Method and system for detecting loose circle of surrounding rock of water-immersed roadway

Abstract

The invention relates to the technical field of roadway surrounding rock stability detection, and discloses a water immersion roadway surrounding rock loosening circle detection method and system, and the method comprises the steps: drilling small-angle inclined drill holes in two sides of a roadway, and injecting pressure water to form a water immersion saturated environment; sound time data are collected through an ultrasonic probe, and a wave velocity-hole depth curve is constructed; identifying a wave velocity gradient abrupt change area based on attenuation characteristics of surrounding rock fractures to sound waves; the inner boundary and the outer boundary of the loose circle are dynamically judged through the wave velocity gradient change rate, and finally a detection report containing the loose circle range is generated. By actively simulating the water immersion coupling environment and combining gradient change rate analysis, the problem of inaccurate boundary recognition caused by water influence of a traditional acoustic wave method is solved, and the accuracy and reliability of a detection result are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of roadway surrounding rock stability detection, and particularly relates to a water immersion roadway surrounding rock loose circle detection method and system. BACKGROUND

[0002] The surrounding rock fissure of a water immersion roadway is often in a water saturated state due to underground seepage or construction water penetration. The traditional acoustic wave detection method faces fundamental limitations in this environment:

[0003] Water saturated fissures cause abnormal attenuation of acoustic wave energy, and acoustic wave velocity presents irregular fluctuations. Conventional velocity criteria (such as absolute velocity threshold) cannot distinguish between water immersion induced acoustic wave attenuation and surrounding rock structural degradation, resulting in a blurred boundary between the loose zone and the stable zone.

[0004] The existing technology relies on empirical velocity correction models (such as linear water pressure compensation algorithm), but the water-rock coupling effect has strong nonlinear characteristics. In particular, in the critical zone of fissure development (loose circle boundary), small structural differences are masked by the water medium, which can lead to internal boundary misjudgment, i.e., the compression tight zone is mistakenly identified as the loose zone, and further causes overdesign of support; it can also lead to external boundary misjudgment, and the fissure expansion zone weakened by water immersion cannot be detected, thereby causing the problem of insufficient support strength. Therefore, there is an urgent need for a detection method that can adapt to the water immersion environment and capture the critical state of fissures to overcome the problem of inaccurate boundary identification caused by the influence of water on acoustic wave propagation in the traditional method. SUMMARY

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present application provide a water immersion roadway surrounding rock loose circle detection method to solve the problems raised in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides a water immersion roadway surrounding rock loose circle detection method, comprising:

[0007] Drilling inclined boreholes with a preset small angle depression angle on both sides of the roadway, the axis of the inclined borehole forms the preset small angle depression angle with the horizontal plane;

[0008] Injecting pressure water into the inclined borehole until the orifice overflows to form a water immersion saturated surrounding rock coupling environment;

[0009] Moving the ultrasonic probe outward from the bottom of the inclined borehole at a preset interval, and recording the acoustic time data in real time;

[0010] Constructing a velocity-hole depth curve based on the acoustic time data, and identifying the velocity gradient mutation zone in the curve according to the attenuation characteristics of the surrounding rock fissure to the acoustic wave in the surrounding rock coupling environment;

[0011] The wave velocity gradient mutation zone is used to determine the boundary of the loose circle of the roadway surrounding rock, including: when the wave velocity gradient change rate first exceeds the crack development characteristic value of the surrounding rock, marking the inner boundary of the loose circle; and when the wave velocity gradient change rate decreases to the structure stability characteristic value of the surrounding rock, marking the outer boundary of the loose circle.

[0012] A detection report containing the range of the loose circle is generated according to the inner boundary and the outer boundary.

[0013] To solve the above problems, the application further provides a water immersion roadway surrounding rock loose circle detection system, which comprises:

[0014] A tilt hole drilling module is configured to drill a tilt hole with a preset small angle of depression on both sides of the roadway, and the axis of the tilt hole forms the preset small angle of depression with the horizontal plane.

[0015] A water immersion environment construction module is configured to inject pressure water into the tilt hole until the orifice overflows, forming a water immersion saturated surrounding rock coupling environment.

[0016] An ultrasonic detection module is configured to move an ultrasonic probe out of the bottom of the tilt hole at a preset interval and record acoustic time data in real time.

[0017] A wave velocity curve analysis module is configured to construct a wave velocity-hole depth curve based on the acoustic time data, and identify a wave velocity gradient mutation zone in the curve according to the attenuation characteristics of the crack of the surrounding rock to the acoustic wave in the surrounding rock coupling environment.

[0018] A loose circle boundary determination module is configured to determine the boundary of the loose circle of the roadway surrounding rock based on the wave velocity gradient mutation zone, including: when the wave velocity gradient change rate first exceeds the crack development characteristic value of the surrounding rock, marking the inner boundary of the loose circle; and when the wave velocity gradient change rate decreases to the structure stability characteristic value of the surrounding rock, marking the outer boundary of the loose circle.

[0019] A detection report generation module is configured to generate a detection report containing the range of the loose circle according to the inner boundary and the outer boundary.

[0020] This invention significantly improves the detection accuracy of the loosened zone boundary in water-saturated tunnels by constructing a water-saturated surrounding rock coupling environment and combining it with wave velocity gradient abrupt change analysis. First, by drilling small-angle inclined boreholes and injecting pressurized water, the actual water immersion condition is actively simulated, forming a water-rock coupled acoustic wave propagation environment and eliminating acoustic wave propagation distortion caused by uneven distribution of fissure water. Second, the wave velocity gradient change rate is used as a dynamic criterion. The inner boundary is determined by capturing the abrupt change point where the wave velocity gradient first exceeds the characteristic value of fissure development, and the outer boundary is determined by the turning point where the wave velocity gradient drops to the stable characteristic value. This effectively solves the problem of fuzzy boundary identification under water immersion conditions in traditional methods. In addition, by recording acoustic time data in real time and constructing a wave velocity-hole depth curve, a quantitative analysis of the degree of fissure development in the surrounding rock is realized, which can accurately delineate the range of the loosened zone and generate a detection report including thickness and stability level. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating a method for detecting the loosened zone of surrounding rock in a water-soaked tunnel according to an embodiment of the present invention.

