A deep tunnel hard rock typical disaster type energy ratio ERI criterion method

Abstract

The application discloses a kind of deep tunnel hard rock typical disaster type energy ratio ERI criterion method, according to the principle that disaster type criterion should follow, based on the thought of "stress intensity ratio", establish the energy ratio index ERI of the main typical disaster type of deep tunnel hard rock;Select the deep tunnel hard rock section needing to be carried out the deep tunnel hard rock typical disaster type discrimination as target criterion section, according to the peak elastic strain energy of the field rock mass under the true three-dimensional stress condition of target criterion section and the peak elastic strain energy of indoor test rock mass under the true three-dimensional stress condition Determine the energy ratio index ERI of the main typical disaster type of deep tunnel hard rock;According to the following formula, calculate the energy ratio index ERI of the main typical disaster type of deep tunnel hard rock: in the formula, it is the peak elastic strain energy of field rock mass under the true three-dimensional stress condition;It is the peak elastic strain energy of indoor test rock mass under the true three-dimensional stress condition.Through the above technical scheme, the problems in the background art can be effectively solved.

Description

Technical Field

[0001] This invention relates to the field of tunnel hard rock technology, and in particular to a method for determining the energy ratio (ERI) criterion for typical disaster types in deep tunnel hard rock. Background Technology

[0002] In deep rock engineering, considering the scope of damage, the degree of harm, and corresponding support and protection measures, deep fracturing occurs at depths of several meters or even tens of meters within the rock mass. Its damage range is relatively small, the harm to the project is less severe, and the required support measures are weaker. Stress-induced collapses, depending on their size, can produce a damage radius of several meters to tens of meters, causing significant damage to the project, even leading to work stoppages or loss of life. These require strong support measures such as shotcrete anchors, steel arch supports, and advanced consolidation grouting. Rockbursts vary in severity depending on the magnitude of the damage. Similarly, moderate to severe rockbursts can produce a damage radius of tens of meters, with enormous destructive power, often causing significant casualties, work stoppages, and damage to valuable construction equipment such as TBMs. They not only require timely shotcreting, the use of steel fiber reinforced concrete, impact-resistant anchor bolts, and advanced support measures, but also necessitate optimized excavation schemes, the adoption of short advances and weak blasting, the use of smooth blasting techniques, and the implementation of stress relief and water softening measures. Engineering construction can determine the protective measures to be taken based on the typical disaster types of hard rock in deep tunnels; therefore, it is necessary to establish a model to realize the Energy Ratio (ERI) criterion for typical disaster types of hard rock in deep tunnels. Summary of the Invention

[0003] The main objective of this invention is to provide a method for determining the energy ratio (ERI) of typical disaster types in hard rock tunnels, which can effectively solve the problems in the background art.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for determining the Energy Ratio (ERI) criterion for typical disaster types in hard rock tunnels in deep tunnels includes the following steps:

[0006] S1. Select the hard rock section of the deep tunnel that needs to be identified as the target criterion section. Determine the energy ratio index (ERI) of the main typical disaster types of hard rock in deep tunnels based on the peak elastic strain energy of the field rock mass under true triaxial stress and the peak elastic strain energy of the indoor test rock block under true triaxial stress of the target criterion section.

[0007] S2. Calculate the Energy Ratio Index (ERI) for the main typical disaster types in hard rock tunnels of deep tunnels according to the following formula:

[0008]

[0009] In the formula, The peak elastic strain energy of the in-situ rock mass under true triaxial stress conditions; The peak elastic strain energy of the indoor test rock block under true triaxial stress conditions;

[0010] S3. Calculated according to the following formula

[0011]

[0012] In the formula, Let σ1, σ2, and σ3 be the elastic strains of the rock mass at any given time t.

[0013] S4 The peak elastic strain energy of the rock block from the indoor true triaxial test can be calculated using the following formula:

[0014]

[0015] In the formula, σ1, σ2, and σ3 are the maximum principal stress, intermediate principal stress, and minimum principal stress, respectively; E is the elastic modulus.

[0016] S5. The boundary thresholds of the ERI index for combined rockburst, stress-induced collapse, and deep fracturing, and the final ERI criterion for the main typical disaster types in hard rock of deep tunnels are calculated according to the following formula:

[0017]

[0018] Among them, the material parameters of the hard rock, the elastic modulus E and the true triaxial stress combination form are as follows:

[0019] x=[(σ1-σ2) 2 +(σ2-σ3) 2 +(σ3-σ1) 2 ] / E;

[0020] The fitting relationship selected for the peak elastic strain energy of hard rock under true triaxial stress conditions is: y = 376.81e [0.0002x] .

