A modulus of deformation ev2 settlement detection device

Abstract

The utility model provides a kind of modulus Ev2 settlement detection device, including support frame, lifting rod, balance lever, support rod and pressure plate, the support frame is made of cross bar and the fixed rod being set perpendicular to cross bar, two cross bars are parallelly arranged with certain spacing, and the end of two cross bars is connected together by a connecting rod, the end of fixed rod and the middle part of connecting rod are all provided with a through hole, lifting rod passes through through hole and is fixed by a locking mechanism, three lifting rods constitute a stable triangular pedestal, the end of balance lever is inserted into the gap between two cross bars, the other end is suspended and is set to form a cantilever, balance lever is connected between two cross bars by a rotating shaft, the support rod is movably installed at the front end of balance lever, and the pressure plate is connected to the lower end of support rod. The utility model utilizes lever amplification principle, can mechanically amplify tiny vertical settlement, to facilitate more accurate measurement and reading vertical settlement.

Description

Technical Field

[0001] This utility model relates to the field of testing equipment, specifically to a deformation modulus Ev2 settlement testing device for testing the quality of roadbed construction. Background Technology

[0002] The deformation modulus Ev2, as a key parameter for evaluating the deformation characteristics of soil, plays an irreplaceable role in modern geotechnical engineering and roadbed engineering. Ev2 refers to the soil deformation modulus measured during the second loading of a plate load test. It reflects the bearing capacity and deformation characteristics of soil under static load. Compared with Ev1 measured during the first loading, Ev2 eliminates the influence of plastic deformation of the fill material, resulting in less dispersion in the test results and a more accurate reflection of the strength characteristics of the roadbed soil.

[0003] The deformation modulus EV2 (secondary loading modulus) test is a core component of the static plate load test (PLT). It is mainly used to evaluate the deformation characteristics (stiffness) of subgrade, foundation, or base material when subjected to load. Its focus is on accurately measuring the deformation behavior of the material in the elastic stage, thereby evaluating its load-bearing capacity and resistance to deformation. It is widely used for the quality control and acceptance of layered compaction in subgrade filling such as railway subgrade, highway subgrade, and airport roadbed. The core difficulty of the EV2 test lies in settlement measurement. Any error will directly lead to incorrect modulus calculation. Therefore, it is crucial to accurately measure the vertical settlement of the bearing plate under various load levels.

[0004] Traditional measurement methods typically place two measurement points on the outer edge of the bearing plate and determine the settlement by averaging the values. However, in current plate load tests, the settlement of the foundation soil under load is usually very small, especially in the initial stage or in hard soil, which may be only a few tenths of a millimeter or even less. Furthermore, situations such as the bearing plate tilting or eccentric loading may occur. Traditional measurement methods cannot directly obtain the vertical settlement at the center point of the plate. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a deformation modulus Ev2 settlement detection device. Utilizing the lever amplification principle, it can mechanically amplify minute vertical settlement amounts, thereby enabling more accurate measurement of vertical settlement.

[0006] The technical solution adopted in this utility model is as follows: A deformation modulus Ev2 settlement detection device includes a support frame, lifting rods, a balance lever, and a pressure plate. There are two support frames, each consisting of a crossbar and a fixed rod perpendicular to the crossbar. The two crossbars are parallel and spaced at a certain interval, with their ends connected by a connecting rod. There are three lifting rods. Each fixed rod has a through hole at its end and in the middle of the connecting rod. The lifting rods pass through these through holes and are fixed by a locking mechanism. The three lifting rods form a stable triangular base. One end of the balance lever is inserted into the gap between the two crossbars, while the other end is suspended, forming a cantilever structure. The balance lever is connected to the two crossbars via a pivot, forming a lever structure with the pivot as the fulcrum. The support rod is movably mounted at the front end of the balance lever, and the pressure plate is connected to the lower end of the support rod.

[0007] Furthermore, both the crossbar and the fixing rod are made of metal square tubing, and the crossbar and the fixing rod form a T-shaped structure.

[0008] Furthermore, a horizontal bubble is provided on both the crossbar and the fixing rod of one of the support frames.

