Methods for assessing and controlling the stress disturbance of surrounding rock under TBM rock breaking and vibration

Abstract

This invention primarily relates to the field of surrounding rock stability technology in tunnel engineering. To address the problems of lack of dynamic coupling in predicting surrounding rock disturbance, insufficient model adaptability, and poor real-time performance, this invention provides a method for assessing and controlling the stress disturbance of surrounding rock under the action of TBM rock breaking and vibration. Its core is: obtaining the static stress field distribution of the surrounding rock through numerical simulation and calculating the static disturbance degree; analyzing the dominant frequency energy of the vibration signal based on elastic wave theory and calculating the dynamic disturbance degree formed by the attenuation of the vibration wave propagation in the surrounding rock. The static and dynamic disturbance degrees are integrated into a comprehensive disturbance degree index, and the value of the comprehensive disturbance degree is divided into three disturbance levels. The TBM control system is automatically linked to execute corresponding parameter adjustments and support measures, forming a real-time closed loop of monitoring, assessment, and control. This transforms the surrounding rock disturbance from traditional experience-based judgment into calculable and controllable engineering parameters, effectively improving the safety and intelligence level of TBM construction.

Description

Technical Field

[0001] This invention mainly relates to the field of surrounding rock stability technology in tunnel engineering, and in particular to a method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration. Background Technology

[0002] TBMs primarily break rocks using disc cutters. First, they undergo compression crushing, where the cutters are pressed into the rock mass by the propulsion force of hydraulic jacks (cutterhead thrust). The rock below the cutter tip reaches its compressive strength limit, forming a crushing zone (compacted core). Then, cracks propagate as the cutters roll, applying radial pressure and tangential shear force to the rock, creating radial tensile cracks around the crushing zone. Next, rock flakes peel off. When the depth of the penetrating crack exceeds a critical value, the rock flakes are stripped off under gravity or the rotational force of the cutterhead, completing one crushing cycle.

[0003] The vibration generation mechanism of TBM is multi-source coupled excitation. Its vibration mainly comes from four types of sources, with the frequency range concentrated in 1-200Hz, including cutter-rock impact, cutterhead torque fluctuation, equipment mechanical vibration, and geological interface abrupt change.

[0004] During TBM (Tunnel Boring Machine) construction, the cutterhead's rock breaking and mechanical vibrations cause significant dynamic disturbances to the surrounding rock, leading to stress redistribution and consequently affecting the tunnel's stability and safety. Traditional rock stress analysis is mostly based on static or quasi-static assumptions, failing to fully consider the high-frequency vibrations, dynamic load accumulation effects, and the coupling effect of rock breaking and vibration during TBM construction. This results in deviations between stress disturbance assessments and actual working conditions.

[0005] Currently, the main methods for quantitative characterizing the stress disturbance degree of surrounding rock include the following categories, but all of them have certain limitations:

[0006] 1. Stress disturbance analysis method based on static excavation. Elasticity mechanics or numerical simulation (such as FLAC3D, ANSYS) are used to calculate the stress changes in the surrounding rock after excavation. Commonly used indicators include stress release rate and plastic zone range. However, this method does not consider the dynamic load of the TBM: the impact load and mechanical vibration (dominant frequency usually between 1 and 200 Hz) of the TBM cutterhead breaking rock significantly change the stress state of the surrounding rock, and the static model cannot reflect this transient effect; it also cannot distinguish the contribution of rock breaking and vibration: traditional methods simplify the TBM load to a uniformly distributed load, ignoring the local high stress gradient of the cutterhead breaking rock and the propagation attenuation characteristics of vibration waves.

