Tunnel face surrounding rock grade prediction method and system based on ultrasonic while drilling

Abstract

The invention belongs to the technical field of rock and soil center survey, and particularly relates to a tunnel face surrounding rock grade prediction method and system based on ultrasonic while drilling, and the method comprises the steps: obtaining ultrasonic while drilling parameters of a tunnel face drilling test; calculating a tunnel face drilling coefficient based on the obtained while-drilling ultrasonic parameters, and constructing a drilling coefficient-surrounding rock grade relation library; and 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 drilling coefficient-surrounding rock grade relation library, and completing the prediction of the surrounding rock grade of the tunnel face based on the ultrasonic while drilling. According to the method, the current tunnel face surrounding rock grade is efficiently and accurately predicted through the drilling parameters, the field data acquisition efficiency is improved, the dependence on the working experience of field operators is avoided, the construction cost is reduced, and engineering disasters are prevented.

Description

Technical Field

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

[0002] The statements in this section merely provide background 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 has a great impact on the quality of the project. Reasonable determination of the surrounding rock grade and full understanding of the tunnel rock quality are important bases for avoiding geological disasters and determining excavation methods and support plans.

[0004] At present, surrounding rock classification is generally determined by field experience and calculated by corresponding formulas. Traditional surrounding rock classification methods mostly rely on the experience of field personnel, and often have problems such as insufficient use of tunnel geological information, resulting in inaccurate rock quality evaluation and time lag, which greatly reduces 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 ultrasonic while drilling. The method can efficiently and accurately predict the current surrounding rock grade of the tunnel face through drilling parameters, improve the efficiency of field data collection, get rid of the dependence on the work experience of field operators, help reduce construction costs, and prevent engineering disasters.

[0006] According to some embodiments, a first solution of the present invention provides a method for predicting the surrounding rock grade of a tunnel face based on ultrasonic drilling, which adopts the following technical solution: A method for predicting surrounding rock grade of tunnel face based on ultrasonic while drilling, comprising: 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.

[0007] As a further technical limitation, 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.

[0008] Furthermore, 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 while drilling and surrounding rock.

[0009] Furthermore, 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 drill pipe speed while drilling.

[0010] Furthermore, under the same drilling conditions, the drilling coefficient K 1 Drilling distance h ,amplitude A , Drill pipe speed while drilling N , drilling pressure P Positively correlated, negatively correlated with speed, simplified drilling coefficient for The drilling conditions include the drill pipe frequency, the contact area between the drill bit and the surrounding rock, and the moment of inertia of the drill pipe.

[0011] As a further technical qualification, 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, which satisfies ; 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.

[0012] According to some embodiments, the second solution of the present invention provides a tunnel face surrounding rock grade prediction system based on while-drilling ultrasound, which adopts the tunnel face surrounding rock grade prediction method based on while-drilling ultrasound provided by the first solution, and adopts the following technical solutions: A tunnel face surrounding rock grade prediction system based on ultrasonic while drilling 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 a variable amplitude rod and the drill rod, and a restoring spring and a bearing sleeve are sleeved at the tail of the drill rod; the excitation piezoelectric ceramic generates mechanical vibration through the reverse electric effect under the excitation of an ultrasonic driving circuit board, the variable amplitude rod amplifies the mechanical vibration, and the free mass block reciprocates between the variable amplitude rod and the drill rod.

[0013] As a further technical limitation, the tunnel face surrounding rock grade prediction system based on ultrasonic while drilling 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 while drilling parameters of the tunnel face drilling test is completed.

[0014] As a further technical limitation, the tunnel face surrounding rock grade prediction system based on ultrasonic drilling 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 set at the bottom of the switch and the indicator light.

[0015] As a further technical limitation, the tunnel face surrounding rock grade prediction system based on ultrasonic drilling 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.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention changes the traditional surrounding rock classification method, realizes efficient rock drilling through the ultrasonic impact rotation system, and significantly improves the data acquisition efficiency; the post-processing module h , drilling speed V , drilling pressure P ,amplitude A , speed N Determine the drilling coefficient of the current face Kand compared with the database to determine the current surrounding rock grade of the face, overcoming the problem of deviation in prediction results caused by human factors, greatly improving construction efficiency and providing a scientific basis for tunnel design and tunnel support.

[0017] The present invention first proposed the drilling coefficient K 2 , the drilling coefficient is clarified K 2 It is only related to the drilling distance, drilling speed, drilling pressure, rotation speed and amplitude. At the same time, a drilling coefficient-surrounding rock grade relationship database was established based on a large amount of drilling data and the normal distribution method. On-site personnel can obtain the current surrounding rock grade of the face in real time based on the drilling parameters, solving the problem of low utilization of geological information. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings in the specification that constitute a part of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments of this embodiment and their descriptions are used to explain this embodiment and do not constitute improper limitations on this embodiment.

