Page - 853 - in Book of Full Papers - Symposium Hydro Engineering

For example, some cores from the Kahir dam project are demonstrated in Fig. 7. As clearly indicated in this figure, undesirable bonding is observed between the Hardfill layers. Fig. 7 Core samples from the Kahir Hardfill dam From the aforementioned facts, we can elicit that the layered behavior of the dam body under loadings (which affects the mass modulus of the dam body deformation) should not be neglected. As also discussed in the next section, the estimation of the modulus of deformation must be sufficiently close to reality in order to give valid stress analysis results. Among the available approaches to overcome this challenge in finite element method, one is to model the layers of the dam body one by one, and considering their interfaces using the appropriate approach [6]. Although this method is more reliable than ignoring the multilayer properties of the materials, performing this complicated method is far more time- consuming and thus impractical, especially in dynamic loads. Two other approaches based on the probabilistic approach are discussed here: 1- The strength properties of the CMD layers are reduced in the direction normal to the layers. Employing the mechanics of multilayered or composite materials, we can define an orthogonal material with two different moduli in two perpendicular directions. The parameters which the derived formulas require (the shear and normal stiffness between successive layers) are unknown variables and need large-scale experiments that may not be feasible in regular Hardfill dams. To solve this issue, performing a dilatometry test in the constructed Hardfills will help gather useful data. A set of estimations are also available in rock mechanics [3], including the following equation: Where “Th” and “Kn” are the layer thickness and the normal-stiffness, respectively. Assuming the Hardfill layer thicknesses and the normal 853