[0007] 2. Dynamic monitoring-based surrounding rock response analysis. Vibration response of the surrounding rock is monitored using vibration sensors (such as accelerometers) and acoustic emission (AE), and the degree of disturbance is assessed using peak particle velocity (PPV) or energy density. However, this method only reflects the vibration effect and does not couple the rock-breaking stress: existing dynamic monitoring methods mostly focus on the vibration propagation law, but do not combine it with the TBM rock-breaking mechanics model, resulting in a one-sided calculation of the disturbance degree; there is a lack of unified quantitative standards: indicators such as PPV only describe vibration intensity and cannot directly correlate with changes in the stress state of the surrounding rock.

[0008] 3. Energy-based disturbance assessment. Damage accumulation in the surrounding rock is calculated using strain energy density or dissipated energy, such as D = Ud × U0, where Ud is the disturbance energy and U0 is the initial energy. However, this method does not consider the TBM load characteristics: the energy method typically assumes uniform load distribution, while TBM rock breaking exhibits localized concentration (e.g., extremely high stress in the cutter contact zone), leading to model errors; it is also difficult to apply in real-time: energy calculation relies on high-precision numerical simulation, making it difficult to link with TBM tunneling parameters in real time.

[0009] Therefore, there is an urgent need in this field for a method that can integrate the static load of TBM rock breaking with the dynamic load of mechanical vibration to solve the problems of lack of dynamic coupling, insufficient model adaptability, and poor real-time performance in TBM tunneling. Summary of the Invention

[0010] This invention provides a method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration, aiming to solve the problems of lack of dynamic coupling in the prediction of surrounding rock disturbance degree, insufficient model adaptability, and poor real-time performance.

[0011] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0012] A method for assessing and controlling the stress disturbance of surrounding rock under TBM rock breaking and vibration, the method comprising:

[0013] Step S1: Calculate the contact stress of the cutter rock breaking based on the uniaxial compressive strength of the rock mass and the joint dip angle, and obtain the static stress field distribution of the surrounding rock through numerical simulation, and calculate the static disturbance degree of the surrounding rock;

[0014] Step S2: Obtain the vibration signal during the TBM tunneling process, and use the elastic wave attenuation theory to calculate the dynamic stress field generated by the vibration wave in the surrounding rock, and calculate the dynamic disturbance degree of the surrounding rock.

[0015] Step S3: Based on the rock mass integrity coefficient and joint dip angle, dynamically adjust the weights of static and dynamic disturbance degrees, and calculate the comprehensive disturbance degree;

[0016] Step S4: Divide the overall disturbance degree into different disturbance levels, and generate and execute TBM tunneling parameter adjustment instructions or surrounding rock support instructions according to the disturbance level.

[0017] Furthermore, step S1 includes:

[0018] The contact pressure of the cutter intruding into the rock mass was calculated using an improved CSM model: ,in, The contact pressure of the cutter intruding into the rock mass. The rock mass fracture coefficient is... The diameter of the hob is... Penetration degree;

[0019] The stress distribution of surrounding rock under rock-breaking load was simulated using finite element software. ;

[0020] Calculation of static disturbance degree based on surrounding rock stress distribution: , ,in, For the original rock stress tensor, This represents the critical strength of the surrounding rock. The uniaxial compressive strength of the rock mass. Represents the norm.

[0021] Furthermore, the rock mass fracture coefficient Calibration was performed through triaxial testing, and based on the joint dip angle. Dynamic corrections are performed.

[0022] Furthermore, step S2 includes:

[0023] Based on elastic wave theory, the attenuation law of vibration waves in surrounding rock is calculated: , , ,in, For transmission distance, The material attenuation coefficient, For frequency, The rock mass damping ratio, For longitudinal wave velocity, For characteristic frequency band energy, The elastic modulus of the rock mass. Poisson's ratio of the rock mass Density of the rock mass;

[0024] Extract the dynamic stress amplitude corresponding to the dominant vibration frequency and calculate the dynamic disturbance degree: ,in, This represents the critical dynamic stress of the rock mass.

[0025] Furthermore, the material attenuation coefficient calculated in step S2 It is also dynamically adjusted based on the rock mass integrity coefficient.

