CN211978534U - Rockfill material testing device - Google Patents
Rockfill material testing device Download PDFInfo
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- CN211978534U CN211978534U CN201922244842.2U CN201922244842U CN211978534U CN 211978534 U CN211978534 U CN 211978534U CN 201922244842 U CN201922244842 U CN 201922244842U CN 211978534 U CN211978534 U CN 211978534U
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Abstract
The utility model discloses a rockfill material testing device, which is characterized by comprising a container, a water permeable bottom plate, a water permeable top plate, a round cylinder, a pressurizing mechanism, a measuring mechanism and a control system; the outer diameters of the water-permeable bottom plate and the water-permeable top plate are matched with the inner diameter of the circular cylinder, the water-permeable bottom plate is arranged at the bottom of the container, and a space for containing the rockfill material is formed by the water-permeable bottom plate, the circular cylinder and the water-permeable top plate; the pressurizing mechanism is used for applying downward testing force to the water-permeable top plate; the measuring mechanism is used for measuring the displacement and the testing force of the permeable top plate; the control system is respectively communicated with the measuring mechanism and the pressurizing mechanism and is used for receiving and processing the data acquired by the measuring mechanism and controlling the pressurizing mechanism. The utility model provides a test device can be used for studying the humidifying characteristic of rockfill material under the axial stress state and the softening characteristic under the long-term state of soaking, finally obtains the rockfill material humidifying constitutive model parameter and unipolar rheological model parameter under the unipolar stress state.
Description
Technical Field
The utility model relates to a water and electricity hydraulic engineering rockfill material characteristic test technical field, concretely relates to rockfill material test device.
Background
For high face rockfill dams, deformation control is the core of dam design and construction. The deformation of the face rockfill dam mainly comprises the soaking, wetting and rheological deformation of the rockfill body.
The wet deformation of the rockfill material refers to the deformation of the rockfill material when meeting water under a certain stress state. The reason for this is that some particles soften and break when they encounter water and contact the water-soaked lubricating particles, which triggers an imbalance in the forces applied to the particles, causing the particles to rearrange, adjust and gradually restore balance, causing a redistribution of stresses in the rock-fill mass and deformation. Rheology is a fundamental deformation characteristic of a rock mass, which is an aggregate of rock particles with a certain gradation, whose stress and deformation are functions of time. Under the action of the framework stress, the rearrangement of the particles and the dislocation of the framework have time effect, and the internal stress of the rockfill particles must be adjusted. According to the measured data, the dam body can generate humidification deformation under the actions of primary water storage, fluctuation of the water level of the reservoir in the operation period, rainwater immersion in the dam body or evaporation and the like. The wet deformation generated by upstream rockfill in the primary water storage process of the rockfill dam often influences the safe operation of the dam, the light can generate a wet-falling crack at the top of the dam, the heavy can cause deep cracks at important parts such as a dam abutment and the like, even a leakage channel is formed, and the safety of the dam body is threatened.
Due to the importance of the humidifying and softening characteristics of the rockfill material, the complexity of a deformation mechanism, the difficulty of a humidifying and softening test and the like, at present, in the design of a high rockfill dam, no matter the experiment and theory of humidifying, softening and deformation of the rockfill material or numerical simulation is well solved, and the research on the rheological characteristics under the long-term soaking effect is not carried out by people.
SUMMERY OF THE UTILITY MODEL
In order to overcome the problem that exists among the prior art, the utility model provides an experimental test device of rockfill material can carry out long-term stable pressure test to the rockfill material to gather the information of meeting an emergency in the test procedure, provide data support reliably for the characteristic research of rockfill material. The specific technical scheme is as follows.
A rockfill material test device is characterized by comprising a container, a water permeable bottom plate, a water permeable top plate, a circular cylinder, a pressurizing mechanism, a measuring mechanism and a control system;
the outer diameters of the water-permeable bottom plate and the water-permeable top plate are matched with the inner diameter of the circular cylinder, the water-permeable bottom plate is placed at the bottom of the container, the water-permeable bottom plate and the water-permeable top plate are respectively positioned at the lower end and the upper end of the circular cylinder, and a space for containing rockfill materials is defined by the water-permeable bottom plate, the circular cylinder and the water-permeable top plate; the pressurizing mechanism is used for applying downward testing force to the water-permeable top plate; the measuring mechanism is used for measuring the displacement of the permeable top plate and the testing force; the control system is respectively communicated with the measuring mechanism and the pressurizing mechanism and is used for receiving and processing the data acquired by the measuring mechanism and controlling the pressurizing mechanism.
