A method and device for predicting surface vibration in tunnel blasting construction in a seasonal freezing region

Abstract

The application provides a kind of seasonal freezing area tunnel blasting construction ground surface vibration prediction method and device, it is related to tunnel blasting construction ground surface vibration prediction method technical field, the reflection wave propagation time of each measurement cross line is acquired, the frozen layer thickness of each measurement cross line is calculated;Subfunction is used to define the wave velocity propagation speed of each measurement cross line;Exponential decay method is used to construct the temperature distribution term of the axial of measurement cross line;The vibration velocity prediction model is constructed to calculate the predicted vibration velocity corresponding to each measurement cross line, and based on the predicted vibration velocity corresponding to adjacent measurement cross line, the distance interpolation method is used to calculate the predicted vibration velocity corresponding to any axial coordinate.Introduce axial vibration velocity interpolation method, realize full tunnel axial continuous prediction by the vibration velocity data of adjacent measurement cross line, construct frozen layer thickness model based on electromagnetic wave reflection time and axial node constant, accurately depict the non-uniform distribution characteristics of frozen layer thickness along the axial of tunnel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel blasting construction ground surface vibration prediction methods, in particular to a tunnel blasting construction ground surface vibration prediction method and device in a seasonal frozen region. BACKGROUND

[0002] In the tunnel blasting construction in the seasonal frozen region, the ground surface vibration prediction faces complex challenges: the dramatic changes in the physical properties of the stratum caused by the freeze-thaw cycle lead to dynamic fluctuations in the wave velocity of the rock mass, the traditional vibration model often ignores the nonlinear effects of the spatial heterogeneity of the frozen layer thickness and the axial temperature gradient on the wave velocity, resulting in significant prediction errors. The existing technology relies on local drilling data or a single temperature assumption, making it difficult to accurately characterize the wave velocity gradient law of the transition zone between the frozen layer and the unfrozen area, and lacking quantitative modeling of the coupling effect of the axial temperature distribution and the wave velocity. In addition, the propagation of blasting vibration energy in the frozen soil area is greatly affected by the sudden change in propagation impedance, and the existing impedance model does not combine the temperature-corrected wave velocity parameters, which cannot adapt to the dynamic environment in the seasonal frozen region, restricting the accuracy of vibration control.

[0003] In the prior art, the publication number CN116258285A discloses a small clear distance tunnel blasting vibration velocity calculation method by studying the reduction factor of blasting seismic waves in different media. However, this method does not consider the spatial distribution of the frozen layer, does not quantify the wave velocity attenuation gradient near the frozen layer interface, is prone to wave velocity distortion problems, does not embed the time-varying effect of the temperature gradient on the wave velocity into the vibration prediction, makes the corrected wave velocity more consistent with the actual thermodynamic state in the seasonal frozen region, does not dynamically reflect the interface energy dissipation characteristics of the frozen layer through the impedance parameters, and lacks precision in measuring the vibration velocity in the transition zone of the frozen layer, so there is an urgent need for an efficient and reliable vibration prediction method.

[0004] The above information disclosed in the background section is only intended to enhance the understanding of the background of the present disclosure, and therefore it can include information that does not constitute the prior art known to those of ordinary skill in the art. SUMMARY

[0005] The purpose of the present application is to provide a tunnel blasting construction ground surface vibration prediction method and device in a seasonal frozen region to solve the problems raised in the background.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] A tunnel blasting construction ground surface vibration prediction method in a seasonal frozen region, the specific steps comprising:

[0008] S1: taking the blasting point as the origin, setting a measuring horizontal line on the inner wall of the tunnel surrounding rock every fixed interval along the axial direction of the tunnel mined, and uniformly setting a plurality of measuring points on each measuring horizontal line, using the geological radar method to determine the reflection wave propagation time at each measuring point;

[0009] S2: using the inverse distance weighting method to process the frozen layer thickness of each measuring point on each measuring horizontal line to obtain the frozen layer thickness of each measuring horizontal line, and using the depth distance method to define the wave velocity propagation speed of each measuring horizontal line based on the frozen layer thickness of each measuring horizontal line and the minimum distance of each measuring horizontal line from the origin;

[0010] S3: obtaining the constant temperature of the tunnel and the average temperature of the ground as the parameters of the temperature distribution term, using the exponential decay method to construct the temperature distribution term of the axial direction of the measuring horizontal line, and taking the temperature distribution term of the axial direction as the correction term of the wave velocity propagation speed to obtain the corrected wave velocity propagation speed;

[0011] S4: based on the corrected wave velocity propagation speed, using the temperature distribution term gradient product method to define the propagation impedance at the measuring horizontal line; based on the propagation impedance, constructing a vibration velocity prediction model to calculate the predicted vibration velocity corresponding to each measuring horizontal line, and based on the predicted vibration velocity corresponding to the adjacent measuring horizontal line, using the distance interpolation method to calculate the predicted vibration velocity corresponding to any axial coordinate.

[0012] Further, the frozen layer thickness of each measuring horizontal line is obtained, and the specific steps are:

[0013] For each measuring point on each measuring horizontal line, the distance between each measuring point and the center point of the measuring horizontal line is determined as the first distance, and a non-zero constant is introduced, and the reciprocal of the sum of the first distance and the non-zero constant is represented as the position weight of the measuring point on the measuring horizontal line;

[0014] The position weights of each measuring point in each measuring horizontal line are superimposed and summed up, and the total weight of the measuring horizontal line is marked;

[0015] The reflection wave propagation time at each measuring point is determined using the geological radar method, and the first time is marked, the product of the first time and the position weight of each measuring point in each measuring horizontal line is obtained, and the sum of all products is marked as the relative propagation time at the measuring horizontal line;

[0016] For each measuring horizontal line, the ratio of the relative propagation time and the total weight is taken as the reflection wave propagation time of the measuring horizontal line.

