Pulling-resistant model test loading device based on pulley and lever principle
Through the anti-pull model test loading device of pulley and lever principle, the problem that the lever must be located directly above the loaded object and is inflexible in loading is solved, and flexible loading and high-precision testing of the anti-pull model is realized, providing convenience, flexibility and The economical loading method ensures the measurement of the ultimate bearing capacity of the pile resistant to pulling.
Patent Information
- Application Number
- CN202421227663.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-31
- Publication Date
- 2025-01-14
- Estimated Expiration
- 2034-05-31
AI Technical Summary
The existing pull-resistant model test loading device has the problem that the lever must be located directly above the loaded object, the loading is inflexible and the lever tilt affects the test accuracy.
Using the anti-pull model test loading device based on the principle of pulley and lever, the setting of fixed pulley A and fixed pulley B, combined with the power arm and resistance arm of the steel strand and lever, the flexible loading of the pile pulling model is achieved, and the tilt is achieved. The instrument calculates the ratio of the power arm to the resistance arm to ensure loading accuracy.
It realizes flexible loading of the anti-pile pulling model, improves testing accuracy, is convenient to load, is low cost, and can accurately obtain the ultimate bearing capacity of the anti-pile pulling.
Smart Images
Figure CN222349782U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a loading device for rock and soil tests, in particular to an anti-pulling model test loading device based on the principle of a pulley and a lever. Background Art
[0002] With the rapid development of the power industry in high-altitude mountainous areas in my country, transmission lines are inevitably routed on steep slopes. Extreme weather conditions such as strong winds and snowstorms throughout the year and the tension of power lines pose huge challenges to the safety and stability of transmission line foundations. Under the action of natural loads such as strong winds and snowstorms, the foundation of the transmission tower is subjected to the alternating combination of periodic compression / pulling and horizontal forces, among which the pull-out capacity is the main controlling factor for foundation stability. Therefore, with the increase in extreme weather conditions around the world, the bearing deformation capacity of the transmission tower foundation system has received great attention from scholars at home and abroad.
[0003] Model tests have the advantages of strictly controlling the main parameters of the test object without being affected by the external environment, saving manpower, material resources and time, and have become the most important research method in civil engineering science research. Model tests use models instead of prototypes for testing and research according to certain geometric and physical relationships, thereby showing similar bearing performance and failure mechanisms as the prototype, and using the research results for the prototype test method. Model tests with transmission tower foundations as the research object require the application of pull-out loads to the model foundation. The Technical Specifications for Building Foundation Pile Testing (JGJ 106-2014) stipulates that the slow-maintained load method is often used for loading tests in foundation static load tests.
[0004] At present, the loading methods commonly used in model tests are mainly jack loading, pulley loading, and lever loading. However, jack loading must be equipped with corresponding load sensors to test the size of the applied load, and the loading connection position must be designed, which is cumbersome and expensive. In addition, jack loading is applied to the pile top by displacement control, but the stability of the load acting on the pile top is poor as the pull-out pile moves. Pulley-equipped heavy object loading is convenient and easy to know the loading size, but the maximum loading value is limited, especially for rock-embedded piles, which are difficult to load and damage. Lever-equipped heavy object loading is relatively convenient and the maximum loading value is easy to adjust, but the lever must be located directly above the loaded object, the loading is not flexible, and once the lever loading is tilted, the force arm will change, thus affecting the test accuracy. Utility Model Content
[0005] In view of the above-mentioned deficiencies in the prior art, the pulley and lever principle-based pull-out model test loading device provided by the utility model solves the problems that the lever of the prior loading device must be located directly above the loaded object, resulting in inflexible loading and tilted lever affecting test accuracy.
