In-borehole and out-borehole integrated while-drilling testing equipment and method for strength of deep rock mass

Abstract

In-borehole and out-borehole integrated while-drilling testing equipment for the strength of deep rock mass, comprising a drilling rig (1), an out-borehole drilling parameter testing unit (2), a drill pipe (3), an in-borehole rock strength testing unit (4), a borehole-surface seismic geophone (5), a laser rangefinder (6), a control processing unit (7), and an external drilling device (8). By means of while-drilling tests conducted in the borehole, outside the borehole and at the borehole surface, the discrete rock strength, continuous rock strength, longitudinal wave velocity of rock mass and identification of rock mass structural planes are respectively implemented; and rock mass strength parameters are calculated on the basis of the rock mass structural planes and rock strength information. The present invention can be used for while-drilling measurement of the actual strength parameters of rock mass penetrated by a drill bit, thus being conducive to improving the accuracy of deep underground engineering investigation and providing reliable geological data for engineering disaster risk assessment and support design and construction. The present invention also relates to an in-borehole and out-borehole integrated while-drilling testing method for the strength of deep rock mass.

Description

Equipment and methods for combined internal and external drilling testing of deep rock mass strength Technical Field

[0001] This invention relates to the field of rock mass exploration technology, and in particular to a combined drilling test equipment for deep rock mass strength inside and outside the borehole, and a combined drilling test method for deep rock mass strength inside and outside the borehole. Background Technology

[0002] In various fields such as mining engineering, water conservancy and water conservancy construction, tunnel transportation, and slope engineering, rock is the primary research object, and in-situ identification of rock types, structural characteristics, and rock mass quality evaluation are crucial. These tasks are necessary steps in construction scheme selection, structural design, and slope support. However, due to the lack of sufficient geological structure and rock mass parameters in many projects, delays in construction period, economic losses, and even dynamic disasters such as rock bursts and collapses may occur, causing significant losses. Therefore, seeking safe, economical, and efficient methods for obtaining rock mass characteristics has always been a goal pursued by geotechnical engineers.

[0003] Considering that drilling is involved in various geotechnical engineering projects, some scholars have proposed drilling methods based on measurement while drilling technology. This method monitors, records and extracts effective information during the drilling process to make a preliminary judgment on the structure of the drilled strata and the properties of the rock mass. It effectively solves the problems of difficult core sampling, poor timeliness and limited application scenarios of traditional exploration methods, and has therefore received widespread attention.

[0004] For example, Chinese invention patent application CN116624137A discloses a method and related equipment for processing data while drilling in deep rock masses. The method includes acquiring the torque, pressure, rotational speed, and drilling speed of the drill pipe during drilling into deep rock masses; performing median filtering on the torque, pressure, rotational speed, and drilling speed to obtain filtered torque, filtered pressure, filtered rotational speed, and filtered drilling speed; determining the test rock strength index of the deep rock mass based on the filtered torque, filtered pressure, filtered rotational speed, and filtered drilling speed; and determining the uniaxial compressive strength of the deep rock mass based on the standard uniaxial compressive strength, the standard rock strength index, and the test rock strength index. This allows for the determination of the uniaxial compressive strength of deep rock masses through measurements taken while drilling into them.

[0005] For example, Chinese invention patent application CN117908118A discloses a method and related equipment for identifying rock discontinuities based on seismic wakes during drilling. The method includes acquiring seismic wave signals generated during the drilling process of the drill pipe into the rock mass to be identified, and determining a first wake signal and a second wake signal at a preset source spacing from the seismic wave signals; determining the propagation velocity of the seismic wake in the local rock mass corresponding to the preset source spacing based on the first wake signal and the second wake signal; and identifying the discontinuities of the rock mass to be identified based on the propagation velocity. By analyzing the wake, the propagation velocity of the seismic wake in the local rock mass can be accurately determined, thereby accurately identifying the discontinuities of the rock mass through this propagation velocity.

[0006] Currently, research on rock strength testing while drilling, including the aforementioned patent applications, mainly obtains drilling parameters based on monitoring of drilling rig oil pressure. It lacks direct measurement of drilling parameters and usually cannot perform testing while drilling. It can only measure rock strength parameters at discrete points, and the test results obtained are only rock mechanical parameters. It is usually impossible to accurately investigate the mechanical parameters of the rock mass, resulting in low reliability of the test results for rock mass characteristics. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a deep rock mass strength test equipment that can accurately investigate the mechanical parameters of rock mass both inside and outside the borehole.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a combined drilling and testing equipment for deep rock mass strength inside and outside the borehole, including a drilling rig, a drilling parameter testing unit outside the borehole, a drill rod, a rock strength testing unit inside the borehole, a seismic wave detector on the borehole surface, a laser rangefinder, a control and processing unit, and an external drilling device;

[0009] The external drilling parameter testing unit is connected between the drilling rig and the drill rod, the internal rock strength testing unit is connected between the drill rod and the external drilling device, the surface seismic detector is set on the drilling free surface, and the laser rangefinder is installed on the drilling rig; the drilling rig, the external drilling parameter testing unit, the internal rock strength testing unit, the surface seismic detector, and the laser rangefinder are all communicatively connected to the control and processing unit.

[0010] As an improvement to the above scheme: the in-hole rock strength testing unit includes an in-hole testing section, a hydraulic probe device, a distance counter, and a pressure counter;

[0011] The in-hole test section has a rod-shaped structure and is connected between the drill rod and the external drilling device;

[0012] The hydraulic probe device has a drive end and a probe end. The drive end of the hydraulic probe device is fixed inside the test section inside the hole, and the probe end of the hydraulic probe device extends to the outside of the test section inside the hole. The drive end of the hydraulic probe device is used to drive the probe end of the hydraulic probe device to move in a direction perpendicular to the central axis of the test section inside the hole.