[0009] Furthermore, the balancing lever is a square steel tube made of metal.

[0010] Furthermore, the front end of the balance lever to the pivot forms a power arm with a length of L1, and the pivot to the rear end of the balance lever forms a resistance arm with a length of L2. The ratio of L1 to L2 is between 1:2 and 1:4, that is, with the pivot as the fulcrum, the length ratio of the power arm to the resistance arm of the balance lever is between 1:2 and 1:4.

[0011] Furthermore, the support rod has a Z-shaped structure and includes a support end, a connecting end, and a measuring end. The support end is vertically installed at the front end of the balance lever, the connecting end is vertically connected to the lower end of the support end, that is, the connecting end is parallel to the balance lever, and the measuring end is vertically connected to the end of the connecting end, that is, the measuring end is parallel to the support end. The measuring end is connected to the pressure plate.

[0012] Furthermore, the pressure plate includes a disc-shaped base plate and a pressure column vertically arranged at the axial center of the pressure plate. The base plate is made of metal, and the pressure column is a cylindrical structure made of metal. A hollow groove is opened in the upper middle part of the pressure column, and a through hole is opened on the peripheral wall of the pressure column corresponding to the hollow groove. The through hole communicates with the hollow groove. The measuring end of the support rod is inserted into the hollow groove of the pressure column and fixed.

[0013] Furthermore, the diameter of the hollowed-out groove is significantly larger than the diameter of the measuring end of the support rod.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention places the measuring point at the center of the pressure plate. By using the fulcrum, power arm (input end), and resistance arm (output end) of the balance lever, the small vertical displacement (settlement) of the pressure plate is amplified using the lever principle, making the readings clearer, easier, and more accurate. This reduces the error in modulus calculation caused by settlement measurement errors, making the test results more accurate. Attached Figure Description

[0015] Appendix Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Appendix Figure 2 This is a top view of the present invention; Appendix Figure 3 This is a side view of the present invention; Appendix Figure 4 It is attached Figure 1 The diagram shows the structure of the pressure plate. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. In the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and embodiments.

[0017] like Figure 1 , Figure 2As shown, a deformation modulus Ev2 settlement detection device includes a support frame 1, lifting rods 2, a balance lever 3, support rods 4, and a pressure plate 5. There are two support frames 1, each consisting of a crossbar 11 and a fixed rod 12 perpendicular to the crossbar 11. Both the crossbar 11 and the fixed rod 12 are made of square metal tubing and form a T-shape. The two crossbars 11 are parallel and spaced at a certain interval, and their ends are connected by a connecting rod 13. The gap between the two crossbars 11 is used to install the balance lever 3. There are three lifting rods 2, each a round metal tubular structure, used for adjusting the measurement... To balance the measuring device, a through hole is provided at the end of the fixed rod 12 and the middle of the connecting rod 13. The lifting rod 2 passes through the through hole and is fixed by a locking mechanism 21. The balance of the measuring device is achieved by adjusting the height of the lifting rod 2. To quickly observe the balance of the measuring device, the three lifting rods 2 form a stable triangular base. A horizontal bubble 15 is provided on the crossbar 11 and the fixed rod 12 of one of the support frames 1. By observing the two horizontal bubbles 15 and adjusting the three lifting rods 2, the balance of the entire measuring device is achieved. Preferably, the lifting rod 2 is provided with a scale to facilitate quick recording of the height of the three support positions at the measurement location.

[0018] The balance lever 3 is a square steel tube made of metal. One end of the balance lever 3 is inserted into the gap between the two crossbars 11, and the other end is suspended to form a cantilever structure. The balance lever 3 is connected to the two crossbars 11 by a pivot 31. The balance lever 3 can rotate about the pivot 31. Preferably, the pivot 31 is a low-friction bearing with high sensitivity. The balance lever 3 forms a lever structure with the pivot 31 as the fulcrum. Figure 3 As shown, the support rod 4 is movably installed at the front end of the balance lever 3. The support rod 4 has a Z-shaped structure and includes a support end 41, a connecting end 42, and a measuring end 43. The support end 41 is vertically installed at the front end of the balance lever 3, and the height of the support end 41 can be adjusted up and down as needed. The connecting end 42 is vertically connected to the lower end of the support end 41, that is, the connecting end 42 is parallel to the balance lever 3. The measuring end 43 is vertically connected to the end of the connecting end 42, that is, the measuring end 43 is parallel to the support end 41. The measuring end 43 is connected to the pressure plate 5. According to the above structure, the support end 41, the connecting end 42, and the measuring end 43 form a Z-shaped structure.

