Search

This paper describes a simplified analytical method that considers postinstallation normal stress, normal stress due to soil dilation, and grouting pressure when calculating the maximum shear stress of the nail-soil interface. Systematic test results from two previous publications were used to verify the accuracy of the proposed method. The Hong Kong design method was also used to determine the maximum shear stress of the nail-soil interface. These analyses confirmed that the experimental data were more accurately predicted by the proposed analytical method. An extensive parametric study was conducted to examine the effects of several key parameters on the maximum shear stress. It was observed that when there was no grouting pressure, maximum shear stress increased with increasing overburden pressure, failure surface distance, dilation angle, or decreased drill hole radius. Analysis using the proposed model also demonstrates that grouting and overburden pressures share an interactional effect. The larger the grouting pressure, the greater the influence of the overburden pressure; and, consequently, the larger the maximum shear stress at the nail-soil interface. [ABSTRACT FROM AUTHOR]

Underground mine caving may induce collapse of the ground during ore caving, particularly when there is a loose material on top of the mine. In the present paper, a laboratory test is performed to model this mining problem which is followed by a particle flow simulation to simulate the interaction and movement between the two materials. For this nonhomogeneous problem, an interesting columniform channel for the loose material is formed during the drawing in both the experiment tests and the numerical modeling. The formation of this channel greatly affects the efficiency of ore drawing and the stability of the mine caving. The numerical modeling can be used for the optimization of ore drawing, ore drawing management and the prediction of ore loss and dilution indexes. The importance of the moisture content on ore drawing process and the efficiency of ore drawing are also investigated by both experimental and numerical tests, and useful results are found from the present study. [ABSTRACT FROM AUTHOR]