[0026] Furthermore, step S2 further includes: calculating the microcrack propagation rate based on the dynamic disturbance degree. ,when When the value exceeds a set threshold, an early warning signal is automatically generated and sent. The set adjustment coefficient.

[0027] Furthermore, the comprehensive perturbation degree mentioned in step S3 is: , and These are the weighting coefficients for static and dynamic disturbance degrees, respectively.

[0028] Furthermore, the weights for dynamically adjusting the static and dynamic disturbance degrees based on the rock mass integrity coefficient and joint dip angle include: , ,in, and These are the weighting coefficients for static and dynamic disturbance degrees, respectively. For the joint dip angle, RQD is the rock mass integrity coefficient, where θ is the TBM tunneling direction angle.

[0029] Furthermore, step S4 includes:

[0030] like No need to adjust tunneling parameters;

[0031] like This reduces TBM thrust by 10% to 20%.

[0032] like This triggers a shutdown and requires enhanced support.

[0033] Where A and B are the set comprehensive disturbance thresholds.

[0034] Furthermore, step S4 also includes: calculating the comprehensive perturbation degree The data is mapped in real time to the tunnel BIM model to generate a 3D disturbance degree cloud map. Areas with disturbance degrees exceeding a set threshold are highlighted in the 3D disturbance degree cloud map.

[0035] The beneficial effects of this invention are:

[0036] (1) The present invention constructs a rock breaking-vibration dual stress field coupling model, wherein the static component is based on the improved CSM model to calculate the local high stress generated by the cutter intruding into the rock mass, and the dynamic component extracts the equivalent dynamic stress from the main frequency energy of the vibration signal. Finally, the dynamic component is fused into a comprehensive disturbance degree through a weighted coupling formula, which effectively improves the accuracy and precision of the surrounding rock disturbance assessment results.

[0037] (2) When the overall disturbance degree is in different levels, different emergency control strategies are adaptively output, which effectively reduces the rock burst occurrence rate and reduces the time for handling machine jam accidents;

[0038] (3) This invention, through a lithology-adaptive weighting mechanism, can automatically adjust the contribution ratio of static and dynamic disturbances based on the rock mass integrity coefficient and joint dip angle obtained from the inversion. When the rock mass integrity is poor (such as fault fracture zones), vibration waves are more likely to induce instability, and the weight of dynamic disturbances is higher; when the rock mass integrity is good, the weights of the two tend to be balanced. This mechanism effectively covers various complex strata from intact hard rock to fracture zones, and has high engineering applicability;

[0039] (4) The present invention can quantitatively calculate the propagation rate of microcracks in surrounding rock based on dynamic disturbance degree. When the rate exceeds the set threshold, an early warning signal is automatically issued, making the previously difficult-to-detect hidden risks explicit and providing early warning. Attached Figure Description

[0040] Figure 1 This is a schematic flowchart of the method for evaluating and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration as described in this invention. Detailed Implementation

[0041] Traditional surrounding rock stress analysis is mostly based on static or quasi-static assumptions, which fail to fully consider the high-frequency vibration, dynamic load accumulation effect, and rock breaking-vibration coupling effect during TBM construction, resulting in deviations between stress disturbance assessment results and actual working conditions.

[0042] The core of this invention in solving this technical problem is: calculating the static stress field generated by the roller cutter's extrusion and intrusion, and calculating the static disturbance degree to characterize the local high stress concentration and stress redistribution caused by rock-breaking loads; based on elastic wave theory, analyzing the dominant frequency energy of the vibration signal, calculating the dynamic stress field formed by the attenuation of the vibration wave propagation in the surrounding rock, and obtaining the dynamic disturbance degree to characterize the fatigue damage and disturbance accumulation of the surrounding rock caused by high-frequency vibration. The static and dynamic disturbance degrees are integrated into a comprehensive disturbance degree index to fully quantify the deviation of the surrounding rock stress state under the combined action of TBM rock breaking and vibration. Finally, based on the value of the comprehensive disturbance degree, the disturbance level is classified, and the TBM control system is automatically linked to execute corresponding parameter adjustments and support measures, forming a real-time closed loop of monitoring, evaluation, and control. This transforms the surrounding rock disturbance from traditional experience-based judgment into calculable and controllable engineering parameters, effectively improving the safety and intelligence level of TBM construction.