[0006] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the utility model is:
[0007] Provided is a pulley and lever principle-based anti-pulley model test loading device, comprising a lever and a model box, wherein a fixed pulley A is arranged above the model box, and a fixed pulley B whose height is lower than the fixed pulley A is arranged on the side of the model box; the lever is located above the side of the fixed pulley B, and is divided into a power arm and a resistance arm through a rotating shaft fulcrum; the vertical height between the fixed pulley B and the lever is greater than the length of the resistance arm when the lever is horizontal; a steel strand is arranged at the end of the resistance arm, bypassing the fixed pulley A and the fixed pulley B and connected to the anti-pulley pile model in the model box; and a loading basket for loading graded loads is connected to the end of the power arm.
[0008] Furthermore, the ends of the resistance arm and the power arm are respectively provided with an A-end connecting hole and a B-end connecting hole, the steel strand is connected to the A-end connecting hole, and the loading basket is connected to the B-end connecting hole.
[0009] Furthermore, when the steel strand is straightened and the loading basket is not loaded, the lever is in a horizontal state, and the steel strand between the resistance arm and the fixed pulley B is perpendicular to the lever and tangent to the fixed pulley B in the straightened state.
[0010] Furthermore, fixed pulley B is located in the same vertical section of the anti-pulling pile model and fixed pulley A, and the vertical height of fixed pulley B from end A of lever is significantly greater than the length of the resistance arm when the lever is horizontal.
[0011] Furthermore, an inclinometer for measuring the inclination of the lever is arranged on the lever.
[0012] Furthermore, the lever tilts θ i When , the ratio of the power arm to the resistance arm is:
[0013]
[0014]
[0015] Where n′ is the lever tilt θ i is the ratio of the power arm to the resistance arm of the lever when the lever is tilted; n is the ratio of the power arm to the resistance arm when the lever is not tilted; l is the length of the resistance arm of the lever; θ i is the inclination angle of the lever when the graded load is applied for the i-th time; h is the height from the lever in the horizontal state to the center of fixed pulley B; r is the radius of fixed pulley B; ξ i is the transition parameter.
[0016] Furthermore, the lever is made of profiled steel.
[0017] Furthermore, the length of the power arm is greater than the length of the resistance arm.
[0018] The beneficial effects of the utility model are as follows: the scheme adopts a model test loading device composed of a pulley, a lever, and a steel strand, and can realize loading in different directions of the anti-pullout pile model by changing the spatial position of the fixed pulley A, and can improve the test accuracy of the lever loading by controlling the height of the fixed pulley B and the lever, and can set different sizes of loading maximum values by changing the length of the lever power arm; the loading device integrates the advantages of the pulley changing the direction of force and the lever saving effort, and has the advantages of convenient and flexible loading methods, large loading maximum values, high testing accuracy, and low cost.
[0019] After obtaining the inclination angle of the lever, the loading device of this scheme can calculate a relatively accurate latest ratio of the power arm to the resistance arm, thereby accurately obtaining the tension loaded on the anti-sliding pile model, laying the foundation for the subsequent accurate acquisition of the ultimate bearing capacity of the pull-out pile. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a schematic diagram of the structure of the pulley and lever principle based on the pulley and lever principle of the pulley model test loading device.
[0021] Among them, 1. pulley model; 2. model box; 3. geotechnical model; 4. fixed pulley A; 5. fixed pulley B; 6. steel strand; 7. lever; 8. pivot point; 9. loading basket; 10. weight; 11. A-end connecting hole; 12. B-end connecting hole. DETAILED DESCRIPTION
[0022] The specific implementation methods of the utility model are described below to facilitate technical personnel in this technical field to understand the utility model, but it should be clear that the utility model is not limited to the scope of the specific implementation methods. For ordinary technical personnel in this technical field, as long as various changes are within the spirit and scope of the utility model defined and determined by the attached claims, these changes are obvious, and all utility model creations using the concept of the utility model are protected.
[0023] The pull-out model test loading device based on the principle of pulley and lever 7 of the present scheme includes a lever 7 and a model box 2. When performing the loading test, the model box 2 is filled with a geotechnical model 3 consistent with the geotechnical properties of the installation location under study, and the pull-out pile model 1 is installed in the geotechnical model 3; the lever 7 is made of steel sections, such as channel steel and square tube steel.
