Tunnel blasting unit consumption design method considering rock critical energy storage

Abstract

The embodiment of the invention provides a tunnel blasting unit consumption design method considering rock critical energy storage. The method is applied to the technical field of tunnel construction and data processing and comprises the steps that a rock test sample is collected, the energy storage limit of rock in different stress states is analyzed through a split Hopkinson pressure bar test, and a stress-strain empirical model of the rock test sample is constructed; on the basis of the stress-strain empirical model of the rock test sample, a blasting vibration method is adopted to calculate the fracture range of the explosive in the rock under the action of stress waves in the rock blasting process, and the rock crack length is obtained; explosive performance parameters are obtained, an explosive unit consumption equivalent design model is established according to the crack length and the explosive performance parameters, and explosive design unit consumption of tunnel blasting in different states is obtained through calculation. In this way, the method focuses on the significant difference of the energy storage limits of the rocks in different stress states, tunnel blasting explosive unit consumption design is guided based on the rock energy storage limits, and the method has important significance on cost reduction and efficiency improvement.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction and data processing, and in particular to a tunnel blasting unit consumption design method considering the critical energy storage of rock. Background Art

[0002] The drilling and blasting method for tunnel blasting construction is a common method in the field of tunnel blasting construction. Among them, the design of explosives is of great significance for tunnel blasting. Usually, tunnel blasting excavation is carried out under the conditions of combined dynamic and static loading. If the dynamic load applied is too small, the rock material of the excavated part cannot be broken. If the dynamic load applied is too large, the rock material of the protected part is very easy to lose its bearing capacity. Therefore, the quantitative control of the dynamic load is particularly important, which is inseparable from the critical energy consumption characteristics of rock materials. The current explosive unit consumption design methods do not take into account the critical properties of rock materials, and it is impossible to reasonably design the explosive unit consumption according to actual working conditions. The energy storage limit of rocks under different stress states has significant differences. Guiding the design of tunnel blasting explosive unit consumption based on the rock energy storage limit is of great significance to reducing costs and increasing efficiency. Therefore, there is an urgent need for a method that can guide the design of tunnel blasting explosive unit consumption based on the rock energy storage limit. Summary of the invention

[0003] The present invention provides a tunnel blasting unit consumption design method considering the critical energy storage of rock. By guiding the design of tunnel blasting explosive unit consumption based on the rock energy storage limit, the technical problem that the existing methods do not take into account the critical performance of rock materials and cannot perform reasonable explosive unit consumption design according to actual working conditions is solved.

[0004] According to a first aspect of the present disclosure, a method for designing a tunnel blasting unit consumption taking into account the critical energy storage of rock is provided, comprising the following steps:

[0005] Collect rock test samples, use the split Hopkinson pressure bar test to analyze the energy storage limit of rock under different stress states, and construct an empirical stress-strain model of the rock test samples;

[0006] Based on the stress-strain empirical model of rock test samples, the blasting vibration method is used to calculate the fracture range of rock produced by stress waves during rock blasting, and the length of rock cracks is obtained.

[0007] The performance parameters of explosives are obtained, and an equivalent design model of explosive unit consumption is established based on the modified Proctor formula and according to the crack length and explosive performance parameters. The design unit consumption of explosives for tunnel blasting under different conditions is calculated according to the model.

[0008] According to the above aspects and any possible implementation, an implementation is further provided, wherein the process of collecting rock test samples, analyzing the energy storage limit of rock under different stress states by using a split Hopkinson pressure bar test, and constructing a stress-strain empirical model of the rock test samples is as follows:

[0009] Cut the rock into sample state and calculate the structure and performance parameters of the rock sample;

[0010] The sample is placed on a stress wave generating device and a strain gauge is attached to the sample, the stress wave generating device is used to impact the sample to generate stress waves, and the generated strain is recorded;

[0011] A stress-strain empirical model of the rock test sample is constructed according to the strain and the rock test structure and performance parameters.

[0012] According to the aspects described above and any possible implementation method, an implementation method is further provided, wherein the rock test structure and performance parameters include: the end face area of ​​the initial end of the rock sample, the elastic modulus of the rock material, the Poisson's ratio of the rock, and the initial length of the initial end of the rock sample; the rock test sample stress-strain empirical model includes a strain model, a stress model, and a strain rate model.

