A method and system for predicting the surrounding rock grade of a tunnel face based on ultrasonic while drilling

Abstract

The present invention belongs to the technical field of geotechnical center exploration, and specifically relates to a method and system for predicting the surrounding rock grade of a tunnel face based on ultrasonic while drilling, including: obtaining the ultrasonic while drilling parameters of the tunnel face drilling test; calculating the drilling coefficient of the tunnel face based on the obtained ultrasonic while drilling parameters, and constructing a relationship database between the drilling coefficient and the surrounding rock grade; obtaining the surrounding rock grade of the current tunnel face according to the ultrasonic while drilling parameters of the current tunnel face and the constructed relationship database between the drilling coefficient and the surrounding rock grade, and completing the prediction of the surrounding rock grade of the tunnel face based on ultrasonic while drilling. The present invention efficiently and accurately predicts the surrounding rock grade of the current tunnel face through drilling parameters, improves the efficiency of on-site data collection, gets rid of the dependence on the work experience of on-site operators, helps to reduce construction costs, and prevent engineering disasters.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical center survey, and particularly relates to a method and system for predicting the surrounding rock grade of a tunnel face based on downhole ultrasonic. Background Art

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] During the construction of highway tunnels, the stability of the tunnel surrounding rock greatly affects the project quality. Reasonably determining the surrounding rock grade and fully grasping the tunnel rock mass quality are important bases for avoiding geological disasters and determining the excavation method and support plan.

[0004] Currently, the surrounding rock classification is generally determined through on-site experience and calculated by corresponding formulas. Most traditional surrounding rock classification methods rely on the experience of on-site personnel, often resulting in problems such as insufficient utilization of tunnel geological information, inaccurate evaluation of rock mass quality, and time lag, greatly reducing the construction efficiency. Summary of the Invention

[0005] To solve the above problems, the present invention proposes a method and system for predicting the surrounding rock grade of a tunnel face based on downhole ultrasonic, which can efficiently and accurately predict the surrounding rock grade of the current tunnel face through drilling parameters, improve the efficiency of on-site data collection, get rid of the dependence on the work experience of on-site operators, help reduce construction costs, and prevent engineering disasters.

[0006] According to some embodiments, the first solution of the present invention provides a method for predicting the surrounding rock grade of a tunnel face based on downhole ultrasonic, and adopts the following technical solutions:

[0007] A method for predicting the surrounding rock grade of a tunnel face based on downhole ultrasonic, comprising:

[0008] Obtaining the downhole ultrasonic parameters of the drilling test of the tunnel face;

[0009] Based on the obtained downhole ultrasonic parameters, calculating the drilling coefficient of the tunnel face and constructing a relationship database of drilling coefficient - surrounding rock grade;

[0010] According to the current downhole ultrasonic parameters of the tunnel face and the constructed relationship database of drilling coefficient - surrounding rock grade, obtaining the surrounding rock grade of the current tunnel face and completing the prediction of the surrounding rock grade of the tunnel face based on downhole ultrasonic.

[0011] As a further technical limitation, based on ultrasonic-assisted rotary impact rock breaking, the energy required for rock breaking includes mechanical energy, ultrasonic vibration energy, and rotary impact energy.

[0012] Further, the obtained ultrasonic parameters while drilling at least include the drilling distance, the rotation speed of the drill pipe while drilling, the drilling pressure, the drilling speed, and the contact area between the drill bit while drilling and the surrounding rock.

[0013] Further, the tunnel face drilling coefficient is related to the energy required for rock breaking and the drilling speed , that is ; where is the mechanical force energy, is the ultrasonic vibration energy, is the rotary impact energy, P is the drilling pressure, S is the contact area between the drill bit and the rock, h is the drilling distance, m is the mass of the ultrasonic vibration system, f is the vibration frequency, A is the amplitude, I is the moment of inertia, N is the rotation speed of the drill pipe while drilling.