[0019] To calculate the settlement height of the support rod 4, the distance the rear end of the balance lever 3 is raised is measured using the lever principle or the principle of similar triangles. In this invention, the portion from the measuring end 43 of the balance lever 3 to the rotating shaft 31 constitutes the power arm, with a length of L1. The portion from the rotating shaft 31 to the rear end of the balance lever 3 constitutes the resistance arm. A displacement sensor 44 is installed at the end of the resistance arm, which can read the upward displacement distance of the resistance arm. When settlement occurs, the support rod 4 descends with the pressure plate 5, and the power arm of the balance lever 3 moves towards the rotating shaft 31. The axis deflects downwards, and the displacement sensor reads the displacement distance of the resistance arm as it rises upwards. The length of the resistance arm is set as L2, and the ratio of L1 to L2 is between 1:2 and 1:4. That is, with the pivot 31 as the fulcrum, the ratio of the length of the power arm to the resistance arm is between 1:2 and 1:4, and the ratio is preferably an integer ratio. When settlement occurs, the rigid probe descends with the bearing plate, and the power arm of the balance lever 3 deflects downwards with the pivot 31 as the axis. The sensor reads the displacement distance of the resistance arm as it rises upwards. Based on the ratio of L1 to L2 on the balance lever 3, the actual settlement value can be calculated.

[0020] The pressure plate 5 is used to place in the area to be measured. The pressure plate 5 is connected to the lower end of the support rod 4, such as... Figure 4 As shown, the pressure plate 5 includes a disc-shaped base plate 51 and a pressure column 52 vertically arranged at the axial center of the pressure plate 5. The base plate 51 is made of metal material and has a certain weight and rigidity, preferably stainless steel. The pressure column 52 is a cylindrical structure made of metal material. The top of the pressure column 52 is used to support the jack. A hollow groove (not shown) is opened in the upper middle part of the pressure column 52, and a through hole 521 is opened on the peripheral wall of the pressure column 52 corresponding to the hollow groove. The through hole 521 communicates with the hollow groove 521. The diameter of the hollow groove 521 is significantly larger than the diameter of the measuring end 43 of the support rod 4. The measuring end 43 of the support rod 4 is inserted into the hollow groove of the pressure column 52 and fixed so that the support rod 4 can move with the pressure column 52. The fixing method includes but is not limited to clamping and locking, bolt locking, etc. The support rod 4 is designed with a Z-shaped structure to facilitate the insertion of the measuring end 43 into the hollow groove of the pressure column 52.

[0021] The principle and process of this utility model are as follows: Step 1: Place the pressure plate 5 in the area to be measured, set the support frame 1 next to the pressure plate 5 and drive the lifting rod 2 into the compacted soil layer for fixation; insert the measuring end 43 of the support rod 4 into the hollow groove of the pressure column 52 and fix it, and connect the pressure column 52 to the jack and set the preload ≥ 5N; Step 2: Adjust the lifting rod 2 so that the support frame 1 and the balance lever 3 are on the same horizontal line, and establish an absolute horizontal reference by centering the horizontal bubble 15 on both axes; Step 3: Conduct a load test. Start the jack, and the center of the pressure plate 5 sinks, generating a displacement H. The measuring end 43 of the support rod 4 descends with the pressure plate 5, causing the balance lever 3 to rotate around the pivot 31, generating an amplified displacement of 2H at the resistance arm end of the balance lever 3. Step 4: Read the amplified displacement value using the displacement sensor on the balance lever 3, and calculate the actual settlement amount according to the lever ratio.