[0013] The distance counter and pressure counter are fixed on the test section inside the hole and are both connected to the probe end of the hydraulic probe device.

[0014] The hydraulic probe device, distance counter, and pressure counter are all communicatively connected to the control processing unit.

[0015] As an improvement to the above solution: the external drilling parameter testing unit includes an external testing section, a pressure-torque composite sensor, an acceleration sensor, an inclination sensor, and a rotation speed sensor;

[0016] The external test section has a rod-shaped structure and is connected between the drilling rig and the drill rod.

[0017] The pressure-torque composite sensor, acceleration sensor, tilt sensor, and speed sensor are all mounted on the outer wall of the test section outside the hole, and are all communicatively connected to the control processing unit.

[0018] This invention also discloses a method for conducting combined internal and external drilling tests of deep rock mass strength using the aforementioned combined internal and external drilling testing equipment, comprising the following steps:

[0019] S1. Install the combined inside and outside drilling test equipment for the strength of deep rock mass. After installation, start the drilling rig and drill at the free face.

[0020] S2. Measure the drilling depth of the borehole in real time using a laser rangefinder, and obtain a time-drilling depth curve based on the drilling depth;

[0021] S3. Rock strength information at discrete points inside the borehole is obtained by measuring the rock strength testing unit inside the borehole.

[0022] S4. The external drilling parameter information is obtained in real time by measuring the external drilling parameter test unit. Combined with the time-drilling depth curve obtained in step S2, the rock strength information and the external drilling parameter information corresponding to the drilling depth of each single point in the discrete points in the hole are used to form a training set. Based on the training set, a drilling intelligent inversion model of rock mechanical parameters is constructed by using a BP neural network. The drilling intelligent inversion model is trained to obtain a training model. Based on the training model, the rock strength is continuously inverted under the calibration of rock strength information to obtain continuous rock compressive strength.

[0023] S5. Real-time recording of seismic wave signals generated during drilling and rock breaking using a borehole surface seismic wave detector, and identification of rock mass structural surfaces based on the seismic wave signals;

[0024] S6. The rock mass compressive strength is calculated based on the rock compressive strength obtained in step S4 and the rock structural surface obtained in step S5.

[0025] As an improvement to the above scheme: In step S3, when measuring the rock strength information of discrete points inside the borehole using the borehole rock strength testing unit, the following steps are performed:

[0026] S3-1. When the drilling depth increases by 1 to 2 m, stop drilling and drive the probe end of the hydraulic probe device to extend from the test section inside the hole. During the extension of the probe end, measure the displacement value of the probe end by the distance counter and the pressure value of the probe end by the pressure counter. Based on the displacement value and pressure value, obtain the test borehole wall pressure-deformation displacement curve at a single point. Then, based on the test borehole wall pressure-deformation displacement curve at a single point, obtain the elastic modulus of the single point and the compressive strength of the rock inside the hole.

[0027] S3-2. After the displacement and pressure values ​​are measured, the probe end of the hydraulic probe device is driven to retract into the test section inside the hole through the drive end of the hydraulic probe device, and the drilling machine is started to continue drilling. Step S3-1 is repeated to obtain the elastic modulus of multiple single points and the compressive strength of the rock inside the hole at multiple single points. Finally, the elastic modulus of multiple single points and the compressive strength of the rock inside the hole at multiple single points are combined to obtain the rock strength information of discrete points inside the hole.

[0028] As an improvement to the above scheme: In step S5, the identification of rock mass structural surfaces based on seismic wave signals is performed according to the following steps:

[0029] S5-1. Perform interferometric analysis on two adjacent seismic wave signals with a source movement distance of d. Take one of the two seismic wave signals as the reference signal and the other seismic wave signal as the disturbance signal. Calculate the correlation coefficient R between the reference signal and the disturbance signal according to formula (1).

[0030] In equation (1), A(t) represents the information without disturbance in the reference channel, B(t[1+∈]) represents the information with disturbance in the disturbed channel, t represents the drilling time, and t1 and t2 represent the time windows corresponding to the signals without disturbance in the reference channel and the signals with disturbance in the disturbed channel.

[0031] S5-2. The variance is calculated based on the correlation coefficient R obtained in equation (1) and equation (2).

[0032] In equation (2), To record the main mean square frequencies in the waveform;

[0033] S5-3, Based on the variance obtained in equation (2) The longitudinal wave velocity v of the rock mass along the borehole depth direction is calculated using equation (3);

[0034] S5-4. Identify rock mass structural surfaces based on the obtained longitudinal wave velocity v.

[0035] As an improvement to the above scheme: In step S6, the rock mass compressive strength σ is calculated according to equation (4). c ;

[0036] In equation (4), σ ci S represents the rock compressive strength, and S is a parameter obtained from the RMR engineering rock mass evaluation system and rock mass structure surface.

[0037] As an improvement to the above scheme, the evaluation indicators of the RMR engineering rock mass evaluation system include the uniaxial compressive strength of rock blocks, rock quality indicators, rock mass structural plane spacing, rock mass structural plane conditions, groundwater conditions, and the relationship between the rock mass structural plane orientation and the engineering direction.

[0038] As an improvement to the above scheme: In step S1, when installing the deep rock mass strength borehole-inside-outside drilling joint testing equipment, the borehole surface seismic wave detector is fixed to the drilling free surface with hot melt adhesive, a pre-drilled hole is set on the drilling free surface, and there is a 1m gap between the borehole surface seismic wave detector and the pre-drilled hole on the drilling free surface in the radial direction of the hole.

[0039] As an improvement to the above scheme: In step S4, the external drilling parameter information obtained in real time by the external drilling parameter testing unit includes torque parameter, pressure parameter, rotational speed parameter and inclination angle parameter.