[0014] Further, under the same drilling conditions, the drilling coefficient K 1 is positively correlated with the drilling distance h , the amplitude A , the rotation speed of the drill pipe while drilling N , the drilling pressure P , and is negatively correlated with the speed. The simplified drilling coefficient is ; The drilling conditions include the frequency of the drill pipe while drilling, the contact area between the drill bit while drilling and the surrounding rock, and the moment of inertia of the drill pipe while drilling.

[0015] As a further technical limitation, assume that in i grade surrounding rock, the drilling coefficient K 2 is K 21 、K 22 …K 2n , use the normal distribution method to screen the data. The screened data will be used as the drillability coefficient - surrounding rock grade relationship database for this grade of surrounding rock. The screening process is as follows: i The average value of the drilling coefficient in grade surrounding rock is ; The standard deviation is: i Then the confidence interval of the average value of the drillability index in grade surrounding rock is: ; where the confidence level is ​​Integrate the data of different surrounding rock grades together to form a drilling coefficient - surrounding rock grade database for each surrounding rock grade, and complete the construction of the relationship database of drilling coefficient - surrounding rock grade.

[0016] According to some embodiments, the second solution of the present invention provides a prediction system for the surrounding rock grade of a tunnel face based on ultrasonic while drilling, which adopts the method for predicting the surrounding rock grade of a tunnel face based on ultrasonic while drilling provided by the first solution, and adopts the following technical solutions:

[0017] A prediction system for the surrounding rock grade of a tunnel face based on ultrasonic while drilling includes a drilling mechanism. In the drilling mechanism, a transmission shaft and a drill pipe are fixedly connected; a rotary motor is located above the inner shell and connected to the transmission shaft for driving the transmission shaft to rotate the drill pipe; a piezoelectric transducer and a free mass block are arranged on the periphery of the transmission shaft, the free mass block is arranged between the horn and the drill pipe, and a recovery spring and a bearing sleeve are sleeved on the tail of the drill pipe; the exciting piezoelectric ceramic generates mechanical vibration through the inverse piezoelectric effect under the excitation of the ultrasonic driving circuit board, the horn amplifies the mechanical vibration, and the free mass block reciprocates between the horn and the drill pipe.

[0018] As a further technical limitation, the prediction system for the surrounding rock grade of a tunnel face based on ultrasonic while drilling further includes a monitoring module. The monitoring module includes a displacement sensor, a piezoelectric acceleration sensor and a Hall element; the displacement sensor monitors the drilling distance of the drill pipe, calculates the drilling speed according to the displacement and time, the piezoelectric acceleration sensor monitors the acceleration and amplitude of the drill pipe, calculates the drilling pressure according to the acceleration and in combination with Newton's law, and combines the Hall element to monitor the rotation speed of the drill pipe; to obtain the ultrasonic while drilling parameters for the tunnel face drilling test.

[0019] As a further technical limitation, the prediction system for the surrounding rock grade of a tunnel face based on ultrasonic while drilling further includes a power supply mechanism. The power supply mechanism includes a switch, an indicator light and an ultrasonic driving circuit board. The switch and the indicator light are arranged side by side, and the ultrasonic driving circuit board is arranged at the bottom of the switch and the indicator light.

[0020] As a further technical limitation, the prediction system for the surrounding rock grade of a tunnel face based on ultrasonic while drilling further includes a post - processing module; the post - processing module calculates the current drilling coefficient of the tunnel face through the drilling distance, drilling speed, drilling pressure, amplitude and rotation speed collected on site, and substitutes the obtained current drilling coefficient of the tunnel face into the constructed relationship database of drilling coefficient - surrounding rock grade to predict the surrounding rock grade of the current tunnel face.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The present invention changes the traditional surrounding rock classification method, realizes efficient rock drilling through an ultrasonic impact rotation system, and significantly improves the data acquisition efficiency; the post-processing module determines the drilling coefficient h of the current tunnel face according to the drilling distance V , drilling speed P , drilling pressure A , amplitude N , and rotational speed K , and compares it with the database to determine the surrounding rock grade of the current tunnel face, overcomes the problem of deviation in prediction results caused by human factors, greatly improves the construction efficiency, and provides a scientific basis for tunnel design and tunnel support.