[0022] Figure 2 A functional block diagram of a water-soaked tunnel surrounding rock loosening zone detection system provided in an embodiment of the present invention;

[0023] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0025] This application provides a method for detecting the loosened zone of surrounding rock in water-damaged tunnels. The execution entity of this method includes, but is not limited to, at least one of the following electronic devices that can be configured to execute the method provided in this application: a server, a terminal, etc. In other words, the method for detecting the loosened zone of surrounding rock in water-damaged tunnels can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster. The server can be an independent server or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery networks, and big data and artificial intelligence platforms.

[0026] Reference Figure 1 The diagram shown is a flowchart illustrating a method for detecting the loosened zone of surrounding rock in a water-soaked tunnel according to an embodiment of the present invention. In this embodiment, the method for detecting the loosened zone of surrounding rock in a water-soaked tunnel includes:

[0027] S1. Drilling an inclined borehole with a preset small-angle inclination on both sides of the roadway, the axis of the inclined borehole forms a preset small-angle inclination with the horizontal plane.

[0028] In some embodiments, the step of drilling an inclined borehole with a preset small-angle inclination on both sides of the roadway comprises:

[0029] Positioning the drilling starting point at the same horizontal height on both sides of the roadway using a geological drilling machine;

[0030] Adjusting the angle of the drilling machine drill rod so that the drill rod axis forms a preset small-angle inclination with the horizontal plane, wherein the direction of the preset small-angle inclination is towards the direction of roadway excavation;

[0031] Starting the drilling machine to drill along the preset small-angle inclination to a preset hole depth to form an inclined borehole, the hole diameter of the inclined borehole is matched with the outer diameter of the ultrasonic probe.

[0032] In the embodiments of the present application, the two sides of the roadway refer to the rock walls on the left and right sides of the roadway, which are the lateral surrounding rock structures formed after the roadway is excavated. The preset small-angle inclination refers to a small downward inclination angle formed between the axis of the inclined borehole and the horizontal plane, which is pre-set according to the geological conditions of the roadway and the detection requirements before detection. The inclined borehole refers to a hole with a certain inclination formed by drilling into the surrounding rock of the roadway at a preset small-angle inclination.

[0033] In the embodiments of the present application, the step of drilling an inclined borehole with a preset small-angle inclination on both sides of the roadway first requires the use of a geological drilling machine for operation. The geological drilling machine is a drilling equipment used in the fields of geological exploration, geotechnical engineering, etc., which can drill into hard media such as rock to form a borehole. During operation, the drilling starting point is first determined at the same horizontal height on both sides of the roadway. This horizontal height is usually selected according to the actual situation of the roadway, such as the height of the roadway, the stress characteristics of the surrounding rock, etc. Generally, it is selected at a position that is convenient for operation and can effectively reflect the surrounding rock conditions, for example, at a height of 1.5 meters from the floor of the roadway.

[0034] In the embodiments of the present application, after the drilling starting point is determined, the angle of the drill rod of the drilling machine needs to be adjusted. The drill rod is a rod member in the drilling machine for transmitting power and realizing drilling. By adjusting the angle of the drill rod, the drill rod axis forms a preset small-angle inclination with the horizontal plane, and the direction of the inclination is towards the direction of roadway excavation. The direction towards the direction of roadway excavation is chosen because the excavation of the roadway will cause a certain disturbance to the surrounding rock in front, and drilling in this direction can more accurately detect the loosened circle formed by the excavation. The specific value of the preset small-angle inclination is usually between 3° and 8°, for example, 5°. The selection of this angle needs to consider factors such as drilling depth and surrounding rock stability, which can ensure that the drill hole penetrates a certain distance into the surrounding rock, and can avoid increasing the difficulty of drilling due to too large angle or not effectively reflecting the surrounding rock conditions of the target area due to too small angle.

[0035] In the embodiment of the present application, after adjusting the angle of the drill rod, the drilling machine is started to drill at a preset small angle of inclination to a preset hole depth. The preset hole depth is determined according to the requirements of the detection range, and generally needs to exceed the range of the possible loose circle, for example, is set to 30 meters. During the drilling process, it is necessary to ensure that the hole diameter of the drill hole is matched with the outer diameter of the ultrasonic probe, that is, the diameter of the drill hole is slightly larger than the outer diameter of the ultrasonic probe, for example, when the outer diameter of the ultrasonic probe is 50 mm, the hole diameter of the drill hole is set to 55 mm, so that the ultrasonic probe can be smoothly put into the drill hole and freely moved, and the influence of the gap between the probe and the hole wall on the sound wave propagation is reduced, and the accuracy of the detection data is ensured.

[0036] In the embodiment of the present application, by drilling inclined drill holes with specific angles and depths on both sides of the roadway, the ultrasonic probe can be deep into the surrounding rock of the roadway, so as to obtain the surrounding rock information at different depths.

[0037] In the embodiment of the present application, the inclined drill hole drilled is the place where the subsequent injection of pressure water forms a water-saturated surrounding rock coupling environment, and is also a channel for the ultrasonic probe to move and collect data. Only when the parameters such as the angle, depth, and hole diameter of the drill hole meet the requirements, can the subsequent water injection process be smoothly carried out.

[0038] S2. Injecting pressure water into the inclined drill hole until the overflow of the hole mouth, to form a water-saturated surrounding rock coupling environment.