[0017] Further, the constant temperature of the tunnel and the average temperature of the ground are obtained, and the specific steps are:

[0018] The temperature of each measuring point is acquired in real time to form a first temperature set, the maximum and minimum temperatures in the first temperature set are removed, and the average temperature of the remaining temperature values is calculated as the constant temperature of the tunnel,

[0019] The constant temperature of the tunnel and the average ground temperature are acquired, and the specific steps are as follows:

[0020] The temperature of each measuring point is acquired in real time to form a first temperature set, the maximum and minimum temperatures in the first temperature set are removed, and the average temperature of the remaining temperature values is calculated as the constant temperature of the tunnel, and the average ground temperature is the average ground temperature of the region where the tunnel to be blasted and constructed is located.

[0021] Further, the acquisition step of the frozen layer thickness of each measuring line includes:

[0022] Half of the product of the reflection wave propagation time and the propagation speed of the electromagnetic wave of each measuring line is designated as the one-way propagation time;

[0023] The arithmetic square root of the dielectric constant of the permafrost layer in the region where the tunnel to be blasted and constructed is located is taken as the propagation correction coefficient;

[0024] The ratio of the one-way propagation time corresponding to each measuring line to the propagation correction coefficient is designated as the frozen layer thickness at the measuring line.

[0025] Further, the specific steps of defining the wave propagation speed of each measuring line by using the depth distance method include:

[0026] The frozen layer thickness of each measuring line is taken as the first threshold value of the measuring line, and the sum of the frozen layer thickness and the typical freeze-thaw interface influence width is taken as the second threshold value of the measuring line;

[0027] If the minimum distance of the measuring line from the origin is not greater than the first threshold value, the wave propagation speed of the measuring line is designated as the wave propagation speed of the frozen layer;

[0028] If the minimum distance of the measuring line from the origin is greater than the first threshold value and not greater than the second threshold value, the wave propagation speed of the measuring line is designated as the difference between the wave propagation speed of the frozen layer and the decay speed;

[0029] If the minimum distance of the measuring line from the origin is greater than the second threshold value, the wave propagation speed of the measuring line is designated as the wave propagation speed of the unfrozen layer;

[0030] The acquisition step of the decay speed includes:

[0031] The difference between the minimum distance of the measuring line from the origin and the frozen layer thickness is acquired, and the ratio of the difference to the typical freeze-thaw interface influence width is taken as the decay coefficient;

[0032] The difference between the wave velocity propagation speed of the frozen layer and the wave velocity propagation speed of the unfrozen layer is obtained as a wave velocity variation, and the product of the attenuation coefficient of the measurement traverse and the wave velocity variation is taken as the attenuation speed corresponding to the measurement traverse.

[0033] Further, an exponential decay method is used to construct the temperature distribution term of the measurement traverse in the axial direction, and the specific steps are as follows:

[0034] The product of the natural constant as the base number, the minimum distance of the measurement traverse from the origin, and the negative of the temperature attenuation coefficient of the measurement traverse is taken as the exponential to construct an exponential function as a first attenuation index, and the difference between 1 and the first attenuation index is taken as a second attenuation index.

[0035] The product of the constant temperature of the tunnel and the first attenuation index is taken as a first temperature distribution term corresponding to the measurement traverse, and the product of the average temperature of the ground surface and the second attenuation index is taken as a second temperature distribution term corresponding to the measurement traverse.

[0036] The first temperature distribution term and the second temperature distribution term are superimposed and summed to obtain the temperature distribution term corresponding to the measurement traverse.

[0037] Further, the corrected wave velocity propagation speed is obtained, and the specific steps include the following steps:

[0038] The wave velocity of the original measurement traverse is multiplied by a correction factor to obtain the corrected wave velocity propagation speed, and the correction factor is calculated in the following manner:

[0039] The result of multiplying the maximum wave velocity attenuation speed by the temperature sensitivity function is obtained by subtracting 1, wherein the maximum wave velocity attenuation speed is obtained by laboratory calibration measurement, and the temperature sensitivity function is obtained by The difference between the current temperature and the phase transition critical temperature is calculated by the function, and the result of multiplying the maximum wave velocity attenuation speed by the temperature sensitivity function is multiplied by the relative deviation between the current temperature and the reference temperature of the frozen layer to obtain the corrected wave velocity propagation speed.

[0040] Further, the propagation impedance of the measurement traverse is defined by using the temperature distribution term gradient product method, and the specific steps are as follows:

[0041] The corrected wave velocity propagation speed at the measurement traverse is multiplied by the corresponding temperature gradient to obtain the propagation impedance corresponding to the measurement traverse, wherein the temperature gradient corresponding to the measurement traverse is obtained by taking the derivative of the corresponding temperature distribution term with respect to the depth distance.

[0042] Further, the distance interpolation method is used to calculate the predicted vibration speed corresponding to any axial coordinate, and the specific steps are as follows:

[0043] The propagation impedance of the measurement cross line is multiplied by a parameter term with the depth distance as the base and the rock medium parameters as the exponent, the site correction coefficient is multiplied by an exponential decay term with the natural constant as the base and the negative product of the temperature distribution term of the measurement cross line and the depth distance, and the result is taken as the numerator term to construct a vibration velocity prediction model;

[0044] For any axis coordinate, find its adjacent two measurement cross lines and sequentially number them, and the prediction vibration velocity of the arbitrary axis position is constructed by using the sum of the product of the distance weight factor and the wave velocity propagation velocity at the corresponding measurement cross line, wherein the calculation of the distance weight factor is as follows:

[0045] The axis coordinate of the left measurement cross line is subtracted from the axis coordinate of the target position, and then divided by the difference between the left and right axis coordinates to form the weight coefficient of the left measurement cross line;

[0046] The axis coordinate of the target position is subtracted from the axis coordinate of the right measurement cross line, and then divided by the difference between the left and right axis coordinates to form the weight coefficient of the right measurement cross line.

[0047] The application further provides a tunnel blasting construction ground surface vibration prediction device in a seasonal frozen region, which is used to execute the above-mentioned prediction method and comprises:

[0048] A data acquisition module is configured to set measurement cross lines on the inner wall of the tunnel surrounding rock every fixed interval along the axial direction of the tunnel to be excavated with the blasting point as the origin, and uniformly set a plurality of measurement points on each measurement cross line, and use the ground penetrating radar method to determine the reflection wave propagation time at each measurement point.