Further, the bottom of the side wall of the container is also provided with at least three positioning bolts along the circumferential direction, the positioning bolts penetrate through the side wall of the container along the radial direction of the circular cylinder, and the positioning bolts are in threaded connection with the side wall of the container; the positioning bolt can be switched between a positioning position and a non-positioning position, when the positioning bolt is positioned at the positioning position, the bottom of the circular cylinder is supported at the top of the positioning bolt, the bottom of the circular cylinder is not higher than the upper surface of the water-permeable bottom plate, and when the positioning bolt is positioned at the non-positioning position, the positioning bolt is positioned at the outer side of the circular cylinder.
Further, the pressurizing mechanism comprises a motor, a screw rod mechanism and a bearing plate, the motor is used for driving a screw rod of the screw rod mechanism to move up and down, and the bearing plate is located above the water-permeable top plate. Preferably, the lower end of the screw rod is also provided with a thrust bearing.
Furthermore, the measuring mechanism comprises a data acquisition module, a dynamometer and a dial indicator for measuring the displacement of the water permeable top plate; the top center of the pressure bearing plate is provided with the dynamometer, and the dynamometer and the dial indicator are respectively communicated with the data acquisition module.
The utility model provides a test device can be used for studying the humidifying characteristic of rockfill material under the axial stress state and the softening characteristic under the long-term state of soaking, finally obtains the rockfill material humidifying constitutive model and the unipolar compression rheological model under the unipolar stress state.
Drawings
FIG. 1 is a schematic view of the rockfill material testing apparatus of the present invention;
FIG. 2 is a schematic bottom view of the container of the present invention;
FIG. 3 is a flow chart of the long-term soaking, humidifying and softening test of the rockfill material of the present invention.
In the figure: the device comprises a control system 1, a data acquisition module 2, a motor 3, a chain wheel 4, a screw rod mechanism 5, a screw rod 6, a support 7-1, a base 7-2, a dynamometer 8, a dial indicator 9, a rock-fill material sample 10, a water-permeable bottom plate 11-1, a water-permeable top plate 11-2, a round cylinder 12, a bearing plate 13, a container 14, a positioning bolt 15 and a water injection hole 16.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1-3, a rockfill testing device comprises a container 14, a water permeable bottom plate 11-1, a water permeable top plate 11-2, a circular cylinder 12, a pressurizing mechanism, a measuring mechanism and a control system 1;
the outer diameters of the water-permeable bottom plate 11-1 and the water-permeable top plate 11-2 are matched with the inner diameter of the circular cylinder 12, so that the water-permeable bottom plate 11-1 and the water-permeable top plate 11-2 can be accommodated in the circular cylinder 12 without a large gap, for example, the inner diameter of the circular cylinder 12 is 0.5-3mm larger than the outer diameters of the water-permeable bottom plate 11-1 and the water-permeable top plate 11-2;
the permeable bottom plate 11-1 is placed at the bottom of the container 15, the permeable bottom plate 11-1 and the permeable top plate 11-2 are respectively positioned at the lower end and the upper end of the circular cylinder 14, and the permeable bottom plate, the circular cylinder and the permeable top plate enclose a space for containing the rockfill material 10;
the pressurizing mechanism is used for applying downward testing force to the permeable top plate 11-2; in this embodiment, the pressurizing mechanism includes a motor 3, a sprocket 4, a screw mechanism 5 and a bearing plate 13, the motor 3 drives a screw 6 of the screw mechanism 5 to move up and down through the sprocket-chain mechanism, and the bearing plate 13 is located above the water permeable top plate 11-2. The container 14 is positioned on the base 7-2, the bracket 7-1 is fixed on the base 7-2, and the bracket 7-1 is used for fixing the screw rod mechanism 5. Preferably, in order to eliminate the influence of the rotation torque of the screw 6 on the pressure bearing plate 13, a thrust bearing (not shown) is further provided at the lower end of the screw 6; the motor 3 can be a servo motor and is controlled by the control system 1.
It should be noted that the pressurizing mechanism may also be in other structural forms, such as a hydraulic cylinder for providing pressure, as long as it is convenient to provide a testing force to the rockfill material sample.
