Soil matrix rebound modulus testing device

Abstract

The utility model discloses a soil matrix rebound modulus testing device, which relates to the technical field of soil matrix rebound modulus testing and comprises a pressure device, a bearing plate, a deflectometer and a control device, the pressure device is used for being arranged on a loading vehicle, the bearing plate is used for being arranged on a soil matrix, and the control device is respectively in signal connection with the pressure device and the deflectometer. The control device can control the pressure device to apply vertically downward pressure to the bearing plate, the deflectometer can detect the displacement of the bearing plate when the bearing plate is pressed, the deflectometer can transmit the pressure applied to the bearing plate and the displacement of the bearing plate to the control device, and a mathematical model can be input into the control device in advance. And the rebound modulus of the soil matrix can be obtained according to a pre-input mathematical model, the displacement of the bearing plate and a pressure value applied by the pressure device, and the device can reduce test errors, so that the test result is more accurate.

Description

Technical Field

[0001] The utility model relates to the technical field of soil foundation rebound modulus test, in particular to a soil foundation rebound modulus test device. Background Art

[0002] The soil subgrade elastic modulus is one of the core technical indicators for pavement structure design. At present, the roadbed elastic modulus is mostly tested according to the "Highway Roadbed and Pavement Field Test Regulations" (JTG 3450-2019). In practice, the bearing plate method is widely used. The bearing plate method is to load and unload the bearing plate placed on the roadbed surface step by step, and use the deflectometer to measure the displacement value of the bearing plate. Based on the displacement obtained under each load level and the corresponding load, the soil subgrade elastic modulus is obtained by back-calculating the elastic half-space theoretical formula. However, in the actual bearing plate method test, the single-point soil subgrade surface deflection test usually takes more than 3 hours, which is inefficient and requires a lot of physical strength for the test personnel. Chinese patent CN208501656U discloses a field bearing plate method soil subgrade elastic modulus measurement device. When using the device, the staff only needs to adjust the power part to realize the load loading and unloading function, which improves the efficiency of the test to a certain extent. However, during the test, manual reading or operation is still required, which will introduce human influence into the test process, resulting in large errors in the test results. At the same time, since the test is carried out by step-by-step loading and unloading, the test data at each level must be calculated in a complicated way to obtain the final rebound modulus of the measuring point, and large errors will also occur in the process of direct manual calculation on site. Therefore, there is an urgent need for a soil base rebound modulus test device that can reduce test errors and make test results more accurate. Utility Model Content

[0003] The utility model aims to provide a soil base rebound modulus test device to solve the problems existing in the above-mentioned prior art, reduce the test error and make the test result more accurate.

[0004] To achieve the above purpose, the utility model provides the following solutions:

[0005] The utility model provides a soil foundation rebound modulus test device, comprising: a pressure device, a bearing plate, a deflection meter and a control device, wherein the pressure device is used to be arranged on a loading vehicle, the bearing plate is used to be arranged on a soil foundation, the control device is signal-connected with the pressure device and the deflection meter respectively, the control device can control the pressure device to apply vertical downward pressure to the bearing plate, the deflection meter can detect the displacement of the bearing plate when it is under pressure, the pressure device and the deflection meter can transmit the pressure applied by the pressure device on the bearing plate and the displacement of the bearing plate to the control device, a mathematical model can be pre-input in the control device, and the rebound modulus of the soil foundation can be obtained according to the pre-input mathematical model, the displacement of the bearing plate and the pressure value applied by the pressure device.

[0006] Preferably, the pressure device includes an electrically driven hydraulic jack and a pressure sensor, wherein the pressure sensor is capable of detecting the pressure of the electrically driven hydraulic jack on the bearing plate, and the pressure sensor and the electrically driven hydraulic jack are both connected to the control device signal.

[0007] Preferably, the electrically driven hydraulic jack comprises a hydraulic cylinder, a housing and an oil control assembly, the cylinder body of the hydraulic cylinder being arranged in the housing, the housing being arranged on the upper side of the bearing plate, a through hole being arranged on the upper side of the housing, the hydraulic rod of the hydraulic cylinder being arranged vertically and one end extending from the through hole, the end of the hydraulic rod extending from the through hole being used for connection to the loading vehicle, the oil control assembly being connected to the control device by signal, and the oil control assembly being able to supply oil to or return oil from the cylinder body of the hydraulic cylinder under the control of the control device.