[0023] In the present invention, the drilling coefficient K is first proposed, and it is clarified that the drilling coefficient K is only related to the drilling distance, drilling speed, drilling pressure, rotational speed, and amplitude; at the same time, a relationship database between the drilling coefficient and the surrounding rock grade is established based on a large amount of drilling data and the normal distribution method, and on-site personnel can obtain the surrounding rock grade of the current tunnel face in real time according to the parameters while drilling, solving the problem of low utilization rate of geological information. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings forming a part of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions thereof of this embodiment are used to explain this embodiment and do not constitute an improper limitation to this embodiment.

[0025] Figure 1 is a flowchart of the method for predicting the surrounding rock grade of a tunnel face based on ultrasonic while drilling in Embodiment 1 of the present invention;

[0026] Figure 2 is a flowchart of obtaining the parameters while drilling in Embodiment 1 of the present invention;

[0027] Figure 3 is a schematic structural diagram of the system for predicting the surrounding rock grade of a tunnel face based on ultrasonic while drilling in Embodiment 2 of the present invention;

[0028] Figure 4 is a schematic position structure diagram of the Hall element in Embodiment 2 of the present invention;

[0029] Among them, 1. drill pipe; 2. impact bearing; 3. bearing sleeve; 4. restoring spring; 5. housing; 6. transmission shaft; 7. exciting piezoelectric ceramic; 8. transducer; 9. ultrasonic drive circuit board; 10. indicator light; 11. piezoelectric acceleration sensor; 12. post-processing module; 13. displacement sensor; 14. precision ball bearing; 15. free mass block; 16. inner housing; 17. horn; 18. control handle; 19. slewing bearing; 20. slewing motor; 2001. rotor; 2002. stator; 2003. Hall element; 21. switch; 22. handrail; 23. electrical box. Specific Embodiment

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0033] In the present invention, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only relationship terms determined for the convenience of describing the structural relationship of each component or element of the present invention and do not specifically refer to any component or element of the present invention. It should not be construed as a limitation of the present invention.

[0034] In the present invention, terms such as "fixed connection", "connected", "connected" should be understood in a broad sense, which may mean a fixed connection, an integral connection or a detachable connection; it may be directly connected or indirectly connected through an intermediate medium. For those skilled in the relevant scientific research or technology in this field, the specific meaning of the above terms in the present invention can be determined according to specific circumstances and should not be construed as a limitation of the present invention.

[0035] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0036] Embodiment 1

[0037] Embodiment 1 of the present invention introduces a method for predicting the surrounding rock grade of a tunnel face based on downhole ultrasonic waves.

[0038] As Figure 1 shown, a method for predicting the surrounding rock grade of a tunnel face based on downhole ultrasonic waves includes:

[0039] Obtain the downhole ultrasonic parameters of the tunneling test of the tunnel face;

[0040] Based on the obtained downhole ultrasonic parameters, calculate the tunneling coefficient of the tunnel face and construct a relationship database of tunneling coefficient - surrounding rock grade;

[0041] According to the current downhole ultrasonic parameters of the tunnel face and the constructed relationship database of tunneling coefficient - surrounding rock grade, obtain the surrounding rock grade of the current tunnel face and complete the prediction of the surrounding rock grade of the tunnel face based on downhole ultrasonic waves.

[0042] In this embodiment, under the same tunneling conditions (certain conditions such as frequency, contact area, moment of inertia, etc.), the tunneling coefficient is only related to the tunneling distance, tunneling speed, amplitude, tunneling pressure, and rotational speed; a relationship database of tunneling coefficient - surrounding rock grade is established based on the previous tunneling data, and on-site personnel determine the current tunneling coefficient of the tunnel face according to the downhole parameters and predict the surrounding rock grade of the current tunnel face; specifically:

[0043] During the process of ultrasonic - assisted rotary impact rock breaking, the energy required for rock breaking is mainly generated by mechanical force, ultrasonic vibration, and rotary impact, that is:

[0044] The energy generated by mechanical force E 1 is mainly provided by the drilling pressure P That is:

[0045] ;

[0046] ;

[0047] Among them, P is the drilling pressure, S is the contact area between the drill bit and the rock, h is the tunneling distance, h 0 is the initial distance from the sensor to the rock, h 1 is the final distance from the sensor to the rock.

