Weathering and its relation to geomechanical properties of Cavusbasi granitic rocks in northwestern Turkey

The effect of mainly mechanical weathering on the granodiorites, granites and quartz diorites of the Cavusbasi area of northwest Turkey are described, the samples having been taken from cores and field exposures. The primary characteristics of these rocks are affected by the weathering process which results in a significant constraint on their use in engineering works. The tests undertaken on samples in the various weathering grades included point load and uniaxial compressive strength, slake durability, porosity, loss on ignition, dry and saturated unit weight and water absorption. A tentative correlation between these properties is presented. Electronic Publication     

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)      

Determination of physical properties of carbonate rocks from P-wave velocity

Velocity, density, porosity, void ratio, water absorption by weight and P-wave velocity tests were conducted on 14 different carbonate rocks. Strong correlations between P-wave velocity and all the physical properties of the rock were found. The relations follow a linear function. The equations developed were compared with others in the literature. Although it appears that the physical properties of the tested carbonate rocks can be estimated from P-wave velocity, the validity of the derived equations must be checked for other carbonate rocks as the equations given are likely to be specific to the test method and vary with rock type, degree of saturation and presence of bedding planes.      

Engineering aspects of limestone weathering in Istanbul, Turkey

 Devonian limestones are widespread in the eastern part of Istanbul, Turkey. To assess the influence of weathering on the geological and geomechanical characteristics of these rocks, research was carried out on some profiles from the study area. Field observations show that the weathering has been rapid and the bedrock has been weathered to a depth of up to 8 m. A model for the weathering of limestones is established and modifications proposed to the material and mass weathering schemes for characterisation of the limestone for engineering uses, as both foundation and construction material. The paper also presents the results of field and laboratory investigations, including weathering characteristics and physical and mechanical properties. Interrelationships were determined for all test results. It is concluded that chemical characteristics and the porosity are good indicators of weathering. Received: 10 July 1999 · Accepted: 17 September 1999     

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     

An application of the interaction matrices method for slope failure susceptibility zoning: Dogankent settlement area (Giresun, NE Turkey)

Large-scale instability phenomena frequently occur in slopes in such geologically complex areas as Dogankent in NE Turkey. This study presents an application of the interaction matrices (IM) methodology, as a semi-qualitative method sensitive to large-scale slope instability. For both rock and soil slopes, the main interactive factors were distance from faults, degree of weathering and slope angle. Using IM, a slope failure susceptibility map was created for the Dogankent area and checked again field evidence. The results indicated that IM could be a useful method for slope stability assessment.      

The effect of crude oil pollution and subsequent fire on the engineering properties of soils in the Niger Delta

The Niger Delta is a major area of crude oil exploration, exploitation and processing. This brief paper reports laboratory tests on polluted and unpolluted soils following an oil blow-out and fire outbreak and concludes that the effects were minimal.      

Engineering geological assessment of the Diyarbakir solid waste landfill site (SE Turkey)

The paper reports a study to investigate the geological, hydrogeological and geotechnical properties of a proposed solid waste landfill site for Diyarbakır city, southeastern Anatolia. The study area is located in the vicinity of the Diyarbakır–Mardin highway and 6 km away from the city. The paper describes the topography, geology and hydrogeological characteristics of the bedrock and based on water absoprtion (Packer) and laboratory measures, gives permeability values for the firm to stiff clays on which the landfill will be placed as well as the secondary permeabilities of the basalts and the intergranular permeabilities of the sand and gravel layers within the claystone–mudrock sequence. Recommendations are made for the construction of the landfill.      