[0013] According to the above aspects and any possible implementation, an implementation is further provided, wherein the stress-strain empirical model based on the rock test sample is used to calculate the fracture range generated in the rock under the action of stress waves during the rock blasting process by the blasting vibration method, and the process of obtaining the crack length is as follows:

[0014] The rock Poisson's ratio is obtained based on the rock test structure and performance parameters, and the rock tensile strength is calculated based on the stress-strain empirical model of the rock test sample;

[0015] Obtain blasting parameters of the blasthole, and calculate the initial pressure on the blasthole wall according to the blasting parameters in an uncoupled charging mode;

[0016] The rock crack length is calculated according to the initial pressure on the blasthole wall, the rock tensile strength and the rock Poisson's ratio.

[0017] According to the above aspects and any possible implementation, an implementation is further provided, wherein the calculation method of the initial pressure on the blasthole wall is:

[0018] The average detonation pressure is calculated according to the blasting parameters of the blasthole, and the initial pressure calculation value on the blasthole wall is calculated according to the average detonation pressure;

[0019] The radial uncoupling coefficient and the axial uncoupling coefficient of the blasthole wall are calculated according to the blasthole blasting parameters;

[0020] The initial pressure calculation value is converted and calculated using the radial uncoupling coefficient and the axial uncoupling coefficient to obtain the initial pressure on the blast hole wall.

[0021] According to the above aspects and any possible implementation, an implementation is further provided, wherein the calculation method of the rock crack length is:

[0022]

[0023] Among them, R is the rock fracture range, r b is the blasthole radius, b is the lateral stress coefficient, ρ0 is the explosive density, v is the explosive detonation velocity, K r is the radial uncoupling coefficient, K l is the axial uncoupling coefficient, k is the impact coefficient, α is the stress wave attenuation coefficient, and σ1 is the tensile strength of the rock.

[0024] According to the above aspects and any possible implementation, an implementation is further provided, wherein the explosive unit consumption equivalent design model is:

[0025]

[0026] Among them, q is the design unit consumption of explosives, k0 is the correction coefficient of unit consumption of explosives, f is the rock strength coefficient, Rc is the rock compressive strength, S is the tunnel excavation area, Qv is the isochoric explosion heat per unit mass of explosives, and δ is the water content of explosives.

[0027] According to the aspects and any possible implementations described above, an implementation is further provided, wherein the explosive performance parameters include rock strength coefficient, explosive unit consumption correction coefficient, isochoric explosion heat per unit mass of explosive, and water content of explosive.

[0028] According to the aspects and any possible implementations described above, an implementation is further provided, wherein the method further comprises: based on the explosive unit consumption equivalent design model, according to the power difference between different explosives, calculating the specific design unit consumption of different categories of explosives.

[0029] The present invention discloses the following technical effects:

[0030] The present invention combines a separate Hopkinson pressure bar test system to carry out dynamic impact compression tests on different types of rocks under complex stress states, determine the energy storage limits of different types of rocks under different stress states, analyze the changing law of the energy storage limit with the stress state, establish an empirical model for predicting the energy storage limit, and establish an equivalent design model of the rock energy storage limit and the unit consumption of explosives based on the energy storage limit of the rock under complex stress states. The optimal design unit consumption of tunnel blasting under different external stress states is determined, and different blasting unit consumptions can be effectively designed according to different rock limit performances, which is of great significance for tunnel blasting.

[0031] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present disclosure. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, among which:

[0033] Figure 1 A schematic flow chart of a method for designing unit consumption of tunnel blasting considering critical energy storage of rock according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Please refer to Figure 1 As shown, this embodiment provides a tunnel blasting unit consumption design method considering rock critical energy storage, comprising the following steps:

[0037] S101. Collect rock test samples, use the split Hopkinson pressure bar test to analyze the energy storage limit of rock under different stress states, and construct an empirical stress-strain model of the rock test samples.

[0038] In this embodiment, a split Hopkinson pressure bar (SHPB) test is used to carry out dynamic impact compression tests on different types of rocks under complex stress states to determine the energy storage limits of different rocks under different stress states. By constructing an empirical model for predicting the energy storage limit, the stress, strain and strain rate of the rock material are calculated.

[0039] In SHPB, it is mainly used to evaluate the relationship between stress, strain and strain rate of materials under dynamic loading conditions, and is suitable for the impact characteristics of various materials such as metals, polymers, composite materials, etc. Its test system is mainly composed of incident / transmission rods, gas gun devices, dynamic strain gauges and data acquisition systems, which can collect the stress waveform of the pressure rod in real time during the test, so as to calculate the stress, strain and strain rate of the test material.