[0048] The energy generated by ultrasonic vibration E 2 is:

[0049] ;

[0050] Among them, m is the mass of the ultrasonic vibration system, f is the vibration frequency, A is the amplitude.

[0051] Energy generated by rotary impact E 3 is:

[0052] ;

[0053] Among them, is the moment of inertia, is the angular velocity, N is the rotational speed.

[0054] Therefore, the energy E required for rock breaking is the total energy acting on the rock E , that is:

[0055] .

[0056] Through the ratio of the total energy E and the drilling speed V , the drilling coefficient is obtained, that is:

[0057] ;

[0058] Substitute , and we can get:

[0059] ;

[0060] That is, under the same drilling conditions (constant frequency, contact area, moment of inertia), the drilling coefficient K 1 is positively correlated with the drilling distance h , the amplitude A , the rotational speed N , and the drilling pressure P , and negatively correlated with the speed, and the simplified formula is obtained, that is:

[0061] ;

[0062] Among them, K 2 is used as the basis for building the drillability coefficient - surrounding rock grade relationship database.

[0063] As Figure 2 shown, conduct on-site drilling experiments. Substitute the drilling parameters in each surrounding rock level into the formula . Assume that the drilling coefficient in the i-level surrounding rock is K 21 、K 22 …K 2n . Use the normal distribution method to screen the data. The screened data will be used as the drillability coefficient - surrounding rock grade relationship database for this level of surrounding rock. The screening process is as follows:

[0064] Mean value of drilling coefficient of i-level surrounding rock is ;

[0065] Standard deviation is ;

[0066] Then the confidence interval of the mean drillability index of grade - i surrounding rock is:

[0067] ;

[0068] Wherein, the confidence level is , taking α = 0.1, then it conforms to:

[0069] ;

[0070] Integrate the data of different surrounding - rock grades together to form a drilling coefficient - surrounding - rock grade database for each surrounding - rock grade K 2

[0071] In this embodiment, the ultrasonic impact rotation system realizes efficient rock drilling, significantly improving the data - collection efficiency; the post - processing module determines the drilling coefficient of the current tunnel face according to the h drilling distance V drilling speed P drilling pressure A amplitude N rotation speed K , and compares it with the database to determine the surrounding - rock grade of the current tunnel face, changing the traditional surrounding - rock classification method, overcoming the problem of deviation in prediction results caused by human factors, greatly improving the construction efficiency, and providing a scientific basis for tunnel design and tunnel support.

[0072] Embodiment Two

[0073] Embodiment Two of the present invention introduces a tunnel - face surrounding - rock grade prediction system based on ultrasonic - while - drilling.

[0074] As Figure 3 shown, a tunnel - face surrounding - rock grade prediction system based on ultrasonic - while - drilling includes an electrical box 23, a drilling rig, a monitoring module, and a post - processing module 12; wherein, the drilling rig includes a power - supply mechanism and a drilling mechanism.

[0075] In this embodiment, the power - supply mechanism includes a switch 21, an indicator lamp 10, and an ultrasonic - drive circuit board 9. The switch 21 and the indicator lamp 10 are arranged side by side, and the ultrasonic - drive circuit board 9 is arranged at the bottom of the switch 21 and the indicator lamp 10, exciting the piezoelectric ceramic 7 to generate mechanical vibration and providing a stable and efficient voltage for the transducer 8 at the same time.

[0076] In this embodiment, as Figure 3 and Figure 4As shown in the figure, the drilling mechanism includes a rotary motor 20, a rotor 2001, a stator 2002, a slewing bearing 19, a transmission shaft 6, a transducer 8, an exciting piezoelectric ceramic 7, a horn 17, a restoring spring 4, a drill pipe 1, an impact bearing 2, a precision ball bearing 14, a bearing sleeve 3, an inner shell 16, an outer shell 5, and a handrail 22.

