of the Middle–Upper Miocene basalts were determined at the Boztepe dam site in Malatya, eastern Turkey. An engineering geology map of the Boztepe dam site was made and the joint sets and the degree of weathering determined in the field. The degree of weathering and RQD values were obtained on some 1,195 m of core which was then compared with a series of geomechanical tests including unit weight, porosity, water absorption, uniaxial compressive strength and compressive wave velocity. The geomechanical properties were compared with the weathering classifications of ISRM (Rock characterization, testing and monitoring, p 211, 1981) and Kilic (Environ Eng Geosci 4:475–483, 1999)      

Fracture toughness anisotropy in granitic rocks

Four relatively fine grained and homogeneous granitic rocks have been studied to investigate the relationship between their microstructural properties and fracture toughness behaviour. The apparently homogeneous rocks have been found to exhibit strong anisotropy in terms of microcrack distribution and their orientation. The fracture toughness values for these rocks, measured with the cracked chevron notch Brazilian disc method (CCNBD), varied from 0.71 to 1.89 MPa m^0.5, with similar variation observed within the same rock type depending on the specific fracture plane studied. The relationship between these variations and the corresponding microstructural properties along specified planes has been investigated in detail to show a strong correlation between the two. Further confirmation is provided by taking into account the seismic velocity anisotropy observed along the same specified directions. The nature of these variations and their effect on the resulting fracture path and surface are discussed. The results clearly show the difficulty in assigning a unique value of fracture toughness to rocks and rock-like materials without cognizance of their microstructural characteristics.     

Weathering indices and their applicability for crystalline rocks

In the recent past, several weathering indices have been proposed to characterize the extent of weathering and weatherability depending upon the nature and requirement of the study. The weathering index provides a quantitative measure of the extent of weathering of rock; hence it can provide input to the prediction models to assess the strength and deformational properties of rocks and classifications of weathered rock material. In the present study some of the important weathering indices, broadly categorized as chemical, (micro) petrographical and engineering weathering indices, are reviewed and studied experimentally for three common rocks of India, namely granite of Malanjkhand, basalt of Nagpur and quartzite of Delhi, along with results of other rocks reported by other researchers. The study reveals that none of the existing chemical weathering indices is valid for genetically different common rock types and useful for engineering purposes. However, loss on ignition (LOI) may provide an approximate estimation of altered minerals (clays and hydroxides) in tested rocks. It has also shown good correlation with petrographic indices and engineering index properties. Among the petrographic indices, crack density (ρ_cr) and unsound constituent (an input to the micropetrographic index) indices provide good correlation with engineering index properties. To quantify the extent of weathering in terms of strength degradation due to weathering in rock, an index is suggested – strength ratio (R_s) – which is the percentage of uniaxial compressive strength (σ_c) of weathered rock with respect to σ_c of fresh rock. Its significance is shown statistically through the relationships with other indices for several rock types including sedimentary and metamorphic rocks. Electronic Publication     

Engineering properties of the magmatic rocks at the Pamukluk Dam site, Turkey

 The paper discusses the magmatic rocks that form the foundation material for the Pamukluk Dam, Tarsus, Turkey. The area has suffered extensive dyke intrusion and significant tectonic disturbance. The paper reports the results of both in situ tests and laboratory tests on block and borehole core samples. In general, the diorites and microdiorites have suffered little alteration and remained strong. The granophyres and less weathered acidic rocks are moderately strong while the gabbros are the weakest materials. The elastic moduli vary between 830 and more than 3500 MPa. Pressuremeter tests indicated that for a 120 m high dam, the settlement would vary between some 33 and 69 mm. Received: 3 August 1999 · Accepted: 18 May 2000     

Linear thermal expansion of granitic rocks: influence of apparent porosity,grain size and quartz content

Values for the linear thermal expansion coefficients () of some Brazilian granitic rocks commercially used as facings for building are presented. The coefficients were determined within a temperature range of 0 to 50 °C, with the temperature raised at a rate of 0.3 °C/min. The values obtained were related to the apparent porosity, grain size and quartz content of the rocks. It is concluded that while increases with an increase in quartz content, it decreases with increases in apparent porosity and mineral grain size.     

Physico-thermal and mechanical properties of Sanliurfa limestone,Turkey

Sanliurfa limestone is becoming increasingly popular for both interior and exterior building applications in the local area in south east Turkey, being easy to cut and shape and suitable for many purposes. Although these limestones are low cost construction materials, they are not widely used elsewhere due to the lack of data regarding their chemical, physico-thermal and mechanical properties and the requirement for highly skilled labour. A total of 264 samples of Sanliurfa limestone from four quarries were tested to determine their physico-thermal and mechanical properties. The data obtained confirmed they satisfy the main international standards for the use of limestone in the construction industry.     