[0039] In some embodiments, the injection of pressure water into the inclined drill hole until the overflow of the hole mouth forms a water-saturated surrounding rock coupling environment, comprising:

[0040] Sealingly connecting the water outlet of the high-pressure water pipe to the hole mouth of the inclined drill hole, and the high-pressure water pipe is provided with a pressure regulating valve;

[0041] Opening the pressure regulating valve to inject pressure water into the inclined drill hole at a constant pressure, and the constant pressure does not exceed the initial stress value of the surrounding rock of the roadway;

[0042] Continuously injecting water until continuous overflow of the hole mouth, recording the water injection time and the total water injection amount, to form the water-saturated surrounding rock coupling environment.

[0043] In the embodiments of the present application, the high-pressure water pipe is a pipe for conveying water with a certain pressure, and the material and pressure resistance performance thereof need to meet the requirement of water injection pressure. The pressure regulating valve is a device installed on the high-pressure water pipe for controlling and regulating the water flow pressure, and can keep the output water pressure at a constant set value. The orifice of the inclined borehole refers to the opening end of the inclined borehole close to the inside of the roadway. The constant pressure refers to the water flow pressure value that remains unchanged during water injection. The initial stress value of the surrounding rock of the roadway refers to the stress size of the surrounding rock before the roadway is excavated, which can be obtained by geomechanics test. The continuous overflow of the orifice refers to the continuous flow of water from the orifice, which is no longer absorbed by the surrounding rock. The water injection duration refers to the time experienced from the start of water injection to the continuous overflow of the orifice. The total water injection volume refers to the total volume of water injected into the inclined borehole within the water injection duration. The water-saturated surrounding rock coupling environment refers to the surrounding rock around the inclined borehole being fully soaked by water, the pores and fissures being filled with water, and the water and the surrounding rock being in a state of close combination.

[0044] In the embodiments of the present application, the water outlet of the high-pressure water pipe is sealingly connected to the orifice of the inclined borehole, and the high-pressure water pipe is provided with a pressure regulating valve, comprising: first, a suitable high-pressure water pipe and a pressure regulating valve are prepared, and it is ensured that the water outlet of the high-pressure water pipe matches the size of the orifice of the inclined borehole. Then, a sealing connector such as a sealing flange or a special sealing joint is used to connect the water outlet of the high-pressure water pipe and the orifice of the inclined borehole, so as to ensure the sealing property of the connection and prevent water leakage during water injection. At the same time, it is confirmed that the pressure regulating valve has been correctly installed on the high-pressure water pipe, and the valve can work normally to regulate the water pressure. For example, in the detection of a certain coal mine roadway, a high-pressure water pipe with a diameter of 20 mm is selected, the water outlet thereof is connected to the orifice of the inclined borehole with a hole diameter of 55 mm through a sealing flange, and the pressure regulating valve installed on the high-pressure water pipe has a range of 0-5 MPa, which can meet the requirement of water injection pressure regulation.

[0045] In the embodiments of the present application, the pressure regulating valve is opened to inject pressure water into the inclined borehole at a constant pressure, and the constant pressure does not exceed the initial stress value of the surrounding rock of the roadway, comprising: after the pipe is connected, the pressure regulating valve is slowly opened, and the constant pressure value is gradually adjusted. The determination of the constant pressure needs to refer to the initial stress value of the surrounding rock of the roadway, for example, the initial stress value of the surrounding rock of the roadway is 3 MPa through the previous geology test, and the constant pressure can be selected as 2 MPa, so as to avoid the additional disturbance of the high pressure to the surrounding rock and affect the original state of the surrounding rock. During water injection, the water pressure is monitored and maintained stable in real time through the pressure regulating valve, so as to ensure that the pressure water is continuously injected into the inclined borehole at a constant pressure. The pressure water gradually penetrates into the pores and fissures of the surrounding rock during flow, so that the surrounding rock is gradually soaked by water.

[0046] In the embodiment of the present application, the water injection is continued until continuous overflow appears at the orifice, and the injection time and the total injection amount are recorded to form the water immersion saturated surrounding rock coupling environment, which comprises: continuously injecting water into the inclined borehole under constant pressure, and as the injection time is prolonged, the pores and fissures in the surrounding rock are gradually filled with water. When continuous overflow appears at the orifice, it indicates that the surrounding rock has reached the water immersion saturated state, at which time the water injection is stopped. At the same time, the time from the start of water injection to the appearance of continuous overflow at the orifice, i.e. the injection time, and the total injection amount during this period are recorded. For example, in the above detection of the coal mine roadway, continuous water injection for 45 minutes results in continuous overflow at the orifice, and the total injection amount is 1.2 cubic meters, at which time the surrounding rock around the inclined borehole forms a water immersion saturated coupling environment, providing stable medium conditions for the subsequent ultrasonic detection.

[0047] In the embodiment of the present application, step S2 creates a water immersion saturated surrounding rock coupling environment, solving the problem of distortion of the sound wave propagation characteristics caused by uneven distribution of fissure water in the surrounding rock in the traditional acoustic wave detection, so that the sound time data collected subsequently can more accurately reflect the actual condition of the surrounding rock.

[0048] S3. Moving the ultrasonic probe outward from the bottom of the orifice of the inclined borehole at a preset interval, and recording the sound time data in real time.

[0049] In some embodiments, the moving of the ultrasonic probe outward from the bottom of the orifice of the inclined borehole at a preset interval and the recording of the sound time data in real time comprise:

[0050] Fixing the ultrasonic transmitting probe and the receiving probe at the front end of the same detection rod, and the length of the detection rod is not less than the hole depth of the inclined borehole;

[0051] Moving the detection rod carrying the probes outward from the bottom of the orifice of the inclined borehole at the preset interval;

[0052] Collecting the sound time data of the probes at each position in real time by the ultrasonic detector to generate an original data set containing the hole depth-sound time correspondence.