[0040] Specifically, in this embodiment, the rock samples collected in this embodiment are analyzed and processed by using a split Hopkinson pressure bar test:

[0041] Specifically expressed as:

[0042]

[0043] Where σ is stress, ε i is the incident wave strain, ε r is the reflected wave strain, ε t is the transmitted wave strain, S0 is the initial end surface area of ​​the rock sample, E is the elastic modulus of the rock material, and S1 is the end surface area of ​​the compression rod.

[0044]

[0045] Among them, ε is the strain, v1 is the stress wave velocity, and l0 is the initial length of the initial end of the rock sample.

[0046]

[0047] in, is the strain rate.

[0048] At the same time, this embodiment uses the JC constitutive equation with strain rate effect to describe the dynamic mechanical properties of the sample, and describes the influence of strain, strain rate and temperature on yield stress and failure strain through a multiplication relationship. The obtained JC constitutive equation is as follows:

[0049]

[0050] Among them, σ1 is the initial yield stress, A is the strain hardening modulus of the material, m is the material hardening index, B is the material strain rate hardening parameter, t is the material softening index, T r is the reference temperature, T m is the melting temperature, is the quasi-static strain rate.

[0051] S102. Based on the stress-strain empirical model of the rock test sample, the blasting vibration method is used to calculate the fracture range generated in the rock under the action of stress waves during the rock blasting process of the explosive, and the crack length is obtained.

[0052] In the actual blasting process, the process of this embodiment can determine the unit consumption of explosives by calculating the crack length, specifically:

[0053] The radial movement of the particles generates tensile stress. When the radial tensile stress is greater than the tensile strength of the rock, cracks will be generated. Therefore, the calculation method for the blasting fracture range in this embodiment is:

[0054]

[0055] Where b is the lateral stress coefficient, Where μ is the Poisson's ratio of rock, p1 is the peak initial pressure of the blasthole wall, and σ1 is the tensile strength of rock, which is: α is the stress wave attenuation coefficient, r a is the blast hole radius.

[0056] When the uncoupled charging method is used, the calculation formula for the initial pressure on the blasthole wall is:

[0057]

[0058] Among them, V c is the volume of the explosive package, V c =πl c r c 2 , where l c is the length of the explosive package, r c is the radius of the explosive package, V b is the volume of the explosion hole, Among them, l b is the length of the blasthole after removing the blasthole mud, r b is the borehole radius, P1 is the initial detonation pressure, and k is the impact coefficient.

[0059] In this embodiment, the initial detonation pressure P1 can be calculated by the following formula:

[0060]

[0061] Among them, ρ0 is the density of explosive and v is the detonation velocity of explosive.

[0062] At the same time, the initial pressure on the blasthole wall can also be expressed as:

[0063]

[0064] Among them, Kr is the radial uncoupling coefficient, specifically: Kl is the axial uncoupling coefficient, specifically:

[0065] Finally, the crack range under the action of stress wave can be obtained, specifically:

[0066]

[0067] Where R is the length of the rock crack generated by the stress wave.

[0068] S103, obtaining explosive performance parameters, establishing an equivalent design model for explosive unit consumption according to the crack length and the explosive performance parameters, and calculating the explosive design unit consumption for tunnel blasting under different conditions according to the model.

[0069] Specifically, in this embodiment, the crack length can directly reflect the unit consumption of explosives, and the rock strength coefficient is also used to characterize the influence of surrounding rock properties on the unit consumption of explosives, and the influence of explosive properties on the unit consumption of explosives is usually characterized by the working capacity of explosives. This embodiment is based on the modified Proctor formula to calculate the unit consumption model of explosives for rock strength coefficient and crack length, which is specifically:

[0070]

[0071] Among them, q is the unit consumption of explosives, f is the rock strength coefficient, specifically, f = Rc / 10, Rc is the compressive strength of rock, S is the tunnel excavation area, k0 is the correction coefficient of unit consumption of explosives, Qv is the isochoric explosion heat per unit mass of explosives, and δ is the water content of explosives.

[0072] In this embodiment, since different explosives have different explosive blasting properties, the following formula exists according to different explosives:

[0073]

[0074] Wherein, qr is the explosive consumption per unit of other explosives, Pp is the explosive power index of this embodiment, and Pr is the power index of other types of explosives.

