ABSTRACT:
A series of cemented rock fill (CRF) beams were tested in the laboratory to determine the peak vertical stress for a given span. Spans ranged from 51-cm to 163-cm (20 in to 64-in) with the cross sectional dimension of 20-cm by 20-cm (8-in by 8-in) remaining constant. Numerical models of the CRF beams were developed and compared to the results from the physical models. CRF material properties used in numerical models were established from additional laboratory testing of CRF which included shear tests, indirect tensile tests, and unconfined compressive tests. Good correlation was achieved between the model and lab beams.
1 INTRODUCTION
As part of a study on cemented rock fill (CRF) spans in underground mines, laboratory testing of CRF beams was conducted. Additional laboratory testing was performed on CRF samples to determined material properties to be used in the construction of numerical models of the tested beams. The following paper presents the results of the physical and numerical models.
2 SPAN ANALYSIS
Evans (1941) developed the Voussoir Beam theory for evaluating a beam constructed of blocks or voussoirs. The theory is based on blocks forming an arch (Voussoir beam) in reaction to the redistribution of a vertical load to a lateral load applied at the abutments, and the Voussoir Beam theory (or Linear Arch theory) is the basis for all other analytical studies. In deriving a static equilibrium equation for the maximum compressive stress (Fig. 1), Evans made an error in the treatment of the static equilibrium for ½ the span as detailed by Sterling (1977).
3 LABORATORY EXPERIMENTS
The CRF samples tested were a mixture of 51-mm (2-in) minus limestone aggregate, cement, and water. Cement content average 5.7% by weight and the water content was 2.5% by weight. Mixed CRF samples were cured 28 days before testing.
