Mahmut MUTLUTÜRK

OZ Zemin siniflamalari, dunyada yaygin bir sekilde zemin bilesenlerinin agirlikca yuzde dagilimlarina gore yapilmaktadir. Bu uygulanmasi basit, kolay ve baska sonuclar ile karsilastirilmasi mumkun olan bir uygulamadir. Ancak, muhendislik islerinde, zemin davranisini denetleyen o zemine ait dane boyu dagilimi, kokeni, sekli ve dizilimdir. Bu nedenle diger ozellikleri goz ardi edip sadece agirlikca dane boyu dagilimina bakarak zemini siniflandirmak bazi hatali sonuclar alinmasina neden olabilir. Iri dane hacmi yuksek olan bir zeminde ince dane agirligi fazla ise bu durum siniflamada fark edilmeyecektir. Bu calismada, iri daneleri pomzalardan olusan 150 adet volkanik zemin ornegi kullanilmistir. Deneysel calismalarda iri ve ince dane agirliklarinin birbirine yakin oldugu orneklerde farkli sonuclar elde edilmistir. Birlestirilmis Zemin Siniflamasina (BZS) gore, zemin sinifi iyi derecelenmis kum (SW) ya da siltli kum (SM) olan zemin orneklerinin hacimce yapilan siniflamada iyi derecelenmis cakil (GW) olduklari gozlenmistir. Sonuc olarak, muhendislik amacli zemin siniflamalarinda zemini olusturan bilesenlerin, koken, yogunluk gibi ozelliklerinin yani sira, siniflamada agirlik-hacim iliskisinin hatali bir sonuca neden olup olmayacaginin kontrol edilmesi, benzer calismalarin degisik zeminlerde de denenerek sonuclarin daha kapsamli ele alinmasi gereklidir.

ABSTRACT Volcanic soils are widely distributed group of soils, which cover significant parts of the world’s surface and include areas occupied by urban settlements, structures and infrastructures, and may create geo-engineering problems. These soils exhibit a distinctive behaviour that is a consequence of their formation history, mineralogy and structure. Some part of the subsoil of a large area surrounding the city of Isparta (western Turkey) mainly consists of volcaniclastic deposits. This paper presents the results of the part of a research programme aiming at geotechnically characterizing the uppermost layer of this volcaniclastic sequence, particularly focusing on its collapse potential, shear behaviour and the influence of microstructure on these behaviours. In addition, its main futures were compared with those of some similar volcanic soils at different parts of the world, and the stability of sub-vertical cuts in this soil was also assessed. The experimental investigation mainly consisted of index and classification tests, double oedometer and direct shear box tests to assess the collapse potential and shear behaviour of the soil, respectively. Matric suction of the samples were also determined for preliminary evaluation of the influence of suction on collapse and shear behaviours of the soil. In addition, thin-section studies, and X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were also conducted to determine mineralogical and microstructural features and to evaluate their influences on the mechanical behaviour of the volcanic soil. The deposit is composed of weakly bonded firm silty sand with an open structure, low unit weight and high porosity, generally unsaturated in-situ. The results of the double oedometer tests suggest that the volcanic soil generally falls in the category of slight collapse potential at normal stresses ranging between 5 and 100 kPa, while at normal stresses greater than 100 kPa its collapse potential increases and ranges between moderate and moderately severe collapse potential classes. At normal stresses lower than 100 kPa, matric suction may have an effect on collapse behaviour. The direct shear box test results indicated that the volcanic soil has two different types of shear strength behaviour represented by bi-linear failure envelopes. In other words, the shear strength parameters of the volcanic soil within a low normal stress range (generally between about 6 and 200 kPa) exceed those of determined at higher normal stresses. Since no matric suction was measured during the direct shear box tests, it could not be possible to evaluate the effect of suction on the bi-linear failure envelopes. However, some differences between the suction and degree of bonding of the samples taken from different locations might probably have been contributed to the separation of the bi-linear behaviour at different normal stress levels. The destruction of the bonding (cementation) between the particles is probably more responsible from the bi-linear form of the failure envelope. Comparisons between the SEM micrographs taken from natural and tested specimens revealed that the mechanical behaviour of the volcanic soil is strongly influenced by the bonding material. The results of the stability analyses showed a good agreement with the current situation of the cut slopes observed in the study site and suggested that vertical cut slopes with a height of 14-15 m will maintain their stability based on a reasonable factor of safety such as 1.5.