[0077] In this embodiment, the ultrasonic drive circuit board 9 is connected to the exciting piezoelectric ceramic 7, the electric box 23, the sensor, and the post-processing module 12 through a series of circuits. The volume of the equipment is greatly reduced through circuit integration.

[0078] In this embodiment, the rotary motor 20 is located above the inner shell 16 and drives the drill pipe 1 to rotate through the transmission shaft 6, solving the problem of chip removal and greatly improving the drilling efficiency.

[0079] In this embodiment, the exciting piezoelectric ceramic 7 generates mechanical vibration under the excitation of the ultrasonic drive circuit board 9. The horn 17 amplifies the mechanical vibration and transmits it to the free mass block 15. The free mass block 15 reciprocates between the drill pipe 1 and the horn 17, driving the drill pipe 1 to impact the rock at high frequency.

[0080] The monitoring module in this embodiment includes a displacement sensor 13, a piezoelectric acceleration sensor 11, and a Hall element 2003. The displacement sensor 13 monitors the drilling distance of the drill pipe 1. The piezoelectric acceleration sensor 11 monitors the acceleration and amplitude of the drill pipe 1. The Hall element 2003 monitors the rotation speed of the drill pipe 1. The post-processing module 12 calculates the drilling coefficient K based on the drilling distance h, drilling speed V, drilling pressure P, amplitude A, and rotation speed N, and substitutes it into the database for comparison to predict the surrounding rock grade of the current tunnel face.

[0081] During the use process, the operator holds the ultrasonic drill through the control handle 18 to drill the rock efficiently, and real-time collects the drilling data parameters through various sensors set. Under the action of the post-processing module 12, the drilling coefficient is obtained according to the parameters while drilling, and is substituted into the relationship database between the drilling coefficient and the surrounding rock grade to predict the surrounding rock grade of the current tunnel face.

[0082] This embodiment efficiently and accurately predicts the surrounding rock grade of the current tunnel face through drilling parameters, improves the efficiency of on-site data collection, gets rid of the dependence on the work experience of on-site operators, and helps to reduce construction costs and prevent engineering disasters.

[0083] The detailed steps are the same as those provided in Embodiment 1 for a method for predicting the surrounding rock grade of a tunnel face based on ultrasonic while drilling, and will not be elaborated here.

[0084] The above are only the preferred embodiments of this embodiment and are not intended to limit this embodiment. For those skilled in the art, various changes and modifications can be made to this embodiment. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this embodiment shall be included within the protection scope of this embodiment.

Claims

1. A method for predicting the surrounding rock grade of a tunnel face based on ultrasonic drilling, characterized in that: Use ultrasonic impact rotary system to drill rock, determine the drilling coefficient of the current face according to the drilling distance, drilling speed, drilling pressure, amplitude and rotation speed, and determine the surrounding rock grade of the current face in combination with the database, including: Obtain ultrasonic parameters while drilling for tunnel face drilling test; Based on the acquired ultrasonic parameters while drilling, the drilling coefficient of the tunnel face is calculated, and a relationship database between drilling coefficient and surrounding rock grade is constructed; According to the ultrasonic drilling parameters of the current tunnel face and the constructed drilling coefficient-surrounding rock grade relationship library, the surrounding rock grade of the current tunnel face is obtained, and the surrounding rock grade prediction of the tunnel face based on ultrasonic drilling is completed; Based on ultrasonic-assisted rotary impact rock breaking, the energy required for rock breaking includes mechanical force energy, ultrasonic vibration energy and rotary impact energy; The acquired ultrasonic parameters while drilling include at least drilling distance, drilling rod rotation speed while drilling, drilling pressure, drilling speed and contact area between the drilling bit and surrounding rock; The tunnel face drilling coefficient Energy required to break rock and drilling speed The ratio of is related, that is ;in, is the mechanical energy, is the ultrasonic vibration energy, is the rotational impact energy, P is the drilling pressure, S is the contact area between the drill bit and the rock, h is the drilling distance, m is the mass of the ultrasonic vibration system, f is the vibration frequency, A is the amplitude, I is the moment of inertia, N is the drilling rod speed while drilling; Drilling coefficient K 1 and drilling distance h ,amplitude A , Drill pipe speed while drilling N , drilling pressure P Positively correlated with drilling speed Negatively correlated, simplified drilling coefficient for The drilling conditions include the drilling rod frequency, the contact area between the drilling bit and the surrounding rock, and the drilling rod moment of inertia; The drilling distance is obtained by monitoring the displacement sensor, the drilling speed is calculated according to the displacement and time, the acceleration and amplitude of the drill rod are monitored based on the piezoelectric acceleration sensor, the drilling pressure is calculated according to the acceleration and Newton's law, and the drill rod speed is monitored in combination with the Hall element to complete the acquisition of the ultrasonic parameters while drilling of the tunnel face drilling test.

