Numerical Simulation of the Effect of Double Hole Dip Angle on Tensile Strength and Failure Characteristics of Red Sandstone

Abstract

In order to study the effect of dip angle on the tensile strength and failure characteristics of red sandstone, based on the results of the Brazilian splitting test for indoor double-hole red sandstone samples, using the PFC2D particle flow numerical simulation technique to simulate the Brazilian splitting test of precast double-hole red sandstone samples, the effect of dip angle on the tensile strength and failure characteristics of red sandstone samples is studied, further, the evolution characteristics of the surface stress field of the double-hole red sandstone specimen during the tension process are analyzed, and the failure mechanism of the red sandstone in the double-hole red sandstone is revealed. The results show: (1) Increasing the inclination angle of the double hole from 0°to 60°the tensile strength of the sample is stepped down, the maximum drop is when the double hole is inclined at 45°;(2)When the double hole inclination angle is 0°-30°, the crack extends through a single hole; when the double hole inclination angle is 45°-60°, the crack propagates through the double hole.(3)The tensile stress concentration zone near the double hole is the main factor affecting the tensile strength and crack propagation of the sample: ① When the tensile stress concentration region at the edge of the hole A and the hole B is not penetrated (0°, 15°, 30°), the tensile strength of the sample is large, when the crack propagates, only a single hole is penetrated; ② When the tensile stress concentration region at the edge of the hole A and the hole B is penetrated (45°, 60°), the tensile strength of the sample is greatly reduced, the double hole is penetrated when the crack propagates.