[0024] like Figure 1 As shown, a fixed pulley A 4 is arranged above the model box 2, and the above here is not limited to directly above, as long as it is at any position above the model box 2, so that when performing a loading test, the steel strand 6 between the pull-out pile model 1 and the fixed pulley A can be at different angles with the vertical direction to achieve loading of the pull-out pile model 1 in different directions.
[0025] A fixed pulley B 5 whose height is lower than that of the fixed pulley A 4 is arranged on the side of the model box 2; the fixed pulley B is located in the same vertical section of the pull-out pile model 1 and the fixed pulley A to avoid multiple changes in direction of force during transmission, reduce the transmission efficiency, and affect the subsequent loading on the pull-out pile model 1. Tension conversion.
[0026] The lever 7 is located above and to the side of the fixed pulley B 5, and is divided into a power arm and a resistance arm by a rotating shaft fulcrum 8; the vertical height of the fixed pulley B 5 from the lever 7 should be significantly greater than the length of the resistance arm when the lever is horizontal, so as to reduce the influence of the lever tilt on the ratio of the power arm to the resistance arm. In this scheme, the length of the power arm is preferably greater than the length of the resistance arm, so as to amplify the load loaded on the loading basket 9. The end of the resistance arm is provided with a steel strand 6 that bypasses the fixed pulley A 4 and the fixed pulley B 5 and is connected to the pulley model 1 in the model box 2; the end of the power arm is connected to a loading basket 9 for loading graded loads.
[0027] During implementation, the present scheme preferably provides an A-end connecting hole 11 and a B-end connecting hole 12 at the ends of the resistance arm and the power arm respectively, the steel strand 6 is connected to the A-end connecting hole 11, and the loading basket 9 is connected to the B-end connecting hole 12; the length between the rotating shaft fulcrum 8 and the A-end connecting hole 11 is l, and the length between the rotating shaft fulcrum 8 and the B-end connecting hole 12 is nl, and the loading range can be increased by adjusting the n value.
[0028] The arrangement of the connection hole 11 at the A end and the connection hole 12 at the B end of the present solution can ensure the stability of the connection between the steel strand 6 and the loading basket 9, and can avoid displacement of the steel strand 6 or the loading basket 9, thereby ensuring accurate calculation of the tension transmitted to the anti-slip pile.
[0029] When conducting a loading test, in order to ensure accurate calculation of the tension transmitted to the anti-sliding pile model, the loading device needs to be adjusted before loading. Specifically, when the steel strand 6 is straightened and the loading basket 9 is not loaded, the lever 7 is in a horizontal state, and the steel strand 6 between the resistance arm and the fixed pulley B 5 is perpendicular to the lever 7 in the straightened state and tangent to the fixed pulley B.
[0030] During implementation, the present solution preferably has an inclinometer on the lever 7 for measuring the inclination of the lever 7. After the inclinometer is set, the inclination angle of the lever 7 can be quickly and accurately obtained, so that the ratio of the power arm to the resistance arm can be quickly converted. When the lever 7 is inclined θ i When , the ratio of the power arm to the resistance arm is:
[0031]
[0032]
[0033] Where n′ is the lever tilt θ iis the ratio of the power arm to the resistance arm of the lever when the lever is tilted; n is the ratio of the power arm to the resistance arm when the lever is not tilted; l is the length of the resistance arm of the lever; θ i is the inclination angle of the lever when the graded load is applied for the i-th time; h is the height from the lever in the horizontal state to the center of fixed pulley B; r is the radius of fixed pulley B; ξ i is the transition parameter.
[0034] When the loading device of this scheme is loading the anti-pullout pile model 1, its operation method includes the following main steps:
[0035] S1. Install fixed pulley A 4 above the pullout pile model 1, install fixed pulley B 5 in the same vertical section of the pullout pile model 1 and fixed pulley A 4, and ensure that fixed pulley B 5 is located below the side of fixed pulley A 4 and outside the model box 2.