The measuring mechanism is used for measuring the displacement of the permeable top plate 11-2 and the testing force applied by the pressurizing mechanism (the testing force can be converted into the compressive stress applied to the rockfill material sample); the control system 1 is respectively communicated with the measuring mechanism and the pressurizing mechanism, and is used for receiving and processing data acquired by the measuring mechanism and controlling the pressurizing mechanism; the communication mode can be data line connection communication or wireless communication, and the control system 1 can simultaneously control a plurality of test devices to perform tests; the control system 1 may employ a computer having a display function, and can draw the acquired data into a corresponding curve.
The measuring mechanism comprises a data acquisition module 2, a dynamometer 8 and a dial indicator 9 for measuring the displacement of the permeable top plate 11-2; the center of the top of the water-permeable top plate 11-2 is provided with a dynamometer 8, and the dynamometer 8 and a dial indicator 9 are respectively communicated with the data acquisition module 2 to transmit detection data. The dial indicator 9 can be fixedly arranged on the container 14 through a support, a plurality of dial indicators can be symmetrically distributed around the permeable top plate 11-2 according to actual conditions, if the readings of the dial indicators are inconsistent, and the difference exceeds a set error range, the rockfill material sample is determined to be unqualified to be prepared, and the sample preparation is required to be carried out again to carry out experiments.
Preferably, the bottom of the side wall of the container 14 is further provided with at least three positioning bolts 15 along the circumferential direction, the positioning bolts 15 penetrate through the side wall of the container 14 along the radial direction of the circular cylinder, and the positioning bolts 15 are in threaded connection with the side wall of the container 14; the positioning bolt 15 can be switched between a positioning position and a non-positioning position in a screwing mode, when the positioning bolt 15 is screwed to the positioning position, the bottom of the circular cylinder 12 is supported on the top of the positioning bolt 15, the bottom of the circular cylinder 12 is not higher than the upper surface of the water-permeable bottom plate 11-1, and when the positioning bolt 15 is screwed back to the non-positioning position, the positioning bolt 15 is positioned on the outer side of the circular cylinder; when the test is in progress, the positioning bolt 15 is in a non-positioning position, and the circular cylinder 12 can freely move downwards along with the rockfill material test along with the compression of the rockfill material test sample, so that the influence of the friction force between the circular cylinder and the rockfill material test sample on the test precision can be reduced; if the positioning bolt 15 is not used, the circular cylinder 12 is always abutted against the container 14 or the water-permeable bottom plate 11-1, so that the circular cylinder 12 generates large upward friction force on the rockfill material test during the compression test, and the data obtained by the test is far from the actual situation.
After the container 14 is filled with water, in order to prevent water leakage from the positioning bolt, the screw hole on the sidewall of the container 14, which is matched with the positioning bolt 15, may be made of an elastic material, so as to form a sealing effect on the threaded connection.
To fill the container 14 with water, a water filling port 16 may be provided in a side wall of the container, or water may be directly filled from an open port of the container without providing a water filling port.
The test method adopting the rockfill material test device mainly comprises the following steps:
the test device mounting step comprises:
step S1: screwing the positioning bolt 15 to a positioning position, erecting the circular cylinder 12 on the positioning bolt 15, placing a water permeable cloth (not shown) on the water permeable bottom plate 11-1, and preparing the rockfill material sample 10 in a space formed by the circular cylinder 12 and the water permeable bottom plate 11-1; calculating and determining the mass of each grain group according to the dry density, the sample size and the grading curve required by the test, weighing corresponding samples required by the test, dividing the prepared samples into a plurality of equal parts, uniformly mixing, and uniformly preparing the samples by adopting a surface vibration method;
step S2: flattening the upper surface of the sample, sequentially placing a permeable cloth (permeable cloth), a permeable top plate 11-2 and a bearing plate 13, screwing back the positioning bolt 15 to a non-positioning position, releasing the support of the positioning bolt 15 on the circular cylinder 12, and installing a dynamometer 8 and a dial indicator 9;
the rockfill material sample test step comprises the following steps:
step SS 1: taking 2 rockfill material samples to carry out a contrast test, wherein one rockfill material sample is in a dry state, the other rockfill material sample is in a saturated state, starting a pressurizing mechanism through a control system 1, applying a pre-stress of 3-5 kPa to the rockfill material sample, injecting water into a container to saturate the rockfill material test when the rockfill material sample is stable under the pre-stress (for example, the difference of readings of a dial indicator per hour is not more than 0.05mm), and adding no water to the rockfill material sample in the dry state; then respectively carrying out compression tests on the two rockfill material samples, starting to apply preset compressive stress step by step, simultaneously acquiring data of the dynamometer 8 and the dial indicator 9 by the measuring mechanism in real time, applying the compressive stress of the next stage after the rockfill material sample reaches a rheological deformation stable state under the compressive stress of each stage, and applying the compressive stress of each stage according to a formula kX 2N-1MPa, where N is a natural number and not less than 4, such as: the first stage has a compressive stress of 0.1MPa, the second stage has a compressive stress of 0.2MPa, and the compressive stresses of 0.4MPa, 0.8MPa, 1.6MPa, 3.2MPa and 6.4MPa are applied in a stepwise manner by a secondary analogy.