[0008] Preferably, the deflection meter includes a Beckman beam, a dial indicator and a support member, one end of the Beckman beam is arranged on the supporting plate, the support of the Beckman beam is fixedly arranged on the ground, the supporting member is fixedly arranged on the ground, the dial indicator is fixedly connected to the support member, the probe of the dial indicator is in contact with the upper side of one end of the Beckman beam away from the supporting plate, and the dial indicator is connected to the control device signal.

[0009] Preferably, it also includes a connecting member and a connecting rod, one end of the connecting rod is used to be detachably connected to the loading vehicle, and the other end is detachably connected to one side of the connecting member, and the other side of the connecting member is provided with a mounting groove, and one end of the loading rod of the electrically driven hydraulic jack can be snapped into the mounting groove.

[0010] Preferably, the pressure sensor is arranged between the connecting rod and the loading vehicle, the pressure sensor is detachably connected to the loading vehicle, and one end of the connecting rod is detachably connected to the pressure detection end of the pressure sensor.

[0011] Preferably, the control device is a programmable control device.

[0012] Preferably, a plurality of deflection meters are provided, and each deflection meter is signal-connected to the control device.

[0013] Compared with the prior art, the utility model has achieved the following technical effects:

[0014] The soil base rebound modulus testing device provided by the utility model is provided with a control device, which can control the pressure device to apply pressure to the bearing plate, and can also obtain the soil base rebound modulus according to the pre-input mathematical model, the displacement of the bearing plate and the pressure value applied by the pressure device. The entire experimental process is completed through the control device, which reduces labor costs, improves work efficiency, and avoids errors caused by manual reading or manual calculation, making the test results more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of the structure of a soil base rebound modulus test device provided by the utility model;

[0017] Figure 2 A schematic diagram of the structure of a control device in a soil base rebound modulus test device provided by the utility model;

[0018] Figure 3 for Figure 1 Front view of the dial indicator;

[0019] Figure 4 for Figure 1 A cross-sectional view of the middle connecting piece parallel to the axial direction of the hydraulic rod;

[0020] In the figure: 1-electrically driven hydraulic jack, 11-hydraulic rod, 12-housing, 13-oil control assembly, 2-pressure sensor, 3-bearing plate, 4-deflection meter, 41-Beckman beam, 42-dial indicator, 5-control device, 6-connecting rod, 7-connecting piece, 71-installation slot, 8-loading car. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] The utility model aims to provide a soil base rebound modulus test device to solve the problems existing in the above-mentioned prior art, reduce the test error and make the test result more accurate.

[0023] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] Embodiment 1

[0025] This embodiment provides a soil base rebound modulus test device, such as Figure 1-4 As shown, it includes: a pressure device, a bearing plate 3, a deflection meter 4 and a control device 5. The pressure device is used to be set on a loading vehicle 8, and the bearing plate 3 is used to be set on a soil foundation. The control device 5 is signal-connected with the pressure device and the deflection meter 4 respectively. The control device 5 can control the pressure device to apply vertical downward pressure to the bearing plate 3. The deflection meter 4 can detect the displacement of the bearing plate 3 when it is pressed. The pressure device and the deflection meter 4 can transmit the pressure applied to the bearing plate 3 to the control device 5. The mathematical model can be pre-input in the control device 5, and the rebound modulus of the soil foundation can be obtained according to the pre-input mathematical model, the displacement of the bearing plate 3 and the pressure value applied by the pressure device.

[0026] The soil base rebound modulus test device provided in this embodiment is provided with a control device 5. The control device 5 can control the pressure device to apply pressure to the bearing plate 3, and can also obtain the soil base rebound modulus according to the pre-input mathematical model, the displacement of the bearing plate 3 and the pressure value applied by the pressure device. The entire experimental process is completed through the control device 5, which reduces labor costs, improves work efficiency, and avoids errors caused by manual reading or manual calculation, making the test results more accurate.

[0027] In a preferred implementation of this embodiment, the pressure device includes an electrically driven hydraulic jack 1 and a pressure sensor 2. The pressure sensor 2 can detect the pressure of the electrically driven hydraulic jack 1 on the bearing plate 3. The pressure sensor 2 and the electrically driven hydraulic jack 1 are both connected to the control device 5 by signals. The electrically driven hydraulic jack can use an electrically driven hydraulic jack in the prior art.

