THE EFFECT OF MOISTURE CONTENT ON THE TENSILE STRENGTH AND FRACTURE TOUGHNESS OF CLAY CORE EARTH DAMS
Message:
Article Type:
Research/Original Article (دارای رتبه معتبر)
Abstract:

According to statistics, internal erosion and piping have been known as the main causes of the destruction of earth and rock-fill dam. In earth dams, hydraulic fracturing and internal erosion are two interdependent phenomena. Hydraulic fracturing causes expansion of the cracks. The flow of water in cracks causes the leaching of soil, materials and internal erosion occurs.The Bidwaz dam is an earth and rock-fill dam. About seven and a half years after the start of the first impounding, a subsidence appeared on the upstream face of the dam body. This dam is located in a narrow valley; therefore, hydraulic fracturing and internal erosion are proposed as one of the main causes of subsidence.Using the concepts of fracture mechanics is one of the prediction methods in hydraulic fracturing. Fracture mechanics is the field of mechanics concerned with the study of the crack propagation in materials. Fracture toughness modes I and II are two important parameters of materials in fracture mechanics, which can be determined by the method provided in ASTM E399.In this study, through 3-point and 4-point bending tests, the tensile strength, mode I and mode II fracture toughness of core's soil at different moisture contents are evaluated. Due to the low tensile strength of the soil, the direction of load is perpendicular to that of weight to reduce the influence of the weight. The ability to perform experiments is provided by making some changes in direct shear apparatus.Moisture content is the most important factor affecting the tensile strength and fracture toughness of soil. Experiments have been conducted with different moisture contents to evaluate the effect of this parameter. The results show that based on the moisture content, soils can be divided into three categories: 1. Brittle, 2. Semi-brittle, and 3. Elastic-Plastic. Increasing the moisture content reduces tensile strength and increases flexibility.In general, fracture toughness of mode 1 is obtained to be more than that of mode 2. Therefore, the probability of crack expansion with tensile mechanism is less than shear mechanism. At the end, based on the results of laboratory tests, mode I and II interaction diagram has been plotted as a fracture criterion at different moisture contents.

Language:
Persian
Published:
Sharif Journal Civil Engineering, Volume:35 Issue: 1, 2019
Pages:
119 to 128
magiran.com/p1996197  
دانلود و مطالعه متن این مقاله با یکی از روشهای زیر امکان پذیر است:
اشتراک شخصی
با عضویت و پرداخت آنلاین حق اشتراک یک‌ساله به مبلغ 990,000ريال می‌توانید 70 عنوان مطلب دانلود کنید!
اشتراک سازمانی
به کتابخانه دانشگاه یا محل کار خود پیشنهاد کنید تا اشتراک سازمانی این پایگاه را برای دسترسی نامحدود همه کاربران به متن مطالب تهیه نمایند!
توجه!
  • حق عضویت دریافتی صرف حمایت از نشریات عضو و نگهداری، تکمیل و توسعه مگیران می‌شود.
  • پرداخت حق اشتراک و دانلود مقالات اجازه بازنشر آن در سایر رسانه‌های چاپی و دیجیتال را به کاربر نمی‌دهد.
دسترسی سراسری کاربران دانشگاه پیام نور!
اعضای هیئت علمی و دانشجویان دانشگاه پیام نور در سراسر کشور، در صورت ثبت نام با ایمیل دانشگاهی، تا پایان فروردین ماه 1403 به مقالات سایت دسترسی خواهند داشت!
In order to view content subscription is required

Personal subscription
Subscribe magiran.com for 50 € euros via PayPal and download 70 articles during a year.
Organization subscription
Please contact us to subscribe your university or library for unlimited access!