Safe blasting method for saturated zone deep rock stratum under low-temperature condition

Abstract

The invention relates to the technical field of safe blasting, in particular to a safe blasting method for a saturated zone deep rock stratum under a low-temperature condition, which comprises the following steps of: performing a rock mechanical property test on the saturated zone deep rock stratum under a low-temperature environment to obtain main mechanical parameters of rock density, wave velocity, porosity and Young modulus under different temperature conditions; based on test data, a dynamic constitutive model of the saturated zone low-temperature rock under the impact load effect is established, and the strain rate and the low-temperature effect are considered; according to the dynamic constitutive model, blasting parameters are optimized, and the blasting parameters comprise the explosive type, the explosive loading amount, the blast hole arrangement and the delay time; the method has the beneficial effects that the static and dynamic mechanical characteristics of the saturated zone low-temperature rock under different temperature and strain rate conditions are deeply revealed, the dynamic constitutive model is established, and a scientific basis is provided for cold region engineering design and blasting parameter optimization. An engineer can more accurately predict and control the rock breaking behavior in the blasting process, and the blasting efficiency and safety are improved.

Description

Technical Field

[0001] This invention relates to the field of safe blasting technology, specifically a safe blasting method for deep rock strata in water-saturated zones under low-temperature conditions. Background Technology

[0002] my country has the third largest area of ​​frozen rock distribution in the world, covering approximately 75% of its land area, with the highest concentration of frozen rock at high altitudes. The scale of engineering construction and mineral resource development in my country's cold regions is expanding year by year. However, seasonally frozen areas are susceptible to freeze-thaw cycles caused by seasonal changes and diurnal temperature variations during mining operations. Combined with dynamic loads from mechanical construction, blasting, and seismic disturbances, these factors can easily trigger a series of engineering geological disasters, severely hindering the sustainable development of engineering projects in cold regions and the safe and efficient exploitation of mineral resources.

[0003] Frozen rock exhibits significant dispersion and temperature sensitivity, while dynamic loading itself is random, requiring ample experiments to test its dynamic mechanical properties. Currently, domestic research on the mechanical properties of frozen rock is insufficient, particularly regarding the static and dynamic mechanical properties of low-temperature rocks under saturated conditions and their blastability classification. This leads to unsatisfactory on-site blasting results, a high proportion of large rock fragments, and low excavation and loading efficiency.

[0004] Under low-temperature conditions, the multiphase media within rock pores undergo phase transitions, and mineral particles and matrix shrink upon cooling, leading to significant changes in the rock's mechanical properties. Although scholars both domestically and internationally have conducted extensive research on the strength and dynamic parameters of frozen rocks, much of this research focuses on the deterioration of rock mechanical properties after freeze-thaw cycles. Studies on the dynamic mechanical properties of rocks under freezing conditions are relatively limited, especially research on the dynamic mechanical characteristics of frozen rocks in a saturated state.

[0005] Currently, the blasting techniques used in cold-region rock and soil blasting engineering are mostly based on empirical formulas under conventional conditions, failing to fully consider the impact of factors such as low temperature and water saturation on the mechanical properties of rock and blasting effects. This leads to unreasonable blasting parameter settings and poor blasting results in actual engineering projects, increasing construction costs and safety risks. Summary of the Invention

[0006] The purpose of this invention is to provide a safe blasting method for deep rock strata in water-saturated zones under low-temperature conditions, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a safe blasting method for deep rock strata in water-saturated zones under low-temperature conditions, comprising the following steps:

[0008] Rock mechanical properties were tested in the deep rock strata of the water-saturated zone under low temperature conditions to obtain the main mechanical parameters of rock density, wave velocity, porosity and Young's modulus under different temperature conditions.

[0009] Based on test data, a dynamic constitutive model of saturated low-temperature rocks under impact loading is established, taking into account strain rate and low-temperature effect.

[0010] Based on the dynamic constitutive model, the blasting parameters are optimized, including the type of explosive, the amount of explosive, the arrangement of boreholes, and the delay time.

[0011] Preferably, the rock mechanical property test includes:

[0012] Different low-temperature conditions were simulated using a high-low temperature alternating damp heat test chamber; uniaxial and triaxial compression tests were conducted using a rock triaxial press to obtain the compressive strength, shear strength, elastic modulus, and Poisson's ratio of the rock; dynamic impact tests were conducted using a split Hopkinson bar test system to obtain the strain rate, strain, and stress time history curves of the rock under impact load.

