Study on the Size Effect of high-water materials

Abstract

The use of high-water materials in mining and filling is conducive to stope stress control and goaf stability. Since the filling body is huge, the size effect tends to affect the mechanical and deformation characteristics to some extent. Therefore, study in this respect is beneficial to engineering design and construction. To study the size effect of the high-water materials with different water-cement ratios, this paper first carries out experimental analysis of the size effect of high-water materials with different aspect ratios and explores the influence of aspect ratio changes on their mechanical characteristics; this paper then studies the size effect of high-water materials while taking the aspect ratio as 2:1. The test results are as follows: (1) the strength of high-water materials decreases first and then decreases with the increase of aspect ratio; the strength reaches the minimum with a low degree of discretization when the ratio is 2. (2) With the increase of aspect ratio, the plasticity of high-water materials decreases, while its modulus increases continuously; the strain corresponding to the peak strength decreases, and the residual peak ratio decreases continuously, so the specimen is more prone to instability. (3) Splitting failure is the failure mode of high-water materials, which does not change with size; based on Von. Mises theorem, the consistency of theoretical and experimental results is proved. (4) The strength of the high-water material decreases with the increase of size; the size effect becomes more significant as the water-cement ratio increases.