A Method for Determining Rock Mass Damage Threshold Based on the Growth Rate of Mesoscopic Cracks

Abstract

The present invention provides a meso-crack growth rate based rock mass damage threshold determination method. The method is characterized by comprising: carrying out an conventional physical mechanics property experiment and thin slice analysis on a target rock mass specimen; according to the obtained rock mass strength, deformation characteristics, and mesoscopic particle shape and cemented state, reconstructing a numerical model of the rock mass specimen by using a computer; carrying out numerical reproduction of the mechanical behavior and deformation process on the reality experiment process of the specimen; and investigating the change rule of the growth number of meso-cracks that change with the strain, introducing a parameter of the growth rate of the meso-cracks, and defining a damage threshold value through rock mass damage corresponding to the peak point. According to the method disclosed by the present invention, the growth rule of the rock meso-cracks under the loading condition is disclosed, and the concept of the growth rate of meso-cracks is introduced, and a new rock mass damage threshold determination method is provided; and by virtue of the analysis method of the present invention, the normalized damage threshold of the rock mass can be obtained, and a perfect foundation is laid for the threshold to be promoted and applied in water conservancy and hydropower, nuclear power and geotechnical engineering.

Description

technical field [0001] The invention relates to the fields of water conservancy and hydropower, nuclear power and geotechnical engineering, in particular to a method for determining the rock mass damage threshold based on the growth rate of mesoscopic cracks. Background technique [0002] At present, a number of large-scale water conservancy, hydropower and nuclear power projects are being or will be built in my country, such as Xiangjiaba, Baihetan Hydropower Station and Lufeng and Taipingling Nuclear Power Station projects. During the blasting and excavation of dams, tunnels or powerhouses, the retained bedrock and tunnel surrounding rock will inevitably be damaged under the impact of the explosion, forming a blasting damage zone. When the damage area is too large and exceeds the allowable value, it will directly affect the safety of the project. Therefore, in practice, it is necessary to accurately predict the damage range caused by blasting according to conditions such ...

AI Technical Summary

Problems solved by technology

However, all these methods obtain the static crack distribution characteristics of the rock mass in a certain state, and only correspond to the crack distribution in the local area of ​​the rock slice or sample, and cannot reflect the overall and the whole process of crack generation and expansion. The dynamic process of the dynamic process cannot judge the critical state in the process, so it cannot be used to determine the rock mass damage threshold

The acoustic emission method can be used to detect the dynamic crack growth of rock mass, which has the advantages of high sensitivity and long-term continuous monitoring, but it also has limitations: the rock mass must bear new cracks to detect, and the original cracks cannot be detected; electrical noise, The surrounding environment such as mechanical noise has a great influence; the positioning accuracy is low; the crack information that can be measured is limited; the most important thing is that it is difficult to interpret the measurement results, and it is difficult to locate the critical point from the acoustic emission characteristics and then determine the damage threshold

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