[0043] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0044] like Figure 1 As shown, the method for evaluating and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration described in this invention includes the following steps.

[0045] (1) Tunneling parameters and rock mass data acquisition and preprocessing

[0046] The purpose of this step is to collect parameters in real time during the subsequent calculation of static and dynamic disturbance degrees, and to preprocess the corresponding parameters to improve the efficiency and accuracy of subsequent data calculations.

[0047] TBM tunneling parameter acquisition: cutterhead thrust is acquired in real time via a PLC system. Penetration ; and through the thrust of the cutter head and number of hobs Calculate the force on a single hob. .

[0048] Vibration signal monitoring: Triaxial accelerometers are deployed on the cutterhead, shield, and surrounding rock surface, with a sampling frequency ≥1kHz. Wavelet thresholding is used to denoise the original signal, and FFT transform is used to perform frequency domain analysis on the denoised signal to extract energy from characteristic frequency bands. ,in, Power spectral density function, This is the lower limit frequency of the characteristic frequency band. In this embodiment, the upper limit frequency of the characteristic frequency band is... , .

[0049] Real-time inversion of surrounding rock parameters: obtaining the uniaxial compressive strength of the rock mass, the rock mass integrity coefficient, and the joint dip angle. Among these, the uniaxial compressive strength of the rock mass is... ,in, and All are constants. The rock mass integrity coefficient is... , 50-200Hz These are characteristic frequencies of the rock mass, obtained through on-site calibration. and All are constants.

[0050] (2) Simulate the static stress field distribution of the surrounding rock and calculate the static disturbance degree of the surrounding rock.

[0051] The improved CSM model is based on the traditional CSM model for the rock mass fracturing coefficient. Dynamic calibration is performed, and the joint dip angle is used as a reference. Corrected rock mass fracture coefficient The improved CSM model establishes a stress superposition effect of multiple cutters working together to break rock by calculating the contact stress of a single cutter. Then, based on finite element software (such as COMSOL), the three-dimensional stress distribution near the excavation face is solved. The static perturbation degree is defined using the Frobenius norm to characterize the degree to which the stress field deviates from the original rock state, enabling a more accurate prediction of the cutter stress in a tunnel boring machine (TBM). Specifically, it includes the following steps:

[0052] S1: Rock breaking stress calculation of the cutter: The contact pressure of the cutter penetrating the rock mass is calculated using the improved CSM (Colorado School of Mines) model.

[0053] ;

[0054] In the formula, The contact pressure of the cutter intruding into the rock mass. The contact pressure of a single cutter penetrating the rock mass. The rock mass fracture coefficient is... The diameter of the hob is... For a single hob subjected to force, Penetration degree;

[0055] S2: Static stress disturbance calculation: Simulate the stress distribution of surrounding rock under rock-breaking load using finite element software (such as COMSOL). ;

[0056] S3: Calculation of static disturbance degree based on surrounding rock stress distribution:

[0057] , ;

[0058] In the formula, For the original rock stress tensor, This represents the critical strength of the surrounding rock. The uniaxial compressive strength of the collected rock mass is... This represents the norm, specifically the Frobenius norm.

[0059] (3) Simulate the dynamic stress field distribution of the surrounding rock and calculate the dynamic disturbance degree of the surrounding rock.

[0060] The vibration dynamic stress field is based on elastic wave theory. It calculates the attenuation law of vibration waves in the surrounding rock, and then extracts the dynamic stress amplitude corresponding to the dominant vibration frequency to calculate the dynamic disturbance degree. Specifically, it includes the following steps:

[0061] S1: Vibration stress wave propagation analysis: Based on elastic wave theory, the attenuation law of vibration waves in the surrounding rock is calculated.