A method to model the effect of pre-existing cracks on P-wave velocity in rocks

Crack closure is one of the reasons inducing changes of P-wave velocity of rocks under compression.In this context,a method is proposed to investigate the relationships among P-wave velocity,pre-existing cracks,and confining pressure based on the discrete element method(DEM).Pre-existing open cracks inside the rocks are generated by the initial gap of the flat-joint model.The validity of the method is evaluated by comparing the P-wave velocity tested on a sandstone specimen with numerical result.As the crack size is determined by the diameter of particles,the effects of three factors,i.e.number,aspect ratio,and orientation of cracks on the P-wave velocity are discussed.The results show that P-wave velocity is controlled by the(i.e.number) of open micro-cracks,while the closure pressure is determined by the aspect ratio of crack.The reason accounting for the anisotropy of P-wave velocity is the difference in crack number in measurement paths.Both of the number and aspect ratio of cracks can affect the responses of P-wave velocity to the applied confining pressure.Under confining pressure,the number of open cracks inside rocks will dominate the lowest P-wave velocity,and the P-wave velocity of the rock containing narrower cracks is more sensitive to the confining pressure.In this sense,crack density is difficult to be back-calculated merely by P-wave velocity.The proposed method offers a means to analyze the effect of pre-existing cracks on P-wave velocity.     

谈岩石（体）波速测试在工程地质勘察中的应用

结合具体工程,在岩石钻孔中采用波速测试方法,测取了岩石（体）波速,根据波速测试结果取得有关的物理力学参数,以此来评定岩石的物理力学性质及岩体完整性,以期为工程地质勘察评价奠定基础。     

Changes in the engineering properties of marble in fire-exposed columns

Two marble columns in the bottom floor of a school building were exposed to intensive heat in the fire, and were subject of a debate about their load-carrying capacity following the event. After their removal from their original spots, series of tests on column samples were carried out to investigate variations in their engineering characteristics due to fire hazard. The temperature at the surface of the marble columns hit by the flames directly during the fire was estimated to be on the order of 500 °C using an empirically established relationship between porosity and temperature on intact marble core samples. Results of mechanical tests indicated that marble columns were still holding a significant load-carrying capacity despite 23% loss of strength at fire temperature. The spallings at the corners of the blocks forced the board of education to give the decision of replacing the gray marble columns with steel members. Occurrence of these spallings is attributed to stress concentrations and widening of micro fractures. Based on the results of mechanical, physical and chemical tests, a methodology to assess influence of fire hazard on marble and similar geological materials was developed.     

Evaluation of ornamental plant resources to urban biodiversity and cultural changing: A case study of residential landscapes in Trabzon city (Turkey)

The residential vegetation features in urban landscapes play an important role as indicators regarding urban biodiversity potential and cultural changing. They also include ornamental resources in the context to landscape appreciation for human environment. Therefore, this paper provides quantitative information on the distribution of plant species in urban residential landscape areas of Trabzon city (Turkey). In a total of 218 sampled areas, 274 plants species belonging to 70 families were surveyed with respect to residential use types of the city. The study results showed that among the species recorded in five residential type (traditional housing, detached housing, villa, apartment blocks and sites, mass housing for employees), non-native taxa frequency of a total species are much and dominantly represent residential landscape structure. Additionally, the species richness and diversity is positively related to new urban development areas. But, it was clearly determined that the vegetation structure has tended to ornamental purposes different from traditional residential gardens including fruit and other benefiting species. Consequently, it can be evidence that the residential vegetation is ornamental plant resources to urban biodiversity and that the distribution of the species in urban landscapes follows necessities of city and human quality.     

不同结构形式的后期热液充填裂隙花岗岩常温下物理力学性质研究

在干热岩开采的实际工程中,利用岩体结构面作为热交换通道将减小工程投入,并获得更好的工程效果.而在实际中花岗岩体中的结构面通常被热液充填,形成后期热液充填花岗岩体.研究后期热液填充裂隙花岗岩体 的物理力学性质对实际地热开发中建设人工储留层具有重要指导意义.利用后期热液填充裂隙花岗岩体制备不同结构形式试样,在常温下对4种结...     