2. A method for predicting surrounding rock grade of a tunnel face based on ultrasonic drilling as claimed in claim 1, characterized in that: Assume that i Drilling coefficient in surrounding rock K 2 for K 21 、K 22 …K 2n , use the normal distribution method to filter the data, and the filtered data will be used as the surrounding rock drillability coefficient-surrounding rock grade relationship library. The screening process is: i Average value of surrounding rock drilling coefficient for ; Standard deviation for: ;but i The confidence interval of the mean value of the drillability index of the surrounding rock is: ; where the confidence level is , α is 0.1, then it meets ; Integrate the data of different surrounding rock grades together to form a drilling coefficient-surrounding rock grade database under each surrounding rock grade, and complete the construction of the drilling coefficient-surrounding rock grade relationship library.

3. A tunnel face surrounding rock grade prediction system based on ultrasonic while drilling, which adopts the tunnel face surrounding rock grade prediction method based on ultrasonic while drilling as described in any one of claims 1-2, characterized in that: It comprises a drilling mechanism, in which a transmission shaft and a drill rod are fixedly connected; a rotary motor is located above an inner shell and connected to the transmission shaft, and is used to drive the transmission shaft to rotate the drill rod; a piezoelectric transducer and a free mass block are arranged on the periphery of the transmission shaft, and the free mass block is arranged between the amplitude variable rod and the drill rod, and a restoring spring and a bearing sleeve are sleeved at the tail of the drill rod; the excited piezoelectric ceramic generates mechanical vibration through the reverse electric effect under the excitation of an ultrasonic driving circuit board, the amplitude variable rod amplifies the mechanical vibration, and the free mass block reciprocates between the amplitude variable rod and the drill rod.

4. A tunnel face surrounding rock grade prediction system based on ultrasonic drilling as claimed in claim 3, characterized in that: It also includes a monitoring module, which includes a displacement sensor, a piezoelectric acceleration sensor and a Hall element; the displacement sensor monitors the drilling distance of the drill rod and calculates the drilling speed according to the displacement and time, the piezoelectric acceleration sensor monitors the acceleration and amplitude of the drill rod, calculates the drilling pressure according to the acceleration and combined with Newton's law, and monitors the drill rod rotation speed in combination with the Hall element; the acquisition of ultrasonic parameters while drilling the tunnel face drilling test is completed.

5. The tunnel face surrounding rock grade prediction system based on ultrasonic drilling as claimed in claim 3, characterized in that: It also includes a power supply mechanism, which includes a switch, an indicator light and an ultrasonic drive circuit board. The switch and the indicator light are arranged side by side, and the ultrasonic drive circuit board is arranged at the bottom of the switch and the indicator light.

6. A tunnel face surrounding rock grade prediction system based on ultrasonic drilling as claimed in claim 3, characterized in that: It also includes a post-processing module; the post-processing module calculates the current face drilling coefficient through the drilling distance, drilling speed, drilling pressure, amplitude and rotation speed collected on site, substitutes the obtained current face drilling coefficient into the constructed drilling coefficient-surrounding rock grade relationship library, and predicts the current face surrounding rock grade.

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