Large-span overhead cable anchoring structure and stress calculation method

Abstract

The present application relates to the field of large-span overhead steel cable anchoring structure, and discloses a large-span overhead steel cable anchoring structure and a stress calculation method, comprising the following steps: step one, obtaining the structural model parameters of the large-span overhead steel cable; step two, taking the cable tension Ti-1 behind the i-1th support as an input value, superimposing the input value and the tension increment to obtain the cable tension Ti behind the ith support; wherein the tension increment is determined based on the equivalent uniform load of the cable between the i-1th support and the ith support; wherein when i=1, the input value is the initial end tension value T0; step three, calculating the cable tensile safety factor n=TN / T p When n is less than the preset safety threshold, at least one design parameter of the anchoring structure is automatically adjusted by the computer until the calculated n is greater than or equal to the preset safety threshold. The steel wire rope anchoring safety of the large-span overhead steel cable belt conveying system is calculated.

Description

Technical Field

[0001] This invention relates to the field of long-span overhead steel cable anchorage structures, specifically to long-span overhead steel cable anchorage structures and stress calculation methods. Background Technology

[0002] In overhead steel cable belt conveyor systems, the anchoring reliability of the wire ropes directly affects the operational safety of the entire conveyor line. Existing anchoring technologies have the following main shortcomings: 1. Transition joints are prone to damage: Rigid connections are often used between the wire rope and the anchoring foundation. During installation, this can squeeze and damage the external anti-corrosion sealing layer of the wire rope. In the high dust and high humidity environment of coal mines, the internal steel wires are prone to corrosion and breakage after the sealing layer is damaged, posing a safety hazard.

[0003] 2. The anchoring method is simple and lacks special stress calculation: The existing anchoring mainly relies on buried cages or winding anchors, but there is a lack of targeted stress calculation methods. The size, burial depth and number of windings of the cage are mostly determined by experience, the safety factor is not clear, and slippage or breakage is easy to occur.

[0004] 3. Lack of full-condition verification: The existing stress model does not fully consider complex conditions such as wind load, impact, and overload, which makes it impossible to accurately assess the actual load-bearing capacity of the anchoring device, resulting in prominent safety hazards.

[0005] 4. Poor corrosion and loosening resistance: In the high dust and high humidity environment of coal mines, anchor joints are prone to corrosion and loosening, and most existing anchor structures do not have self-locking function, which poses a risk of loosening when subjected to impact.

[0006] Therefore, it is necessary to develop a wire rope anchoring device and a safe stress calculation method suitable for long-span overhead steel cable belt conveyor systems to solve the above problems from a design perspective. Summary of the Invention

[0007] The present invention aims to provide a long-span overhead steel cable anchorage structure and a stress calculation method to calculate the anchorage safety of steel wire ropes in long-span overhead steel cable belt conveyor systems and solve the above-mentioned problems.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a large-span overhead steel cable anchorage structure and a stress calculation method, comprising the following steps: Step 1: Obtain the structural model parameters of the long-span overhead steel cable. The structural model includes the steel cable, multiple supports, and anchoring structures. One end of the steel cable is the initial end, and the other end passes around the multiple supports and connects to the anchoring structure to form the anchoring end. The multiple supports are arranged in order from the initial end to the anchoring end as the 1st to the Nth supports, and the initial end tension value T0 is obtained. Step 2: For the 1st to Nth supports, the computer sequentially executes the fulcrum tension calculation process to obtain the anchorage end tension TN: The cable tension Ti-1 behind the (i-1)th support is used as the input value, and the input value is superimposed with the tension increment to obtain the cable tension Ti behind the ith support; where the tension increment is determined based on the equivalent uniformly distributed load of the cable between the (i-1)th support and the ith support; where, when i=1, the input value is the initial end tension value T0; Step 3: Calculate the tensile safety factor of the steel cable n = TN / T p Tp is the minimum breaking tensile force of the steel cable. When n is less than the preset safety threshold, the computer automatically adjusts at least one design parameter of the anchoring structure and returns to step one based on the adjusted design parameter until the calculated n is greater than or equal to the preset safety threshold.

[0009] The beneficial effects of this plan are: 1. The initial end tension value is a parameter that must be involved in the design of the steel cable to determine the tension of the steel cable. Input the initial end tension value, calculate the tension at each support, consider the impact of each segment load on the anchor cable tension in segments, and then calculate the steel cable tension TN up to the last support. Calculate the steel cable tensile safety factor based on TN to control the design results. When n is greater than the preset safety threshold, it means that the sealing rope surface will not be damaged under this tension, thus increasing the steel cable life by 90%. 2. The tensile safety factor of steel cables is mainly calculated based on the parameters of the steel cables and does not involve the specific anchoring structure. Therefore, it is compatible with the calculation of buried cages and spiral anchoring, and has strong versatility.

[0010] 3. The main purpose of this calculation is to prevent self-locking corrosion and eliminate slippage and breakage; 4. An anchoring design and verification process has been established, which is easy to promote.