[0022] This method utilizes the principle of mechanical amplification, which is simple and intuitive, does not rely on a power supply, has strong anti-interference ability, good stability, and relatively low cost. Example

[0023] Scenario: EV2 test of railway subgrade, bearing plate diameter 300mm, settlement resolution required ≤0.01mm.

[0024] operate: 1. Place the support frame 1 next to the bearing plate 5, and drive the lifting rod 2 into the compacted soil layer for fixation; level the support frame 1 and the balance lever 3 using the horizontal bubble 15; 2. The lever arm parameters of the balance lever 3 are: L1=200mm, L2=100mm, which means the magnification is 2 times; 3. Connect a 0.001mm resolution LVDT sensor to the end of the balance lever 3 and measure the magnified displacement of 0.82mm. According to the calculation formula based on the lever principle: L1*0.82=L2*h, the actual center settlement h=0.41mm can be calculated.

[0025] This invention utilizes the lever amplification principle to mechanically amplify the minute vertical displacement settlement of the pressure plate, making the readings clearer, easier, and more accurate, reducing errors in modulus calculation caused by settlement measurement errors, and making the test results more accurate.

[0026] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A modulus of deformation Ev2 settlement detection device comprising a support frame, a lifting rod, a counterbalance lever, a support rod and a load plate, characterised in that: The support frame consists of two crossbars and fixed rods perpendicular to the crossbars. The two crossbars are parallel and spaced at a certain distance, and their ends are connected by a connecting rod. There are three lifting rods. Each fixed rod has a through hole at its end and in the middle of the connecting rod. The lifting rods pass through the through holes and are fixed by a locking mechanism. The three lifting rods form a stable triangular base. One end of the balance lever is inserted into the gap between the two crossbars, and the other end is suspended to form a cantilever structure. The balance lever is connected to the two crossbars by a pivot. The balance lever forms a lever structure with the pivot as the fulcrum. The support rod is movably installed at the front end of the balance lever, and the pressure plate is connected to the lower end of the support rod.

2. The modulus Ev2 settlement detection apparatus of claim 1, wherein: Both the crossbar and the fixing bar are made of metal square tubing, and the crossbar and the fixing bar form a T-shaped structure.

3. The modulus Ev2 settlement detection apparatus of claim 1, wherein: A horizontal bubble is provided on both the crossbar and the fixing rod of one of the support frames.

4. The modulus Ev2 settlement detection apparatus of claim 1, wherein: The balancing lever is a square steel tube made of metal.

5. The modulus Ev2 settlement detection apparatus of claim 1, wherein: The front end of the balance lever to the pivot forms the power arm, with a length of L1. The pivot to the rear end of the balance lever forms the resistance arm, with a length of L2. The ratio of L1 to L2 is between 1:2 and 1:4, that is, with the pivot as the fulcrum, the length ratio of the power arm to the resistance arm is between 1:2 and 1:

4.

6. The modulus Ev2 settlement detection apparatus of claim 1, wherein: The support rod has a Z-shaped structure and includes a support end, a connecting end, and a measuring end. The support end is vertically installed at the front end of the balance lever. The connecting end is vertically connected to the lower end of the support end, that is, the connecting end is parallel to the balance lever. The measuring end is vertically connected to the end of the connecting end, that is, the measuring end is parallel to the support end. The measuring end is connected to the pressure plate.

7. The modulus Ev2 settlement detection apparatus of claim 6, wherein: The pressure plate includes a disc-shaped base plate and a pressure column vertically arranged at the center of the pressure plate. The base plate is made of metal, and the pressure column is a cylindrical structure made of metal. A hollow groove is opened in the upper middle part of the pressure column, and a through hole is opened on the peripheral wall of the pressure column corresponding to the hollow groove. The through hole communicates with the hollow groove. The measuring end of the support rod is inserted into the hollow groove of the pressure column and fixed.

8. The modulus Ev2 settlement detection apparatus of claim 7, wherein: The diameter of the hollowed-out groove is significantly larger than the diameter of the measuring end of the support rod.

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