[0049] A wave velocity calculation module is configured to use the inverse distance weighting method to weight the frozen layer thickness of the measurement points on each measurement cross line to obtain the frozen layer thickness of each measurement cross line, and use the depth distance method to define the wave velocity propagation velocity of each measurement cross line based on the frozen layer thickness of each measurement cross line and the minimum distance of each measurement cross line from the origin.

[0050] A wave velocity correction module is configured to obtain the constant temperature of the tunnel and the average temperature of the ground surface as the parameters of the temperature distribution term, use the exponential decay method to construct the temperature distribution term of the axial direction of the measurement cross line, take the temperature distribution term of the axial direction as the correction term of the wave velocity propagation velocity, and obtain the corrected wave velocity propagation velocity.

[0051] A vibration prediction module is configured to use the temperature distribution term gradient product method to define the propagation impedance at the measurement cross line based on the corrected wave velocity propagation velocity, construct a vibration velocity prediction model based on the propagation impedance to calculate the predicted vibration velocity corresponding to each measurement cross line, and use the distance interpolation method to calculate the predicted vibration velocity corresponding to any axis coordinate based on the predicted vibration velocities corresponding to the adjacent measurement cross lines.

[0052] Compared with the prior art, the present application has the beneficial effects of:

[0053] By adopting the inverse distance weighting method to fuse the geological radar multi-point data, local abnormal interference is suppressed, and the spatial distribution of the frozen layer thickness is accurately reconstructed; the depth distance method is combined to define the wave velocity, the linear transition model of the wave velocity inside and outside the frozen layer is used to quantify the wave velocity attenuation gradient near the freezing-thawing interface, and the distortion problem of the traditional step wave velocity assumption is overcome; the axial temperature distribution correction term is introduced, the exponential decay correlation between the tunnel constant temperature and the ground surface temperature is used to embed the time-varying influence of the temperature gradient on the wave velocity into the vibration prediction, so that the corrected wave velocity is more in line with the actual thermodynamic state in the seasonal frozen region; and the temperature-wave velocity gradient product mode of the propagation impedance is proposed, the energy dissipation characteristics of the freezing-thawing interface are dynamically reflected through the impedance parameter, the distance interpolation method is combined to realize the continuous prediction of the axial vibration velocity of the whole tunnel, and the prediction error of the vibration velocity is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is a schematic diagram of the overall method flow of the present application;

[0055] Figure 2 It is a schematic diagram of the change of the propagation impedance and the vibration velocity of the present application;

[0056] Figure 3 It is a schematic diagram of the change of the depth distance and the vibration velocity of the present application;

[0057] Figure 4 It is a schematic diagram of the change of the temperature distribution term and the vibration velocity of the present application;

[0058] Figure 5 It is a structure block diagram of the overall device of the present application. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application is further described in detail below in combination with specific embodiments.

[0060] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the meanings that can be commonly understood by a person with ordinary skill in the art to which this application belongs. The terms "first", "second", and similar terms in the present application do not denote any order, quantity, or importance, but are used to distinguish different components. The terms "include", "contain", and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are used only to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships can also change accordingly.

[0061] Embodiment:

[0062] Please refer to Figures 1-4 The present application provides a technical solution:

[0063] A tunnel blasting construction ground surface vibration prediction method in a seasonal frozen region, the specific steps comprising:

[0064] S1: Taking the blasting point as the origin, setting a measurement horizontal line on the inner wall of the tunnel surrounding rock every fixed interval along the axial direction of the tunnel that has been mined, and uniformly setting a plurality of measurement points on each measurement horizontal line, and using the geological radar method to determine the reflection wave propagation time at each measurement point;

[0065] Obtain the thickness of the frozen layer of each measurement horizontal line, the specific steps are:

[0066] For each measurement point on each measurement horizontal line, determine the distance between each measurement point and the center point of the measurement horizontal line as the first distance, and introduce a non-zero constant, and the reciprocal of the sum of the first distance and the non-zero constant is characterized as the position weight of the measurement point on the measurement horizontal line;

[0067] Superimpose and sum the position weights of each measurement point in each measurement horizontal line, and mark it as the total weight of the measurement horizontal line;

[0068] Determine the reflection wave propagation time at each measurement point using the geological radar method, and mark it as the first time, obtain the product of the first time and the position weight of each measurement point in each measurement horizontal line, and mark the sum of all products as the relative propagation time at the measurement horizontal line;

[0069] For each measurement horizontal line, the ratio of the relative propagation time and the total weight is taken as the reflection wave propagation time of the measurement horizontal line.

[0070] The formula on which the above process is based is:

[0071] The measurement horizontal line numbered has measurement points, the distance from the center point of the horizontal line to the measurement point is , and the reflection wave propagation time at each measurement point is determined by using the geological radar method. The reflection wave propagation time of each measurement point is multiplied by its corresponding weight , and then summed up and divided by the sum of all weights to obtain the reflection wave propagation time of the measurement horizontal line numbered , wherein the weight is calculated by taking the reciprocal of the sum of the distance from the measurement point to the center of the measurement horizontal line and the zero constant , and the formula on which the above process is based is:

[0072] ;

[0073] wherein,

[0074] ;

[0075] represents the reflection wave propagation time at the measurement point on the measurement horizontal line numbered ; represents the weight coefficient of the measurement point on the measurement horizontal line numbered ; represents the distance from the center point of the horizontal line to the measurement point on the measurement horizontal line numbered , i.e., the first distance; represents the measurement point number index.

[0076] The principle of the above process is to use the weighted average method to combine the reflection wave propagation times of multiple measurement points on the measurement horizontal line numbered into a representative reflection wave propagation time , wherein the weight is calculated according to the reciprocal of the sum of the distance from the measurement point to the center point of the horizontal line and the zero constant , the farther the distance, the smaller the weight, and the closer the distance, the larger the weight, thereby giving the measurement points close to the center higher influence, this weighted processing effectively reduces the noise or instability that may be introduced by remote measurement points, enhances the accuracy and reliability of the reflection wave propagation time calculation, and can more accurately represent the geological radar reflection wave propagation time of the measurement horizontal line as a whole, making it comprehensive and representative.

