A coupled experimental and numerical simulation of rock slope joints behavior

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ORIGINAL PAPER

A coupled experimental and numerical simulation of rock slope joints behavior Hadi Haeri & Alireza Khaloo & Mohammad Fatehi Marji

Received: 9 August 2014 / Accepted: 26 November 2014 # Saudi Society for Geosciences 2014

Abstract In this research, a coupled numerical-experimental analysis of crack propagation, crack coalescence, and breaking process of jointed rock slopes is performed by studying the mechanical behavior of pre-cracked brittle substances considering the specially prepared rock-like specimens (rock-like specimens are specially prepared by a proper mixing of Portland Pozzolana Cement (PPC), fine sand, and water in a rock mechanics laboratory) and natural rock slopes, simultaneously. The numerical analyses are accomplished using a numerical code based on the higher-order displacement discontinuity method (HODDM). A cubic displacement discontinuity variation along each boundary element is assumed to evaluate the mode I and mode II stress intensity factors (SIFs). Based on the LEFM theory, the maximum tangential stress criterion is implemented in the proposed code for predicting the crack initiation and its direction of propagation (crack coalescence path). Experimental tests are accomplished to evaluate the crack propagation process, crack coalescence, and final breakage path of rock-like specimens containing three parallel cracks (simulating the natural joint set in a rock slope). There is a good agreement between the numerical and experimental results obtained from the tested specimens demonstrating the accuracy and effectiveness of the proposed approach.

H. Haeri (*) Department of Civil Engineering, Sharif University of Technology, Member of National Elites Foundation, Tehran, Iran e-mail: [email protected] A. Khaloo Head of Center of Excellence in Structure and Earthquake Engineering, Sharif University of Technology, Tehran, Iran M. F. Marji Engineering Department, Faculty of Mining and Metallurgy, Institution of Engineering, Yazd University, Yazd, Iran

Keywords Crack propagation process . Parallel cracks . Rock-like specimens . LEFM . Experimental and numerical simulations . HODDM

Introduction The joints, cracks, and discontinuities more frequently exist in most rock engineering structures. Thereby, in the design of these rock structures, the effect of joints and discontinuities on the rock mass properties is to be considered (Erdogan and Sih 1963; Hussian et al. 1974; Ke et al. 2008). The mechanism of failure, fracturing, and crack coalescence in the pre-cracked brittle rocks is useful in the numerical rock fracture mechanics applications in the field of geotechnical engineering such rock slope stability, surface and underground rock excavation projects, hydraulic fracturing, etc. Fracture mechanics principles have been applied by Tharp and Coffin (1985) to investigate the stability of small rock slopes containing single cracks. The safety factor of small rock slopes containing single isolated joint and edge crack under mixed mode I/II loading had been computed based on fract