Physical and numerical tests of the excavation walls in jointed rock masses

This paper examines the magnitude and distribution of earth pressure on the support systems of open cuts in jointed rock masses. A physical model test was carried out using concrete blocks with man-made joints to represent a jointed rock mass. The model test was simulated numerically to provide a justifiable basis for extended numerical parametric studies. This study focused on the overall procedures of the physical model test, its numerical simulation, and extended numerical parametric studies. A comparison of the results from both the physical model test and numerical simulation confirmed that the applied numerical approach and methodology were suitable for further extended numerical parametric studies. The controlled parameters were the different rock types and joint characteristics including joint shear condition, joint spacing, and joint inclination angle. Results of the earth pressures from the numerical parametric tests in jointed rock masses were compared with Peck’s empirical earth pressure for soil ground. The comparison showed that the earth pressure in jointed rock masses can be very different from that in the soil ground. Accordingly, the effect of the rock types and joint characteristics needs to be considered when designing excavation support systems in jointed rock masses.