A Simple Method to Predict Tensile Strength of Gravelly Soil Using Shear Strength Indexes
- PDF / 238,109 Bytes
- 4 Pages / 594 x 792 pts Page_size
- 39 Downloads / 212 Views
EXPERIMENTAL INVESTIGATIONS A SIMPLE METHOD TO PREDICT TENSILE STRENGTH OF GRAVELLY SOIL USING SHEAR STRENGTH INDEXES
UDC 624.131.212:624.131.439 Enyue Ji,* Shengshui Chen, and Zhongzhi Fu Geotechnical Engineering Department, Nanjing Hydraulic Research Institute, Nanjing, China; Key Laboratory of Earth-Rock Dam Failure Mechanism and Safety Control Techniques, Ministry of Water Resources, Nanjing, China, *Corresponding author Email: [email protected].
The tensile strength of gravelly soil plays a decisive role in the formation or initiation of longitudinal cracks or hydraulic fracturing in the core of earth and rockfill dams. For this study, a series of uniaxial tensile tests and consolidated drained triaxial shear tests was carried out to study the relationships between the tensile strength and shear strength indexes of gravelly soils with gravel contents ranging from 0% to 50%. The test results indicate that the tensile strength decreases linearly with increasing gravel content when the soil is at its maximum dry density and optimum water content. An equation for estimating tensile strength of gravelly soil without tensile strength testing is proposed. The relevant test results can provide guidance for anti-crack designs for earthcore rockfill dams.
Introduction In the field of geotechnical engineering, there are relatively few published studies on the tensile properties of soil. In most cases, the structural stability calculations do not consider the tensile strength of the soil [1]. However, completed structures commonly show obvious tensile cracks on their surfaces before serious damage develops [2-3]. In recent years, some tall earth-core rockfill dams in China [4, 5] have developed serious longitudinal cracks at the top of the core. These problems emphasize the importance of studying the tensile strength of gravelly soil to understand crack formation and crack initiation in dam cores. The relationship between tensile strength and dry density as well as the relationship between tensile strength and water content in gravelly soil were investigated [6, 7]. However, the influence of gravel content on the tensile strength is still not clear. A special device [8] was constructed to perform uniaxial tensile tests to determine the tensile strength of gravelly soil. The end effect and membrane restraint effect inherent in standard triaxial tensile tests [9] results in inaccurate test data. Consequently, establishing the relationship between the shear strength index and tensile strength is a simple approach. For this study, a series of uniaxial tensile tests and consolidated drained (CD) triaxial shear tests was carried out to study the relationship between tensile strength and the shear strength indexes (cohesion c and friction angle ϕ) of gravelly soil with gravel contents ranging from 0% to 50%. Based on the results of the tests, the influence of gravel content on the tensile strength was determined and a quantitative expression to predict tensile strength based on shear strength is put forward.
Translated from Osnov
Data Loading...