ABSTRACT Volcanic soils, which cover significant parts of the world’s surface, including urban areas, structures and infrastructures, may create geo-engineering problems. These soils exhibit distinctive geomechanical behaviours that are a consequence of their formation history, mineralogy and structure. This paper presents the results of an experimental investigation into geo-engineering properties of a volcanic soil observed in the city of Isparta, Turkey. The study focuses on the difficulties experienced in geotechnical sampling of the soil, its microstructural, mineralogical and physical properties, and particularly the estimation of its uniaxial compressive strength (UCS) using practical approaches. For this purpose, laboratory experiments covering the determination of mineralogical–petrographical and geomechanical properties, such as physical properties, UCS, and needle penetration index (NPI) using a specially manufactured needle, were conducted. The volcanic soil is weakly bonded, highly porous, well-graded silty sand and has a hypocrystalline texture. The weak bonding of the soil is volcanic ash formed by disintegration of volcanic glass, and the soil has some voids and a considerable amount of intact bonding between grains. The most important difficulty associated with this volcanic soil is field sampling and sample preparation for laboratory testing due to the weak bonding that governs internal stability. The UCS of the soil ranges between 29 and 132 kPa, and except for in a few samples, the UCS is lower than 100 kPa. The soil generally shows strain softening behaviour during the UCS tests; however, a few samples failed in a brittle fashion. As the natural water content and degree of saturation increases above approximately 11 and 42 %, respectively, there is a decline in the UCS of the soil. This is due to the increased exposure to water, which apparently softens the bonding, causing some loss of interlocking among the grains. Statistical evaluations suggest that the UCS of the volcanic soil can be estimated from the NPI using a needle with a diameter of 1.7 mm. In practical terms, the study provides some approaches and recommendations for the estimation of strength of weakly bonded volcanic soils for which geotechnical sampling is extremely difficult and/or impossible.

... The location categories (Table 2) are established by considering the strength, land use, and natural hazard potential of the site, the capacity of the ... LAQ aims to fill such a gap ... It is an effective and easy-to-apply procedure, as shown by its use in selection of a landfill site for the city ...

Mediterranean region, within the boundaries of the province of Hatay (southeast of Turkey), irrigation, drinking water and the aim of producing electricity, the Big Basin Karacay, Big Karacay Dam and Hydroelectric Power Plant (HEPP) construction continues. This project is planned to be constructed within the scope of the derivation tunnel, engineering geology, is the subject of review in this study. Big Karacay Dam Derivation Tunnel is located on the route Kızıldağ Ophiolites. State Hydraulic Works on the route of the tunnel made by the foundation drilling results, field and laboratory studies using the results obtained by discontinuous measurements of rock mass classification systems, applied to the route. The tunnel route for the best, worst and average assessments have been made according to the conditions. The results of this study are, RMR class very good-poor rock, maximum unsupported span between 20 cm to 3.5 m, stand-up time between 16 years 7 months with a immediate collapse.

OZ Zemin siniflamalari, dunyada yaygin bir sekilde zemin bilesenlerinin agirlikca yuzde dagilimlarina gore yapilmaktadir. Bu uygulanmasi basit, kolay ve baska sonuclar ile karsilastirilmasi mumkun olan bir uygulamadir. Ancak, muhendislik islerinde, zemin davranisini denetleyen o zemine ait dane boyu dagilimi, kokeni, sekli ve dizilimdir. Bu nedenle diger ozellikleri goz ardi edip sadece agirlikca dane boyu dagilimina bakarak zemini siniflandirmak bazi hatali sonuclar alinmasina neden olabilir. Iri dane hacmi yuksek olan bir zeminde ince dane agirligi fazla ise bu durum siniflamada fark edilmeyecektir. Bu calismada, iri daneleri pomzalardan olusan 150 adet volkanik zemin ornegi kullanilmistir. Deneysel calismalarda iri ve ince dane agirliklarinin birbirine yakin oldugu orneklerde farkli sonuclar elde edilmistir. Birlestirilmis Zemin Siniflamasina (BZS) gore, zemin sinifi iyi derecelenmis kum (SW) ya da siltli kum (SM) olan zemin orneklerinin hacimce yapilan siniflamada iyi derecelenm...