[0040] The beneficial effects of this invention are as follows: This invention measures drilling parameters outside the borehole through an external drilling parameter testing unit located between the drilling rig and the drill rod; measures rock strength inside the borehole through an internal rock strength testing unit; records seismic wave signals generated when the core tube or drill bit breaks rock through a surface seismic detector; and measures the current drilling depth through a laser rangefinder, thereby obtaining parameters such as drilling speed. A control processing unit controls the drilling rig, the external drilling parameter testing unit, the internal rock strength testing unit, the surface seismic detector, and the laser rangefinder, and processes the detected data. Through drilling-while-drilling tests inside the borehole, outside the borehole, and at the surface, discrete rock strength, continuous rock strength, rock mass longitudinal wave velocity, and rock mass structural surfaces are identified, respectively. Rock mass strength parameters are calculated using rock mass structural surfaces and rock strength information. This can be used to measure the actual rock mass strength parameters drilled by the drill bit during drilling, helping to improve the accuracy of deep underground engineering exploration and providing reliable geological data for engineering disaster risk assessment and support design and construction. Attached Figure Description

[0041] Figure 1 is a schematic diagram of the combined drilling test equipment for deep rock mass strength inside and outside the borehole in this invention.

[0042] Figure 2 is a schematic diagram of the structure of the rock strength testing unit inside the hole in this invention;

[0043] Figure 3 is a schematic diagram of the external drilling parameter testing unit in this invention;

[0044] Figure 4 is a diagram of the internal structure of the rock strength testing unit inside the hole in this invention.

[0045] Figure 5 is a diagram of the internal structure of the borehole external drilling parameter testing unit in this invention.

[0046] Figure 6 is a technical roadmap of the deep rock mass strength test method using both inside and outside the borehole during drilling in this invention.

[0047] Figure 7 is a schematic diagram of the test borehole wall pressure-deformation displacement curve in this invention;

[0048] Figure 8 is a schematic diagram of the test results of the compressive strength of the rock inside the hole at multiple single points along the drilling direction in this invention;

[0049] Figure 9 is a schematic diagram of the curve of the inclination angle parameter changing with drilling depth in the external drilling parameter information of the present invention;

[0050] Figure 10 is a schematic diagram of the pressure parameter changing with drilling depth in the external drilling parameter information of the present invention;

[0051] Figure 11 is a schematic diagram of the rotation speed parameter as a function of drilling depth in the external drilling parameter information of the present invention;

[0052] Figure 12 is a schematic diagram of the torque parameter changing with drilling depth in the external drilling parameter information of the present invention;

[0053] Figure 13 is a topology diagram of the BP neural network structure in this invention;

[0054] Figure 14 is a schematic diagram of the rock strength-drilling depth curve after multi-point strength testing and calibration in the borehole in this invention.

[0055] Figure 15 shows the surface seismic wave signal monitoring diagram corresponding to two adjacent depth points in this invention;

[0056] Figure 16 shows the wave velocity along the borehole depth obtained by the surface seismic wave interferometry calculation in this invention, where the gray columnar part is the identified rock structure surface.

[0057] The markings in the diagram are as follows: 1-Drilling rig, 2-External drilling parameter testing unit, 21-External testing section, 22-Second male head, 23-Second female head, 3-Drill rod, 4-Internal rock strength testing unit, 41-Internal testing section, 42-Hydraulic probe device, 43-First female head, 44-First male head, 5-Surface seismic wave detector, 6-Laser rangefinder, 7-Control and processing unit, 8-External drilling device, 9-Drilling free face. Detailed Implementation

[0058] To facilitate understanding of the present invention, the invention will be further described below with reference to the accompanying drawings.

[0059] In the description of this invention, it should be noted that the terms "front", "rear", "left", "right", "up", "down", "inner", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0060] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art; therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; in case of any conflict, this specification shall prevail. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention are commercially available or can be prepared by existing methods.

[0061] As shown in Figures 1 to 5, the deep rock mass strength testing equipment disclosed in this invention includes a drilling rig 1, an external drilling parameter testing unit 2, a drill rod 3, an internal rock strength testing unit 4, a surface seismic detector 5, a laser rangefinder 6, a control and processing unit 7, and an external drilling device 8. One end of the external drilling parameter testing unit 2 is connected to the power head of the drilling rig 1, and the other end is connected to one end of the drill rod 3, so as to measure drilling parameters outside the hole through the external drilling parameter testing unit 2 between the drilling rig 1 and the drill rod 3. One end of the internal rock strength testing unit 4 is connected to the other end of the drill rod 3, and the other end is connected to an external drilling device 8 such as a core tube or drill bit, so as to measure rock strength inside the hole through the internal rock strength testing unit 4. A surface seismic detector 5 is installed on the drilling free face 9. It records the seismic wave signals generated when the core tube or drill bit breaks rock. The drilling free face 9 is the working face where the borehole location meets the outer diameter. The surface seismic detector 5 is a high-frequency detector, covering the rock-breaking signal frequency band from 10Hz to 1500Hz. A laser rangefinder 6 is installed on the control panel of the drilling rig 1. It measures the current drilling depth and synchronizes with the time of the on-site host, thus obtaining parameters such as drilling speed. The control processing unit 7 is communicatively connected to the drilling rig 1, the external drilling parameter testing unit 2, the internal rock strength testing unit 4, the surface seismic detector 5, and the laser rangefinder 6. The control processing unit 7 is the on-site host. The control and processing unit 7 can control the drilling rig 1, the external drilling parameter testing unit 2, the internal rock strength testing unit 4, the surface seismic wave detector 5, and the laser rangefinder 6, and process the data obtained from them. Through drilling tests inside the hole, outside the hole, and on the surface, it can identify discrete rock strength, continuous rock strength, rock mass longitudinal wave velocity, and rock mass structural surfaces, respectively. The rock mass strength parameters can be calculated using the rock mass structural surfaces and rock strength information. This can be used to measure the actual rock mass strength parameters drilled by the drill bit during drilling, which helps to improve the accuracy of deep underground engineering exploration and provides reliable geological data for engineering disaster risk assessment and support design and construction.