[0053] In the embodiment of the present application, the ultrasonic transmitting probe is a device capable of transmitting ultrasonic signals, the ultrasonic receiving probe is a device capable of receiving ultrasonic signals, the detection rod is a rod member for carrying the ultrasonic probes and moving in the inclined borehole, the preset interval refers to the distance of each movement of the detection rod carrying the probes when moving outward, the ultrasonic detector is a device for receiving and recording the sound time data collected by the ultrasonic probes, and the hole depth-sound time correspondence refers to the correlation of the ultrasonic propagation time at different borehole depths, and the original data set refers to a set containing each hole depth position and the corresponding sound time data.

[0054] In the embodiment of the present application, the ultrasonic emission probe and the receiving probe are fixed to the front end of the same detection rod, and the length of the detection rod is not less than the hole depth of the inclined borehole. The method comprises the following steps: selecting a detection rod with a length not less than the hole depth of the inclined borehole, for example, the hole depth of the inclined borehole is 30 meters, and the length of the detection rod should be not less than 30 meters, so as to ensure that the probe can reach the bottom of the hole and move in the whole length of the borehole. The ultrasonic emission probe and the receiving probe are fixed to the front end of the detection rod at a certain interval, for example, the interval between the two probes is set to 200 millimeters, and the fixing mode can adopt a special clamp to ensure the stability of the position of the probe during movement and avoid affecting the accuracy of the acoustic time data due to the change of the interval caused by loosening.

[0055] In the embodiment of the present application, the detection rod carrying the probe is moved outward step by step from the bottom of the inclined borehole at the preset interval, which comprises the following steps: when the detection rod carrying the probe is put into the inclined borehole, the detection rod is slowly pushed until the probe reaches the position of the bottom of the hole. The preset interval is set according to the requirement of detection accuracy, for example, it is set to 50 centimeters, that is, the detection rod is stopped after moving outward by 50 centimeters each time, and the probe is stabilized at this position for a period of time, so as to accurately collect the acoustic time data. The detection rod needs to be kept stable during movement to avoid affecting the probe and the hole wall due to violent shaking, and at the same time, the distance of each movement is ensured to be accurate, which can be assisted by marking scales on the detection rod to control the movement distance.

[0056] In the embodiment of the present application, the acoustic time data of the probe at each position is collected in real time by the ultrasonic detector to generate an original data set containing the corresponding relationship between the hole depth and the acoustic time, which comprises the following steps: after the probe moves to the preset position and stabilizes each time, the ultrasonic detector is started. The ultrasonic emission probe emits an ultrasonic signal, which is received by the receiving probe after passing through the surrounding water-saturated surrounding rock, and the ultrasonic detector records the time from signal emission to reception, that is, the acoustic time data. For example, the acoustic time data is 40 microseconds at a hole depth of 5 meters, 35 microseconds at a hole depth of 10 meters, and so on. As the probe moves outward step by step, the acoustic time data of each position is continuously collected, and the hole depth information of each position is correspondingly matched with the acoustic time data to form an original data set after arrangement, which provides basic data for subsequent wave velocity calculation.

[0057] In the embodiment of the present application, the water-saturated surrounding rock coupling environment formed in step S2 is used as the basis, and the inclined borehole drilled is used as the detection path; and the original data set collected is the key data source for subsequent construction of the wave velocity-hole depth curve and identification of the wave velocity gradient mutation zone, which lays a data foundation for accurately determining the boundary of the loose circle.

[0058] S4. Based on the acoustic time data, a wave velocity-hole depth curve is constructed, and according to the attenuation characteristics of the surrounding rock cracks to the acoustic waves in the surrounding rock coupling environment, a wave velocity gradient mutation zone in the curve is identified.

[0059] In some embodiments, the wave velocity-hole depth curve is constructed based on the acoustic time data, and a wave velocity gradient mutation zone in the curve is identified according to the attenuation characteristics of the acoustic wave by the surrounding rock fracture in the surrounding rock coupling environment, including:

[0060] The acoustic wave propagation velocity at each hole depth position is calculated based on the acoustic time data, and the acoustic wave propagation velocity is the ratio of the probe spacing to the acoustic time;

[0061] The wave velocity-hole depth curve is plotted with the hole depth as the horizontal axis and the wave velocity as the vertical axis;

[0062] The first derivative of the curve at each point is calculated to obtain the wave velocity gradient, and when the absolute value of the gradient value exceeds the preset gradient threshold, it is marked as a wave velocity gradient mutation zone.

[0063] In the embodiments of the present application, the acoustic wave propagation velocity refers to the distance of the ultrasonic wave propagating in the water-saturated surrounding rock per unit time. The wave velocity-hole depth curve is a curve plotted with the drilling depth as the horizontal axis and the acoustic wave propagation velocity corresponding to the depth as the vertical axis, which is used to intuitively reflect the wave velocity variation at different hole depth positions. The wave velocity gradient refers to the first derivative of the wave velocity-hole depth curve at a certain position, which represents the rate of change of the wave velocity with the hole depth. The preset gradient threshold is a value preset according to the fracture development characteristics of the surrounding rock and the detection accuracy requirement, which is used to determine whether it is a wave velocity gradient mutation zone. The wave velocity gradient mutation zone refers to the region where the absolute value of the wave velocity gradient exceeds the preset gradient threshold, which usually corresponds to the vicinity of the boundary of the surrounding rock loose circle.