[0021] Compared with existing technologies, this invention has the following advantages: by substituting the discovered true triaxial energy characteristic law into the proposed ERI index, it realizes the possibility of numerical simulation of the ERI index. Finally, based on the preliminary analysis of engineering cases, it gives the boundary thresholds for different disaster types, completing the transformation of the ERI index into an ERI criterion. The advantages of the proposed criterion are mainly reflected in reflecting the influence of true triaxial stress on failure in deep rock masses, reflecting the changes in the stress field and the deviatoric stress characteristics of the initial stress field, and realizing the development towards numerical simulation. It can be applied in engineering. Attached Figure Description

[0022] Figure 1 This is a characteristic relationship diagram of energy under true triaxial stress conditions for the energy ratio (ERI) criterion method for typical disaster types in hard rock of deep tunnels according to the present invention. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0024] Example

[0025] like Figure 1 The method for determining the Energy Ratio (ERI) criterion for typical disaster types in hard rock tunnels in deep tunnels, as shown, includes the following steps:

[0026] S1. Select the hard rock section of the deep tunnel that needs to be used as the target criterion section for judging the typical disaster types of hard rock in deep tunnels. Determine the energy ratio index (ERI) of the main typical disaster types of hard rock in deep tunnels based on the peak elastic strain energy of the rock mass in the field under true triaxial stress and the peak elastic strain energy of the test rock block in the laboratory under true triaxial stress of the target criterion section.

[0027] S2. Calculate the Energy Ratio Index (ERI) for the main typical disaster types in hard rock tunnels of deep tunnels according to the following formula:

[0028]

[0029] In the formula, The peak elastic strain energy of the in-situ rock mass under true triaxial stress conditions; The peak elastic strain energy of the indoor test rock block under true triaxial stress conditions;

[0030] S3. Calculated according to the following formula

[0031]

[0032] In the formula, Let σ1, σ2, and σ3 be the elastic strains of the rock mass at any given time t.

[0033] S4 The peak elastic strain energy of the rock block from the indoor true triaxial test can be calculated using the following formula:

[0034]

[0035] In the formula, σ1, σ2, and σ3 are the maximum principal stress, intermediate principal stress, and minimum principal stress, respectively; E is the elastic modulus.

[0036] S5. The boundary thresholds of the ERI index for combined rockburst, stress-induced collapse, and deep fracturing, and the final ERI criterion for the main typical disaster types in hard rock of deep tunnels are calculated according to the following formula:

[0037]

[0038] To identify the characteristic patterns in the relationship between hard rock energy and its true triaxial stress under true triaxial stress conditions, extensive analysis is required. First, it is necessary to find regular true triaxial stress combinations among different hard rock types. Second, it is necessary to establish a connection between these regular true triaxial stress combinations and the energy of hard rock under true triaxial stress conditions, thus finding the optimal relationship between hard rock energy and its true triaxial stress combinations under true triaxial stress conditions—that is, the characteristic patterns. Figure 1 This is a characteristic relationship diagram of energy under true triaxial stress conditions. This criterion, by considering the true triaxial high-stress characteristics of deep rock masses, unifies deep fracturing, stress-induced collapse, and rockburst—common characteristics of deep rock mass disasters—through stress-driven energy, without considering the effects of rock mass structure. This allows for the evaluation of different disaster types together. Furthermore, starting from the differences in energy accumulation and release during the failure processes of these three disasters, it draws on the advantages and ideas of the "strength-stress ratio" index, pointing out three major principles for establishing the index, and ultimately establishing the energy characteristics of the main typical disaster types in hard rock of deep tunnels. The ERI index was developed through extensive research. Characteristic patterns between the peak elastic energy of hard rock under true triaxial stress and its true triaxial stress conditions and rock material parameters were obtained. These patterns can accurately predict the peak elastic energy of rock given the true triaxial stress conditions and the elastic modulus of the rock material parameters. Based on this, the discovered characteristic patterns of true triaxial energy were substituted into the proposed ERI index, enabling numerical simulation of the ERI index. Finally, based on preliminary analysis of engineering cases, boundary thresholds for different disaster types were given, completing the transformation of the ERI index into an ERI criterion.

[0039] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for determining the Energy Ratio (ERI) criterion for typical disaster types in hard rock tunnels, characterized in that, Includes the following steps: S1. Select the hard rock section of the deep tunnel that needs to be identified as the target criterion section. Determine the energy ratio index (ERI) of the main typical disaster types of hard rock in deep tunnels based on the peak elastic strain energy of the field rock mass under true triaxial stress and the peak elastic strain energy of the indoor test rock block under true triaxial stress of the target criterion section. S2. Calculate the Energy Ratio Index (ERI) for the main typical disaster types in hard rock tunnels of deep tunnels according to the following formula: ； In the formula, The peak elastic strain energy of the in-situ rock mass under true triaxial stress conditions; The peak elastic strain energy of the indoor test rock block under true triaxial stress conditions; S3. Calculated according to the following formula : ； In the formula, , , For any time t The rock mass corresponds to σ 1. σ 2. σ 3 elastic strain; S4 The peak elastic strain energy of the rock block from the indoor true triaxial test can be calculated using the following formula: ; In the formula, σ 1. σ 2. σ 3 represent the maximum principal stress, intermediate principal stress, and minimum principal stress, respectively; E It is the elastic modulus; S5. The boundary thresholds of the ERI index for combined rockburst, stress-induced collapse, and deep fracturing, and the final ERI criterion for the main typical disaster types in hard rock of deep tunnels are calculated according to the following formula: 。 2. The method for determining the Energy Ratio (ERI) criterion for typical disaster types in hard rock tunnels according to claim 1, characterized in that, The material parameters of the hard rock, including the elastic modulus E and the true triaxial stress combination, are as follows: .

3. The method for determining the energy ratio (ERI) of typical disaster types in hard rock tunnels according to claim 2, characterized in that, The peak elastic strain energy of hard rock under true triaxial stress conditions was fitted to select the fitting relationship: .

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