Remote monitoring method for safety coefficient of falling dangerous rock mass based on acoustic echo ranging
Through acoustic echo ranging technology, the crack depth of the bonding surface between dangerous rock and parent rock is monitored, and a vibration dynamic model is established, which solves the problems of monitoring time lag and uncertainty in the existing technology, and achieves efficient early warning and stability evaluation of the collapse of falling dangerous rock and rock.
Patent Information
- Application Number
- CN202411712997.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-02-28
AI Technical Summary
The existing technology is difficult to effectively monitor and early warning of instability and collapse of falling dangerous rock bodies, resulting in lag in monitoring time and great uncertainty, and it is impossible to effectively prevent and control the collapse of dangerous rock bodies.
A remote monitoring method based on acoustic echo range measurement is adopted, and the crack depth of the bonding surface between the dangerous rock mass and the parent rock is measured through an echo detector, a vibration dynamic model is established, the maximum bending moment and positive stress are calculated, and the safety coefficient of the dangerous rock mass is evaluated.
It improves the speed, accuracy and reliability of collapse prediction, realizes quantitative analysis of the stability of dangerous rock mass, avoids the danger of staff contact, and ensures personal safety.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to a remote monitoring method of the safety factor of a falling dangerous rock mass based on acoustic echo ranging, and in particular to the field of acoustics and geological disaster monitoring. Background Art
[0002] The instability and collapse of falling dangerous rock masses is a geological phenomenon in which the falling dangerous rock masses break away from the parent rock and suddenly collapse. It is one of the common geological disasters in mountainous areas. The instability and collapse of falling dangerous rock masses can often cause huge losses of life and property.
[0003] The stability of falling dangerous rock mass depends on the crack depth of the bonding surface between the falling dangerous rock mass and the parent rock. The safety factor of the falling dangerous rock mass is negatively correlated with the crack depth of the bonding surface between the falling dangerous rock mass and the parent rock. The crack depth of the bonding surface between the falling dangerous rock mass and the parent rock will inevitably increase before the falling dangerous rock mass is destroyed. The instability of the falling dangerous rock mass shows the characteristics of randomness in spatial position, uncertainty in time and suddenness. Common monitoring indicators based on displacement, stress-strain, etc. have certain time lag and uncertainty in monitoring and early warning. Based on the current monitoring technology, it is still impossible to effectively prevent and control the instability of the falling dangerous rock mass.
[0004] In the current field of stability monitoring of falling dangerous rock masses, acoustic echo ranging technology has gradually become a key non-destructive detection method. This technology can effectively locate and evaluate the damage of falling dangerous rock masses, such as crack depth, by analyzing the reflection characteristics of sound waves inside building materials. Compared with traditional detection methods, acoustic echo ranging technology has many significant advantages, including higher detection accuracy, deeper penetration ability, and adaptability to complex structures. Therefore, this technology plays an increasingly important role in the stability monitoring of falling dangerous rock masses.
[0005] At present, the instability monitoring of falling dangerous rock masses generally adopts manual observation and recording measurement, which not only wastes a lot of social resources, but also does not guarantee the personal safety of monitoring personnel. In addition, manual measurement is affected by human factors, has low measurement accuracy, and data cannot be transmitted in real time. Summary of the invention
[0006] In order to solve the above technical problems, the present invention provides a remote monitoring method for the safety factor of falling dangerous rock masses based on acoustic echo special ranging. The acoustic echo ranging technology is used to measure the change in the crack depth of the bonding surface between the falling dangerous rock mass and the parent rock before it is destroyed, thereby achieving the purpose of rapid identification of falling dangerous rock masses, damage monitoring, stability evaluation and safety warning, which has stronger practical significance and scientific predictiveness.
[0007] The object of the present invention is achieved in the following manner:
[0008] A remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging includes the following steps:
[0009] S1: An echo sounder is arranged on the top of the bonding surface between the dangerous rock mass and the parent rock, and the depth of the crack on the bonding surface between the falling dangerous rock mass and the parent rock is measured by measuring the time interval from the ultrasonic wave self-emission through air reflection to reception.