[0019] Figure 1 This is a flow chart of a method for predicting surrounding rock grade of a tunnel face based on ultrasonic drilling in the first embodiment of the present invention; Figure 2 This is a flow chart of obtaining parameters while drilling in the first embodiment of the present invention; Figure 3 It is a structural schematic diagram of a tunnel face surrounding rock grade prediction system based on ultrasonic drilling in the second embodiment of the present invention; Figure 4 Schematic diagram of the position structure of the Hall element in the second embodiment of the present invention; Among them, 1. drill rod; 2. impact bearing; 3. bearing sleeve; 4. restoring spring; 5. outer shell; 6. transmission shaft; 7. excitation piezoelectric ceramics; 8. transducer; 9. ultrasonic drive circuit board; 10. indicator light; 11. piezoelectric acceleration sensor; 12. post-processing module; 13. displacement sensor; 14. bead bearing; 15. free mass block; 16. inner shell; 17. amplitude rod; 18. control handle; 19. slewing bearing; 20. slewing motor; 2001. rotor; 2002. stator; 2003. Hall element; 21. switch; 22. handrail; 23. electrical box. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit 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 "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention and should not be understood as limitations on the present invention.

[0024] In the present invention, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meanings of the above terms in the present invention can be determined according to specific circumstances, and they cannot be understood as limitations on the present invention.

[0025] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0026] Embodiment 1 Embodiment 1 of the present invention introduces a method for predicting the surrounding rock grade of a tunnel face based on ultrasonic drilling.

[0027] like Figure 1 A method for predicting the surrounding rock grade of a tunnel face based on ultrasonic drilling is shown, comprising: 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.

[0028] In this embodiment, under the same drilling conditions (frequency, contact area, moment of inertia and other conditions are constant), the drilling coefficient is only related to the drilling distance, drilling speed, amplitude, drilling pressure and rotation speed; a drilling coefficient-surrounding rock grade relationship library is established based on the previous drilling data, and the on-site personnel determine the current face drilling coefficient based on the drilling parameters and predict the current face surrounding rock grade; specifically: In 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, namely: Energy from mechanical force E 1 Mainly due to drilling pressure P Provide, that is: ; ; in, P is the drilling pressure, S is the contact area between the drill bit and the rock, h is the drilling distance, h 0 is the initial distance between the sensor and the rock, h 1 is the distance between the end sensor and the rock.

[0029] Energy generated by ultrasonic vibration E 2 for: ; Where m is the mass of the ultrasonic vibration system, f is the vibration frequency, A is the amplitude.

[0030] Energy from rotational impact E 3 for: ; in, is the moment of inertia, is the angular velocity, N is the rotation speed.

[0031] Therefore, the energy E required to break the rock is the total energy acting on the rock. E ,Right now: .

[0032] Through the total energy E and drilling speed V The ratio of is the drilling coefficient, that is: ; Substitution , we can get: ; That is, under the same drilling conditions (frequency, contact area, and moment of inertia are constant), the drilling coefficient is K 1 Drilling distance h ,amplitude A , speed N , drilling pressure P It is positively correlated with speed and negatively correlated with speed, and the simplified formula is obtained, namely: ; in, K 2 It serves as the basis for building a database of drillability coefficient-surrounding rock grade relationships.

[0033] like Figure 2 The drilling parameters in each surrounding rock level are substituted into the formula , assuming that the drilling coefficient in the i-level surrounding rock is 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 as follows: Average drilling coefficient of surrounding rock of level i for ; Standard Deviation for ; Then the confidence interval of the mean value of the drillability index of surrounding rock of level i is: ; The confidence level is , α is 0.1, then it meets the following conditions: ; Integrate the data of different surrounding rock grades together to form a drilling system-surrounding rock grade database for each surrounding rock grade K 2 .

[0034] This embodiment achieves efficient rock drilling through the ultrasonic impact rotation system, significantly improving data collection efficiency; the post-processing module h , drilling speed V , drilling pressure P ,amplitude A , speed N Determine the drilling coefficient of the current face K, and compared with the database to determine the current surrounding rock grade of the tunnel face, which changed the traditional surrounding rock classification method, overcame the problem of deviation in prediction results caused by human factors, greatly improved construction efficiency, and provided a scientific basis for tunnel design and tunnel support.

[0035] Embodiment 2 The second embodiment of the present invention introduces a tunnel face surrounding rock grade prediction system based on ultrasonic drilling.