[0028] In a preferred implementation of the present embodiment, the electrically driven hydraulic jack 1 includes a hydraulic cylinder, a housing 12 and an oil control assembly 13. The cylinder body of the hydraulic cylinder is arranged in the housing 12. The housing 12 is arranged on the upper side of the bearing plate 3. A through hole is arranged on the upper side of the housing 12. The hydraulic rod 11 of the hydraulic cylinder is arranged vertically and one end extends out of the through hole. The end of the hydraulic rod 11 extending out of the through hole is used to be connected to the loading vehicle 8. The oil control assembly 13 is connected to the control device 5 by signal. The oil control assembly 13 can deliver or return oil to the cylinder body of the hydraulic cylinder under the control of the control device 5. The housing 12 can protect the cylinder body of the hydraulic cylinder. At the same time, compared with the method of applying force to the bearing plate through the housing 12 and the method of directly applying force to the bearing plate using the hydraulic rod 11, the contact area between the housing 12 and the bearing plate 3 is larger, and the force on the bearing plate 3 is more uniform. The oil control assembly 13 includes an oil storage cylinder, an oil delivery pipe, an oil return pipe, an oil delivery motor and an oil return motor. The two ends of the oil delivery pipe and the two ends of the oil return pipe are respectively connected and communicated with the cylinder body of the oil storage cylinder and the hydraulic cylinder. The oil delivery electrode and the oil return motor are respectively arranged on the oil delivery pipe and the oil return pipe. Solenoid valves are arranged on the oil delivery pipe and the oil return pipe. The oil delivery motor, the oil return motor and each solenoid valve are connected to the control device 5 by signal. The control device 5 can control the opening and closing of the oil delivery motor, the oil return motor and the solenoid valve. The oil control assembly can also use the hydraulic control system in the prior art.

[0029] In a preferred implementation of the present embodiment, the deflection meter 4 includes a Beckman beam 41, a dial indicator 42 and a support. One end of the Beckman beam 41 is arranged on the bearing plate 3, the support of the Beckman beam 41 is fixedly arranged on the ground, the support is fixedly arranged on the ground, the dial indicator 42 is fixedly connected to the support, the probe of the dial indicator 42 contacts the upper side of the end of the Beckman beam 41 away from the bearing plate 3, and the dial indicator 42 is connected to the control device 5 by signal. In use, the distance between one end of the Beckman beam 41 arranged on the bearing plate 3 and the support is greater than the distance between the other end and the support. When the pressure device applies pressure to the bearing plate 3, the soil foundation under the bearing plate 3 sinks, and one end of the Beckman beam 41 arranged on the bearing plate 3 moves downward under the action of the weight of the Beckman beam 41 itself, and the other end is displaced upward, and the dial indicator 42 can measure the displacement value and transmit it to the control device 5. Of course, one end of the Beckman beam 41 can also be fixedly arranged on the bearing plate. Among them, the dial indicator 42 is preferably a digital display dial indicator.

[0030] In a preferred implementation of this embodiment, the soil base rebound modulus test device provided in this embodiment also includes a connector 7 and a connecting rod 6, one end of the connecting rod 6 is used to be detachably connected to the loading vehicle 8, and the other end is detachably connected to one side of the connector 7, and the other side of the connector 7 is provided with a mounting groove 71, and one end of the hydraulic rod 11 of the hydraulic cylinder can be snapped into the mounting groove 71. The mounting groove 71 on the connector 7 can limit the hydraulic rod 11, thereby preventing the hydraulic rod 11 from deflecting during the force application process, thereby enhancing the reliability of the device. Among them, the two ends of the connecting rod 6 are threadedly connected to the connector 7 and the loading vehicle 8 respectively.

[0031] In a preferred implementation of this embodiment, the pressure sensor 2 is disposed between the connecting rod 6 and the loading vehicle 8, the pressure sensor 2 is detachably connected to the loading vehicle 8, and one end of the connecting rod 7 is detachably connected to the pressure detection end of the pressure sensor 2. In the process of the pressure device applying pressure to the load-bearing plate 3, the pressure of the hydraulic rod 11 is transmitted to the connecting rod 6 through the connecting piece 7, the connecting rod 6 can transmit the pressure to the pressure detection end of the pressure sensor 2, the pressure sensor 2 can transmit the pressure value to the control device 5, and the control device 5 can process the pressure value according to a preset program.

[0032] In a preferred implementation of this embodiment, the control device 5 is a programmable control device. Specifically, the control device 5 includes a control device and a computer, and the control device 5 is connected to the computer via Bluetooth.

[0033] In a preferred implementation of this embodiment, a plurality of deflectometers 4 are provided, and each deflectometer 4 is signal-connected to the control device 5. During the test, the control device 5 can obtain the displacement values ​​on each deflectometer 4 and obtain the average as the measured displacement value, thereby reducing the error and making the test result more accurate. Preferably, two deflectometers 4 are provided.