[0010] The relationship between the time interval from the ultrasonic wave's emission to its reflection in the air to its reception and the crack depth at the rear edge of the falling dangerous rock mass is:
[0011]
[0012] Where: S is the crack depth at the rear edge of the falling dangerous rock mass, v is the ultrasonic self-emission speed of the echo sounder, and T is the time from the echo sounder emitting the ultrasonic wave to receiving the ultrasonic wave;
[0013] S2: Establish a vibration dynamics model of the relationship between the crack strength of the falling type dangerous rock mass and the bonding surface of the parent rock and obtain a vibration equation, and calculate the amplitude of the falling type dangerous rock mass and the maximum bending moment of the bonding surface of the falling type dangerous rock mass and the parent rock through the vibration equation;
[0014] S3: Then, the maximum normal stress on the bonding surface between the falling type dangerous rock mass and the parent rock can be obtained by determining the crack depth between the bonding surface between the falling type dangerous rock mass and the parent rock;
[0015] S4: Falling dangerous rock mass is mainly destroyed by normal stress, so its current safety factor is F s The safety factor of the falling dangerous rock mass and the relationship between the crack depth of the bonding surface between the falling dangerous rock mass and the parent rock before the destruction measured by the echo sounder are combined to obtain a quantitative model of the stability of the falling dangerous rock mass.
[0016] In the above-mentioned remote monitoring method for the safety factor of falling dangerous rock mass based on acoustic echo special ranging, the vibration equation of the relationship between the crack strength of the bonding surface between the falling dangerous rock mass and the parent rock in S2 is:
[0017] I0θ”(t)+kθ(t)=0 (2)
[0018]
[0019] Where: I0 is the moment of inertia of the falling type dangerous rock mass; θ(t) is the general solution of the vibration equation, θ″(t) is the acceleration generated by the initial displacement, I is the section moment of inertia of the bonding surface between the falling type dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling type dangerous rock mass and the parent rock; E is the elastic modulus of the bonding surface between the falling type dangerous rock mass and the parent rock, the height of the falling type dangerous rock mass is H; the width is L; the crack depth is S;
[0020] The amplitude of the falling dangerous rock mass and the maximum bending moment of the bonding surface between the falling dangerous rock mass and the parent rock are:
[0021]
[0022] Where: M max is the amplitude of the falling type dangerous rock mass and the maximum bending moment on the bonding surface between the falling type dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling type dangerous rock mass and the parent rock; m is the mass of the falling type dangerous rock mass; g is the gravitational acceleration; E is the elastic modulus of the falling type dangerous rock mass; V is the initial rotation speed of the falling type dangerous rock mass; ω is the natural vibration frequency of the falling type dangerous rock mass; A is the amplitude of the falling type dangerous rock mass; the width of the falling type dangerous rock mass is L; the thickness is B; the height is H; and the crack depth is S.
[0023] In the above-mentioned remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging, the relationship between the amplitude A and deformation θ(t) of the falling dangerous rock mass is:
[0024] General solution of the vibration equation: θ(t) = Asin(ωt+μ) (5)
[0025]
[0026] By solving the general solution of the vibration equation and substituting the initial conditions: when t = 0, θ(0) = 0, θ'(0) = V, we can obtain:
[0027]
[0028] In the formula: θ(t) is the general solution of the vibration equation; A is the amplitude of the falling type dangerous rock mass; ω is the natural vibration frequency of the falling type dangerous rock mass; μ is the phase difference; C1 and C2 are the unknown coefficients of the general solution before the initial conditions are brought in; the height of the falling type dangerous rock mass is H; the width is L; the thickness is B; and the crack depth is S.
