Method for judging rock drillability based on drilling rotary speed, torque and axial pressure

Abstract

The present application relates to a method for judging rock mass drillability based on rotary speed, torque and axial pressure of a drill bit, characterized by the following steps: Step 1, conducting drilling test, collecting drilling axial pressure, rotary speed and torque in real time, and drawing time history curve; Step 2, establishing multiple linear regression model; Step 3, solving the multiple linear regression model in Step 2 to obtain regression coefficient a i ; Step 4, establishing standard normal distribution function of drillability, defining drillability index as f(K z ); Step 5, dividing drillability grade, and evaluating rock mass drillability according to drillability grade. The present application is based on the above method. By extracting relevant data of drilling blast hole of a field drilling machine, the formula is analyzed, drillability grade is divided, and rock mass drillability is evaluated according to drillability grade.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, specifically to a method for determining rock drillability based on borehole rotation speed, torque, and axial pressure. Background Technology

[0002] Known methods for evaluating rock drillability can be divided into two main categories: one is the method of conducting rock sample tests under laboratory conditions; the other is the method of determining rock grade during the production process, where technicians classify the drillability of different rocks based on their personal experience. The results obtained by the first method will differ from the actual data in the field, and it also suffers from problems such as high measurement costs and measurement lag. The second method, on the other hand, is difficult to avoid the influence of human factors, and the blasting effect is difficult to control effectively.

[0003] Drilling operations in open-pit mines primarily utilize rotary drilling rigs, which apply high drilling pressure and torque to the drill bit through pushing and rotating mechanisms, causing the rock to break under static pressure, minimal impact, and shearing. With the advent of digital drilling testing technology, real-time acquisition of drilling parameter changes during rock drilling is possible, providing a more efficient testing method for determining rock drillability. Therefore, this patent proposes a method for quantitatively determining rock drillability based on borehole rotation speed, torque, and pressure. Summary of the Invention

[0004] In order to make full use of drilling parameters to evaluate the engineering mechanical properties of rock mass, the purpose of this invention is to propose a method for judging the drillability of rock mass based on borehole rotation speed, torque and pressure.

[0005] The objective of this invention is achieved through the following technological process:

[0006] The present invention provides a method for determining the drillability of rock mass based on the drilling rotation speed, torque, and axial pressure, characterized by comprising the following steps:

[0007] Step 1: Conduct rock drilling tests with varying strength ranges.

[0008] Step 1.1 Collect and monitor rotational speed, torque, and axial pressure data using drilling rig sensors, and plot the time history curves of rotational speed, torque, and axial pressure;

[0009] Step 1.2 Based on the time history curves of rotational speed, torque and axial pressure, calculate the average rotational speed N, average axial pressure F and average torque M of the time history curves of rotational speed, torque and axial pressure.

[0010] Step 2: Establish a multiple linear regression model based on the average rotational speed N, average axial pressure F, and average torque M.

[0011] K z=a0+a1Q+a2N+a3F+a4M (1)

[0012] In equation (1), K z a is the drillability score; a0 is the constant of the multiple linear regression equation; a i (i = 1, 2, 3, 4) are partial regression coefficients; Q is the rock compressive strength, MPa; N is the average rotational speed, r / min; F is the average axial pressure, kN; M is the average torque, N·m;

[0013] Step 3: Solve the multiple linear regression model described in Step 2 to obtain the regression coefficients a. i (i = 1, 2, 3, 4);

[0014] Step 4: Establish the standard normal distribution function of drillability, and define the drillability index as f(K). z ),

[0015]

[0016] Step 5: Divide the drillability grade according to formula (2) and evaluate the drillability of the rock mass according to the drillability grade.

[0017] Preferably, the classification of drillability levels is based on the drillability index f(K). z ), divided into four levels from 0 to 1, when 0.85≤f(K z When 0.75 < 1, the drillability grade is I; when 0.75 ≤ f(K) z When 0.60 < 0.85, the drillability grade is II; when 0.60 ≤ f(K) z When f(K) < 0.75, the drillability grade is III. z When the value is less than 0.60, the drillability of the rock can be determined.

[0018] The advantages of this invention are:

[0019] This invention proposes a method for determining rock drillability based on borehole rotation speed, torque, and pressure. By extracting relevant data from boreholes drilled by on-site drilling rigs and analyzing them using formulas, the method can determine the level of drillability of the surrounding rock. Combining indoor tests and field data, this method has a certain degree of reliability and can provide a reference for blasting charge and wiring, improving blasting effects and providing guidance for the implementation design of blasting processes in mining. Attached Figure Description

[0020] Figure 1 This invention relates to a method for determining the drillability of rock mass based on the drilling rotation speed, torque, and axial pressure.

[0021] Figure 2 This is a schematic diagram of drillability classification. Detailed Implementation

[0022] To describe the present invention, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0023] Example

[0024] In an open-pit iron mine, a YZ-55 roller cone drill was used for drilling. Core samples were taken, and the rock compressive strength was 100.78 MPa. During the drilling process, the drilling speed, axial pressure, and torque were monitored in real time. After data processing, the average rotation speed was 118 r / min, the average axial pressure was 78.9 kN, and the average torque was 306 N·m.

[0025] like Figure 1 As shown, the method of the present invention for determining rock drillability based on borehole rotation speed, torque, and axial pressure includes the following steps:

[0026] Step 1: Conduct rock drilling tests with varying strength ranges;

[0027] Step 1.1 Collect and monitor rotational speed, torque, and axial pressure data using drilling rig sensors, and plot the time history curves of rotational speed, torque, and axial pressure;

[0028] Step 1.2 Based on the time history curves of rotational speed, torque and axial pressure, calculate the average rotational speed N, average axial pressure F and average torque M of the time history curves of rotational speed, torque and axial pressure.

