Experimental study on the reasonable proportions of rock-like materials for water-induced strength degradation in rock slope model test

Abstract

Water-induced strength deterioration of rock mass is a crucial factor for rock slope instability. To better show the degradation process of rock slope water–rock interaction, we used bentonite as a water-sensitive regulator to build a new rock-like material that matches the features of water-induced strength degradation based on the cement-gypsum bonded materials. Twenty-five schemes of the material mixture proportion were designed using the orthogonal design method considering four factors with five variable levels, and a variety of experiments were conducted to obtain physico-mechanical parameters. In addition, one group of rock-like material proportion was selected and applied to the large-scale physical model test. The experiment results reveal that: (1) The failure mode of this rock-like material is highly similar to that of natural rock masses, and the physico-mechanical parameters vary over a wide range; (2) The bentonite content has a significant influence on the density, elastic modulus, and tensile strength of rock-like materials; (3) It is feasible to obtain the regression equation based on the linear regression analysis to determine the proportion of rock-like material; (4) Through application, the new rock-like material can effectively simulate or reveal the startup mechanism and instability characteristics of rock slopes under water-induced degradation. These studies can serve as a guide for the fabrication of rock-like material in the other model tests.

Investigation of Sandstone-like Material for Damaged Rock Mass Based on Orthogonal Experimental Method

“…Moreover, the analysis in Table 5 reveals that the largest range of elastic modulus is observed under different levels of factor A, which measures 0.11. Cui et al [36] found that the elastic modulus of rock-like materials decreases with the ratio of aggregate and binder and that this ratio has the most significant effect on elastic modulus, which is consistent with the pattern presented in this paper. This indicates that factor A has the greatest degree of influence on the elastic modulus, and there is a negative correlation between the elastic modulus and the level of factor A. et al [36] found that the elastic modulus of rock-like materials decreases with the ratio of aggregate and binder and that this ratio has the most significant effect on elastic modulus, which is consistent with the pattern presented in this paper.…”

“…Cui et al [36] found that the elastic modulus of rock-like materials decreases with the ratio of aggregate and binder and that this ratio has the most significant effect on elastic modulus, which is consistent with the pattern presented in this paper. This indicates that factor A has the greatest degree of influence on the elastic modulus, and there is a negative correlation between the elastic modulus and the level of factor A. et al [36] found that the elastic modulus of rock-like materials decreases with the ratio of aggregate and binder and that this ratio has the most significant effect on elastic modulus, which is consistent with the pattern presented in this paper. This indicates that factor A has the greatest degree of influence on the elastic modulus, and there is a negative correlation between the elastic modulus and the level of factor A.…”