[0029] The above-mentioned remote monitoring method of the safety factor of the falling type dangerous rock mass based on the dedicated acoustic echo ranging, the crack depth of the bonding surface between the falling type dangerous rock mass and the parent rock can be obtained by calculating the maximum normal stress on the bonding surface between the falling type dangerous rock mass and the parent rock:
[0030]
[0031] Where: max M is the maximum normal stress on the bonding surface; maxis the amplitude of the falling type dangerous rock mass and the maximum bending moment on the bonding surface between the falling type dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling type dangerous rock mass and the parent rock; I0 is the moment of inertia of the falling type dangerous rock mass; I is the section moment of inertia of the bonding surface between the falling type dangerous rock mass and the parent rock; m is the mass of the falling type dangerous rock mass; g is the acceleration of gravity; E is the elastic modulus of the falling type dangerous rock mass; V is the velocity of the initial rotation angle of the falling type dangerous rock mass; ω is the natural vibration frequency of the falling type dangerous rock mass; A is the amplitude of the falling type dangerous rock mass; the width of the falling type dangerous rock mass is L; the thickness is B; the height is H; and the depth of the crack is S.
[0032] The above-mentioned remote monitoring method for the safety factor of falling dangerous rock mass based on acoustic echo special ranging, said S4, the safety factor F of falling dangerous rock mass s for:
[0033]
[0034] Where: max is the maximum normal stress of the bonding surface between the falling dangerous rock mass and the parent rock; [σ] is the maximum normal stress allowed at the bonding surface between the falling dangerous rock mass and the parent rock; σ b is the strength limit value of the falling type dangerous rock mass; n is the reduction factor, take n=3.
[0035] In the above-mentioned remote monitoring method for the safety factor of falling dangerous rock masses based on acoustic echo-specific ranging, the frequency of the echo sounder is in the range of 20kHz to 100kHz, and the pulse width is a short pulse (0.5 to 2μs).
[0036] The above-mentioned remote monitoring method for the safety factor of falling dangerous rock mass based on acoustic echo special ranging, the mechanical parameters of rock materials include: the moment of inertia I0 of the falling dangerous rock mass; the mass m of the falling dangerous rock mass; the gravitational acceleration g of the falling dangerous rock mass; the elastic modulus E of the falling dangerous rock mass; the velocity V of the initial rotation angle of the falling dangerous rock mass; the natural vibration frequency ω of the falling dangerous rock mass; the amplitude A of the falling dangerous rock mass; the width L of the falling dangerous rock mass; the height H; and the thickness B; which can be directly measured.
[0037] Compared with the prior art, the present invention has the following technical effects:
[0038] The present invention makes a quantitative analysis of the stability of the falling dangerous rock mass from the perspective of acoustic echo ranging, thereby improving the speed, accuracy and reliability of collapse prediction. At the same time, the acoustic echo ranging technology is used to obtain the crack depth of the bonding surface between the falling dangerous rock mass and the parent rock before it is destroyed. Its advantages include higher detection accuracy, deeper penetration ability and adaptability to complex structures. At the same time, the present invention avoids direct contact between the staff and the dangerous rock block, thus ensuring the personal safety of the staff. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Figure 1 It is a schematic diagram of the weathering process of the falling type dangerous rock mass of the present invention.
[0040] Figure 2 It is the internal module diagram of the echo sounder of the present invention.
[0041] Figure 3 It is a relationship diagram between the crack depth of the bonding surface between the falling type dangerous rock mass and the parent rock and the safety factor of the falling type dangerous rock mass of the present invention.
[0042] Figure 4 It is a schematic diagram of the force of the falling type dangerous rock mass of the present invention.
[0043] Figure 5 It is a cross-sectional diagram of the bonding surface between the falling dangerous rock mass and the parent rock of the present invention.
[0044] Figure 6 It is a mechanical model diagram of the falling type dangerous rock mass of the present invention.
[0045] Figure 7 It is a vibration schematic diagram of the falling type dangerous rock mass of the present invention.