... The location categories (Table 2) are established by considering the strength, land use, and natural hazard potential of the site, the capacity of the ... LAQ aims to fill such a gap ... It is an effective and easy-to-apply procedure, as shown by its use in selection of a landfill site for the city ...

Volcanic soils are widely distributed group of soils, which cover significant parts of the world’s surface and include areas occupied by urban settlements, structures and infrastructures, and may create geo-engineering problems. These soils exhibit a distinctive behaviour that is a consequence of their formation history, mineralogy and structure. Some part of the subsoil of a large area surrounding the city of Isparta (western Turkey) mainly consists of volcaniclastic deposits. This paper presents the results of the part of a research programme aiming at geotechnically characterizing the uppermost layer of this volcaniclastic sequence, particularly focusing on its collapse potential, shear behaviour and the influence of microstructure on these behaviours. In addition, its main futures were compared with those of some similar volcanic soils at different parts of the world, and the stability of sub-vertical cuts in this soil was also assessed. The experimental investigation mainly con...

ABSTRACT Volcanic soils, which cover significant parts of the world’s surface, including urban areas, structures and infrastructures, may create geo-engineering problems. These soils exhibit distinctive geomechanical behaviours that are a consequence of their formation history, mineralogy and structure. This paper presents the results of an experimental investigation into geo-engineering properties of a volcanic soil observed in the city of Isparta, Turkey. The study focuses on the difficulties experienced in geotechnical sampling of the soil, its microstructural, mineralogical and physical properties, and particularly the estimation of its uniaxial compressive strength (UCS) using practical approaches. For this purpose, laboratory experiments covering the determination of mineralogical–petrographical and geomechanical properties, such as physical properties, UCS, and needle penetration index (NPI) using a specially manufactured needle, were conducted. The volcanic soil is weakly bonded, highly porous, well-graded silty sand and has a hypocrystalline texture. The weak bonding of the soil is volcanic ash formed by disintegration of volcanic glass, and the soil has some voids and a considerable amount of intact bonding between grains. The most important difficulty associated with this volcanic soil is field sampling and sample preparation for laboratory testing due to the weak bonding that governs internal stability. The UCS of the soil ranges between 29 and 132 kPa, and except for in a few samples, the UCS is lower than 100 kPa. The soil generally shows strain softening behaviour during the UCS tests; however, a few samples failed in a brittle fashion. As the natural water content and degree of saturation increases above approximately 11 and 42 %, respectively, there is a decline in the UCS of the soil. This is due to the increased exposure to water, which apparently softens the bonding, causing some loss of interlocking among the grains. Statistical evaluations suggest that the UCS of the volcanic soil can be estimated from the NPI using a needle with a diameter of 1.7 mm. In practical terms, the study provides some approaches and recommendations for the estimation of strength of weakly bonded volcanic soils for which geotechnical sampling is extremely difficult and/or impossible.

Circular diamond sawing is a widely applied method in marble, granite and other natural stone block cutting operations. Cutting, squaring and some sizing operations of the plates are also carried out by circular diamond sawing machines. The different characteristic structures of the circular diamond disks occur the basis of sawing applications. Wears of a circular diamond disks are generally affected by a series of parameters such as rock hardness, porosity, UCS, etc. In this paper, the research findings of an analysis for determining the wear dynamics of diamond sockets were presented based on the in-situ applications. Three types of rocks were cut in the marble plants with circular diamond sawing application. Peripheral speed was used as constant and the cutting dimensions of the rock plates were determined as 33.5 cm for depth, 246 cm for length and 5 cm for thickness. Wear values of diamond sockets were measured after a series of tests for each rock type. The cutting analyses of...