[0064] In the embodiments of the present application, the acoustic wave propagation velocity at each hole depth position is calculated based on the acoustic time data, and the acoustic wave propagation velocity is the ratio of the probe spacing to the acoustic time, including: the spacing between the ultrasonic wave transmitting probe and the receiving probe is fixed, for example, in the previous setting, the spacing between the two probes is 200 mm. The acoustic time data corresponding to each hole depth position is extracted from the original data set, and the calculation is performed according to the formula that the acoustic wave propagation velocity is equal to the probe spacing divided by the acoustic time. For example, at a hole depth of 5 meters, the acoustic time data is 40 microseconds, so the acoustic wave propagation velocity at this position is 200 mm divided by 40 microseconds, i.e. 5000 m / s; at a hole depth of 10 meters, the acoustic time data is 35 microseconds, and the acoustic wave propagation velocity is 200 mm divided by 35 microseconds, which is about 5714 m / s. Through such a calculation method, the acoustic wave propagation velocity corresponding to each hole depth position can be obtained.

[0065] In the embodiment of the present application, a wave velocity-hole depth curve is drawn with hole depth as the horizontal axis and wave velocity as the vertical axis, including: taking the calculated hole depth positions and their corresponding sound wave propagation velocities as data points, and marking them in the coordinate system. The horizontal axis of the coordinate system represents hole depth, in meters, ranging from 0 meters to 30 meters (i.e., the preset hole depth); the vertical axis represents wave velocity, in meters per second, which can be set according to the range of calculated wave velocities, for example, from 4000 meters per second to 6000 meters per second. Then, these data points are sequentially connected by a smooth curve to form a wave velocity-hole depth curve. Through the curve, the change trend of the sound wave propagation velocity with the change of the hole depth can be clearly observed, for example, the wave velocity rises rapidly in some hole depth intervals, and the wave velocity changes relatively gently in some intervals.

[0066] In the embodiment of the present application, the first derivative of the curve at each point is calculated to obtain the wave velocity gradient, and when the absolute value of the gradient value exceeds the preset gradient threshold, it is marked as a wave velocity gradient mutation zone, including: for the drawn wave velocity-hole depth curve, the first derivative of each point on the curve, i.e., the wave velocity gradient, is solved by mathematical calculation method. The calculation of the wave velocity gradient can reflect the speed of the change of the wave velocity with the change of the hole depth, for example, at a certain hole depth position, the wave velocity gradient is 300 meters / (second-meter), indicating that the wave velocity increases by 300 meters per second for every 1 meter increase in hole depth. The preset gradient threshold is determined according to the characteristics of the coal mine roadway surrounding rock, for example, set to 500 meters / (second-meter). When the absolute value of the calculated wave velocity gradient of a certain point exceeds 500 meters / (second-meter), the region where the point is located is marked as a wave velocity gradient mutation zone. For example, at a hole depth of 8 meters, the absolute value of the wave velocity gradient is 600 meters / (second-meter), which exceeds the preset gradient threshold, so the region near the hole depth of 8 meters is marked as a wave velocity gradient mutation zone.

[0067] In the embodiment of the present application, the originally dispersed acoustic time information is converted into an intuitive wave velocity change curve, and the region of the wave velocity gradient mutation is identified, which provides a key feature basis for subsequent accurate determination of the loose circle boundary.

[0068] S5. Determine the loose circle boundary of the roadway surrounding rock based on the wave velocity gradient mutation zone, including: when the wave velocity gradient change rate first exceeds the surrounding rock fracture development characteristic value, mark the inner boundary of the loose circle; when the wave velocity gradient change rate decreases to the surrounding rock structure stability characteristic value, mark the outer boundary of the loose circle.

[0069] In the embodiments of the present application, the wave velocity gradient change rate refers to the change rate of the wave velocity gradient between adjacent hole depth positions, and is used to reflect the degree of change of the wave velocity gradient with the hole depth. The surrounding rock fracture development characteristic value is a value pre-set based on geological survey data of similar roadways, and is used to determine whether the surrounding rock enters a region where the fracture development is relatively obvious. The inner boundary of the loose circle refers to the boundary of the side of the loose circle close to the roadway, and is the starting position of the transition of the surrounding rock from a relatively stable state to a loose state.

[0070] In some embodiments, the marking of the inner boundary of the loose circle when the wave velocity gradient change rate first exceeds the surrounding rock fracture development characteristic value comprises:

[0071] extracting the wave velocity gradient change rate in the wave velocity gradient mutation zone;

[0072] point-by-point comparing the wave velocity gradient change rate with a preset surrounding rock fracture development characteristic value, the surrounding rock fracture development characteristic value being determined based on geological survey data of similar roadways;

[0073] when the wave velocity gradient change rate first exceeds the surrounding rock fracture development characteristic value, recording the hole depth position corresponding to the wave velocity gradient change rate as the inner boundary of the loose circle.

[0074] In the embodiments of the present application, the extraction of the wave velocity gradient change rate in the wave velocity gradient mutation zone comprises: selecting the wave velocity gradients corresponding to adjacent hole depth positions to calculate the wave velocity gradient change rate. For example, in the detection of a certain coal mine roadway, the wave velocity gradient mutation zone involves a range of hole depths from 7 meters to 9 meters, wherein the wave velocity gradient at a hole depth of 7 meters is 400 m / (s·m), the wave velocity gradient at a hole depth of 7.5 meters is 600 m / (s·m), the wave velocity gradient at a hole depth of 8 meters is 800 m / (s·m), and so on. The wave velocity gradient change rate is calculated based on the wave velocity gradients at these adjacent positions.

[0075] In the embodiments of the present application, the point-by-point comparison of the wave velocity gradient change rate with a preset surrounding rock fracture development characteristic value, the surrounding rock fracture development characteristic value being determined based on geological survey data of similar roadways, comprises: the preset surrounding rock fracture development characteristic value is determined through statistical analysis based on the collection of geological survey data of similar roadways in the region where the coal mine is located, for example, being set to 1000 m / (s·m). The wave velocity gradient change rates at all points are compared with the characteristic value one by one, such as the wave velocity gradient change rate at a hole depth of 7 meters to 7.5 meters being 400 m / (s·m), which is less than 1000 m / (s·m); the wave velocity gradient change rate at a hole depth of 7.5 meters to 8 meters being 1600 m / (s·m), which is greater than 1000 m / (s·m). 2 2 2 2 2 ​​​​), etc.