[0077] The constant temperature of the tunnel is obtained and the average ground temperature is obtained, and the specific steps are as follows:

[0078] The temperature of each measuring point is obtained in real time to form a first temperature set, the maximum and minimum values of the first temperature set are removed, and the average temperature of the remaining temperature values is calculated as the constant temperature of the tunnel,

[0079] The constant temperature of the tunnel is obtained and the average ground temperature is obtained, and the specific steps are as follows:

[0080] The temperature of each measuring point is obtained in real time to form a first temperature set, the maximum and minimum values of the first temperature set are removed, and the average temperature of the remaining temperature values is calculated as the constant temperature of the tunnel, and the average ground temperature is the average ground temperature of the region where the tunnel to be blasted is located.

[0081] S2: The frozen layer thickness of each measuring line is obtained by using the inverse distance weighting method to process the frozen layer thickness of each measuring point on each measuring line, and the wave velocity propagation speed of each measuring line is defined based on the frozen layer thickness of each measuring line and the minimum distance of each measuring line from the origin.

[0082] The frozen layer thickness of each measuring line is obtained by using the inverse distance weighting method to process the frozen layer thickness of each measuring point on each measuring line, and the wave velocity propagation speed of each measuring line is defined based on the frozen layer thickness of each measuring line and the minimum distance of each measuring line from the origin.

[0083] Half of the product of the reflection wave propagation time of each measuring line and the propagation speed of the electromagnetic wave is calibrated as the one-way propagation time;

[0084] The arithmetic square root of the dielectric constant of the frozen soil layer in the region where the tunnel to be blasted is located is used as the propagation correction coefficient;

[0085] The ratio of the one-way propagation time corresponding to each measuring line to the propagation correction coefficient is calibrated as the frozen layer thickness at the measuring line.

[0086] The frozen layer thickness of each measuring line is obtained, and the specific formula is as follows:

[0087] ;

[0088] The dielectric constant of the frozen soil layer is represented by The coordinates of the axial measuring line numbered with the blasting point as the origin are represented by The reflection wave propagation time of the measuring line numbered is represented by The frozen layer thickness of the measuring line numbered extending from the inner wall of the tunnel surrounding rock to the outside is represented by The propagation speed of the electromagnetic wave is represented by

[0089] In the above formula, the frozen soil boundary position is obtained by electromagnetic wave reflection time inversion, and the frozen layer thickness is quickly and non-destructively measured by fusing the electromagnetic wave propagation characteristics and the dielectric response of frozen soil, Correlation, Positive, The longer, the thicker the frozen layer, and the larger the dielectric constant The smaller the frozen layer thickness, The propagation speed of the electromagnetic wave, the time Conversion to the actual propagation distance ratio factor, to ensure that the thickness calculation conforms to the electromagnetic wave propagation theory.

[0090] The frozen layer thickness refers to the soil layer formed by freezing outside the inner wall of the tunnel surrounding rock, and the solid state of the water in the frozen layer has a higher dielectric constant, thereby affecting the propagation characteristics of the electromagnetic wave, Reflects the depth of the frozen area extending outward from the tunnel inner wall.

[0091] The specific steps of defining the wave propagation speed of each measurement line using the depth distance method include:

[0092] The frozen layer thickness of each measurement line is taken as the first threshold value of the measurement line, and the sum of the frozen layer thickness and the typical freeze-thaw interface influence width is taken as the second threshold value of the measurement line;

[0093] If the minimum distance of the measurement line from the origin is not greater than the first threshold value, the wave propagation speed of the measurement line is set as the wave propagation speed of the frozen layer;

[0094] If the minimum distance of the measurement line from the origin is greater than the first threshold value and not greater than the second threshold value, the wave propagation speed of the measurement line is set as the difference between the wave propagation speed of the frozen layer and the attenuation speed;

[0095] If the minimum distance of the measurement line from the origin is greater than the second threshold value, the wave propagation speed of the measurement line is set as the wave propagation speed of the unfrozen layer;

[0096] The attenuation speed acquisition step includes:

[0097] The difference between the minimum distance of the measurement line from the origin and the frozen layer thickness is obtained, and the ratio of the difference to the typical freeze-thaw interface influence width is taken as the attenuation coefficient;

[0098] The difference between the wave propagation speed of the frozen layer and the wave propagation speed of the unfrozen layer is obtained as the wave speed variation, and the product of the attenuation coefficient of the measurement line and the wave speed variation is taken as the attenuation speed of the corresponding measurement line.

[0099] The wave velocity propagation speed of each measurement horizontal line is defined by using the deep distance method, and the specific formula is:

[0100] ;

[0101] represents the measurement horizontal line numbered , the deep distance of the measurement horizontal line extending outward along the inner wall surface of the tunnel surrounding rock is , the wave velocity propagation speed is , the second threshold value represents .

[0102] In the above formula, the wave velocity is defined by segmentation to depict the gradual change characteristics of the wave velocity near the freezing-thawing interface. When , at this time, it represents the frozen rock mass, and the wave velocity is constant; when , the wave velocity decreases linearly with the increase of , corresponding to the transition zone, until the wave velocity in the unfrozen zone is stable. In the transition zone, i.e. , and present a negative correlation, reflecting the characteristics that the stiffness of the material near the freezing-thawing interface decreases with the depth; in the frozen layer and the unfrozen layer , and have no direct correlation, respectively maintaining a constant high wave velocity and a low wave velocity.

[0103] wherein m represents the typical freezing-thawing interface influence width, the wave velocity propagation speed of the frozen layer is 3250 meters per second, which is derived from the longitudinal wave velocity of the frozen layer measured by experiment. Since the density increases due to frost heaving after the rock-soil freezes, the longitudinal wave velocity is large, and the wave velocity propagation speed of the unfrozen layer is , which is derived from the geological exploration measurement data, and 1350 represents the difference between the wave velocity propagation speed of the frozen layer and the wave velocity propagation speed of the unfrozen layer, i.e. the wave velocity variation.

