Influence of joint angle on the instability failure characteristics and AE evolution law of underground caverns

Abstract

The existence of joints is the key factor for the instability of underground caverns. In this paper, the instability failure behaviours, acoustic emission (AE) characteristics and damage evolution rules of green sandstone caverns with different joint angles were investigated. First, the influences of joint angles on the strength and failure behaviour of the caverns were analysed. Then, the AE characteristics and damage evolution rules of jointed caverns in the process of failure were discussed. The research results showed that the UCS and elastic modulus presented obvious anisotropy. Furthermore, the existence of joints with various angles had a strong influence on the failure pattern of caverns. However, the damage of the cavern is mainly concentrated on the side wall, the top and bottom and the maximum value of AE in jointed caverns are smaller than that in intact cavern, but the occurrence time of AE maximum value is generally earlier than that of intact cavern. The damage progress of jointed caverns is divided into four stages: damage stable stage, damage slow increase stage, damage rapid increase stage and damage termination stage. The joint angle mainly affected the second and third stages of damage variable of the caverns.

Keywords:

• Underground caverns
• joint angle
• failure behaviours
• AE characteristics
• damage evolution rules

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research was supported by the Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. KYCX19_0094), the National Natural Science Foundation of China (NSFC) (41941018), Guangdong Basic and Applied Basic Research Foundation (2019A1515110836) and the Fundamental Research Funds for the Central Universities (DUT20GJ204).