[0076] In the embodiments of the present application, when the wave velocity gradient change rate first exceeds the surrounding rock crack development characteristic value, the hole depth position corresponding to the wave velocity gradient change rate is recorded as the inner boundary of the loose circle, including: in the point-by-point comparison process, when it is found that the wave velocity gradient change rate at a certain position first exceeds the surrounding rock crack development characteristic value, the hole depth corresponding to the position is the inner boundary of the loose circle. For example, the wave velocity gradient change rate at the hole depth of 7.5 meters to 8 meters is 1600 m / (s·m 2 ), which first exceeds 1000 m / (s·m 2 ), and the hole depth of 8 meters is recorded as the inner boundary of the loose circle.

[0077] In some embodiments, the wave velocity gradient change rate in the wave velocity gradient mutation zone is extracted, including:

[0078] The wave velocity gradients corresponding to two adjacent hole depth positions in the wave velocity gradient mutation zone are determined.

[0079] The difference between the two adjacent wave velocity gradients is calculated to obtain a wave velocity gradient difference value.

[0080] The distance between the two adjacent hole depth positions is calculated to obtain a hole depth difference value.

[0081] The wave velocity gradient difference value is compared with the hole depth difference value to obtain the wave velocity gradient change rate.

[0082] In the embodiments of the present application, the wave velocity gradients corresponding to two adjacent hole depth positions in the wave velocity gradient mutation zone are determined, including: in the wave velocity gradient mutation zone, two adjacent hole depth positions are selected, for example, the hole depth of 8 meters and the hole depth of 8.5 meters, and the wave velocity gradients corresponding to the two positions are found from the previously calculated wave velocity gradient data. It is assumed that the wave velocity gradient at the hole depth of 8 meters is 800 m / (s·m), and the wave velocity gradient at the hole depth of 8.5 meters is 1200 m / (s·m).

[0083] In the embodiments of the present application, the difference between the two adjacent wave velocity gradients is calculated to obtain a wave velocity gradient difference value, including: the wave velocity gradient at the deeper position of the two adjacent hole depth positions is subtracted from the wave velocity gradient at the shallower position, that is, 1200 m / (s·m) is subtracted from 800 m / (s·m), to obtain a wave velocity gradient difference value of 400 m / (s·m).

[0084] In the embodiments of the present application, the distance between the two adjacent hole depth positions is calculated to obtain a hole depth difference value, including: the distance between the two adjacent hole depth positions is the hole depth difference value. The distance between the hole depth of 8.5 meters and the hole depth of 8 meters is 0.5 meters, and therefore the hole depth difference value is 0.5 meters.

[0085] In the embodiment of the present application, the wave velocity gradient difference value is divided by the hole depth difference value, that is, 400 m / (s·m) is divided by 0.5 m, to obtain a wave velocity gradient change rate of 800 m / (s·m) 2 )。

[0086] In some embodiments, when the wave velocity gradient change rate decreases to the surrounding rock structure stability characteristic value, the outer boundary of the loose circle is marked, including:

[0087] The wave velocity gradient change rate of the wave velocity gradient mutation zone is analyzed along the hole depth direction until the wave velocity gradient change rate decreases to a preset surrounding rock structure stability characteristic value, wherein the surrounding rock structure stability characteristic value is determined based on a statistical value of the acoustic wave velocity gradient of undisturbed surrounding rock.

[0088] The hole depth when the wave velocity gradient change rate decreases to the characteristic value is recorded as the outer boundary of the loose circle.

[0089] In the embodiment of the present application, the wave velocity gradient change rate of the wave velocity gradient mutation zone is analyzed along the hole depth direction until the wave velocity gradient change rate decreases to a preset surrounding rock structure stability characteristic value, wherein the surrounding rock structure stability characteristic value is determined based on a statistical value of the acoustic wave velocity gradient of undisturbed surrounding rock, including: the surrounding rock structure stability characteristic value is determined according to the statistical data of the acoustic wave velocity gradient of surrounding rock not disturbed by roadway excavation, for example, set to 300 m / (s·m) 2 ) and so on. 2 2 2 2 ) and so on.

[0090] In the embodiment of the present application, the hole depth when the wave velocity gradient change rate decreases to the characteristic value is recorded as the outer boundary of the loose circle, including: when the wave velocity gradient change rate decreases to the surrounding rock structure stability characteristic value, the corresponding hole depth position is the outer boundary of the loose circle. For example, when the wave velocity gradient change rate at the hole depth of 18 m decreases to 300 m / (s·m) 2 ), the hole depth of 18 m is recorded as the outer boundary of the loose circle.

[0091] In the embodiment of the present application, step S5 accurately determines the inner boundary and the outer boundary of the loose circle, solving the problem that the traditional method is difficult to accurately distinguish the boundary between the loose zone and the stable zone in a water immersion environment.

[0092] ​​​In the embodiments of the present application, the identified wave velocity gradient mutation zone is taken as the analysis object, and the boundary of the loose circle is determined by calculating and comparing the wave velocity gradient change rate.

[0093] S6. Generating a detection report containing the range of the loose circle according to the inner boundary and the outer boundary.

[0094] In some embodiments, the generating a detection report containing the range of the loose circle according to the inner boundary and the outer boundary comprises:

[0095] calculating the difference in hole depth between the inner boundary and the outer boundary as the thickness of the loose circle;

[0096] generating a detection report containing the range of the loose circle based on the thickness of the loose circle.

