Abstract
With the increase of the depth of the underground engineering, the phenomenon of splitting failure of the deep rock will appear, which is very different from the shallow cavern. In order to reveal the formation mechanism of splitting failure, mechanical model test and numerical simulations of splitting failure were carried out respectively. Using the Pubugou Hydropower Station as the engineering background, a three-dimensional (3D) geomechanical model test was conducted relying on a high stress three-dimensional load test system. The splitting failure phenomenon of high sidewall cavern was observed, and the oscillation variations of displacement and stress were measured. Based on strain gradient theory and continuum damage mechanics, an elastic–plastic damage softening model for splitting damage was established. The relationship between rock damage and energy dissipation was analyzed. Based on the strain energy density theory, the splitting failure criterion based on the strain gradient is established. A numerical analysis method for splitting damage was proposed, and a regional disintegration calculation program was developed based on a commercial finite element code. The numerical simulation results are in basic agreement with the 3D geomechanical model test.
Highlights
As a renewable energy source, hydropower has received increasing attention in China
The splitting failure of cavern with high sidewall is an engineering failure phenomenon caused by the release of strain energy stored in rock mass due to excavation-induced unloading, which results in the initiation, expansion and penetration of cracks in surrounding rock
The study indicates that when the width-to-height ratio of hard rock pillars is less than 2.5, the dominant failure mode is progressive slabbing and spalling which eventually leads to an hour-glass shape
Summary
As a renewable energy source, hydropower has received increasing attention in China. Many large hydropower projects are under construction or have been completed. Li et al (2013) applied elastic damage mechanics to model the softening behavior of rock masses They proposed a numerical method based on the maximum tensile stress criterion and strain energy density theory to simulate the zonal fracture phenomenon. The local strain in the rock is usually accompanied by strain softening It is precisely because the influence of strain gradient is ignored that the previous numerical analysis methods are difficult to explain the problems of splitting failure (Zhang et al, 2017). Based on the strain gradient theory and plastic deformation theory, Gao et al (2019) established the elastic-plastic damage softening model and elaborated the formation mechanism and development law of ZDP. On the basis of theoretical analysis and numerical simulation, the formation mechanism of deep high sidewall cavern splitting failure is described
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