[0062] Specifically, as shown in Figure 2, the borehole rock strength testing unit 4 used in this invention includes a borehole testing section 41, a hydraulic probe device 42, a distance counter, a pressure counter, a first female head 43, and a first male head 44. The borehole testing section 41 has a rod-like structure. One end of the borehole testing section 41 is threadedly connected to the other end of the drill rod 3 via the first female head 43, and the other end of the borehole testing section 41 is threadedly connected to the external drilling device 8 via the first male head 44. The hydraulic probe device 42 has a drive end and a probe end. The drive end of the hydraulic probe device 42 is fixed inside the borehole testing section 41, and the probe end of the hydraulic probe device 42 passes through the sidewall of the borehole testing section 41 and extends to the outside of the borehole testing section 41. The drive end of the hydraulic probe device 42 is used to drive the probe end of the hydraulic probe device 42 to move in a direction perpendicular to the central axis of the borehole testing section 41. The distance counter is fixed to the borehole testing section 41 and connected to the probe end of the hydraulic probe device 42. The pressure counter is fixed on the test section 41 inside the hole and connected to the probe end of the hydraulic probe device 42; the hydraulic probe device 42, the distance counter, and the pressure counter are all connected to the control processing unit 7.

[0063] One end of the rod-shaped borehole test section 41 is connected to the other end of the drill rod 3 via a first female head 43, and the other end is connected to the external drilling device 8 via a first male head 44, so that the borehole test section 41 is installed as a small drill rod between the drill rod 3 and the external drilling device 8. The drive end of the hydraulic probe device 42 is fixed inside the borehole test section 41, and the probe end of the hydraulic probe device 42 passes through the side wall of the borehole test section 41 and extends to the outside of the borehole test section 41, so that the drive end of the hydraulic probe device 42 drives the probe end of the hydraulic probe device 42 to move in a direction perpendicular to the central axis of the borehole test section 41, so that the probe end of the hydraulic probe device 42 can be pressed into the rock of the borehole wall. Specifically, the drive end of the hydraulic probe device 42 can be a hydraulic power mechanism with components such as a motor, hydraulic cavity, and hydraulic plunger; the probe end of the hydraulic probe device 42 is a probe, which is driven to probe downward by the hydraulic power mechanism. A distance counter fixed to the test section 41 inside the borehole is connected to the probe end of the hydraulic probe device 42. The distance counter can be used to measure the displacement change of the probe end of the hydraulic probe device 42 during the pressing process. A pressure counter fixed to the test section 41 inside the borehole is also connected to the probe end of the hydraulic probe device 42. The pressure counter can be used to measure the pressure change of the probe end of the hydraulic probe device 42 during the pressing process. The hydraulic probe device 42, the distance counter, and the pressure counter are all communicatively connected to the control processing unit 7. The control processing unit 7 can control the hydraulic probe device 42 and process and analyze the displacement, pressure, and other data detected by the distance and pressure counters.

[0064] As shown in Figure 4, in some possible implementations, the borehole rock strength testing unit 4 further includes a microcontroller, an A / D conversion circuit, and a signal amplification circuit. The microcontroller is equipped with a data storage module, a motor-hydraulic drive module, and a self-powered module. The distance counter is connected to the signal amplification circuit through a corresponding signal acquisition circuit, and the pressure counter is connected to the signal amplification circuit through a corresponding signal acquisition circuit. The signal amplification circuit is connected to the microcontroller through the A / D conversion circuit. The microcontroller is connected to the hydraulic probe device 42 and wirelessly communicates with the control processing unit 7, so that the hydraulic probe device 42, the distance counter, and the pressure counter communicate with the control processing unit 7 through the microcontroller. The data detected by the distance counter and the pressure counter is recorded in the data storage module of the microcontroller through the A / D conversion circuit and transmitted to the control processing unit 7. The hydraulic probe device 42 is controlled by the motor-hydraulic drive module, and the self-powered module provides power.

[0065] Specifically, as shown in Figure 3, the external drilling parameter testing unit 2 used in this invention includes an external testing section 21, a pressure-torque composite sensor, an acceleration sensor, an inclination sensor, a rotational speed sensor, a second male connector 22, and a second female connector 23. The external testing section 21 is configured as a rod-shaped structure. One end of the external testing section 21 is threadedly connected to the power head of the drilling rig 1 via the second male connector 22, and the other end of the external testing section 21 is threadedly connected to one end of the drill rod 3 via the second female connector 23. The pressure-torque composite sensor is mounted on the outer wall of the external testing section 21. The acceleration sensor is mounted on the outer wall of the external testing section 21. The inclination sensor is mounted on the outer wall of the external testing section 21. The rotational speed sensor is mounted on the external testing section 21. The pressure-torque composite sensor, acceleration sensor, inclination sensor, and rotational speed sensor are all communicatively connected to the control processing unit 7.

[0066] One end of the rod-shaped external test section 21 is connected to the drilling rig 1 via a second male connector 22, and the other end is connected to one end of the drill rod 3 via a second female connector 23, so that the external test section 21 is installed as a small drill rod between the drill rod 3 and the drilling rig 1. A pressure-torque composite sensor, an acceleration sensor, and an inclination sensor are installed on the outer wall of the external test section 21, and a speed sensor is installed on the external test section 21 to measure drilling parameters such as torque, pressure, speed, and inclination angle. The pressure-torque composite sensor, acceleration sensor, inclination sensor, and speed sensor are all communicatively connected to the control processing unit 7 to acquire and process the data detected by the pressure-torque composite sensor, acceleration sensor, inclination sensor, and speed sensor.

