پديد آورندگان :
قبادي، محمدحسين دانشگاه بوعلي سينا - دانشكدۀ علوم پايه , اميري, مهرداد دانشگاه بوعلي سينا - دانشكدۀ علوم پايه , آلياني, فرهاد دانشگاه بوعلي سينا - دانشكدۀ علوم پايه
چكيده فارسي :
بخش اعظم شرق و جنوب شرق استان كرمانشاه از رخنمون پريدوتيت ها تشكيل شده است. شناخت ويژگي هاي زمين شناسي مهندسي پريدوتيت هاي هرسين به شناخت عمومي زمين شناسي مهندسي محل كمك زيادي مي كند. هدف اين مقاله بررسي و معرفي خصوصيات زمين شناسي مهندسي پريدوتيت هاي هرسين در استان كرمانشاه است. در اين پژوهش، به منظور شناخت خصوصيات و رفتار مهندسي اين سنگ ها، 15 بلوك از پريدوتيت هاي هرسين انتخاب شد و براي انجام آزمايش هاي آزمايشگاهي به آزمايشگاه انتقال داده شد. خصوصيات سنگ شناسي، ويژگي هاي فيزيكي و مكانيكي پريدوتيت ها تعيين شده است. نمونه ها تحت آزمايش هاي سختي چكش اشميت، دوام وارفتگي، شاخص بار نقطه اي، مقاومت فشاري تك محوري، مقاومت كشش برزيلي و سرعت موج قرار گرفته اند. نتايج اين تحقيق نشان داد كه تفاوت در خصوصيات سنگ شناسي و فيزيكي منجر به تغيير در خصوصيات مكانيكي آن ها شده است. با استفاده از آناليزهاي رگرسيون نرم افزار Excell، ارتباط بين خصوصيات فيزيكي و مكانيكي پريدوتيت ها تعيين شد. بر اساس نتايج به دست آمده، ميزان انطباق بيش تري بين نتايج خصوصيات مكانيكي در حالت خشك نسبت به اشباع وجود دارد. بيش ترين انطباق بين آزمايش مقاومت كششي برزيلي (BTS) با سختي اشميت (SHV) در حالت خشك است كه ميزان ضريب تعيين (r2) برابر 0/95 است
چكيده لاتين :
Because of the diversity in petrography, peridotites have variable physical and mechanical properties. For this reason, knowledge of resistance properties and their deformation will help with the prediction of engineering behavior of these rocks. Due to the large spread of igneous rocks, especially peridotite, in Zagros, northeastern and central Iran, special attention has been paid to their petrographic, physical and mechanical characteristics. The construction of the structure within or on the peridotites and the choice for the purpose of the stone borrow depends on the recognition of its engineering geology characteristics. In this paper, in addition to the field and laboratory study, the geological characteristics of peridotite engineering has been investigated.
Material and methods
In order to study the geological characteristics of the peridotites of Harsin region, 15 suitable blocks were selected and transferred to the laboratory. Accordingly, from collected rock samples, 150 cylindrical cores of diameter 54 mm were prepared and physical and mechanical tests were performed according to (ISRM, 2007) and (ASTM, 2001) guidelines. In this research, after sampling of the study area and preparing the core for the lithological characteristics of the samples by providing thin sections of them with polarizing microscopy was studied.
Results and discussion
By considering the results of laboratory tests and analysis from Harsin peridotites in Kermanshah province, we can acclaim that with increasing the percentage of minerals in olivine and pyroxene in rock, the strength was decreased and the levels weaknesses, which is due to the weak structure of the mineral-olivine and pyroxene. According to the physical properties test and Anon classification, the porosity percentage in porosity percentage is low and as a result the amount of water absorption index is low. Based on the Gamble classification, all peridotites are very resistant to durability and based on the Franklin and Chandra classification, all samples are extremely resistant. The results of this study showed that the single axial compressive strength, elasticity modulus, point load index and tensile strength were decreased with an increase in humidity content of peridotite samples. This is due to the fact that with the increase of humidity pore pressure of water increases. According to the Anon classification, the peridotites are very high in terms of the length of the longitudinal passage through the rock. The highest compliance between the Brazilian Tensile strength test (BTS) and Schmidt hammer (SHV) was achieved in the dry condition and the determination coefficient (R2) equals to 0.95 was obtained. Also there is an acceptable relation between the Brazilian Tensile Strength Test (BTS) and the dry volume unit weight (γd) with the determination coefficient (R2) of 0.93. In addition, there is an admissible relationship between durability test and single-axial compressive strength, with a coefficient determination (R2) of 0.94. Regarding the obtained regressions in this study, the physical and mechanical properties show good agreement and most of the equations have an acceptable coefficient determination.