[0034] Embodiment 2

[0035] When using the soil base rebound modulus test device in Example 1 to conduct the test, the steps are as follows:

[0036] Test preparation: clean the soil foundation surface to ensure that there is no debris on the soil foundation surface; use a truck with a rear axle weight of not less than 60kN as the loading vehicle 8, use a floor scale to weigh the load Q of the loading vehicle 8 on the soil foundation when it is parked on the soil foundation, and at the same time, measure the wheelbase T1 between the front and rear axles of the loading vehicle 8, set a stiffening beam near the rear axle of the vehicle, measure the distance T2 between the stiffening beam and the rear axle of the vehicle, and park the loading vehicle 8 at the test point of the soil foundation rebound modulus; sprinkle a small amount of dry and clean fine sand on the soil foundation surface (the fine sand cannot cover the entire soil foundation surface of the measuring point to avoid the accumulation of fine sand affecting the test results); hang a plumb bob on the stiffening beam, place a bearing plate 3 with a diameter of D and a thickness of h on the soil foundation surface, and align the center of the bearing plate 3 with the tip of the plumb bob, and use a level to calibrate the bearing plate 3 horizontally, and put away the plumb bob after the calibration is completed.

[0037] Install the pressure device and the deflection meter 4: arrange the pressure sensor 2, the connecting rod 6, the connecting piece 7 and the housing 12 with the built-in hydraulic cylinder in sequence from the stiffening beam to the bearing plate and connect them respectively; then install the deflection meter 4 on the bearing plate 3, and adjust the probe of the dial indicator 42 to contact the upper side of the Beckmann beam 41 away from the end of the bearing plate 3; then connect the data interface of the control device 5 to the data interfaces of the pressure sensor 2, the oil control component 13 and the dial indicator 42 respectively.

[0038] Test process: Turn on the control device 5, and the test is automatically controlled by the control device 5, including:

[0039] Preloading: According to the test principle of the soil base rebound modulus of the bearing plate method, in order to ensure the close contact between the rigid bearing plate 3 and the soil base, preloading is required before the formal loading and unloading test. The oil control component 13 supplies oil to the hydraulic cylinder, and the pressure device applies pressure to the bearing plate 3. When the pressure value obtained by the control device 5 on the pressure sensor is the set value (the set value is preferably 0.05MPa-0.1MPa), the control device 5 sends a signal to the pressure device to stop pressurizing and maintain the pressure value. After maintaining the pressure for 1 minute, the control device 5 sends an unloading instruction to the pressure device, and the pressure device releases the pressure on the bearing plate 3 to complete the preloading; after that, the dial indicator 42 is manually adjusted to zero.

[0040] Step-by-step loading and unloading test: The control device 5 controls the pressure device to apply pressure to the load plate. i=0.2MPa pressure. When the pressure sensor 2 detects that the pressure value is 0.2MPa, the control device 5 sends a command to the pressure device to stop pressurizing and maintain the pressure value. After maintaining the pressure for 1 minute, the control device 5 reads the displacement value w1 on the two dial gauges 42. Then the control device 5 sends an unloading command to the pressure device. After unloading for 1 minute, the control device 5 reads the displacement value w2 on the dial gauge. The control device 5 converts w1 and w2 according to the position of the Beckmann beam 41 support to obtain the downward displacement of the bearing plate 3 (which can be converted according to similar triangles). w1 is converted to obtain the displacement w of the bearing plate 3 during loading. 前 , w2 is converted to obtain the displacement w of the pressure plate after unloading 后 For example, the distance between the end of the Beckman beam 41 set on the bearing plate 3 and the support is 6m, and the distance between the other end and the support is 3m, w 前 =w1×2.

[0041] Among them, in order to ensure that the value on the dial indicator 43 will not be input into the control device 5 during the preloading process, the control device 5 can determine whether to preload according to the value on the pressure sensor. When the value on the pressure sensor is less than 0.1MPa, the control device 5 will not receive the value on the dial indicator 43. When the value on the pressure sensor is greater than 0.1MPa, the control device 5 will receive the value on the pressure sensor.

[0042] Determination of the influence quantity: Remove the pressure device, and the control device 5 reads the data on the dial gauge 42 and records it as w 移除压力装置后 Then the loading vehicle is driven away, and the control device 5 reads the data on the dial gauge 42 and records it as w 加载车驶出后 .