[0067] As shown in Figure 5, in some possible implementations, the borehole drilling parameter testing unit 2 further includes a microcontroller, an A / D conversion circuit, and a signal amplification circuit. The microcontroller is equipped with a data storage module, a wireless transmission module, and a self-powered module. The pressure-torque composite sensor, acceleration sensor, tilt sensor, and speed sensor are respectively connected to the signal amplification circuit through their corresponding signal acquisition circuits. The signal amplification circuit is connected to the microcontroller through the A / D conversion circuit. The microcontroller is wirelessly connected to the control processing unit 7, so that the data detected by the pressure-torque composite sensor, acceleration sensor, tilt sensor, and speed sensor are recorded in the data storage module of the microcontroller through the A / D conversion circuit, and wirelessly connected to the control processing unit 7 located in the drilling rig control console through the wireless transmission module, displaying the data on the control processing unit 7 in real time. The self-powered module provides power for operation.

[0068] As shown in Figure 6, the deep rock mass strength test method disclosed in this invention uses the deep rock mass strength test equipment described above and performs the following steps:

[0069] S1. Install the combined borehole strength testing equipment for deep rock mass inside and outside the borehole. Fix the borehole surface seismic detector 5 to the drilling free face 9 with hot melt adhesive. Set a pre-drilled hole on the drilling free face 9. There is a 1m gap between the borehole surface seismic detector 5 and the pre-drilled hole on the drilling free face 9 in the radial direction of the hole. After installation, start the drilling rig 1 to drill at the drilling free face 9.

[0070] S2. The drilling depth of the borehole is measured in real time by the laser rangefinder 6. The laser rangefinder 6 calculates the drilling depth by measuring the forward and backward movement of the power head of the drilling rig 1. The time-drilling depth curve is obtained by combining the time recorded by the host machine on site.

[0071] S3. Rock strength information at discrete points inside the borehole is obtained by measuring the rock strength testing unit 4 inside the borehole.

[0072] S4. The external drilling parameter information is obtained in real time by measuring the external drilling parameter information through the external drilling parameter testing unit 2. Combined with the time-drilling depth curve obtained in step S2, the rock strength information and the external drilling parameter information corresponding to the drilling depth of each single point in the discrete points in the hole are used to form a training set. Based on the training set, a drilling intelligent inversion model of rock mechanical parameters is constructed through a BP neural network. The drilling intelligent inversion model is trained to obtain a training model. Based on the training model, the rock strength is continuously inverted under the calibration of rock strength information to obtain continuous rock compressive strength.

[0073] S5. The seismic wave signal generated during drilling and rock breaking is recorded in real time by the surface seismic wave detector 5, and the rock mass structure surface is identified based on the seismic wave signal.

[0074] S6. The rock mass compressive strength is calculated based on the rock compressive strength obtained in step S4 and the rock structural surface obtained in step S5.

[0075] Specifically, the deep rock mass strength testing method disclosed in this invention, which combines in-hole and out-of-hole drilling testing, is based on the following concept: A laser rangefinder 6 measures the current drilling depth (i.e., the current test depth) in real time; an in-hole rock strength testing unit 4 tests the borehole wall pressure-deformation displacement curve, thereby calculating rock strength information at several discrete points along the drilling direction, including the rock static elastic modulus and rock compressive strength; as shown in Figures 9 to 12, an out-of-hole drilling parameter testing unit 2 measures out-of-hole drilling parameters in real time, including torque, pressure, rotational speed, and inclination angle. Combined with the time-drilling depth curve, the rock strength information obtained from the tests at known in-hole discrete points is used as known information, and the out-of-hole drilling parameter information such as torque, pressure, rotational speed, and inclination angle obtained at corresponding points is used as a training set. The training dataset constructs a drilling-while-use intelligent inversion model of rock mechanics parameters using a BP neural network and trains the model. The training includes evaluating the predictive performance of the model and screening existing models to optimize and calibrate rock strength. The resulting trained model can obtain rock compressive strength information from torque, pressure, rotational speed, and dip angle as inputs. Since the acquisition of borehole parameters is continuous along the borehole, continuous rock compressive strength can be obtained. Furthermore, the seismic wave signals generated during drilling and rock breaking are recorded in real time using a borehole surface seismic detector 5, and the rock mass structural surfaces are identified based on the seismic wave signals. The rock mass compressive strength is calculated based on the rock compressive strength and the rock mass structural surfaces, thus enabling rapid, accurate, and continuous inversion of rock mass strength parameters using drilling-while-use measurement information from outside the borehole, the borehole surface, and inside the borehole.

[0076] The BP neural network used in this invention is an artificial intelligence algorithm that mimics the excitation process of the nervous system in the biological brain. This method allows the neural network to learn the mapping rules between input and output, and then, through error backpropagation, directly construct the nonlinear relationship between input and output, forming a feedforward neural network, namely, a Backpropagation Neural Network. As shown in Figure 13, the BP neural network consists of three layers: an input layer, an output layer, and a hidden layer. Each layer contains several nodes, and the connections between nodes in different layers constitute neurons. Each node can receive input signals from other nodes and generate outputs by performing rule-based operations on the input signals. The training principle of the BP neural network is the error backpropagation algorithm. This algorithm inputs training samples into the neural network, obtains initial prediction results through the hidden and output layers, calculates the error of the output layer, and backpropagates the error. Based on the magnitude of the error, it adjusts the weights and biases of each node in the neural network to make the prediction results of the next network more accurate. The training process of the BP neural network mainly includes the following steps: forward propagation stage, error calculation stage, backpropagation stage, and repeated calculation stage. Compared to other machine learning methods, the backpropagation property of BP neural networks theoretically gives them an advantage in handling nonlinear problems, improving computational efficiency, and enhancing generalization ability. It is a feasible method for constructing complex nonlinear mapping relationships between drilling parameters and rock mechanics parameters. As shown in Figure 14, the trained model can continuously invert rock strength under the calibration of known rock strength tested in the borehole.