[0013] Preferably, the steps for establishing a dynamic constitutive model include:

[0014] The deformation characteristics and dynamic performance evolution of saturated sandstone samples under different low temperatures and strain rates were analyzed; a quantitative relationship between rock mass impact performance and rock mechanical properties based on the impact dynamic performance damage coefficient was proposed; and a dynamic constitutive model of saturated low-temperature sandstone considering strain rate and low-temperature effect was constructed.

[0015] Preferably, the optimized blasting parameters further include:

[0016] Based on the rock mass blastability classification results, the explosive consumption per unit was adjusted; using numerical simulation and field test data, the borehole layout and delay time were optimized to improve the blasting effect.

[0017] Preferably, the method for classifying the blastability of the rock mass includes:

[0018] A decision-making information system for explosiveness was established by using cluster analysis and multi-index comprehensive evaluation. Wave velocity, wave impedance, strain rate, and energy absorption ratio of low-temperature rocks in the water-saturated zone were statistically analyzed under different working conditions. Regression equations for the explosiveness index were obtained by using correlation analysis and multiple regression analysis, and then corrected by field data.

[0019] Preferably, the method also includes preparing concrete models with different porosities to simulate low-temperature rocks in the water-saturated zone with different porosities, conducting uniaxial compression tests and SHPB impact tests, and analyzing the influence of porosity on rock mechanical characteristics and damage processes.

[0020] Concrete models with different porosities were prepared; the variation of elastic modulus, peak stress, and critical damage value with porosity and temperature was analyzed.

[0021] Preferably, the simulated low-temperature rocks in the water-saturated zone with different porosities further include:

[0022] By using foaming agents to approximate the pores in rocks, an empirical formula for concrete strength based on the target porosity is established; by adjusting the foam volume, the porosity of the concrete model is controlled to simulate rocks with different porosities.

[0023] Preferably, it also includes on-site application and effect evaluation steps:

[0024] In actual engineering projects, field blasting tests are conducted to record rock properties, field conditions, blasting effects, explosive performance, and blasting parameters. Based on the field test data, the blasting effect is evaluated, and the blasting parameter model is verified and optimized.

[0025] Preferably, the on-site application and effect evaluation also includes:

[0026] High-speed cameras and 3D laser scanners were used to record crack propagation, deformation, and fragmentation during the blasting process; block size analysis software was used to statistically analyze the distribution of blasted blocks and assess the degree of blasting fragmentation.

[0027] Preferably, it also includes project management and quality control steps:

[0028] Develop detailed project implementation plans and schedules, clarifying the tasks and objectives of each stage; establish a project management and quality control system to ensure that the project proceeds as planned and achieves the expected technical and economic indicators and socio-economic benefits.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] This invention proposes a safe blasting method for deep, water-saturated rock strata under low-temperature conditions. It reveals the static and dynamic mechanical properties of water-saturated low-temperature rocks under different temperatures and strain rates, establishes a dynamic constitutive model, and provides a scientific basis for engineering design and blasting parameter optimization in cold regions. This helps engineers more accurately predict and control rock fragmentation behavior during blasting, improving blasting efficiency and safety.

[0031] A predictive optimization model for blasting parameters is proposed. This model can automatically adjust parameters such as explosive type, charge quantity, borehole layout, and delay time based on actual site conditions, thereby optimizing blasting results. This not only reduces the rate of large fragments and foundation fragments, and improves loading efficiency, but also reduces the impact of flyrock and vibration on the surrounding environment.

[0032] By optimizing blasting parameters, this project can significantly reduce the number of blasts and the amount of explosives consumed, thereby lowering construction costs. At the same time, the optimized blasting parameters can also reduce flyrock and vibration generated during blasting, lowering safety risks to surrounding buildings and personnel, and improving construction safety. Attached Figure Description

[0033] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clear and complete, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some, not all, embodiments of the present invention, and are merely illustrative of the embodiments of the present invention. They are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: This invention provides a technical solution: Low-temperature mechanical property testing and dynamic constitutive model establishment for deep rock strata in water-saturated zones.

[0036] This embodiment focuses on the deep rock strata of the water-saturated zone in the Beskuduk open-pit coal mine in Xinjiang. Rock mechanical properties were tested under low-temperature conditions to establish a dynamic constitutive model and provide a theoretical basis for subsequent safe blasting.

[0037] Step 1: Rock Sample Collection and Processing

[0038] Typical sandstone samples were collected from the Beskuduk open-pit coal mine and processed into standard test specimens: cylinders with a diameter of Ф50mm×100mm and discs with a diameter of 50mm×25mm.

