Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: ewolucja pęknięć

Sortuj według:

Ogranicz wyniki do:

Experimental study on biaxial dynamical compressive test and PFC2D numerical simulation of artificial rock sample with single joint

Liangxiao Xiong, Chen Haijun, Gao Xinghong, Xu Zhongyuan, Hu Deye

Archives of Civil Engineering

2023

Vol. 69, nr 1

213--229

Dynamic biaxial compression tests and Particle Flow Code numerical simulations of the cement mortar specimens with a single joint were carried out to study the mechanical properties and crack evolution of artiﬁcial rock samples with a single joint. The effects of lateral stress σ2, loading rate V, the dip angle β (between the vertical loading direction and the joint) on the biaxial compressive strength σb, and the evolution law of crack were investigated. Test results showed that; (1) when both the dip angle β and the loading rate V remained unchanged, the biaxial compressive strength σb increased with the increase in the lateral stress σ2, while σ2 had no obvious effect on the crack evolution law; (2) when both the dip angle β and the lateral stress σ2 were kept unchanged, the loading rate V had an insignificant effect on the biaxial compressive strength σb and the crack evolution law; (3) when both the lateral stress σ2 and the loading rate V were constant, the biaxial compressive strength σb decreased first and then increased with the increase in the dip angle β; however, the dip angle β did not significantly affect the crack evolution law. The conclusions obtained in this paper are presented for the first time.

Crack evolution and acoustic emission characteristics of rock specimens containing random joints under uniaxial compression

Ma Wenqiang, Wang Jiuting, Li Xiaoxiao, Wang Tongxu

Acta Geophysica

2021

Vol. 69, no. 6

2427--2441

Joints greatly affect the mechanical behavior and crack evolution of jointed rock masses. In this paper, numerical specimens containing pre-existing random joints are constructed based on a combination of the fat-joint and smooth-joint models in the particle flow code in two dimensions (PFC2D). Then, uniaxial compression of these specimens is carried out to reveal the influence of joint length or number on the mechanical behavior, crack development, acoustic emission (AE) event attributes and failure characteristics. The results suggest that a univariant increase in random joint length or number leads to a nonlinear decrease in the uniaxial compressive strength (UCS) and a linear decrease in the elastic modulus, while the fracture behavior of the specimens shows a transformation from brittle to ductile in this process. With increasing joint length or number, the cracks and AE events generated in the joints significantly increase and exceed those generated in the intact rock. Tension cracks play a dominant role in the development of cracks within intact rock, while shear cracks dominate the crack evolution of random joints. More cracks appear in the jointed rock specimens at the elastic deformation stage as the joint length or number increases. The variation in the joint length or number strongly influences the mechanical behavior, crack evolution and failure pattern of the randomly jointed rock specimen.