[0077] In the deep rock mass strength testing method disclosed in this invention, when measuring the rock strength information of discrete points inside and outside the borehole through the borehole rock strength testing unit 4, the following steps are performed:

[0078] S3-1. When the drilling depth of drill rig 1 increases by 1 to 2 m, stop the drilling operation of drill rig 1, and drive the probe end of hydraulic probe device 42 to extend from the side wall of test section 41 in the hole through the drive end of hydraulic probe device 42. During the extension process, the displacement value of probe end is measured by distance counter and the pressure value of probe end is measured by pressure counter. Based on the displacement value and the pressure value, the test borehole wall pressure-deformation displacement curve of a single point is obtained as shown in Figure 7. Based on the test borehole wall pressure-deformation displacement curve, the elastic modulus of a single point and the compressive strength of the rock in the hole are obtained.

[0079] S3-2. After the displacement value and pressure value are measured, the probe end of the hydraulic probe device 42 is driven by the drive end of the hydraulic probe device 42 to extend from the side wall of the test section 41 into the interior of the test section 41 in the hole, and the drilling machine 1 is started to continue drilling. Step S3-1 is repeated to obtain the elastic modulus of multiple single points and the compressive strength of the rock in the hole at several single points. The elastic modulus of multiple single points and the compressive strength of the rock in the hole at several single points are combined to obtain the rock strength information of discrete points in the hole.

[0080] Specifically, the elastic modulus and compressive strength of the rock inside the borehole can be obtained at a single point based on the test borehole wall pressure-deformation displacement curve according to the following principles, or determined according to the curve shape. The pressure segment less than 5 MPa in the test borehole wall pressure-deformation displacement curve is not considered in the data processing. The secant modulus of the stress segment of 5 to 50 MPa is defined as the deformation modulus E, i.e., the elastic modulus. The stress segment above 50 MPa is regarded as the compressive strength of the rock inside the borehole. This is because the rock fails in the stress segment above 50 MPa, the displacement continues to increase but the rock stress does not increase. By testing the rock strength inside the borehole at different depths, discrete rock strength points as shown in Figure 8 can be obtained.

[0081] In the deep rock mass strength testing method disclosed in this invention, the identification of rock mass structural surfaces based on seismic wave signals is carried out according to the following steps:

[0082] S5-1. Perform interferometric analysis on two adjacent seismic wave signals with a source movement distance of d. Take one of the two seismic wave signals as the reference signal and the other seismic wave signal as the disturbance signal. Calculate the correlation coefficient R between the reference signal and the disturbance signal according to formula (1).

[0083] In equation (1), A(t) represents the information without disturbance in the reference channel, B(t[1+∈]) represents the information with disturbance in the disturbed channel, t represents the drilling time, and t1 and t2 represent the time windows corresponding to the signals without disturbance in the reference channel and the signals with disturbance in the disturbed channel.

[0084] S5-2. The variance is calculated based on the correlation coefficient R obtained in equation (1) and equation (2).

[0085] In equation (2), To record the main mean square frequencies in the waveform;

[0086] S5-3, Based on the variance obtained in equation (2) The longitudinal wave velocity v of the rock mass along the borehole depth direction is calculated using equation (3);

[0087] S5-4. Identify rock mass structural surfaces based on the obtained longitudinal wave velocity v.

[0088] In the above steps, the drilling rock-breaking vibrations are recorded by the surface seismic detector 5, and the longitudinal wave velocity of the rock mass along the drilling depth direction is calculated by interference analysis of the signals between unit drilling depths. Then, the dynamic elastic modulus of the rock is obtained, and the rock mass structure surface is determined by identifying the low-velocity region. For example, let one of the two seismic wave signals in Figure 15 be taken as the reference channel, that is, the unperturbed signal A(t), and the other as the perturbed channel, that is, the perturbed signal B(t[1+∈]). By comparing the perturbed signal and the unperturbed signal, it can be found that the two seismic wave signals are very similar overall, and there is a phase difference between the two seismic wave signals. The correlation coefficient R between the reference channel and the perturbed channel can be calculated according to Equation (1). The distance between the source and the receiver and the variance of the inconsistent phase perturbation are related. Since the receiver position remains unchanged in the seismic wave monitoring while drilling, the distance d between the sources of adjacent channels is also related to the variance, and thus to the correlation coefficient R, that is, the cross-correlation value R. max The maximum value is related to the maximum cross-correlation value and variance of travel time disturbance, which can then be derived. The relationship between them is given by equation (2), and the variance is obtained based on equation (2). When the source displacement distance is d, the source displacement distance d can be estimated based on the variance of the travel time disturbance, as shown in equation (5):

[0089] In equation (5), v is the estimated P-wave value of the medium. Since the drilling signal is a continuous percussion drill vibration, in this embodiment, the seismic wave signal is taken every 0.1m for interferometric analysis, i.e., d = 0.1m, so the P-wave velocity v can be calculated by equation (3). By interferometric analysis between two adjacent seismic wave signals with each 0.1m point, the P-wave velocity of the rock mass that varies with depth can be obtained, as shown in Figure 16. The P-wave velocity of the rock mass can be identified. It can be considered that when the velocity is less than 50% of the background velocity, there is an obvious rock mass structure surface, i.e., a low-velocity zone.