[0075] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but the technicians in this field should be aware that the present disclosure is not limited by the described action sequence, because according to the present disclosure, certain steps can be performed in other sequences or simultaneously. Secondly, the technicians in this field should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present disclosure.

[0076] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved, and this document does not limit this.

[0077] The above specific implementations do not constitute a limitation on the protection scope of the present disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A tunnel blasting unit consumption design method considering rock critical energy storage, characterized in that: The following steps are involved: Collect rock test samples, use the split Hopkinson pressure bar test to analyze the energy storage limit of rock under different stress states, and construct an empirical stress-strain model of the rock test samples; Based on the stress-strain empirical model of rock test samples, the blasting vibration method is used to calculate the fracture range of rock produced by stress waves during rock blasting, and the length of rock cracks is obtained. The performance parameters of explosives are obtained, and an equivalent design model of explosive unit consumption is established based on the modified Proctor formula and according to the crack length and explosive performance parameters. The design unit consumption of explosives for tunnel blasting under different conditions is calculated according to the model.

2. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 1 is characterized in that: The process of collecting rock test samples, analyzing the energy storage limit of rocks under different stress states by using a split Hopkinson pressure bar test, and constructing a stress-strain empirical model of the rock test samples is as follows: Cut the rock into sample state and calculate the structure and performance parameters of the rock sample; The sample is placed on a stress wave generating device and a strain gauge is attached to the sample, the stress wave generating device is used to impact the sample to generate stress waves, and the generated strain is recorded; A stress-strain empirical model of the rock test sample is constructed according to the strain and the rock test structure and performance parameters.

3. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 2 is characterized in that: The rock test structure and performance parameters include: the end face area of ​​the initial end of the rock sample, the elastic modulus of the rock material, the Poisson's ratio of the rock and the initial length of the initial end of the rock sample; the rock test sample stress-strain empirical model includes a strain model, a stress model and a strain rate model.

4. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 1 is characterized in that: The stress-strain empirical model based on the rock test sample adopts the blasting vibration method to calculate the fracture range generated in the rock under the action of stress waves during the rock blasting process, and the process of obtaining the crack length is as follows: The rock Poisson's ratio is obtained based on the rock test structure and performance parameters, and the rock tensile strength is calculated based on the stress-strain empirical model of the rock test sample; Obtain blasting parameters of the blasthole, and calculate the initial pressure on the blasthole wall according to the blasting parameters in an uncoupled charging mode; The rock crack length is calculated according to the initial pressure on the blasthole wall, the rock tensile strength and the rock Poisson's ratio.

5. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 4 is characterized in that: The calculation method of the initial pressure on the blasthole wall is: The average detonation pressure is calculated according to the blasting parameters of the blasthole, and the initial pressure calculation value on the blasthole wall is calculated according to the average detonation pressure; The radial uncoupling coefficient and the axial uncoupling coefficient of the blasthole wall are calculated according to the blasthole blasting parameters; The initial pressure calculation value is converted and calculated using the radial uncoupling coefficient and the axial uncoupling coefficient to obtain the initial pressure on the blast hole wall.

6. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 5 is characterized in that: The calculation method of the rock crack length is: Among them, R is the rock fracture range, r b is the blasthole radius, b is the lateral stress coefficient, ρ0 is the explosive density, v is the explosive detonation velocity, K r is the radial uncoupling coefficient, K l is the axial uncoupling coefficient, k is the impact coefficient, α is the stress wave attenuation coefficient, and σ1 is the tensile strength of the rock.

7. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 1 is characterized in that: The explosive unit consumption equivalent design model is: Among them, q is the design unit consumption of explosives, k0 is the correction coefficient of unit consumption of explosives, f is the rock strength coefficient, Rc is the rock compressive strength, S is the tunnel excavation area, Qv is the isochoric explosion heat per unit mass of explosives, and δ is the water content of explosives.

8. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 7 is characterized in that: The explosive performance parameters include rock solidity coefficient, explosive unit consumption correction coefficient, isochoric explosion heat per unit mass of explosive, and water content of explosive.

9. The tunnel blasting unit consumption design method considering rock critical energy storage according to claim 1 is characterized in that: The method further comprises: based on the explosive unit consumption equivalent design model, according to the power difference between different explosives, calculating the specific design unit consumption of different types of explosives.

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