[0097] In the embodiments of the present application, the range of the loose circle refers to the area in the surrounding rock from the inner boundary to the outer boundary, and the surrounding rock in this area is loosened due to the influence of the roadway excavation. The thickness of the loose circle is the difference in hole depth between the outer boundary and the inner boundary of the loose circle, which is used to quantify the size of the loose circle. The detection report is a file that systematically organizes and presents the entire detection process and results, and contains key information such as the range and thickness of the loose circle, which provides a basis for engineering decision-making.

[0098] In the embodiments of the present application, calculating the difference in hole depth between the inner boundary and the outer boundary as the thickness of the loose circle comprises: subtracting the hole depth corresponding to the inner boundary of the known loose circle from the hole depth corresponding to the outer boundary to obtain the difference, which is the thickness of the loose circle. For example, in the detection of a certain coal mine roadway, the hole depth corresponding to the inner boundary of the loose circle is determined to be 8 meters, and the hole depth corresponding to the outer boundary is determined to be 18 meters. Therefore, the thickness of the loose circle is 18 meters minus 8 meters, i.e. 10 meters. This calculation process directly reflects the radial extension range of the loose circle in the surrounding rock, and is an important quantitative index for evaluating the loosening degree of the surrounding rock.

[0099] In the embodiments of the present application, generating a detection report containing the range of the loose circle based on the thickness of the loose circle comprises: after obtaining the thickness of the loose circle, organizing the information such as the inner boundary, outer boundary position and thickness of the loose circle to form a detection report. In addition to clearly marking the range of the loose circle as the inner boundary hole depth to the outer boundary hole depth (such as 8 meters to 18 meters) in the report, the report will also contain the methods used in the detection process, key data charts (such as wave velocity-hole depth curve) and analysis and explanation of the results. For example, the report will explain the range of the loose circle obtained by acoustic detection combined with wave velocity gradient analysis, and evaluate the stability of the surrounding rock of the roadway according to the industry standard for stability level (such as thickness greater than 8 meters as “unstable”), to provide specific parameters and suggestions for subsequent support design.

[0100] For example, Figure 2Fig. 1 is a functional module diagram of a water immersion roadway surrounding rock loose circle detection system according to an embodiment of the present application.

[0101] The water immersion roadway surrounding rock loose circle detection system 100 can be installed in an electronic device. According to the functions implemented, the water immersion roadway surrounding rock loose circle detection system 100 can include a slant hole drilling module 101, a water immersion environment construction module 102, an ultrasonic detection module 103, a wave velocity curve analysis module 104, a loose circle boundary determination module 105, and a detection report generation module 106. The modules of the present application can also be referred to as units, which refer to a series of computer program segments that can be executed by an electronic device processor and can complete a fixed function, which are stored in the memory of the electronic device.

[0102] In the present embodiment, the functions of each module / unit are as follows:

[0103] The slant hole drilling module 101 is used to drill a slant hole with a preset small angle depression angle on both sides of the roadway, and the axis of the slant hole forms the preset small angle depression angle with the horizontal plane.

[0104] The water immersion environment construction module 102 is used to inject pressure water into the slant hole until the overflow at the orifice, forming a water immersion saturated surrounding rock coupling environment.

[0105] The ultrasonic detection module 103 is used to move the ultrasonic probe out of the bottom of the slant hole at a preset interval and record the acoustic time data in real time.

[0106] The wave velocity curve analysis module 104 is used to construct a wave velocity-hole depth curve based on the acoustic time data, and identify the wave velocity gradient mutation zone in the curve according to the attenuation characteristics of the surrounding rock fracture to the acoustic wave in the surrounding rock coupling environment.

[0107] The loose circle boundary determination module 105 is used to determine the surrounding rock loose circle boundary based on the wave velocity gradient mutation zone, including: when the wave velocity gradient change rate first exceeds the surrounding rock fracture development characteristic value, marking the inner boundary of the loose circle; when the wave velocity gradient change rate decreases to the surrounding rock structure stability characteristic value, marking the outer boundary of the loose circle.

[0108] The detection report generation module 106 is used to generate a detection report containing the loose circle range according to the inner boundary and the outer boundary.

[0109] In several embodiments provided by the present application, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For example, the division of the modules is only a logical functional division, and there can be another division way when actually implemented.

[0110] The modules described as separate components may or may not be physically separate, and the components displayed as modules may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0111] In addition, each functional module in various embodiments of the application can be integrated in one processing unit, or each unit can exist physically independently, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of hardware plus software functional modules.

[0112] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application.

[0113] The embodiments of the present application can acquire and process related data based on artificial intelligence technology. Among them, artificial intelligence is to use digital computers or machines controlled by digital computers to simulate, extend and expand human intelligence, perceive the environment, obtain knowledge and use knowledge to obtain the best results.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A water immersion roadway surrounding rock loose circle detection method, characterized in that, The method comprises: Drilling an inclined borehole with a preset small angle inclination angle on both sides of the roadway, the axis of the inclined borehole forms the preset small angle inclination angle with the horizontal plane; Injecting pressure water into the inclined borehole until the orifice overflows to form a water-saturated surrounding rock coupling environment; Moving the ultrasonic probe outward from the bottom of the inclined borehole at a preset interval and recording the sound time data in real time; Based on the sound time data, a wave velocity-hole depth curve is constructed, and according to the attenuation characteristics of the surrounding rock fracture to the acoustic wave in the surrounding rock coupling environment, a wave velocity gradient mutation area in the curve is identified; Based on the wave velocity gradient mutation area, the boundary of the roadway surrounding rock loose circle is determined, including: when the wave velocity gradient change rate exceeds the surrounding rock fracture development characteristic value for the first time, the inner boundary of the loose circle is marked; when the wave velocity gradient change rate decreases to the surrounding rock structure stability characteristic value, the outer boundary of the loose circle is marked; According to the inner boundary and the outer boundary, a detection report containing the range of the loose circle is generated.