[0090] In step S6 of the deep rock mass strength test method disclosed in this invention, the rock mass compressive strength is calculated based on the rock compressive strength and rock mass structure surface, and the rock mass compressive strength σ is calculated according to equation (4). c ;

[0091] The principle behind the above calculation formula is as follows: according to the Hoek-Brown criterion, the rock compressive strength can be converted into the rock mass compressive strength, where σ is the rock compressive strength. ciThe rock strength obtained through drilling is shown in Figure 14. S is the parameter obtained from the RMR engineering rock mass evaluation system and the rock mass structure surface, and is calculated according to equation (6):

[0092] S = exp[(RMR-100) / 9] (6), where RMR can be obtained from the surface seismic wave interferometry and measured in conjunction with the rock mass scoring system proposed by Bieniawski. The RMR engineering rock mass evaluation system in this embodiment is a method for determining the quality grade of rock mass. The evaluation indicators of the RMR engineering rock mass evaluation system include the uniaxial compressive strength of rock blocks (R1), rock quality index RQD (R2), rock mass structural plane spacing (R3), rock mass structural plane conditions (R4), groundwater conditions (R5), and the relationship between the rock mass structural plane attitude and the engineering strike (R6). A total of six indicators are used as basic parameters to score the main factors affecting the stability of rock mass, and their sum is used as the RMR value of the rock mass. That is, the RMR value is calculated according to the formula (7):

[0093] RMR=R1+R2+R3+R4+R5+R6 (7), where the uniaxial compressive strength of the rock block (R1), the rock quality index RQD (R2), and the spacing between rock mass structural surfaces (R3) are quantitative standards, while the conditions of the rock mass structural surfaces (R4), the groundwater conditions (R5), and the relationship between the occurrence of the rock mass structural surfaces and the engineering direction (R6) are qualitative parameters. Specific scoring tables can be found in Tables 1 to 6. R2 is selected based on the rock strength obtained from drilling tests inside and outside the borehole, i.e., according to Figure 14. Joint information R3, R4, and R6 can be identified and statistically analyzed by recognizing the rock mass structural surfaces in the low-velocity zone obtained from borehole surface seismic wave interferometry.

[0094] Table 1. Scoring table for uniaxial compressive strength R1 of intact rock.

[0095] Table 2 Rock Quality Index R2 Scoring Table

[0096] Table 3 Joint Spacing R3 Scoring Table

[0097] Table 4 Joint Characteristics R4 Scoring Table

[0098] Table 5 Groundwater Condition R5 Scoring Table

[0099] Table 6 R6 scoring table for joint direction

[0100] The beneficial effects of the present invention are mainly reflected in the following aspects: (1) Compared with the traditional drilling test method, the rock strength obtained by the drilling test in the borehole can be calibrated by the rock strength inverted from the drilling parameters outside the borehole, thereby obtaining a reliable and continuous rock strength curve that varies with depth; (2) Compared with the traditional drilling test method, the present invention achieves probe-type rock strength testing by drilling test sub for rock strength in the borehole, thereby obtaining in-situ elastic modulus and single-point rock strength information; (3) Compared with the traditional drilling test method, the present invention can obtain the longitudinal wave velocity of the rock mass along the borehole depth direction by using seismic wave interferometry, thereby identifying the rock mass structural surface through the low-velocity region; (4) Compared with the traditional method of identifying rock strength during drilling, the present invention can calculate the rock mass strength information by analyzing the structural surface and rock strength.

[0101] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0102] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments; therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0103] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of this invention; thus, if these modifications and variations of this invention fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A combined in-hole and out-of-hole drilling strength testing equipment for deep rock masses, characterized in that: It includes a drilling rig (1), a borehole drilling parameter testing unit (2), a drill rod (3), a borehole rock strength testing unit (4), a borehole surface seismic wave detector (5), a laser rangefinder (6), a control and processing unit (7), and an external drilling device (8); The external drilling parameter testing unit (2) is connected between the drilling rig (1) and the drill rod (3), the internal rock strength testing unit (4) is connected between the drill rod (3) and the external drilling device (8), the surface seismic wave detector (5) is set on the drilling free face (9), and the laser rangefinder (6) is installed on the drilling rig (1). The drilling rig (1), the external drilling parameter testing unit (2), the internal rock strength testing unit (4), the surface seismic wave detector (5) and the laser rangefinder (6) are all connected to the control and processing unit (7).

2. The combined in-hole and out-of-hole drilling testing equipment for deep rock mass strength as described in claim 1, characterized in that: The borehole rock strength testing unit (4) includes a borehole testing section (41), a hydraulic probe device (42), a distance counter, and a pressure counter; The in-hole test section (41) has a rod-shaped structure and is connected between the drill rod (3) and the external drilling device (8). The hydraulic probe device (42) has a drive end and a probe end. The drive end of the hydraulic probe device (42) is fixed inside the test section (41) in the hole, and the probe end of the hydraulic probe device (42) extends to the outside of the test section (41) in the hole. The drive end of the hydraulic probe device (42) is used to drive the probe end of the hydraulic probe device (42) to move in a direction perpendicular to the central axis of the test section (41) in the hole. The distance counter and pressure counter are fixed on the test section (41) inside the hole and are both connected to the probe end of the hydraulic probe device (42); The hydraulic probe device (42), distance counter, and pressure counter are all connected to the control processing unit (7) via communication.

3. The combined in-hole and out-of-hole drilling testing equipment for deep rock mass strength as described in claim 2, characterized in that: The external drilling parameter testing unit (2) includes an external testing section (21), a pressure-torque composite sensor, an acceleration sensor, an inclination sensor, and a rotation speed sensor; The external test section (21) has a rod-shaped structure and is connected between the drilling rig (1) and the drill rod (3); The pressure-torque composite sensor, acceleration sensor, tilt sensor, and speed sensor are all mounted on the outer wall of the test section (21) outside the hole, and the pressure-torque composite sensor, acceleration sensor, tilt sensor, and speed sensor are all connected to the control processing unit (7) for communication.