[0046] Figure 8 It is a stress-strain curve diagram of the falling type dangerous rock mass of the present invention. DETAILED DESCRIPTION
[0047] Combine the following Figure 1-8 The specific implementation method of the present invention is described in detail.
[0048] A remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging includes the following steps:
[0049] S1: Arrange an echo sounder at the top of the bonding surface between the dangerous rock mass and the parent rock as a data acquisition module to measure the depth of the crack on the bonding surface between the falling dangerous rock mass and the parent rock by measuring the time interval from the ultrasonic self-emission through air reflection to reception.
[0050] The echo sounder frequency is in the range of 20kHz to 100kHz, and the pulse width is short pulse (0.5 to 2μs)
[0051] The relationship between the time interval from the ultrasonic wave's emission to its reflection in the air to its reception and the crack depth at the rear edge of the falling dangerous rock mass is:
[0052]
[0053] Where: S is the crack depth at the rear edge of the falling dangerous rock mass, v is the ultrasonic self-emission speed of the echo sounder, and T is the time from the echo sounder emitting the ultrasonic wave to receiving the ultrasonic wave;
[0054] S2: Establish a vibration dynamics model of the relationship between the crack strength of the falling type dangerous rock mass and the bonding surface of the parent rock and obtain a vibration equation, and calculate the amplitude of the falling type dangerous rock mass and the maximum bending moment of the bonding surface of the falling type dangerous rock mass and the parent rock through the vibration equation;
[0055] The vibration equation of the relationship between the crack strength of the bonding surface between the falling dangerous rock mass and the parent rock is:
[0056] I0θ”(t)+kθ(t)=0 (2)
[0057]
[0058] Where: I0 is the moment of inertia of the falling type dangerous rock mass; θ(t) is the general solution of the vibration equation, θ″(t) is the acceleration generated by the initial displacement, I is the section moment of inertia of the bonding surface between the falling type dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling type dangerous rock mass and the parent rock; E is the elastic modulus of the bonding surface between the falling type dangerous rock mass and the parent rock, the height of the falling type dangerous rock mass is H; the width is L; the crack depth is S;
[0059] The amplitude of the falling dangerous rock mass and the maximum bending moment of the bonding surface between the falling dangerous rock mass and the parent rock are:
[0060]
[0061] Where: M max is the amplitude of the falling dangerous rock mass and the maximum bending moment of the bonding surface between the falling dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling dangerous rock mass and the parent rock; m is the mass of the falling dangerous rock mass; g is the acceleration of gravity; E is the elastic modulus of the falling dangerous rock mass; V is the velocity of the initial rotation angle of the falling dangerous rock mass; ω is the natural vibration frequency of the falling dangerous rock mass; A is the amplitude of the falling dangerous rock mass; the width of the falling dangerous rock mass is L; the thickness is B; the height is H; the crack depth is S;
[0062] The relationship between the amplitude A and deformation θ(t) of the falling type dangerous rock mass is:
[0063] General solution of the vibration equation: θ(t) = Asin(ωt+μ) (5)
[0064]
[0065] By solving the general solution of the vibration equation and substituting the initial conditions: when t = 0, θ(0) = 0, θ'(0) = V, we can obtain:
[0066]
[0067] In the formula: θ(t) is the general solution of the vibration equation; A is the amplitude of the falling type dangerous rock mass; ω is the natural vibration frequency of the falling type dangerous rock mass; μ is the phase difference; C1 and C2 are the unknown coefficients of the general solution before the initial conditions are brought in; the height of the falling type dangerous rock mass is H; the width is L; the thickness is B; and the crack depth is S.