[0011] Furthermore, in step two, the tension increment includes the load increment, and the formula for calculating the load increment is △F(i) = qc × h(i), where qc is the equivalent uniformly distributed load of the line, and h(i) is the height difference between the (i-1)th support and the ith support.

[0012] Furthermore, in step two, the tension increment includes the friction increment, which is determined based on the frictional force between the steel cable and the saddle on the support.

[0013] Furthermore, the formula for calculating the friction increment is: ; ; denoted as the tension of the steel cable on the rear side of the (i-1)th support; μ is the coefficient of friction between the steel cable and the saddle pad; and δmin(i) is the minimum bending angle of the steel cable at the corresponding saddle.

[0014] Furthermore, in step three, the preset safety threshold is 3.

[0015] Furthermore, in step three, the ultimate safety factor s = T_limit / TN is calculated; when s is less than 6, the computer automatically adjusts at least one design parameter of the anchoring structure and returns to step one based on the adjusted design parameter until the calculated s is greater than or equal to 6.

[0016] Furthermore, the tensile safety factor of the steel cable under each working condition is calculated so that the tensile safety factor of all steel cables is greater than the preset safety threshold.

[0017] A large-span overhead steel cable anchoring structure is characterized by: including a base, a support on the base, an anchoring cylinder on the side of the support, and the steel cable being wound around the anchoring cylinder with its end embedded downward into the base.

[0018] This solution also has the following effects: 1. The uniformly distributed load under various working conditions, the friction of the steel cable and the saddle are taken into account in the calculation of each support, and the final tension is calculated by continuously superimposing them.

[0019] This scheme applies to overhead steel cable belt conveyor systems. When the running direction is from the 1st to the Nth support, the direction of friction is the same as the direction of the initial end tension, and a positive value is taken. When the running direction is from the Nth to the 1st support, the direction of friction is opposite to the direction of the initial end tension, and the friction increment is not considered.

[0020] 2. Not only should the tensile safety factor of the steel cable be considered, but also the ultimate safety factor, to prevent the steel wire rope from breaking and to verify the safety of transportation.

[0021] 3. The long-span overhead steel cable anchoring structure not only has anchor cylinders, but also anchors the ends of the steel cables into the base, providing double protection and making the structure more stable. Attached Figure Description

[0022] Figure 1 This is a flowchart of Example 1; Figure 2 This is a schematic diagram of Example 2. Detailed Implementation

[0023] The following detailed description illustrates the specific implementation method: The reference numerals in the accompanying drawings include: steel cable 1, bracket 2, base 3, support 4, and anchor cylinder 5.

[0024] Example 1 The method for calculating the stress of long-span overhead steel cable anchorage structures involves automatically optimizing design parameters through iterative iteration to ensure anchorage safety; the flowchart is as follows. Figure 1 As shown, it includes the following steps: Step 1: Obtain the structural model parameters of the long-span overhead steel cable. The structural model includes the steel cable, multiple supports, and anchoring structures. The left end of the steel cable is the initial end, and the right end passes through multiple supports in sequence before connecting to the anchoring structure to form the anchoring end. The multiple supports are sequentially arranged from the initial end to the anchoring end as the 1st to the Nth supports, and the initial end tension value T0 is obtained.

[0025] Step 2: The computer sequentially performs the fulcrum tension calculation process for the first to Nth supports to obtain the anchorage end tension TN. Specifically, for the i-th support (i ranges from 1 to N), the cable tension T(i-1) on the rear side of the (i-1)-th support is used as the input value. The input value is superimposed with the tension increment to obtain the cable tension Ti on the rear side of the i-th support; where, when i=1, the input value is the initial end tension value T0.

[0026] The tensile force increment comprises two parts: the load increment and the friction increment. The specific determination method is as follows: The formula for calculating the load increment is ΔF(i)=qc×h(i), where qc is the equivalent uniformly distributed load of the line, which covers the line load converted to the unit length based on various working conditions, including the self-weight of the steel cable, icing, and wind load; h(i) is the height difference of the steel cable at the contact point between the (i-1)th support and the ith support.

[0027] The friction increment is determined based on the frictional force between the cable and the saddle on the support. As the cable passes over the saddle, the saddle pad provides the frictional force. The formula for calculating the friction increment is: ; ; in, denoted as the tension of the steel cable on the rear side of the (i-1)th support, μ is the coefficient of friction between the steel cable and the saddle pad, and δmin(i) is the minimum bending angle of the steel cable at the corresponding saddle.

[0028] After obtaining the load increment ΔF(i) and friction increment ΔFμ(i), these two are superimposed with the input value T(i-1) to obtain the cable tension Ti = T(i-1) + ΔF(i) + ΔFμ(i) on the back side of the i-th support. This process is repeated until the anchorage end tension TN is calculated.

[0029] It should be noted that the above process first fully introduces the load increment and its related parameters qc and h(i), then fully describes the friction increment and its dependent parameters T(i-1), μ, and δmin(i), and then uses both for superposition calculation. Each parameter is explained together when it first appears to avoid dispersion.

