توضیحات
ABSTRACT
Rockfill materials have been widely utilized in large structures as well as rockfill breakwaters and rockfill dams construction. Design procedure of such structures requires a rather precise estimation of geomechanical properties of such materials and hence, such properties are often evaluated with great difficulty. In this research, one of the important parameters commonly used in elasto-plastic constitutive model, namely dilation angle, is investigated by studying triaxial test results on five rockfill materials.
INTRODUCTION
In general, the design of rockfill structures are affected by intrinsic properties of parent rock and this dependency distinguishes rockfill structures from other earth structures. The behaviour of the rockfill materials is affected by such factors as mineralogical composition, articles grading, size and shape of particles and stresses. Triaxial tests have been conducted on modeled rockfill materials ,to study the stress strain behavior of rockfill materials and fount that stress-strain characteristics of rockfill materials are non-linear, inelastic and stress dependent behaviour and increasing confining stress, maximum deviatoric stress, axial strain and volumetric strain at failure, increase . In high confining stress, strength of material is dependent on particle breakage. Therefore, friction angle, particle sliding and particle breakage control material’s behaviour . The friction angle of rockfills decreases with a declining ate, with the increase of confining pressure. Rate of dilation is dependent on the degree of breakage. At high confining pressure, the breakage increases, because expansion is restricted . According to investigations of Marachi et al. (1972), axial strain is affected by particle shape and type of parent rock. However, particle shape is more influential. In addition, round shaped particles has greater friction angle. Another factor, which influences the material’s behavior, is particle grading. Particle grading controls the friction angle of rockfills, by breakage process. Comparing uniformly graded materials, well-graded rockfill has lower particle breakage and greater friction angle. Uniformly graded materials have higher ratio of porosity . Porosity is dependent on particle shape and gradation; the porosity increases with decreasing uniformity coefficient and increasing particle roundness. At low confining stresses, porosity and initial relative density affect the rockfill strength. In this paper, it is intended to perform a study on the dilative behaviour of rockfill samples under different test conditions. In addition, the stress-strain-volume change behaviour of the modeled rockfill materials has been investigated. The behaviour of various rockfill materials have been compared.
Year: 2011
Publisher : Sixth National Congress on Civil Engineering
By : M. Nemati , S. Jahangiri , F. Kalantary , M. A. H. Mehrdad and M. Veiskarami
File Information: English Language/ 8 Page / size: 254 KB
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سال : 1390
ناشر : ششمین کنـگره ملی مهنـدسی عمـران
کاری از : نعمتی . جهانگیري، فرهاد کلانتری . حسن مهرداد و . وایشکارامی
اطلاعات فایل : زبان انگلیسی / 8 صفحه / حجم : KB 254
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