[0104] S3: Obtain the constant temperature of the tunnel and the average temperature of the ground surface as the parameters of the temperature distribution term, construct the axial temperature distribution term of the measurement horizontal line by using the exponential decay method, take the axial temperature distribution term as the correction term of the wave velocity propagation speed, and obtain the corrected wave velocity propagation speed;

[0105] The exponential decay method is used to construct the axial temperature distribution term of the measurement horizontal line, and the specific steps are as follows:

[0106] Take the negative number of the product of the natural constant as the base, the minimum distance of the measurement horizontal line from the origin, and the temperature attenuation coefficient of the measurement horizontal line as the exponential to construct an exponential function as the first attenuation exponential, and take the difference between 1 and the first attenuation exponential as the second attenuation exponential.

[0107] the product of the constant temperature of the tunnel and the first decay index as a first temperature distribution term of the corresponding measurement traverse, and the product of the ground average temperature and the second decay index as a second temperature distribution term of the corresponding measurement traverse;

[0108] superimposing and summing the first temperature distribution term and the second temperature distribution term as the temperature distribution term corresponding to the measurement traverse.

[0109] The temperature distribution term of the axial direction of the measurement traverse is constructed by using the exponential decay method, and the specific formula is:

[0110]

[0111]

[0112]

[0113] represents the constant temperature of the tunnel; represents the ground average temperature; represents the decay coefficient of the temperature of the measurement traverse numbered ; represents the basic temperature decay coefficient of the surrounding rock; represents the frozen layer thickness correction coefficient; represents the maximum frozen layer thickness of the tunnel in the axial direction; represents the temperature distribution term of the measurement traverse numbered , which extends outward along the inner wall surface of the tunnel surrounding rock by a depth distance of ; the first decay index refers to ; represents the first temperature distribution term; represents the second temperature distribution term;

[0114] In the above formula, the decay coefficient dynamically reflects the influence of the local frozen layer thickness on the temperature gradient, and describes the non-uniform distribution characteristics of the axial temperature field; and respectively determine the starting point and the ending point of the temperature distribution, when , when tends to infinity, ; is used to quantify the adjusting effect of the local frozen state on the temperature decay rate, the larger the ,the higher the temperature gradient, and the steeper the tunnel temperature influence range; and the tunnel temperature term ​​present a negative correlation, The greater, the smaller the tunnel temperature; With present a positive correlation, The greater, the greater the surface temperature; The greater, The greater, leading to the temperature distribution more quickly close to the surface temperature .

[0115] The corrected wave velocity propagation speed is obtained, specifically comprising the following steps:

[0116] The wave velocity of the original measurement horizontal line is multiplied by the correction factor to obtain the corrected wave velocity propagation speed, and the correction factor is calculated in the following manner:

[0117] Subtract 1 from the product of the maximum wave velocity attenuation rate and the temperature sensitivity function, wherein the maximum wave velocity attenuation rate is obtained through laboratory calibration measurement, and the temperature sensitivity function is obtained by The difference between the current temperature and the phase transition critical temperature is calculated by the function, and the product of the maximum wave velocity attenuation rate and the temperature sensitivity function is multiplied by the relative deviation between the current temperature and the reference temperature of the frozen layer to form the corrected wave velocity propagation speed.

[0118] The corrected wave velocity propagation speed is obtained, specifically comprising the following formula:

[0119] ;

[0120] Wherein, represents the measurement horizontal line numbered , and the depth distance extending outward along the inner wall surface of the tunnel surrounding rock is The corrected wave velocity propagation speed; represents the maximum wave velocity attenuation rate, which is measured by laboratory calibration; represents the reference temperature of the frozen layer; represents the phase transition critical temperature.

[0121] In the above formula, Through the temperature sensitivity function The combination of the function and the linear temperature term dynamically quantifies the nonlinear attenuation characteristics of the wave velocity near the freezing and thawing phase transition critical temperature Significantly improve the temperature correction accuracy of the frozen layer wave velocity, and avoid the adaptability problem of the traditional linear correction model in the phase transition temperature zone; Through the sigmoid function Control the nonlinear attenuation weight of the phase transition critical zone, and combine the linear term Quantify the proportional effect of temperature deviation from the reference value, to jointly constitute the composite correction mechanism of temperature on wave velocity; The maximum attenuation amplitude of wave velocity is limited, and the sensitivity of the material to temperature change is determined by laboratory calibration. The greater the value, the more significant the wave velocity attenuation caused by temperature change; The positive correlation presents a direct transmission of the original wave velocity to the correction result; The negative correlation reflects the physical law that temperature rise leads to wave velocity attenuation; when The negative correlation reflects the physical law that temperature rise leads to wave velocity attenuation; when The negative correlation reflects the physical law that temperature rise leads to wave velocity attenuation; when The negative correlation reflects the physical law that temperature rise leads to wave velocity attenuation; when The gradient of the sigmoid function number is the largest, which is most sensitive to temperature change, reflecting the wave velocity mutation characteristics of the phase change region.

[0122] S4: Based on the corrected wave velocity propagation speed, the temperature distribution term gradient multiplication method is used to define the propagation impedance at the measurement horizontal line; based on the propagation impedance, a vibration speed prediction model is constructed to calculate the predicted vibration speed corresponding to each measurement horizontal line, and based on the predicted vibration speed corresponding to the adjacent measurement horizontal line, the distance interpolation method is used to calculate the predicted vibration speed corresponding to any axis coordinate.

[0123] The specific steps of defining the propagation impedance of the measurement horizontal line by the temperature distribution term gradient multiplication method are as follows:

[0124] The corrected wave velocity propagation speed at the measurement horizontal line is multiplied by the corresponding temperature gradient to obtain the propagation impedance of the corresponding measurement horizontal line, wherein the temperature gradient at the corresponding measurement horizontal line is obtained by taking the derivative of the corresponding temperature distribution term with respect to the depth distance.