[0030] Step 3: Calculate the tensile safety factor of the steel cable n = TN / Tp, where Tp is the minimum breaking tensile force of the steel cable. In this embodiment, the preset safety threshold is 3. Simultaneously, to further ensure reliability under extreme conditions, the ultimate safety factor s = Tlimit / TN is also calculated, where Tlimit is the ultimate breaking tensile force of the steel cable. When the safety factor does not meet the requirements, the computer automatically adjusts at least one design parameter of the anchoring structure and returns to Step 1 for recalculation based on the adjusted design parameters, forming an iterative optimization loop. The specific adjustment rule is: if n < 3 or s < 6, the computer automatically modifies the anchor cylinder diameter, base embedment depth, or anchor cylinder winding parameters, updates the structural model, and re-executes Steps 1 to 3 until the calculated n ≥ 3 and s ≥ 6.

[0031] In practical engineering, various operating conditions need to be considered, such as maximum temperature, minimum temperature, maximum icing, and strong winds. Therefore, parameters such as the equivalent uniformly distributed load qc of the line under each operating condition are obtained. Steps one through three are performed for each condition to calculate the corresponding tensile safety factor and ultimate safety factor of the steel cable. It is ensured that the tensile safety factor n of the steel cable under all operating conditions is greater than the preset safety threshold of 3, and the ultimate safety factor s is greater than or equal to 6. Through this full-condition verification and automatic design adjustment, a large-span overhead steel cable anchorage structure scheme that meets safety requirements is finally obtained.

[0032] Example 2 Example 2 is the anchoring structure in Example 1. The anchoring structure includes a concrete base 3, such as... Figure 2 As shown in the enlarged view, the right side is the left view and the left side is the main view. Two rectangular supports 4 are integrally formed on the base 3, and anchor cylinders 5 are pre-embedded and fixed on the inner side of the supports 4. After the steel cable 1 is wound around the anchor cylinder 5, its end is bent downwards and pre-embedded into the base 3, forming a reliable anchoring end. The design parameters of this anchoring structure, such as the diameter of the anchor cylinder 5, the number of winding turns, the embedment depth, and the dimensions of the base 3, can all be used as variables to be adjusted in the subsequent calculations of Embodiment 1.

[0033] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for calculating the anchorage stress of long-span overhead steel cables, characterized in that, Includes the following steps: Step 1: Obtain the structural model parameters of the long-span overhead steel cable. The structural model includes the steel cable, multiple supports, and anchoring structures. One end of the steel cable is the initial end, and the other end passes around the multiple supports and connects to the anchoring structure to form the anchoring end. The multiple supports are arranged in order from the initial end to the anchoring end as the 1st to the Nth supports, and the initial end tension value T0 is obtained. Step 2: For the 1st to Nth supports, the computer sequentially executes the fulcrum tension calculation process to obtain the anchorage end tension TN: The cable tension Ti-1 behind the (i-1)th support is used as the input value, and the input value is superimposed with the tension increment to obtain the cable tension Ti behind the ith support; where the tension increment is determined based on the equivalent uniformly distributed load of the cable between the (i-1)th support and the ith support; where, when i=1, the input value is the initial end tension value T0; Step 3: Calculate the tensile safety factor of the steel cable n = TN / T p Tp is the minimum breaking tensile force of the steel cable. When n is less than the preset safety threshold, the computer automatically adjusts at least one design parameter of the anchoring structure and returns to step one based on the adjusted design parameter until the calculated n is greater than or equal to the preset safety threshold.

2. The method for calculating the anchorage force of long-span overhead steel cables according to claim 1, characterized in that: In step two, the tension increment includes the load increment. The formula for calculating the load increment is △F(i) = qc × h(i), where qc is the equivalent uniformly distributed load of the line, and h(i) is the height difference between the (i-1)th support and the ith support.

3. The method for calculating the anchorage force of long-span overhead steel cables according to claim 1, characterized in that: In step two, the tension increment includes the friction increment, which is determined based on the frictional force between the steel cable and the saddle on the support.

4. The method for calculating the anchorage force of long-span overhead steel cables according to claim 3, characterized in that: The formula for calculating the friction increment is: ； ； denoted as the tension of the steel cable on the rear side of the (i-1)th support; μ is the coefficient of friction between the steel cable and the saddle pad; and δmin(i) is the minimum bending angle of the steel cable at the corresponding saddle.

5. The method for calculating the anchorage force of long-span overhead steel cables according to claim 4, characterized in that: In step three, the preset safety threshold is 3.

6. The method for calculating the anchorage force of long-span overhead steel cables according to claim 5, characterized in that: In step three, the ultimate safety factor s = T_limit / TN is calculated. When s is less than 6, the computer automatically adjusts at least one design parameter of the anchoring structure and returns to step one based on the adjusted design parameter until the calculated s is greater than or equal to 6.

7. The method for calculating the anchorage force of long-span overhead steel cables according to claim 1, characterized in that: Calculate the tensile safety factor of the steel cable under each working condition, so that the tensile safety factor of all steel cables is greater than the preset safety threshold.

8. A long-span overhead steel cable anchorage structure, characterized in that: It includes a base, a support on the base, and an anchoring cylinder on the side of the support. The steel cable is wrapped around the anchoring cylinder and its end is buried downward into the base.

Images