4. A combined in-hole and out-of-hole drilling strength testing method for deep rock masses, characterized by: The method of using the combined in-hole and out-of-hole drilling testing equipment for deep rock mass strength as described in claim 3 includes the following steps: S1. Install the combined drilling test equipment for the strength of deep rock mass inside and outside the hole. After installation, start the drilling rig (1) and drill at the drilling free face (9). S2. The drilling depth of the borehole is measured in real time using a laser rangefinder (6), and the time-drilling depth curve is obtained based on the drilling depth. S3. The rock strength information of discrete points in the borehole is obtained by measuring the rock strength test unit (4) in the borehole; S4. The external drilling parameter information is obtained by real-time measurement through the external drilling parameter test unit (2). Combined with the time-drilling depth curve obtained in step S2, the rock strength information and the external drilling parameter information corresponding to the drilling depth of each single point in the discrete points in the hole are used to form a training set. Based on the training set, a rock mechanical parameter intelligent inversion model is constructed by BP neural network. The intelligent inversion model is trained to obtain a training model. Based on the training model, the rock strength is continuously inverted under the calibration of rock strength information to obtain continuous rock compressive strength. S5. The seismic wave signal generated during drilling and rock breaking is recorded in real time by the surface seismic wave detector (5), and the rock mass structure surface is identified based on the seismic wave signal. S6. The rock mass compressive strength is calculated based on the rock compressive strength obtained in step S4 and the rock structural surface obtained in step S5.

5. The method for combined in-hole and out-of-hole drilling testing of deep rock mass strength as described in claim 4, characterized in that: In step S3, the rock strength information of discrete points inside the borehole is measured by the borehole rock strength testing unit (4) according to the following steps: S3-1. When the drilling depth increases by 1 to 2 m, stop drilling (1) and drive the probe end of the hydraulic probe device (42) to extend out of the test section (41) inside the hole through the drive end of the hydraulic probe device (42). During the extension of the probe end, measure the displacement value of the probe end through the distance counter and measure the pressure value of the probe end through the pressure counter. Based on the displacement value and pressure value, obtain the test borehole wall pressure-deformation displacement curve at a single point. Then, based on the test borehole wall pressure-deformation displacement curve at a single point, obtain the elastic modulus of the single point and the compressive strength of the rock inside the hole. S3-2. After the displacement and pressure values ​​are measured, the probe end of the hydraulic probe device (42) is driven by the drive end of the hydraulic probe device (42) to retract into the test section (41) inside the hole, and the drilling machine (1) is started to continue drilling. Step S3-1 is repeated to obtain the elastic modulus of multiple single points and the compressive strength of the rock inside the hole of multiple single points. Finally, the elastic modulus of multiple single points and the compressive strength of the rock inside the hole of multiple single points are combined to obtain the rock strength information of the discrete points inside the hole.

6. The method for combined in-hole and out-of-hole drilling testing of deep rock mass strength as described in claim 5, characterized in that: In step S5, the identification of rock mass structural surfaces based on seismic wave signals is performed according to the following steps: S5-1. Perform interferometric analysis on two adjacent seismic wave signals with a source movement distance of d. Take one of the two seismic wave signals as the reference signal and the other seismic wave signal as the disturbance signal. Calculate the correlation coefficient R between the reference signal and the disturbance signal according to formula (1). In equation (1), A(t) represents the information of no disturbance in the reference channel, B(t[1+ε]) represents the information of disturbance in the disturbed channel, t represents the drilling time, and t1 and t2 represent the time windows corresponding to the signals of no disturbance in the reference channel and the signals of disturbance in the disturbed channel. S5-2. The variance is calculated based on the correlation coefficient R obtained in equation (1) and equation (2). In equation (2), To record the main mean square frequencies in the waveform; S5-3, Based on the variance obtained in equation (2) The longitudinal wave velocity v of the rock mass along the borehole depth direction is calculated using equation (3); S5-4. Identify rock mass structural surfaces based on the obtained longitudinal wave velocity v.

7. The method for combined in-hole and out-of-hole drilling testing of deep rock mass strength as described in claim 6, characterized in that: In step S6, the rock mass compressive strength σ is calculated according to equation (4). c ; In equation (4), σ ci S represents the rock compressive strength, and S is a parameter obtained from the RMR engineering rock mass evaluation system and rock mass structure surface.

8. The method for combined in-hole and out-of-hole drilling testing of deep rock mass strength as described in claim 7, characterized in that: The evaluation indicators of the RMR engineering rock mass evaluation system include the uniaxial compressive strength of rock blocks, rock quality indicators, rock mass structural plane spacing, rock mass structural plane conditions, groundwater conditions, and the relationship between the rock mass structural plane orientation and the engineering direction.

9. The method for combined in-hole and out-of-hole drilling testing of deep rock mass strength as described in claim 4, characterized in that: In step S1, when installing the combined borehole strength testing equipment for deep rock mass, the borehole surface seismic detector (5) is fixed on the drilling free face (9) with hot melt adhesive. A pre-drilled hole is set on the drilling free face (9), and there is a 1m gap between the borehole surface seismic detector (5) and the pre-drilled hole on the drilling free face (9) in the radial direction of the hole.

10. The method for combined in-hole and out-of-hole drilling testing of deep rock mass strength as described in claim 4, characterized in that: In step S4, the external drilling parameter information obtained by the external drilling parameter testing unit (2) in real time includes torque parameter, pressure parameter, rotation speed parameter and inclination angle parameter.

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