[0036] like Figure 3 The tunnel face surrounding rock grade prediction system based on ultrasonic drilling is shown, comprising an electric box 23, a drilling rig, a monitoring module, and a post-processing module 12; wherein the drilling rig comprises a power supply mechanism and a drilling mechanism.

[0037] In this embodiment, the power supply mechanism includes a switch 21, an indicator light 10 and an ultrasonic drive circuit board 9. The switch 21 and the indicator light 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 light 10 to excite the piezoelectric ceramic 7 to generate mechanical vibration and provide a stable and efficient voltage to the transducer 8.

[0038] In this embodiment, if Figure 3 and Figure 4 As shown, the drilling mechanism includes a rotary motor 20, a rotor 2001, a stator 2002, a rotary bearing 19, a transmission shaft 6, a transducer 8, an excitation piezoelectric ceramic 7, a variable amplitude rod 17, a restoring spring 4, a drill rod 1, an impact bearing 2, a ball bearing 14, a bearing sleeve 3, an inner shell 16, an outer shell 5 and a handrail 22.

[0039] In this embodiment, the ultrasonic drive circuit board 9 is connected to the excitation piezoelectric ceramic 7, the electric box 23, the sensor and the post-processing module 12 through a series of lines, and the size of the device is greatly reduced through circuit integration.

[0040] In this embodiment, the rotary motor 20 is located above the inner shell 16 and drives the drill rod 1 to rotate through the transmission shaft 6, which solves the chip removal problem and greatly improves the drilling efficiency.

[0041] In this embodiment, the excitation piezoelectric ceramic 7 generates mechanical vibration under the excitation of the ultrasonic driving circuit board 9, and the amplitude transformer 17 amplifies the mechanical vibration and transmits it to the free mass block 15. The free mass block 15 reciprocates between the drill rod 1 and the amplitude transformer 17, and drives the drill rod 1 to impact the rock at high frequency.

[0042] 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 rod 1, the piezoelectric acceleration sensor 11 monitors the acceleration and amplitude of the drill rod 1, and the Hall element 2003 monitors the rotation speed of the drill rod 1. The post-processing module 12 calculates the drilling coefficient K through 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 current face surrounding rock grade.

[0043] During use, the operator uses the control handle 18 to hold the ultrasonic drill to efficiently drill into the rock, and collects drilling data parameters in real time through various sensors. Under the action of the post-processing module 12, the drilling coefficient is obtained according to the drilling parameters, and is substituted into the relationship library between the drilling coefficient and the surrounding rock grade to predict the current surrounding rock grade of the face.

[0044] This embodiment effectively and accurately predicts the surrounding rock grade of the current face through drilling parameters, thereby improving the efficiency of field data collection, getting rid of the dependence on the work experience of field operators, and helping to reduce construction costs and prevent engineering disasters.

[0045] The detailed steps are the same as those of the method for predicting the surrounding rock grade of a tunnel face based on ultrasonic drilling provided in Example 1, and will not be repeated here.

[0046] The above description is only a preferred embodiment of the present embodiment and is not intended to limit the present embodiment. For those skilled in the art, the present embodiment may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present embodiment shall be included in the protection scope of the present embodiment.

Claims

1. A method for predicting the surrounding rock grade of a tunnel face based on ultrasonic drilling, characterized in that: include: 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.

2. A method for predicting surrounding rock grade of a tunnel face based on ultrasonic drilling as claimed in claim 1, characterized in that: 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.

3. A method for predicting surrounding rock grade of tunnel face based on ultrasonic drilling as claimed in claim 2, characterized in that: The acquired ultrasonic parameters while drilling include at least drilling distance, rotation speed of the drill pipe while drilling, drilling pressure, drilling speed and contact area between the drill bit while drilling and the surrounding rock.

4. A method for predicting surrounding rock grade of tunnel face based on ultrasonic drilling as claimed in claim 3, characterized in that: 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 pipe speed while drilling.

5. A method for predicting surrounding rock grade of tunnel face based on ultrasonic drilling as claimed in claim 4, characterized in that: Under the same drilling conditions, the drilling coefficient K 1 and drilling distance h ,amplitude A , Drill pipe speed while drilling N , drilling pressure P Positively correlated, negatively correlated with speed, simplified drilling coefficient for The drilling conditions include the drill pipe frequency, the contact area between the drill bit and the surrounding rock, and the moment of inertia of the drill pipe.

6. A method for predicting surrounding rock grade of 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, which satisfies ; 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.

7. 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 to 6, 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.

8. A tunnel face surrounding rock grade prediction system based on ultrasonic drilling as claimed in claim 7, 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.

9. The tunnel face surrounding rock grade prediction system based on ultrasonic drilling as claimed in claim 7, 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.

10. The tunnel face surrounding rock grade prediction system based on ultrasonic drilling as claimed in claim 7, 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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