Construction and application method of statistical damage constitutive model of rock

Abstract

The invention provides a statistical damage constitutive model of rock. The Mohr-Coulomb criterion is adopted as rock micro-element strength, and the conventional distribution form, namely logarithmic normal distribution, in the field of engineering reliability is adopted as the distribution state of micro-element strength. The mature Mohr-Coulomb criterion with wide application is utilized as the failure criterion of micro-element strength, while the function relationship between the damage parameters A, B, C and H of the constitutive model and the pressure sigma 3 of surrounding rock is given, so that the constitutive model can directly adopt numerical calculation software in the calculation of geotechnical engineering, and the effect is verified in the actual engineering application.

Description

technical field [0001] The invention relates to a construction method of a rock constitutive model, which belongs to the field of geotechnical engineering constitutive model research, and is applicable to the research of various geotechnical engineering constitutive models such as mining, side slopes, tunnels, highways, and dam foundations. [0002] Specifically, it can guide (1) the safe production of underground mining, that is, to maximize the scientific exploitation of underground mineral resources on the premise of ensuring the safety of existing structures and facilities on the ground. (2) Reasonable delineation of the final boundary of the open-pit mine, that is, to determine the appropriate slope angle and final slope angle, so as to ensure the maximum recovery of mineral resources in a safe slope environment, reduce the amount of rock stripping, and reduce mining costs. (3) Other related issues involving the constitutive model in the field of geotechnical engineering....

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Problems solved by technology

Although the constitutive model provides a theoretical basis for expressing the relationship between stress and strain, when the constitutive model is directly applied to numerical calculation software to solve practical problems in production, since the constitutive model has not established In continuous variation of different surrounding rock pressure σ 3 The corresponding functional relational expression under the condition leads to its application in the numerical calculation software to calculate the surrounding rock pressure σ 3 In the process of parameter change, it is necessary to continuously input and change the surrounding rock pressure σ 3 The parameters of the constitutive model correspond to the parameter values ​​of the constitutive model, which determines that the constitutive model cannot be directly applied and promoted in numerical calculation software, let alone play an effective guiding role in engineering application calculations in the field of geotechnical engineering

[0031] In short, in the prior art, the range of application of the rock statistical damage constitutive model has certain limitations and difficulties. For example, D. Krajcinovic, Tang Chunan, etc. proposed to start from the randomness of the distribution of internal defects in the rock, and use the axial strain of the rock as the The micro-element strength, using the micro-element strength to obey the Weibull distribution to establish the rock statistical damage constitutive model, because the axial strain cannot accurately represent the micro-element strength, therefore, the rock statistical damage constitutive model constructed by using the axial strain to express the micro-element strength is also Inability to accurately represent the relationship between rock stress and strain

Cao Wengui, Zhao Minghua et al. discussed the relationship between rock damage softening parameters and confining pressure based on Weibull distribution, proposed a new rock micro-element strength representation method, and established a rock statistical damage constitutive model by using the Drucker-Prager criterion. The Drucker-Prager criterion is more Conservative, therefore, applying the rock statistical damage constitutive model constructed by this criterion to engineering calculations will lead to safe calculation results. Specifically, in the mining field, the calculated mining range will be smaller than the actual mineable range. cause waste of resources

Zhang Ming, Wang Fei, and Yang Qiang used the Mohr-Coulomb criterion as the rock micro-element strength and obeyed the lognormal distribution to build a statistical damage constitutive model of rock under conventional triaxial compression conditions. This model can only be obtained through experiments. Rock pressure σ 3 The finite number of discrete stress-strain relationship expressions can not be obtained with the surrounding rock pressure σ 3 There is still a certain gap between the continuously changing stress and strain function relationship expressions and the actual application in numerical calculation software

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