[0036] S2. Fix the lever 7 above the fixed pulley B 5 to ensure that the plumb line at the connection hole 11 at the A end is tangent to the right wheel surface of the fixed pulley B 5 when the lever 7 is placed horizontally. Adjust the vertical position of the fixed pulley B 5 so that the vertical height of the fixed pulley B 5 from the lever 7 is significantly greater than the length of the resistance arm when the lever 7 is horizontal. Fix one end of the steel strand 6 to the top of the pull-out pile model 1, and the other end passes around the fixed pulley A 4 and the fixed pulley B 5, and finally fixes it at the connection hole 11 at the A end. It is known that the length between the center of the connection hole 12 at the B end and the pivot point 8 is n times the length between the center of the connection hole 11 at the A end and the pivot point 8.
[0037] S3. Adjust the length of the steel strand 6 so that the lever 7 is in a horizontal state when not loaded.
[0038] S4. Hang the loading basket 9 at the connecting hole 12 at the B end, place weights 10 of known mass in the loading basket 9 one by one, and record the mass of the weights 10 placed in each loading stage.
[0039] S5. Repeat step S4 until the pull-out pile model 1 is broken.
[0040] In summary, the loading device of this scheme has the advantages of convenient and flexible loading method, large maximum loading value, high test accuracy and low cost. It will provide the necessary technical means for the model test research on the pull-out bearing characteristics of the transmission tower foundation, thereby providing an important and reliable reference basis for the design and construction of the prototype foundation.
Claims
1. The pulley and lever principle-based anti-pulling model test loading device is characterized by: It includes a lever and a model box, wherein a fixed pulley A is arranged above the model box, and a fixed pulley B with a height lower than the fixed pulley A is arranged on the side of the model box; the lever is located above the side of the fixed pulley B, and is divided into a power arm and a resistance arm through a rotating shaft fulcrum, and the vertical height between the fixed pulley B and the lever is greater than the length of the resistance arm when the lever is horizontal; the end of the resistance arm is provided with a steel strand that bypasses the fixed pulley A and the fixed pulley B and is connected to the pull-out pile model in the model box; the end of the power arm is connected to a loading basket for loading graded loads.
2. The pulley and lever principle-based pull-out model test loading device according to claim 1 is characterized in that: The ends of the resistance arm and the power arm are respectively provided with an A-end connecting hole and a B-end connecting hole, the steel strand is connected to the A-end connecting hole, and the loading basket is connected to the B-end connecting hole.
3. The pulley and lever principle-based pull-out model test loading device according to claim 1, characterized in that: When the steel strand is straightened and the loading basket is not loaded, the lever is in a horizontal state, and the steel strand between the resistance arm and the fixed pulley B is perpendicular to the lever and tangent to the fixed pulley B in the straightened state.
4. The pulley and lever principle-based pull-out model test loading device according to claim 1, characterized in that: The fixed pulley B is located in the same vertical section of the anti-pulling pile model and the fixed pulley A.
5. The pulley and lever principle-based pull-out model test loading device according to claim 1, characterized in that: The lever is provided with an inclinometer for measuring the inclination of the lever.
6. The pulley and lever principle-based pull-out model test loading device according to claim 5, characterized in that: When the lever is tilted θ i When , the ratio of the power arm to the resistance arm is: Where n′ is the lever tilt θ i is the ratio of the power arm to the resistance arm of the lever when the lever is tilted; n is the ratio of the power arm to the resistance arm when the lever is not tilted; l is the length of the resistance arm of the lever; θ i is the inclination angle of the lever when the graded load is applied for the i-th time; h is the height from the lever in the horizontal state to the center of fixed pulley B; r is the radius of fixed pulley B; ξ i is the transition parameter.
7. The pulley and lever principle-based pull-out model test loading device according to any one of claims 1 to 6, characterized in that: The lever is made of section steel.
8. The pulley and lever principle-based pull-out model test loading device according to any one of claims 1 to 6, characterized in that: The length of the power arm is greater than that of the resistance arm.