The alteration degree of the metacrystalline rocks based on UAI,Bolu (Turkey)

The geomechanical properties of the metacrystalline rock masses vary due to alteration. The Devonian aged Yedigoller formation crops out in the Asarsuyu valley (Bolu, Turkey). The aim of this study is to investigate the alteration degree of the amphibolite and metagranodiorites based on their geomechanical and petrographical properties. The P-wave velocity is 1,613–5,588 m/s and the unconfined compressive strength varies between 12.75 and 99.86 MPa. Several weathering products occurred due to carbonisation, oxidation and sericitation. These rocks, subjected to hydrothermal effects, are classified as “fresh” to “completely altered” according to the unified alteration index (UAI). In addition, the values of the loss on ignition, modified weathering potential index and chemical index of alteration were taken into account for supporting the alteration process. Since the main process is hydrothermal alteration, the rocks which were exposed to alteration are weathered on the slopes after excavation. Weathering classification and the chemical indices indicate this process. Thus, UAI is concluded to be more suitable and credible in order to evaluate the hydrothermal alteration process of such crystalline rocks numerically.     

灰缝厚度对墙体性能的影响

对不同砌筑灰缝厚度的墙体进行压力破坏试验,研究灰缝对墙体力学性能的影响,结果表明,随着灰缝厚度的增加,墙体的抗压强度减小,并通过线性回归分析得到规律方程;通过传热分析,对包含1个垂直灰缝和1个水平灰缝的砌筑单元的传热速率进行计算,推导出砌筑单元的传热速率与灰缝厚度之间呈正比函数关系式,对墙体性能的提高具有理论指导意义.     

Laboratory tests on the engineering properties of sensor-enabled geobelts (SEGB)

To measure geosynthetic reinforcement strains, sensor-enabled geobelts (SEGB) that perform the reinforcement and self-measurement functions were developed in this paper. The SEGB of high-density polyethylene (HDPE) filled with carbon black (CB) were fabricated by both the industry and the laboratory. To study the mechanical properties and tensoresistivity performance of the SEGB, in-isolation tests and in-soil tests were performed. Hot pyrocondensation pipes (HPP) were used to protect the SEGB against the influence of water. For the SEGB specimens developed in the laboratory, the optimal CB filler content was 47.5%. For the SEGB fabricated by the industry, the optimal CB content was slightly decreased compared to the SEGB fabricated in the laboratory. For the modified SEGB sealed with HPP, the strain at the fracture was improved, while its tensile stress and the frictional property of the geobelt-soil interfaces both decreased slightly. In the pull-out tests, the self-measurement function of the SEGB was proved to be effective for evaluating the deformation behavior of geosynthetic reinforcement. The results are helpful for further application of SEGB technology in engineering.     

沥青高温指标与其高温路用性能的相关性研究

以5种石油沥青为原料,以车辙试验作为评价高温路用性能的基准,考察了软化点、60℃黏度、动态剪切和重复蠕变试验,表征沥青高温路用性能的准确性和有效性.通过关联和比较表明,软化点在表征沥青高温性能时具有一定的局限性,当两沥青软化点差小于1.0℃,软化点的高低不能反应沥青的高温性能.由于5种沥青黏度相差较大,试验仅得出当两沥青黏度差大于平均值的7.56%时,黏度大小可以表征沥青高温性能.动态剪切试验可以很好地对沥青进行不同温度等级的划分,对于同一温度等级的沥青而言,可以采用重复蠕变试验进行评价,动态剪切和重复蠕变试验的联合应用,可以准确有效地评价沥青的高温路用性能.     

The effect of swelling clays on a water transport canal between Köklüce HPP and Erbaa HPP (Turkey)

Geological mapping has confirmed the presence of swelling clays in the area of the proposed water transport canal between Köklüce and Erbaa, Turkey. A swelling pressure distribution map was prepared for this part of the route, based mainly on the analyses of soils in the Erbaa and Niksar basins. It is concluded that the potential swelling pressures will exceed the overburden weight of the reinforced concrete canal, not only when empty but also when full. In addition, variations in the characteristics of the soil mean differential movement is likely along the alignment, particularly important as the canal is planned to be a rigid structure. Recommendations are made to minimise the effect.     

兰州地区离石黄土(Q_2)工程性质研究

基于兰州地区离石黄土(Q2)地基土的室内、原位测试试验成果,对其湿陷性、承载力等工程性质以及岩土参数评价进行了讨论,结果表明:兰州地区离石黄土(Q2)湿陷起始压力大于建筑物基底压力,为一般高层建筑物基础的良好地基。