[0043] Data calculation: The following mathematical model is pre-entered into the control device 5, and the following data can be calculated:

[0044] (1) Total impact:

[0045] a=w 移除千斤顶后 -w 加载车驶出后

[0046] (2) Influence quantity at each level of pressure:

[0047]

[0048] Where:

[0049] a i is the influence quantity under the i-th level load; T1 is the front and rear wheelbase of the loading vehicle; T2 is the distance between the stiffening beam and the rear axle of the truck; D is the diameter of the load-bearing plate; p i is the bearing plate pressure under the i-th level load; a is the total influence.

[0050] (3) Calculation value of elastic modulus deformation:

[0051] L i =d i +a i

[0052] Where: d i is the empirical value of the elastic modulus at each level of pressure, d i =w 前i -w 后i ; a i is the influence quantity under the i-th level load.

[0053] (4) Soil foundation rebound modulus under various loads:

[0054]

[0055] Where: E i is the soil resilience modulus under the corresponding i-th level load; μ0 is the Poisson's ratio of the soil; L i is relative to the load p i The calculated value of the i-th level springback deformation at

[0056] (5) Value of soil resilience modulus at the test point:

[0057]

[0058] In addition, in the above calculation process, if there are multiple dial gauges, the average value of the values ​​measured by the multiple dial gauges is calculated during loading and after unloading, and the average value is recorded as and

[0059] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A soil base rebound modulus test device, characterized in that: include: A pressure device, a bearing plate, a deflection meter and a control device, wherein the pressure device is used to be arranged on a loading vehicle, and the bearing plate is used to be arranged on a soil foundation. The control device is respectively connected to the pressure device and the deflection meter by signals. The control device can control the pressure device to apply vertical downward pressure to the bearing plate, and the deflection meter can detect the displacement of the bearing plate when it is under pressure. The pressure device and the deflection meter can transmit the pressure applied by the pressure device on the bearing plate and the displacement of the bearing plate to the control device. A mathematical model can be pre-input into the control device, and the rebound modulus of the soil foundation can be obtained according to the pre-input mathematical model, the displacement of the bearing plate and the pressure applied by the pressure device.

2. The soil base rebound modulus test device according to claim 1, characterized in that: The pressure device includes an electrically driven hydraulic jack and a pressure sensor. The pressure sensor can detect the pressure of the electrically driven hydraulic jack on the bearing plate. Both the pressure sensor and the electrically driven hydraulic jack are connected to the control device by signals.

3. The soil base rebound modulus test device according to claim 2, characterized in that: The electrically driven hydraulic jack comprises a hydraulic cylinder, a housing and an oil control assembly. The cylinder body of the hydraulic cylinder is arranged in the housing. The housing is arranged on the upper side of the bearing plate. A through hole is arranged on the upper side of the housing. The hydraulic rod of the hydraulic cylinder is arranged vertically and one end extends out of the through hole. The end of the hydraulic rod extending out of the through hole is used to be connected to the loading vehicle. The oil control assembly is connected to the control device by signal. The oil control assembly can supply oil or return oil to the cylinder body of the hydraulic cylinder under the control of the control device.

4. The soil base rebound modulus test device according to claim 3, characterized in that: The deflection meter includes a Beckman beam, a dial indicator and a support. One end of the Beckman beam is arranged on the supporting plate, the support of the Beckman beam is fixedly arranged on the ground, the supporting member is fixedly arranged on the ground, the dial indicator is fixedly connected to the supporting member, the probe of the dial indicator is in contact with the upper side of one end of the Beckman beam away from the supporting plate, and the dial indicator is connected to the control device signal.

5. The soil base rebound modulus test device according to claim 4, characterized in that: It also includes a connecting piece and a connecting rod, one end of the connecting rod is used to be detachably connected to the loading vehicle, and the other end is detachably connected to one side of the connecting piece. A mounting groove is provided on the other side of the connecting piece, and one end of the loading rod of the electrically driven hydraulic jack can be snapped into the mounting groove.

6. The soil base rebound modulus test device according to claim 5, characterized in that: The pressure sensor is arranged between the connecting rod and the loading vehicle. The pressure sensor is detachably connected to the loading vehicle. One end of the connecting rod is detachably connected to the pressure detection end of the pressure sensor.

7. The soil base rebound modulus test device according to claim 1, characterized in that: The control device is a programmable control device.

8. The soil base rebound modulus test device according to claim 3, characterized in that: A plurality of deflection meters are provided, and each of the deflection meters is connected to the control device by signal.

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