[0039] Step 2: Low Temperature Environment Simulation

[0040] The rock samples were subjected to low-temperature treatment using a high and low temperature alternating damp heat test chamber with different temperature conditions: 10℃, 0℃, -20℃, and -40℃.

[0041] Step 3: Mechanical property testing

[0042] Uniaxial and triaxial compression tests were conducted using a rock triaxial press to record the compressive strength, shear strength, elastic modulus, and Poisson's ratio of the rock at different temperatures.

[0043] Dynamic impact tests were conducted using a split Hopkinson bar (SHPB) testing system to obtain the strain rate, strain, and stress time history curves of the rock under impact load.

[0044] Step 4: Establishing a dynamic constitutive model

[0045] The deformation characteristics and dynamic performance evolution of saturated sandstone samples under different low temperatures and strain rates were analyzed. A quantitative relationship between rock mass impact performance and rock mechanical properties based on the impact dynamic performance damage coefficient was proposed. A dynamic constitutive model of saturated low-temperature sandstone considering strain rate and low temperature effect was constructed.

[0046] A dynamic constitutive model of low-temperature sandstone in the water-saturated zone under different temperature and strain rate conditions was successfully established, providing a theoretical basis for subsequent optimization of blasting parameters.

[0047] Example 2, based on Example 1, proposes a study on the energy evolution law of deformation and damage under low-temperature impact on water-saturated rocks with different porosities.

[0048] This study investigates the energy evolution of deformation and damage in low-temperature water-saturated rocks under impact, in order to provide a basis for optimizing blasting parameters.

[0049] Step 1: Concrete Model Preparation

[0050] Using foaming agents to approximate the pores in rocks, concrete models with different porosities of 2%, 8%, 15%, and 25% were prepared.

[0051] Step 2: Low-temperature treatment

[0052] The concrete model was placed in a high and low temperature alternating damp heat test chamber, and different temperature conditions were set: 10℃, 0℃, -20℃, and -40℃ for low temperature treatment.

[0053] Step 3: Impact Test

[0054] Uniaxial compression tests and SHPB impact tests were conducted on the treated concrete model to record the changes in parameters such as elastic modulus, peak stress, and critical damage value with porosity and temperature.

[0055] Step 4: Analysis of Energy Evolution Laws

[0056] The variation law of absorbed energy density of rock samples was analyzed to obtain the dynamic characteristics of low-temperature saturated rock samples under impact, and the influence of porosity on the energy evolution of rock deformation and damage was explored.

[0057] This study revealed the energy evolution law of deformation and damage of low-temperature rocks in the water-saturated zone with different porosities under impact, providing a scientific basis for optimizing blasting parameters.

[0058] Example 3, based on Example 2, proposes a graded optimization study on the blastability of low-temperature rock masses in water-saturated zones.

[0059] By comprehensively evaluating multiple indicators, a blastability classification system for low-temperature rock masses in water-saturated zones is established to guide the optimization of blasting parameters.

[0060] Step 1: Data Collection

[0061] Data such as wave velocity, wave impedance, strain rate, and energy absorption ratio of low-temperature rocks in the water-saturated zone were collected under different working conditions.

[0062] Step Two: Cluster Analysis and Comprehensive Evaluation

[0063] Cluster analysis was used to comprehensively evaluate the collected data using multiple indicators, and an explosiveness decision-making information system was established.

[0064] Step 3: Regression Analysis and Formula Correction

[0065] By using correlation analysis and multiple regression analysis, the regression equation of the explosiveness index was obtained, and the formula was corrected by field data to improve the accuracy of classification.

[0066] Step 4: On-site verification and application

[0067] In actual engineering projects, field blasting tests are conducted to verify the accuracy of the explosiveness classification system, and blasting parameters are adjusted based on the test results.

[0068] A blastability classification system for low-temperature rock masses in water-saturated zones was successfully established, which effectively guided the optimization of blasting parameters and improved blasting results.

[0069] Example 4, based on Example 3, proposes the optimization and application of blasting parameters for low-temperature rock masses in water-saturated zones based on a prediction model.

[0070] Based on the research results of the previous embodiments, an optimization system for low-temperature rock mass blasting parameters in the water-saturated zone based on the prediction model was established and applied in actual engineering.

[0071] Step 1: Sample Model Building and Data Training

[0072] Based on the research results of the previous embodiments, a sample model was established, and the training conditions for the sample data were determined through correlation analysis and covariance test.

[0073] Step 2: Prediction Model Construction

[0074] Based on blasting conditions (temperature, moisture content, explosiveness classification) and blasting parameters (unit consumption, borehole layout, delay time), a blasting parameter prediction and optimization model is constructed.