2. The method according to claim 1, wherein the water immersion tunnel surrounding rock loose circle is detected. The method comprises: Positioning the borehole starting point at the same horizontal height on both sides of the roadway by using a geological drilling machine; Adjusting the angle of the drilling machine drill rod so that the drill rod axis forms a preset small angle inclination angle with the horizontal plane, wherein the direction of the preset small angle inclination angle is towards the excavation direction of the roadway; Starting the drilling machine to drill along the preset small angle inclination angle to a preset hole depth to form an inclined borehole, the hole diameter of the inclined borehole is matched with the outer diameter of the ultrasonic probe.

3. The method according to claim 1, wherein the water immersion tunnel surrounding rock loose circle is detected. The method comprises: Sealingly connecting the water outlet of the high-pressure water pipe to the orifice of the inclined borehole, the high-pressure water pipe is provided with a pressure regulating valve; Opening the pressure regulating valve to inject pressure water into the inclined borehole at a constant pressure, the constant pressure does not exceed the initial stress value of the surrounding rock of the roadway; Continuously injecting water until continuous overflow occurs at the orifice, recording the water injection time and the total water injection amount to form the water-saturated surrounding rock coupling environment.

4. The method according to claim 1, wherein the water immersion tunnel surrounding rock loose circle is detected. The method comprises: Fixing the ultrasonic transmitting probe and the receiving probe to the front end of the same detection rod, the length of the detection rod is not less than the hole depth of the inclined borehole; Moving the detection rod carrying the probes outward step by step from the bottom of the inclined borehole at the preset interval; Collecting the sound time data of the probes at each position in real time by the ultrasonic detector to generate an original data set containing the corresponding relationship between the hole depth and the sound time.

5. The water inrush roadway surrounding rock loose circle detection method of claim 1, characterized in that, The method comprises: Based on the sound time data, the sound wave propagation speed at each hole depth position is calculated, which is the ratio of the probe interval to the sound time; Drawing a wave velocity-hole depth curve with hole depth as the horizontal axis and wave velocity as the vertical axis; Calculating the first derivative of the curve at each point to obtain the wave velocity gradient, and marking it as a wave velocity gradient mutation area when the absolute value of the gradient value exceeds the preset gradient threshold.

6. The water inrush roadway surrounding rock loose circle detection method of claim 1, characterized in that, The method comprises: When the wave velocity gradient change rate exceeds the surrounding rock fracture development characteristic value for the first time, the inner boundary of the loose circle is marked, including: extracting a wave velocity gradient change rate in the wave velocity gradient mutation zone; point-by-point comparing the wave velocity gradient change rate with a preset surrounding rock crack development characteristic value, the surrounding rock crack development characteristic value being determined based on geological survey data of similar roadways; when the wave velocity gradient change rate first exceeds the surrounding rock crack development characteristic value, recording a hole depth position corresponding to the wave velocity gradient change rate as an inner boundary of the loose circle.

7. The water inrush roadway surrounding rock loose circle detection method of claim 6, wherein, The extracting of the wave velocity gradient change rate in the wave velocity gradient mutation zone comprises: determining wave velocity gradients corresponding to two adjacent hole depth positions in the wave velocity gradient mutation zone; calculating a difference value of the two adjacent wave velocity gradients to obtain a wave velocity gradient difference value; calculating a distance between the two adjacent hole depth positions to obtain a hole depth difference value; comparing the wave velocity gradient difference value with the hole depth difference value to obtain the wave velocity gradient change rate.

8. The water inrush roadway surrounding rock loose circle detection method of claim 1, characterized in that, The marking of the outer boundary of the loose circle when the wave velocity gradient change rate decreases to the surrounding rock structure stability characteristic value comprises: analyzing the wave velocity gradient change rate of the wave velocity gradient mutation zone in the hole depth direction until the wave velocity gradient change rate decreases to a preset surrounding rock structure stability characteristic value, wherein the surrounding rock structure stability characteristic value is determined based on a statistical value of acoustic wave velocity gradients of undisturbed surrounding rock; recording a hole depth at which the wave velocity gradient change rate decreases to the characteristic value as the outer boundary of the loose circle.

9. The water inrush roadway surrounding rock loose circle detection method of claim 1, characterized in that, The generation of a detection report containing a range of the loose circle according to the inner boundary and the outer boundary comprises: calculating a hole depth difference value between the inner boundary and the outer boundary as a thickness of the loose circle; querying a preset surrounding rock stability level reference table based on the thickness of the loose circle, the reference table containing stability levels corresponding to different thickness intervals; generating a detection report containing a range, a thickness and a stability level of the loose circle.

10. A water inrush roadway surrounding rock loose circle detection system, characterized in that, The system comprises: a tilted borehole drilling module configured to drill a tilted borehole with a preset small angle of depression on two sides of a roadway, an axis of the tilted borehole forming the preset small angle of depression with a horizontal plane; a water immersion environment construction module configured to inject pressure water into the tilted borehole until overflow at a borehole opening, forming a water immersion saturated surrounding rock coupled environment; an ultrasonic wave detection module configured to move an ultrasonic wave probe outward from a bottom of the tilted borehole at a preset interval and record acoustic time data in real time; a wave velocity curve analysis module configured to construct a wave velocity-hole depth curve based on the acoustic time data and identify a wave velocity gradient mutation zone in the curve according to an attenuation characteristic of a surrounding rock crack to an acoustic wave in the surrounding rock coupled environment; a loose circle boundary determination module configured to determine boundaries of a roadway surrounding rock loose circle based on the wave velocity gradient mutation zone, comprising: marking an inner boundary of the loose circle when a wave velocity gradient change rate first exceeds a surrounding rock crack development characteristic value and marking an outer boundary of the loose circle when the wave velocity gradient change rate decreases to a surrounding rock structure stability characteristic value; a detection report generation module configured to generate a detection report containing a range of the loose circle according to the inner boundary and the outer boundary.

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