[0125] The specific formula for defining the propagation impedance of the measurement horizontal line by the temperature distribution term gradient multiplication method is as follows:

[0126] ;

[0127] Wherein,

[0128] ;

[0129] represents the propagation impedance of the measurement horizontal line numbered , which extends outward along the inner wall surface of the tunnel surrounding rock with a depth distance of . represents the gradient of the temperature distribution along , which is obtained by taking the derivative of the temperature distribution term with respect to the depth distance.

[0130] In the above formula, By using the product of wave velocity and temperature gradient, the impedance characteristics of the non-uniform temperature field of the frozen layer on the propagation path of vibration waves are directly characterized, dynamically reflecting the coupling effect of wave velocity attenuation and sudden temperature change in the ice-water phase transition region. As a reference dimension for impedance, the larger its value, the greater the propagation impedance, reflecting the dominant influence of wave speed on energy propagation efficiency. The severity of radial temperature change in the surrounding rock is quantified by the absolute value of the gradient. The larger the temperature gradient, the closer to the frozen layer, and the greater the impedance. The significant increase reflects the additional dissipation effect of temperature abrupt changes on the energy of vibration waves; Through the temperature gradient expression Adjusting the amplitude of the temperature gradient, As the thickness of the frozen layer increases, the gradient amplitude decreases in the near-tunnel region. The impedance increases at the point of increase. Local enlargement; With depth Negative correlation characterizes the physical law that impedance decreases with increasing surrounding rock depth; and A positive correlation indicates that the temperature change amplifies the impedance.

[0131] The specific steps for calculating the predicted vibration velocity corresponding to any axis coordinate using the distance interpolation method are as follows:

[0132] The product of the propagation impedance of the measured horizontal line and the parameter term with the depth distance as the base and the rock medium parameter as the exponent is used as the denominator. The site correction coefficient is multiplied by the exponential attenuation term formed by the negative of the product of the temperature distribution term of the measured horizontal line and the depth distance with the natural constant as the base. The result is used as the numerator to construct the vibration velocity prediction model.

[0133] For any axis coordinate, find its two adjacent measurement lines and number them sequentially. Construct the predicted vibration velocity at any axis position using the sum of the products of the distance weighting factor and the wave propagation velocity at the corresponding measurement line. The distance weighting factor is calculated as follows:

[0134] The weighting coefficient of the left measurement line is calculated by subtracting the axis coordinates of the target position from the axis coordinates of the left measurement line and then dividing by the difference between the axis coordinates of the left and right sides.

[0135] The weighting coefficient of the right-side measurement line is calculated by subtracting the axis coordinates of the target location from the axis coordinates of the right-side measurement line, and then dividing by the difference between the axis coordinates of the left and right sides.

[0136] The specific steps for calculating the predicted vibration velocity corresponding to any axis coordinate using the distance interpolation method are as follows:

[0137] Based on the propagation impedance, a vibration velocity prediction model is constructed, specifically including the following formula:

[0138] ;

[0139] wherein, represents the vibration velocity of the measurement horizontal line numbered , extending outward along the inner wall surface of the tunnel surrounding rock with a depth distance of ; represents the medium parameter of the tunnel rock, commonly taken as 1.5; represents the site correction coefficient, calibrated through field blasting experiments, commonly taken as 0.15;

[0140] In the above formula, quantitatively represents the spatial distribution rule of vibration energy in the frozen layer non-uniform medium through the synergistic effect of impedance and temperature-distance attenuation term , and the greater the impedance , the lower the vibration energy propagation efficiency, resulting in the decrease of vibration velocity , which directly regulates the energy dissipation; when the temperature rises, the exponential term attenuation intensifies, and the vibration velocity significantly decreases, reflecting the enhanced effect of temperature on wave propagation energy absorption; through the double effects of geometric attenuation term and temperature attenuation term , the vibration velocity increases with the depth in a non-linear attenuation, which conforms to the physical diffusion law of vibration wave.

[0141] In the above examples, 10 groups of data of dependent variable vibration velocity and independent variables, i.e., impedance, depth distance and temperature distribution term are given, reflecting the relationship between vibration velocity and each independent variable, as shown in Tables 1-3:

[0142] Table 1: Relationship table of vibration velocity with propagation impedance

[0143]

[0144] As can be seen from the above Table 1, when , is fixed, the vibration velocity gradually decreases with the increase of propagation impedance, which conforms to the condition that the greater the impedance , the lower the vibration energy propagation efficiency, resulting in the decrease of vibration velocity .

[0145] Table 2: Relationship table of vibration velocity with depth distance

[0146]

[0147] From the above table 2, it can be seen that, when the fixed , , with the increase of the depth distance, the vibration velocity gradually decreases, which conforms to the physical diffusion law of vibration wave.

[0148] Table 3: Change relationship table of vibration velocity with temperature distribution term

[0149]

[0150] From the above table 3, it can be seen that, when the fixed , , with the increase of the temperature distribution term, the exponential term attenuation intensifies, and the vibration velocity significantly decreases, reflecting the enhanced effect of temperature on wave propagation energy absorption.

[0151] Set any axis coordinate as , and find the labels of its adjacent two measurement horizontal lines, which satisfy:

[0152] ;

[0153] Wherein,

[0154] ;

[0155] Indicates the axis coordinate corresponding to the measurement horizontal line with label ; Indicates the right measurement horizontal line number of any axis coordinate ;

[0156] Based on the vibration velocity of the adjacent measurement horizontal line, the distance weight factor product is used to construct the predicted vibration velocity of the arbitrary axis position:

[0157] ;

[0158] Wherein,

[0159] ;

[0160] ;

[0161] Indicates the predicted vibration velocity of the measurement horizontal line with number , which extends outward along the inner wall surface of the tunnel surrounding rock with a depth distance of ; Indicates the distance weight factor of the measurement horizontal line with number ; denotes the distance weight factor of the measurement horizontal line numbered .