[0075] Step 3: On-site application and effect evaluation

[0076] In actual engineering projects, field blasting tests are conducted, predictive models are applied to optimize blasting parameters, blasting effects are recorded, and the reliability of the model is evaluated.

[0077] Step 4: Continuous Optimization and Feedback

[0078] Based on the field application results, the prediction model is continuously optimized to form a closed-loop feedback mechanism, thereby continuously improving the accuracy and effectiveness of blasting parameter optimization.

[0079] A parameter optimization system for low-temperature rock mass blasting in saturated zones based on a prediction model was successfully established, and significant results were achieved in actual engineering, improving blasting efficiency and safety.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A safe blasting method for deep rock strata in water-saturated zones under low-temperature conditions, characterized in that: Includes the following steps: Rock mechanical properties were tested in the deep rock strata of the water-saturated zone under low temperature conditions to obtain the main mechanical parameters of rock density, wave velocity, porosity and Young's modulus under different temperature conditions. Based on test data, a dynamic constitutive model of saturated low-temperature rocks under impact loading is established, taking into account strain rate and low-temperature effect. Based on the dynamic constitutive model, the blasting parameters are optimized, including the type of explosive, the amount of explosive, the arrangement of boreholes, and the delay time.

2. The safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 1, characterized in that: The rock mechanical property tests include: Different low-temperature conditions were simulated using a high-low temperature alternating damp heat test chamber; uniaxial and triaxial compression tests were conducted using a rock triaxial press to obtain the compressive strength, shear strength, elastic modulus, and Poisson's ratio of the rock; dynamic impact tests were conducted using a split Hopkinson bar test system to obtain the strain rate, strain, and stress time history curves of the rock under impact load.

3. The safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 2, characterized in that: The steps to establish a dynamic constitutive model include: The deformation characteristics and dynamic performance evolution of saturated sandstone samples under different low temperatures and strain rates were analyzed; a quantitative relationship between rock mass impact performance and rock mechanical properties based on the impact dynamic performance damage coefficient was proposed; and a dynamic constitutive model of saturated low-temperature sandstone considering strain rate and low-temperature effect was constructed.

4. The safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 1, characterized in that: The optimized blasting parameters also include: Based on the rock mass blastability classification results, the explosive consumption per unit was adjusted; using numerical simulation and field test data, the borehole layout and delay time were optimized to improve the blasting effect.

5. A safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 4, characterized in that: The method for classifying the explosiveness of rock masses includes: A decision-making information system for explosiveness was established by using cluster analysis and multi-index comprehensive evaluation. Wave velocity, wave impedance, strain rate, and energy absorption ratio of low-temperature rocks in the water-saturated zone were statistically analyzed under different working conditions. Regression equations for the explosiveness index were obtained by using correlation analysis and multiple regression analysis, and then corrected by field data.

6. A safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 1, characterized in that: It also includes preparing concrete models with different porosities, simulating low-temperature rocks in the saturated zone with different porosities, conducting uniaxial compression tests and SHPB impact tests, and analyzing the influence of porosity on rock mechanical characteristics and damage processes: Concrete models with different porosities were prepared; the variation of elastic modulus, peak stress, and critical damage value with porosity and temperature was analyzed.

7. A safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 6, characterized in that: The simulated low-temperature rocks in the saturated zone with different porosities also include: By using foaming agents to approximate the pores in rocks, an empirical formula for concrete strength based on the target porosity is established; by adjusting the foam volume, the porosity of the concrete model is controlled to simulate rocks with different porosities.

8. A safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 1, characterized in that: It also includes on-site application and effect evaluation steps: In actual engineering projects, field blasting tests are conducted to record rock properties, field conditions, blasting effects, explosive performance, and blasting parameters. Based on the field test data, the blasting effect is evaluated, and the blasting parameter model is verified and optimized.

9. A safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 8, characterized in that: The on-site application and effect evaluation also includes: High-speed cameras and 3D laser scanners were used to record crack propagation, deformation, and fragmentation during the blasting process; block size analysis software was used to statistically analyze the distribution of blasted blocks and assess the degree of blasting fragmentation.

10. A safe blasting method for deep water-saturated rock strata under low-temperature conditions according to claim 1, characterized in that: It also includes project management and quality control steps: Develop detailed project implementation plans and schedules, clarifying the tasks and objectives of each stage; establish a project management and quality control system to ensure that the project proceeds as planned and achieves the expected technical and economic indicators and socio-economic benefits.

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