[0068] S3: Then, the maximum normal stress on the bonding surface between the falling type dangerous rock mass and the parent rock can be obtained by determining the crack depth between the falling type dangerous rock mass and the parent rock. This step is the stress calculation module;
[0069] The maximum normal stress on the bonding surface between the falling type dangerous rock mass and the parent rock can be obtained by the crack depth between the falling type dangerous rock mass and the parent rock:
[0070]
[0071] Where: max M is the maximum normal stress on the bonding surface; max is the amplitude of the falling dangerous rock mass and the maximum bending moment of the bonding surface between the falling dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling dangerous rock mass and the parent rock; I0 is the moment of inertia of the falling dangerous rock mass; I is the section moment of inertia of the bonding surface between the falling dangerous rock mass and the parent rock; m is the mass of the falling dangerous rock mass; g is the acceleration of gravity; E is the elastic modulus of the falling dangerous rock mass; V is the velocity of the initial rotation angle of the falling dangerous rock mass; ω is the natural vibration frequency of the falling dangerous rock mass; A is the amplitude of the falling dangerous rock mass; the width of the falling dangerous rock mass is L; the thickness is B; the height is H; the depth of the crack is S;
[0072] S4: Falling dangerous rock mass is mainly destroyed by normal stress, so its current safety factor is F s This step is a safety factor calculation module, which combines the safety factor of the falling type dangerous rock mass with the relationship between the crack depth of the bonding surface between the falling type dangerous rock mass and the parent rock before destruction measured by the echo sounder to obtain a quantitative model of the stability of the falling type dangerous rock mass;
[0073] The safety factor F of the falling dangerous rock mass s for:
[0074]
[0075] Where: max is the maximum normal stress of the bonding surface between the falling dangerous rock mass and the parent rock; [σ] is the maximum normal stress allowed at the bonding surface between the falling dangerous rock mass and the parent rock; σ b is the strength limit value of the falling type dangerous rock mass; n is the reduction factor, take n=3.
[0076] The remote monitoring method for the safety factor of falling dangerous rock mass based on acoustic echo special ranging described in the present invention, the mechanical parameters of rock materials include: the moment of inertia I0 of the falling dangerous rock mass; the mass m of the falling dangerous rock mass; the gravitational acceleration g of the falling dangerous rock mass; the elastic modulus E of the falling dangerous rock mass; the velocity V of the initial rotation angle of the falling dangerous rock mass; the natural vibration frequency ω of the falling dangerous rock mass; the amplitude A of the falling dangerous rock mass; the width L of the falling dangerous rock mass; the height H; and the thickness B; which can be directly measured.
[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several changes and improvements can be made without departing from the overall concept of the present invention, which should also be regarded as the scope of protection of the present invention.
Claims
1. A remote monitoring method for the safety factor of falling dangerous rock mass based on acoustic echo ranging, characterized by: The following steps are involved: S1: An echo sounder is arranged on the top of the bonding surface between the dangerous rock mass and the parent rock, and the depth of the crack on the bonding surface between the falling dangerous rock mass and the parent rock is measured by measuring the time interval from the ultrasonic wave self-emission through air reflection to reception. The relationship between the time interval from the ultrasonic wave's emission to its reflection in the air to its reception and the crack depth at the rear edge of the falling dangerous rock mass is: Where: S is the crack depth at the rear edge of the falling dangerous rock mass, v is the ultrasonic self-emission speed of the echo sounder, and T is the time from the echo sounder emitting the ultrasonic wave to receiving the ultrasonic wave; S2: Establish a vibration dynamics model of the relationship between the crack strength of the falling type dangerous rock mass and the bonding surface of the parent rock and obtain a vibration equation, and calculate the amplitude of the falling type dangerous rock mass and the maximum bending moment of the bonding surface of the falling type dangerous rock mass and the parent rock through the vibration equation; S3: Then, the maximum normal stress on the bonding surface between the falling type dangerous rock mass and the parent rock can be obtained by determining the crack depth between the bonding surface between the falling type dangerous rock mass and the parent rock; S4: Falling dangerous rock mass is mainly destroyed by normal stress, so its current safety factor is F s The safety factor of the falling dangerous rock mass and the relationship between the crack depth of the bonding surface between the falling dangerous rock mass and the parent rock before the destruction measured by the echo sounder are combined to obtain a quantitative model of the stability of the falling dangerous rock mass.