Weathering of building stones and its relationship to the sustainable management of the aggregate resources in Gaza Strip,Palestine

In the last decade, the Gaza Strip witnessed a revolutionary breakthrough in the field of building construction associated with the political development in the aftermath of Oslo Agreement. Towers (buildings composed of more than five floors) were, for the first time being built in the region in its modern history. Environmental conditions have deteriorating weathering impacts on the buildings of about 40 years old. This article aims at investigating such impacts and their features as well as the different types of weathering on the buildings. Chemical, mechanical and biological parameters of weathering were reported to work together in the old buildings. Differential weathering was also reported in some buildings either within the stone itself or the cementing material between the stone blocks. The geographic location along the coast is believed to speed up the weathering process as aerosols and rainwater contain high chloride content, which in turn reacts with the stone components. Baladi stones show higher resistance to weathering than the Israeli stone-type. Weathering rate was calculated and found to have an average of about 0.1 cm per annum. Some measures are taken to protect the buildings from the weathering attack; these include 2–3 layers (about 1 cm thick each) of plastering for about 1 m of the lower part of the external walls of the buildings. These measures are not commonly applied, and if so, they show several types of weathering. Taking protective measures is a necessary step for better sustainable management of the aggregate resources in the Gaza Strip.     

Microstructural, geochemical and geomechanical properties of caliche deposits from the Adana Basin, Turkey

The 1998 Ceyhan (Adana, Turkey) earthquake caused major damage to construction on caliche formations. Caliche (a heterogenous secondary calcium carbonate deposit formed in arid and semi-arid regions) is widespread in the Adana area. The paper distinguishes three types of caliche: massive, containing vegetation remains and containing gravel. The porosity, water absorption and unconfined compressive strength of these three groups of caliche were determined. The compressive strengths are low compared to caliches in other areas—an important consideration as Adana is the fourth largest city in Turkey.      

Weathering and erosion fluxes of arsenic in watershed mass budgets

Arsenic in natural waters and in soils represents a serious health hazard. Natural sources of this element in soil are the subject of this communication. Weathering mass balance of As and rates of weathering in soils are evaluated from monitored inputs and outputs in two small watersheds. These watersheds are located within the Celina-Mokrsko gold district, Czech Republic. Annual chemical weathering fluxes of As are calculated from the monthly weighted means of stream water and groundwater. The fluxes are corrected for atmospheric precipitation, agrochemical inputs, and biological uptake. Mechanical and chemical weathering rates of the arsenopyrite-bearing rocks in the watersheds were estimated from mass balance data on sodium and silica. The input of As due to total weathering of bedrock was estimated to be 1369 g ha(-1)yr(-1) in the Mokrsko watershed (MW) and 81 g ha(-1)yr(-1) in the Celina watershed (CW). These results indicate that the annual weathering rate of As in the watersheds represents more than 95% of the total As input to the soil. Accumulation rate of As in the soil was estimated at 311 g ha(-1)yr(-1) in MW and 69 g ha(-1)yr(-1) in CW. The mass balance method for calculation of weathering rate of As was used, and the results suggest that weathering could be the most important process in the As biogeochemistry of the areas with elevated As content in the bedrock. Simple model of weathering and erosion can be used successfully in estimating their role in As pollution on the scale of small watershed. The method is also useful for indicating the mass balance of As in soils that is controlled by both the natural and anthropogenic inputs and outputs of As.     

Index properties of weathered rocks: inter-relationships and applicability

 The paper describes the change in physical and strength properties due to weathering of three crystalline rocks – granite, basalt and quartzite. It draws attention to the relationship between unconfined compressive strength and other measurements such as the point load index, the Brazilian tensile strength and the Schmidt hammer rebound number. The strength recorded is negatively related to the porosity which is considered an important indicator of the weathering state. Received: 13 December 1997 · Accepted: 30 April 1998     

A quality assessment of public water fountains and relation to human health: a case study from Yozgat,Turkey

Public fountains are very common and everyday people appreciate the benefits a water fountain can bring. However, consumption of public fountain water in some country has decreased because of growing concerns that constituents in fountain water may have adverse effects on health. A few studies have examined the safety of public fountains, proposing only limited evidence of fountain‐related health issues in Turkey. Most of these public fountains are sourced from natural springs in Turkey. In this study, a 177 fountain water and 32 rock samples were analysed for source and quality of water. The geology of the region has the direct impact on the quality of the public fountain water. The results indicate that the level of some elements exceeded the limit values determined by WHO and US.EPA. The most striking high values were observed for iron (Fe), nickel (Ni), aluminum (Al), arsenic (As) and bromine (Br) concentrations.     