[0062] ;

[0063] In the formula, The dynamic stress amplitude represents the distance the vibration wave travels from the earthquake source. The magnitude of dynamic stress generated in the surrounding rock at that time. For transmission distance, The material attenuation coefficient, , This indicates the bunker's ability to absorb vibrational energy, in relation to the rock mass damping ratio. and frequency Related, For longitudinal wave velocity, , The elastic modulus of the rock mass. Poisson's ratio of the rock mass Density of the rock mass;

[0064] In this invention, the calculated material attenuation coefficient The system also dynamically adjusts the parameters based on the rock mass integrity coefficient. For example, if the percentage of the total length of rock cores with a length equal to or greater than a set length (10cm) exceeds a set threshold, the attenuation coefficient is adjusted accordingly. The value of .

[0065] S2: Dynamic Disturbance Calculation: Extract the dynamic stress amplitude corresponding to the dominant vibration frequency; Define dynamic disturbance degree:

[0066] ;

[0067] In the formula, The critical dynamic stress of the rock mass is obtained or calculated directly through rock dynamics testing or by combining empirical formulas and standard manuals for dynamic loads.

[0068] When the dynamic stress amplitude Much less than the critical dynamic stress of the rock mass When the dynamic stress generated by the vibration is much smaller than the bearing capacity of the rock mass, the disturbance can be ignored; when the dynamic stress amplitude is... Approaching or exceeding the critical dynamic stress of the rock mass This indicates that the vibration has caused significant disturbance or even damage to the surrounding rock.

[0069] (4) Coupling of static and dynamic disturbance of surrounding rock

[0070] Based on the rock mass structure and joint orientation, weighting coefficients for static and dynamic disturbance degrees are dynamically allocated. These two components are then fused to output a comprehensive disturbance degree. Specifically, the comprehensive disturbance degree is:

[0071] ;

[0072] In the formula, and These are the weighting coefficients for static and dynamic disturbance, respectively. When the rock mass integrity is poor ( When the joint surface is relatively small and the angle between it and the excavation direction is small, the rock mass is more significantly affected by dynamic vibration, and dynamic disturbance dominates. A larger value indicates better rock mass integrity. When the disturbance is relatively large, the surrounding rock itself has strong resistance to disturbance, and static disturbance is dominant. The value is relatively large; specifically:

[0073] , ;

[0074] in, For the TBM excavation direction angle and joint dip angle... It was calculated based on the anisotropy of the vibration direction.

[0075] (5) Classify the disturbance level based on the comprehensive disturbance degree, and generate and execute TBM tunneling parameter adjustment instructions or surrounding rock support instructions.

[0076] This step defines three levels of disturbance: mild, moderate, and severe. Specifically, if... This is a minor disturbance and no adjustment to the tunneling parameters is required; if This is considered a moderate disturbance; reduce the TBM thrust by 10%~20% and initiate anchor bolt support. This constitutes a severe disturbance, triggering a shutdown, radial grouting, and personnel evacuation, while simultaneously reinforcing the support. A and B are the set comprehensive disturbance thresholds; this embodiment provides an exemplary value: , .

[0077] Furthermore, this invention also calculates the microcrack propagation rate based on the dynamic perturbation degree. ,when When the value exceeds a set threshold, an early warning signal is automatically generated and sent. The set adjustment coefficient.

[0078] Preferably, the calculated comprehensive perturbation degree is also included in this invention. The disturbance is mapped in real time into the tunnel BIM model, generating a 3D disturbance cloud map. Areas with disturbance levels exceeding a set threshold are highlighted in this map. For example, areas with overall disturbance levels exceeding the set threshold are marked in red in the tunnel BIM model to provide an early warning. Then, the process proceeds to the next excavation cycle, continuing the assessment and control of surrounding rock stress disturbance.