2. The remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging according to claim 1 is characterized by: The vibration equation of the relationship between the crack strength of the falling dangerous rock mass and the bonding surface of the parent rock in S2 is: I0θ”(t)+kθ(t)=0 (2) Where: I0 is the moment of inertia of the falling type dangerous rock mass; θ(t) is the general solution of the vibration equation, θ″(t) is the acceleration generated by the initial displacement, I is the section moment of inertia of the bonding surface between the falling type dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling type dangerous rock mass and the parent rock; E is the elastic modulus of the bonding surface between the falling type dangerous rock mass and the parent rock, the height of the falling type dangerous rock mass is H; the width is L; the crack depth is S; The amplitude of the falling dangerous rock mass and the maximum bending moment of the bonding surface between the falling dangerous rock mass and the parent rock are: Where: M max is the amplitude of the falling type dangerous rock mass and the maximum bending moment on the bonding surface between the falling type dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling type dangerous rock mass and the parent rock; m is the mass of the falling type dangerous rock mass; g is the gravitational acceleration; E is the elastic modulus of the falling type dangerous rock mass; V is the initial rotation speed of the falling type dangerous rock mass; ω is the natural vibration frequency of the falling type dangerous rock mass; A is the amplitude of the falling type dangerous rock mass; the width of the falling type dangerous rock mass is L; the thickness is B; the height is H; and the crack depth is S.
3. The remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging according to claim 2 is characterized by: The relationship between the amplitude A and deformation θ(t) of the falling dangerous rock mass is: General solution of the vibration equation: θ(t) = Asin(ωt+μ) (5) By solving the general solution of the vibration equation and substituting the initial conditions: when t = 0, θ(0) = 0, θ'(0) = V, we can obtain: In the formula: θ(t) is the general solution of the vibration equation; A is the amplitude of the falling type dangerous rock mass; ω is the natural vibration frequency of the falling type dangerous rock mass; μ is the phase difference; C1 and C2 are the unknown coefficients of the general solution before the initial conditions are brought in; the height of the falling type dangerous rock mass is H; the width is L; the thickness is B; and the crack depth is S.
4. The remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging according to claim 3 is characterized by: The crack depth of the bonding surface between the S3 falling type dangerous rock mass and the parent rock can be used to obtain the maximum normal stress on the bonding surface between the falling type dangerous rock mass and the parent rock: Where: max M is the maximum normal stress on the bonding surface; max is the amplitude of the falling type dangerous rock mass and the maximum bending moment on the bonding surface between the falling type dangerous rock mass and the parent rock; k is the bending stiffness of the bonding surface between the falling type dangerous rock mass and the parent rock; I0 is the moment of inertia of the falling type dangerous rock mass; I is the section moment of inertia of the bonding surface between the falling type dangerous rock mass and the parent rock; m is the mass of the falling type dangerous rock mass; g is the acceleration of gravity; E is the elastic modulus of the falling type dangerous rock mass; V is the velocity of the initial rotation angle of the falling type dangerous rock mass; ω is the natural vibration frequency of the falling type dangerous rock mass; A is the amplitude of the falling type dangerous rock mass; the width of the falling type dangerous rock mass is L; the thickness is B; the height is H; and the depth of the crack is S.
5. The remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging according to claim 4 is characterized by: S4, safety factor F of falling dangerous rock mass s for: Where: max is the maximum normal stress of the bonding surface between the falling dangerous rock mass and the parent rock; [σ] is the maximum normal stress allowed at the bonding surface between the falling dangerous rock mass and the parent rock; σ b is the ultimate strength value of the falling type dangerous rock mass; n is the reduction factor, take n=3.
6. The remote monitoring method for safety factor of falling dangerous rock mass based on acoustic echo special ranging according to claim 1 is characterized by: The frequency of the echo sounder is in the range of 20kHz to 100kHz, and the pulse width is a short pulse (0.5 to 2μs).