Investigation of the relation between meteorological parameters,North Atlantic Oscillation and groundwater levels in Torbali Region,Turkey

Groundwater, the most reliable fresh water source, is used for drinking, domestic and agricultural purposes. Thereby, understanding its behaviour is important for the sustainability of groundwater sources. In this study, relations between the trends of climate parameters [recharge depending on precipitation, temperature and North Atlantic Oscillation Index (NAOI)] and groundwater levels trend were investigated for Torbali Region in Turkey. The human impact that is one of the deterministic components on the groundwater level has been removed from the groundwater level data sets. An increasing trend was observed in the early 1990s, and turning points were determined by using paired t‐test. The trends of the groundwater levels indicate that climate parameters affect groundwater levels in the similar manner. According to the results of the analyses, it is revealed that there is a similar linear variation that is strong and inverse between the trends of NAOI and meteorological indicator (temperature and recharge) and groundwater level.     

Petrophysical and geomechanical properties of rocks from the oilfields of the Krishna-Godavari and Cauvery Basins, India

The petrophysical and mechanical properties of reservoir rocks from two major basins on the east coast of India were studied using samples cored from 19 wells in the Krishna-Godavari and Cauvery basins. Several of these drill holes are located in the producing oilfields in these basins. The purpose of the study was to investigate the relationships between the properties of the rocks including dry density, effective porosity, uniaxial compressive strength, tensile strength and Young's modulus. Their relationships are further elucidated using regression analyses. The results indicated that the petrophysical and geomechanical properties vary widely for the different sedimentary rocks and basement samples related to their depth and geological age. It is emphasized that the work should be further extended to assess its full potential in reservoir studies of the oilfields in these basins.     

风景园林耐候性的研究缘起与进展

21世纪之交,多个美国现代风景园林标志性作品衰败破旧、急需更新,甚至面临拆除重建的命运引发美国风景园林学者开始关注于风景园林耐候性的研究。通过文献研究,从风景园林耐候性的概念阐释、研究缘起、和经典著作三方面介绍风景园林耐候性在国外的发展情况,最后根据我国研究现状指出该研究在中国开展的重要意义和拓展方向。     

Total copper content and its distribution in acid vineyards soils developed from granitic rocks

Total and extractable (5 extractants) Cu concentrations were determined in thirteen acid vineyards soils. Mean total copper concentration was 259 mg kg(-1) and most of the soil samples (87%) were above the upper limit allowed by the European Union for this element in soils. The largest Cu fraction was found to be that bound to soil organic matter, which accounted for 49% of the total Cu. None of the Cu fractions showed significant differences with depth. Nevertheless, bioavailable Cu (extracted in Na(2)-EDTA) was found to show a strong correlation with Cu bound to soil organic matter, which may indicate that Na(2)-EDTA is able to extract part of the organically bound Cu, resulting in an overestimation of bioavailable Cu. However, practices associated to soil use change and management affecting the stability of Cu organic complexes could induce an increase in bioavailable Cu levels in these soils.     

高性能耐火耐候建筑用钢的力学性能和焊接性能及其典型应用研究

本文对武钢研制的高性能耐火耐候建筑用铜的力学性能、焊接性能及其典型应用进行了研究。试验结果表明：该钢具有优良的综合力学性能．在600C温度下的屈服强度均高于其室温下屈服强度的2／3．完全满足建筑结构用钢耐火安全性的强度许用指标；该钢具备低的冷裂纹敏感性．能承受大线能量焊接(50～100kJ／cm)；该钢在大型建筑应用中的实际效果良好。     

Effect of geomechanical properties on Cerchar Abrasivity Index (CAI) and its application to TBM tunnelling

Abrasiveness of rocks plays an important role in the wear of TBM tunnelling. Cerchar Abrasivity Index (CAI) test is the most commonly used method to estimate rock abrasiveness due to its simple, fast test procedure and economic benefits. This study investigated the correlation between CAI and geomechanical properties of igneous and metamorphic rocks. Single and multiple regression analysis were performed and predictive models for the CAI from geomechanical properties were developed. It is found that single parameter alone is not suitable to predict the value of CAI. The result of the multiple regression analysis shows that quartz content is less influencing factor to predict the value of CAI. Also, the correlation between CAI and NTNU’s Cutter Life Index (CLI) was examined and a predictive model for the CLI from CAI and geomechanical properties was suggested. Finally, the influence of CAI on disc cutter life prediction models was investigated and it was found that the variation of CAI has the maximum effect on the predicted disc cutter life in Gehring model.