Claims

1. A method for assessing and controlling the stress disturbance degree of surrounding rock under TBM rock breaking and vibration, characterized in that, The method includes: Step S1: Calculate the contact stress of the roller cutter breaking the rock based on the uniaxial compressive strength and joint dip angle of the rock mass, and obtain the static stress field distribution of the surrounding rock through numerical simulation, and calculate the static disturbance degree of the surrounding rock; specifically including: The contact pressure of the cutter intruding into the rock mass was calculated using an improved CSM model: ,in, The contact pressure of a single cutter penetrating the rock mass. The rock mass fracture coefficient is... The diameter of the hob is... Penetration degree; The stress distribution of surrounding rock under rock-breaking load was simulated using finite element software. ; Calculation of static disturbance degree based on surrounding rock stress distribution: , ,in, For the original rock stress tensor, This represents the critical strength of the surrounding rock. The uniaxial compressive strength of the rock mass. Represents the norm; Step S2: Obtain vibration signals during TBM tunneling and calculate the dynamic stress field generated by the vibration waves in the surrounding rock using elastic wave attenuation theory, and calculate the dynamic disturbance degree of the surrounding rock; specifically including: Based on elastic wave theory, the attenuation law of vibration waves in surrounding rock is calculated: , , ,in, For transmission distance, The material attenuation coefficient, For frequency, The rock mass damping ratio, For longitudinal wave velocity, For characteristic frequency band energy, The elastic modulus of the rock mass. Poisson's ratio of the rock mass Density of the rock mass; Extract the dynamic stress amplitude corresponding to the dominant vibration frequency and calculate the dynamic disturbance degree: ,in, The critical dynamic stress of the rock mass; Step S3: Based on the rock mass integrity coefficient and joint dip angle, dynamically adjust the weights of static and dynamic disturbance degrees, and calculate the comprehensive disturbance degree; Step S4: Divide the overall disturbance degree into different disturbance levels, and generate and execute TBM tunneling parameter adjustment instructions or surrounding rock support instructions according to the disturbance level.

2. The method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration as described in claim 1, characterized in that, The rock mass fracture coefficient Calibration was performed through triaxial testing, and based on the joint dip angle. Dynamic corrections are performed.

3. The method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration as described in claim 1, characterized in that, The material attenuation coefficient calculated in step S2 It is also dynamically adjusted based on the rock mass integrity coefficient.

4. The method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration according to claim 1 or 3, characterized in that, Step S2 further includes: calculating the microcrack propagation rate based on the dynamic disturbance degree. ,when When the value exceeds a set threshold, an early warning signal is automatically generated and sent. The set adjustment coefficient.

5. The method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration according to claim 1, characterized in that, The overall perturbation degree mentioned in step S3 is: , and These are the weighting coefficients for static and dynamic disturbance degrees, respectively.

6. The method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration according to claim 1 or 5, characterized in that, The weights for dynamically adjusting static and dynamic disturbance degrees based on rock mass integrity coefficient and joint dip angle include: , ,in, and These are the weighting coefficients for static and dynamic disturbance degrees, respectively. For joint dip angle, RQD is the rock mass integrity coefficient, where θ is the TBM tunneling direction angle.

7. The method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration as described in claim 1, characterized in that, Step S4 includes: like No need to adjust tunneling parameters; like This reduces TBM thrust by 10% to 20%. like This triggers a shutdown and requires enhanced support. Where A and B are the set comprehensive disturbance thresholds.

8. The method for assessing and controlling the stress disturbance degree of surrounding rock under the action of TBM rock breaking and vibration according to claim 1 or 7, characterized in that, Step S4 also includes: calculating the overall perturbation degree The data is mapped in real time to the tunnel BIM model to generate a 3D disturbance degree cloud map. Areas with disturbance degrees exceeding a set threshold are highlighted in the 3D disturbance degree cloud map.

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