[0162] In the above formula, The continuous prediction of the vibration velocity at the axis position is realized by the normalized linear combination of the distance weight factors and , breaking through the spatial limitation of discrete measurement point data, and As an interpolation base value, its value directly determines the magnitude range of . The higher the measured or predicted velocity of the adjacent measurement points is, the closer the overall trend of the interpolation result is to the high value area; and Through normalized weight distribution, the relative distance influence of the target position to the adjacent and is quantified. The greater the weight factor is, the more significant the contribution of the corresponding measurement point velocity to is; the axis position drives the interpolation result to smoothly transition in space, ensuring the continuity of the vibration velocity prediction;

[0163] and are negatively correlated, indicating that the farther the distance is, the weaker the weight contribution is; and are negatively correlated, reflecting that the farther the distance is, the greater the weight contribution is.

[0164] Please refer to Figure 5 , the present application further provides a tunnel blasting construction ground surface vibration prediction device in a seasonal frozen region, the prediction device is used for executing the prediction method described above, comprising:

[0165] A data acquisition module is used for setting measurement horizontal lines on the inner wall of the tunnel surrounding rock every fixed interval along the axial direction of the tunnel that has been mined, with the blasting point as the origin, and uniformly setting multiple measurement points on each measurement horizontal line, and using the geological radar method to determine the reflection wave propagation time at each measurement point.

[0166] A wave velocity calculation module is used for weighting the frozen layer thickness of the measurement points on each measurement horizontal line to obtain the frozen layer thickness of each measurement horizontal line by using the inverse distance weighting method, and defining the wave velocity propagation speed of each measurement horizontal line based on the frozen layer thickness of each measurement horizontal line and the minimum distance of each measurement horizontal line from the origin by using the depth distance method.

[0167] The wave velocity correction module is configured to obtain constant temperature of the tunnel and average temperature of the ground surface as parameters of a temperature distribution term, construct the temperature distribution term in the axial direction of the measurement traverse by using an exponential decay method, take the temperature distribution term in the axial direction as a correction term of wave velocity propagation speed, and obtain the corrected wave velocity propagation speed.

[0168] The vibration prediction module is configured to define propagation impedance at the measurement traverse by using a temperature distribution term gradient product method based on the corrected wave velocity propagation speed, construct a vibration speed prediction model to calculate predicted vibration speed corresponding to each measurement traverse based on the propagation impedance, and calculate predicted vibration speed corresponding to any axial coordinate by using a distance interpolation method based on predicted vibration speeds corresponding to adjacent measurement traverses.

[0169] The above formulas are all dimensionless values, and the formulas are obtained by software simulation of a large amount of data to obtain a formula closest to the actual situation. The preset parameters in the formulas are set by a person skilled in the art according to the actual situation.

[0170] The above embodiments can be realized wholly or partially by software, hardware, firmware or any combination thereof. When realized by software, the above embodiments can be realized in the form of a computer program product wholly or partially. Those skilled in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized by hardware or software methods depends on the specific application and design constraints of the technical solutions.

[0171] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, which can be located in one place or distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0172] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for predicting surface vibration during tunnel blasting construction in seasonally frozen areas, characterized by the following steps: include: S1: Taking the blasting point as the origin, along the axial direction of the tunnel that has been mined, set up measuring lines on the inner wall of the surrounding rock of the tunnel at fixed intervals, and evenly set up multiple measuring points on each measuring line. Use ground-penetrating radar to determine the propagation time of the reflected wave at each measuring point. S2: The inverse distance weighting method is used to weight the thickness of the frozen layer at each measurement point on the measurement line to obtain the thickness of the frozen layer of each measurement line. Based on the thickness of the frozen layer of each measurement line and the minimum distance of each measurement line from the origin, the depth distance method is used to define the wave propagation speed of each measurement line. S3: Obtain the constant temperature of the tunnel and the average surface temperature as parameters of the temperature distribution term, use the exponential decay method to construct the axial temperature distribution term of the measurement line, use the axial temperature distribution term as the correction term for the wave propagation speed, and obtain the corrected wave propagation speed. S4: Based on the corrected wave propagation speed, the propagation impedance at the measurement line is defined using the gradient product method of the temperature distribution term. Based on propagation impedance, a vibration velocity prediction model is constructed to calculate the predicted vibration velocity corresponding to each measurement line. Based on the predicted vibration velocities corresponding to adjacent measurement lines, the distance interpolation method is used to calculate the predicted vibration velocity corresponding to any axis coordinate.

2. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 1, characterized in that, The specific steps to obtain the thickness of the frozen layer for each measurement line are as follows: For each measurement point on each measurement line, the distance from each measurement point to the center point of the measurement line is defined as the first distance. A non-zero constant is introduced, and the reciprocal of the sum of the first distance and the non-zero constant is used to represent the position weight of the measurement point on the measurement line. The positional weights of each measurement point within each measurement line are summed and calibrated as the total weight of that measurement line. The propagation time of reflected waves at each measurement point is determined by ground-penetrating radar and marked as the first time. The product of the first time and position weight of each measurement point within each measurement line is obtained, and the sum of all products is marked as the relative propagation time at that measurement line. For each measurement line, the ratio of the relative propagation time to the total weight is taken as the propagation time of the reflected wave for that measurement line.

3. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 2, characterized in that, The specific steps for obtaining the constant temperature of the tunnel and the average surface temperature are as follows: The temperature of each measurement point is acquired in real time to form a first temperature set. The maximum and minimum temperatures in the first temperature set are removed, and the average temperature of the remaining temperatures is calculated as the constant temperature of the tunnel. The specific steps for obtaining the constant temperature of the tunnel and the average surface temperature are as follows: The temperature of each measurement point is acquired in real time to form a first temperature set. The maximum and minimum temperatures in the first temperature set are removed, and the average temperature of the remaining temperature values ​​is calculated as the constant temperature of the tunnel. The average surface temperature is the average surface temperature of the area where the tunnel to be blasted is located.

4. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 2, characterized in that, The steps for obtaining the thickness of the frozen layer for each measurement line include: Half of the product of the reflection wave propagation time and the electromagnetic wave propagation speed for each measurement line is defined as the one-way propagation time. The arithmetic square root of the dielectric constant of the permafrost layer in the area where the tunnel to be blasted is located is used as the propagation correction coefficient. The ratio of the one-way propagation time to the propagation correction coefficient corresponding to each measurement line is calibrated as the thickness of the frozen layer at that measurement line.

5. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 1, characterized in that, The specific steps for defining the wave propagation velocity of each measurement line using the depth-distance method include: The thickness of the frozen layer for each measurement line is taken as the first threshold of that measurement line, and the sum of the thickness of the frozen layer and the width of the typical freeze-thaw interface is taken as the second threshold of that measurement line. If the minimum distance between the measurement line and the origin is not greater than the first threshold, the wave propagation speed of the measurement line is calibrated as the wave propagation speed of the frozen layer. If the minimum distance between the measured horizontal line and the origin is greater than the first threshold and not greater than the second threshold, the wave propagation speed of the measured horizontal line is calibrated as the difference between the wave propagation speed and the attenuation speed of the frozen layer. If the minimum distance between the measurement line and the origin is greater than the second threshold, the wave propagation speed of the measurement line is calibrated as the wave propagation speed of the unfrozen layer. The step of obtaining the decay rate includes: Obtain the difference between the minimum distance of the measurement line from the origin and the thickness of the frozen layer, and use the ratio of this difference to the width of the typical freeze-thaw interface as the attenuation coefficient; The difference between the wave propagation speed of the frozen layer and the wave propagation speed of the unfrozen layer is obtained as the wave speed change. The product of the attenuation coefficient of the measured horizontal line and the wave speed change is taken as the attenuation speed of the corresponding measured horizontal line.

6. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 4, characterized in that, The temperature distribution term along the axial direction of the measurement line is constructed using the exponential decay method. The specific steps are as follows: Using the natural constant as the base, the negative of the product of the minimum distance of the horizontal line from the origin and the temperature decay coefficient of the horizontal line is used as the exponent to construct an exponential function as the first decay exponent, and the difference between 1 and the first decay exponent is used as the second decay exponent. The product of the tunnel's constant temperature and the first attenuation index is used as the first temperature distribution term of the corresponding measurement line, and the product of the average surface temperature and the second attenuation index is used as the second temperature distribution term of the corresponding measurement line. The sum of the first and second temperature distribution terms is taken as the temperature distribution term corresponding to the measured horizontal line.

7. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 1, characterized in that, Obtaining the corrected wave propagation speed specifically includes the following steps: The corrected wave velocity is obtained by multiplying the original measured horizontal line wave velocity by a correction factor. The correction factor is calculated as follows: Subtract the maximum wave velocity decay rate from 1 and multiply by the temperature sensitivity function, where the maximum wave velocity decay rate is obtained through laboratory calibration measurements, and the temperature sensitivity function is obtained through... The corrected wave propagation speed is obtained by multiplying the maximum wave velocity decay rate by the temperature-sensitive function and then multiplying the result by the relative deviation between the current temperature and the reference temperature of the frozen layer.

8. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 1, characterized in that, The method of defining the propagation impedance of the measurement line using the gradient product of temperature distribution terms involves the following steps: The propagation impedance of the corresponding measurement line is obtained by multiplying the corrected wave propagation velocity at the measurement line with the corresponding temperature gradient. The temperature gradient at the measurement line is obtained by differentiating the temperature distribution term at the measurement line with respect to its depth distance.

9. The method for predicting surface vibration during tunnel blasting construction in a seasonally frozen area according to claim 1, characterized in that, The specific steps for calculating the predicted vibration velocity corresponding to any axis coordinate using the distance interpolation method are as follows: The product of the propagation impedance of the measured horizontal line and the parameter term with the depth distance as the base and the rock medium parameter as the exponent is used as the denominator. The site correction coefficient is multiplied by the exponential attenuation term formed by the negative of the product of the temperature distribution term of the measured horizontal line and the depth distance with the natural constant as the base. The result is used as the numerator to construct the vibration velocity prediction model. For any axis coordinate, find its two adjacent measurement lines and number them sequentially. Construct the predicted vibration velocity at any axis position using the sum of the products of the distance weighting factor and the wave propagation velocity at the corresponding measurement line. The distance weighting factor is calculated as follows: The weighting coefficient of the left measurement line is calculated by subtracting the axis coordinates of the target position from the axis coordinates of the left measurement line and then dividing by the difference between the axis coordinates of the left and right sides. The weighting coefficient of the right-side measurement line is calculated by subtracting the axis coordinates of the target location from the axis coordinates of the right-side measurement line, and then dividing by the difference between the axis coordinates of the left and right sides.

10. A surface vibration prediction device for tunnel blasting construction in seasonally frozen areas, characterized in that: The prediction device is used to perform the prediction method according to any one of claims 1-9, including: The data acquisition module is used to set measurement lines on the inner wall of the tunnel surrounding rock at fixed intervals along the axial direction of the already mined tunnel, with the blasting point as the origin. Multiple measurement points are evenly set on each measurement line, and the ground-penetrating radar method is used to determine the propagation time of the reflected wave at each measurement point. The wave velocity calculation module is used to weight the thickness of the frozen layer at each measurement point on each measurement line using the inverse distance weighting method to obtain the thickness of the frozen layer of each measurement line. Based on the thickness of the frozen layer of each measurement line and the minimum distance of each measurement line from the origin, the wave velocity propagation speed of each measurement line is defined using the depth distance method. The wave velocity correction module is used to obtain the constant temperature of the tunnel and the average surface temperature as parameters of the temperature distribution term. It uses the exponential decay method to construct the axial temperature distribution term of the measurement line and uses the axial temperature distribution term as the correction term for the wave velocity propagation speed to obtain the corrected wave velocity propagation speed. The vibration prediction module defines the propagation impedance at the measurement line based on the corrected wave propagation velocity using the gradient product method of the temperature distribution term. Based on the propagation impedance, a vibration velocity prediction model is constructed to calculate the predicted vibration velocity corresponding to each measurement line. Furthermore, based on the predicted vibration velocities corresponding to adjacent measurement lines, the distance interpolation method is used to calculate the predicted vibration velocity corresponding to any axis coordinate.

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