Abstract
In this paper, numerical test research is carried out on the loading rate effect of a numerical specimen (sample C) with a transfixion sawtooth structural plane by using the rock failure process analysis (RFPA) 2D software. In order to study the mechanical characteristics difference between the rock mass with this kind of structural plane and other rock masses, the intact numerical specimen (sample A) of no structural plane and the numerical specimen (sample B) with smooth structural plane are also simulated. The uniaxial compression tests were carried out for each specimen under five loading rates of 0.002, 0.005, 0.008, 0.02, and 0.05 mm/s. The following several conclusions are obtained by the numerical test. When the loading rate is 0.002 or 0.005 mm/s, the failure mode of the numerical specimen C is an inclined linear fracture zone located in the middle and lower part of the rock mass; however, when the loading rate rises to 0.008, 0.02, and 0.05 mm/s, the fracture zone of the numerical specimen C is located in the middle and upper part of the rock mass, and its inclination angle is about 60 degrees. The peak strength, residual strength, and stress drop of the specimens A, B, and C increase with the addition of loading rate; the peak strength and stress drop of the sample C are higher than those of the other two samples. When the loading rate is 0.002 mm/s, the residual strength of sample C is lower than that of samples A and B, and the other four kinds of loading conditions are higher than those of specimens A and B. Based on the acoustic emission (AE) information, it can be seen that the failure modes of the numerical specimen C under five loading conditions are tensile failure. The AE accumulated energy decreases with the increase of loading rate, but the change law of AE accumulated number is opposite.
Highlights
Rock is subjected to various tectonic actions in complex geological environment, resulting in the structural planes with different shapes and various scales [1, 2]. e sawtooth structural plane is widely distributed in natural slope and excavating engineering slope of rock mass [3]
Both the physical and numerical tests on the mechanical characteristics of rock masses with different loading rates consider that the structural surface is smooth, and the undulating pattern of the structural surface is not considered till [14,15,16]. e discontinuities of rock medium can be caused by the existence of structural planes and the fluctuation of structural planes, while the rock failure process analysis (RFPA) software takes into account the discontinuity of the material properties, the heterogeneity, and the randomness of the defect distribution
Numerical Simulation Results and Analysis e mechanical characteristics of rock mass with transfixion regular sawtooth structural surface under different loading rates are studied in this paper
Summary
Rock is subjected to various tectonic actions in complex geological environment, resulting in the structural planes with different shapes and various scales [1, 2]. e sawtooth structural plane is widely distributed in natural slope and excavating engineering slope of rock mass [3]. Gong et al [13] analyzed the correlation between the failure modes of sandstone specimens and the characteristics of stress–strain curves under different strain rates Both the physical and numerical tests on the mechanical characteristics of rock masses with different loading rates consider that the structural surface is smooth, and the undulating pattern of the structural surface is not considered till [14,15,16]. E discontinuities of rock medium can be caused by the existence of structural planes and the fluctuation of structural planes, while the RFPA software takes into account the discontinuity of the material properties, the heterogeneity, and the randomness of the defect distribution Based on these characteristics of RFPA software, this paper uses RFPA to simulate the failure characteristics of transfixion-type regular sawtooth structural surface rock under different loading rates. Based on these characteristics of RFPA software, this paper uses RFPA to simulate the failure characteristics of transfixion-type regular sawtooth structural surface rock under different loading rates. e variation characteristics of peak strength, residual strength, and acoustic emission quantity in three kinds of numerical tests have been discussed. e influence of loading rate on failure mode of rock mass has been analyzed by using AE diagram
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