[0029] Step 2: Based on the average rotational speed N, average axial pressure F, and average torque M, establish a multiple linear regression drillability model.

[0030] K z =a0+a1Q+a2N+a3F+a4M (1)

[0031] In equation (1), K z a is the drillability score; a0 is the constant of the multiple linear regression equation; a i (i = 1, 2, 3, 4) are partial regression coefficients; Q is the rock compressive strength, MPa; N is the average rotational speed, r / min; F is the average axial pressure, kN; M is the average torque, N·m;

[0032] Step 3: Solve the drill-through model of the multiple linear regression described in Step 2 to obtain the regression coefficients a. i (i = 1, 2, 3, 4);

[0033] K z =160.73+-0.89Q+-0.1N+0.55F+0.64M

[0034] Step 4: Establish the standard normal distribution function of drillability, and define the drillability index as f(K). z ),

[0035]

[0036] Step 5: Divide the drillability grade according to formula (2) and evaluate the drillability of the rock mass according to the drillability grade.

[0037] like Figure 2 As shown, the classification of drillability levels in this invention is based on the drillability index f(K) z ), divided into four levels from 0 to 1, when 0.85≤f(K z When 0.75 < 1, the drillability grade is I; when 0.75 ≤ f(K) z When 0.60 < 0.85, the drillability grade is II; when 0.60 ≤ f(K) z When f(K) < 0.75, the drillability grade is III. z When the value is less than 0.60, the drillability of the rock can be determined.

[0038] Based on the drillability index, a drillability evaluation level is established, as shown in Table 1.

[0039] Table 1 Drillability Rating Evaluation

[0040]

[0041]

[0042] When the drillability level is I, the drillability is evaluated as easy to drill; when the drillability level is II, the drillability is evaluated as drillable; when the drillability level is III, the drillability is evaluated as difficult to drill; when the drillability level is IV, the drillability is evaluated as undrillable.

[0043] The drillability index f(K) can be obtained from the drillability function. z =0.86, which belongs to Class I drillability level, and the drillability evaluation is easy to drill.

[0044] Example 2

[0045] A drillability model was obtained through rock drilling tests of various strength ranges.

[0046] K z =160.73+-0.89Q+-0.1N+0.55F+0.64M (1)

[0047] Establish the standard normal distribution function of drillability, and define the drillability index as f(K). z ),

[0048]

[0049] The rock's compressive strength Q is 67 MPa. During the drilling process, the average rotational speed N is 92 r / min, the average axial pressure F is 52.6 kN, and the average torque M is 198 N·m, obtained through real-time monitoring of rotational speed, axial pressure, and torque.

[0050] The drillability index f(K) can be obtained from the drillability function. z The value is 0.93, which belongs to Class I drillability level, and the drillability evaluation is easy to drill.

[0051] Example 3

[0052] A drillability model was obtained through rock drilling tests of various strength ranges.

[0053] K z =160.73+-0.89Q+-0.1N+0.55F+0.64M (1)

[0054] Establish the standard normal distribution function of drillability, and define the drillability index as f(K). z ),

[0055]

[0056] The rock's compressive strength Q is 208 MPa. During the drilling process, the average rotational speed N is 89 r / min, the average axial pressure F is 123 kN, and the average torque N is 408 N·m, obtained through real-time monitoring of rotational speed, axial pressure, and torque.

[0057] The drillability index f(K) can be obtained from the drillability function. z The value is 0.59, which belongs to Class IV drillability level, and the drillability evaluation is non-drillable.

[0058] Example 4

[0059] The rock's compressive strength Q is 153 MPa. During the drilling process, the average rotational speed N is 120 r / min, the average axial pressure F is 89 kN, and the average torque N is 312 N·m, obtained through real-time monitoring of rotational speed, axial pressure, and torque.

[0060] The drillability index f(K) can be obtained from the drillability function. z =0.0.83, which belongs to Class II drillability level, and the drillability evaluation is drillable.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for determining rock drillability based on borehole rotation speed, torque, and axial pressure, characterized in that: Includes the following steps: Step 1: Conduct rock drilling tests with varying strength ranges. Step 1.1 Collect and monitor rotational speed, torque, and axial pressure data using drilling rig sensors, and plot the time history curves of rotational speed, torque, and axial pressure; Step 1.2 Based on the time history curves of rotational speed, torque and axial pressure, calculate the average rotational speed N, average axial pressure F and average torque M of the time history curves of rotational speed, torque and axial pressure. Step 2: Establish a multiple linear regression model based on the average rotational speed N, average axial pressure F, and average torque M. （1） In equation (1), a0 is a constant in the multiple linear regression equation; a i (i=1, 2, 3, 4) are partial regression coefficients; Q is the rock compressive strength, MPa; N is the average rotational speed, r / min; F is the average axial pressure, kN; M is the average torque, N·m; Step 3: Solve the multiple linear regression model described in Step 2 to obtain the regression coefficients a. i (i=1, 2, 3, 4); Step 4: Establish the standard normal distribution function of drillability, and define the drillability index as f(K). z ), （2） Step 5: Divide the drillability grade according to formula (2) and evaluate the drillability of the rock mass according to the drillability grade.

2. A method for determining rock mass drillability based on borehole rotation speed, torque, and axial pressure, characterized in that: The classification of drillability grades is based on the drillability index f(K). z The range is divided into four levels from 0 to 1, when 0.85 ≤ f(K) z When 0.75 < 1, the drillability grade is I; when 0.75 ≤ f(K) z When 0.60 < 0.85, the drillability grade is II; when 0.60 ≤ f(K) z When f(K) < 0.75, the drillability grade is III. z When the value is less than 0.60, the drillability of the rock can be determined.

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