Step SS 2: 12 rockfill material samples are taken for comparison test and divided into two groups: one group is in a dry state, the other group is in a saturated state, the two groups of rockfill material samples are respectively different samples to apply different preset pressure stresses (0.2MPa, 0.4MPa, 0.8MPa, 1.6MPa, 3.2MPa and 6.4MPa),
for a dry sample, after the sample is stable under the pre-stress, a preset pressure stress can be applied, for a saturated sample, water is injected into the water storage tank after the pre-stress and the deformation are stable to saturate the sample, and the measuring mechanism obtains data of the dynamometer 8 and the dial indicator 9 in real time under the preset pressure stress until the rockfill material sample reaches a rheological deformation stable state;
step SS 3: extracting the data obtained in the steps SS1 and SS2, and drawing the relation curve of the height h of the sample and the time t and the axial strainhAnd (5) a relation curve with time t, and acquiring a corresponding data list.
Preferably, in steps SS1 and SS2, the stable state of the rheological deformation is that the deformation amount/total flow variable in 24 hours is less than or equal to 5%;
preferably, according to the result obtained in step SS2, calculating the predetermined compressive stress wet deformation Δ Hi, dry sample compressive deformation Δ Hi, and saturated sample compressive deformation Δ Hi', wherein Δ Hi means that after the sample (dried) is stabilized under the predetermined pressure (0, 0.2MPa, 0.4MPa, 0.8MPa, 1.6MPa, 3.2MPa, and 6.4MPa), the sample is saturated with water, and the sample sinks (keeping the pressure constant), and the amount of sinking is the wet deformation; Δ hi is the amount of subsidence after the deformation of the dried sample is stabilized under two-stage pressure (e.g., 0.2 to 0.4 MPa); Δ Hi' is the amount of subsidence of the saturated sample after deformation is stable under two-stage pressure (e.g., 0.2 to 0.4 MPa); according to the formula
Calculating the humidification coefficient under each level of predetermined pressure stress according to a formula
Calculating the porosity ratio under the preset pressure stress of each level according to a formula
Calculating the compression coefficient under each level of predetermined compressive stress according to a formula
Calculating the compression modulus under each stage of predetermined compressive stress, and drawing a relation curve of p and e-p, wherein the unit settlement is represented, the e represents the unit settlement porosity, and the p represents the pressure.
Preferably, a model of the wetted softened rockfill material is fitted by numerical software, obtained according to step SS 3.
The embodiments of the present invention have been described above with reference to the accompanying drawings, and features of the embodiments and examples of the present invention may be combined with each other without conflict. The present invention is not limited to the above-mentioned embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many forms without departing from the spirit and the scope of the present invention, which is encompassed by the present invention.
Claims (5)
1. A rockfill material test device is characterized by comprising a container, a water permeable bottom plate, a water permeable top plate, a circular cylinder, a pressurizing mechanism, a measuring mechanism and a control system;
the outer diameters of the water-permeable bottom plate and the water-permeable top plate are matched with the inner diameter of the circular cylinder, the water-permeable bottom plate is placed at the bottom of the container, the water-permeable bottom plate and the water-permeable top plate are respectively positioned at the lower end and the upper end of the circular cylinder, and a space for containing rockfill materials is defined by the water-permeable bottom plate, the circular cylinder and the water-permeable top plate; the pressurizing mechanism is used for applying downward testing force to the water-permeable top plate; the measuring mechanism is used for measuring the displacement of the permeable top plate and the testing force; the control system is respectively communicated with the measuring mechanism and the pressurizing mechanism and is used for receiving and processing the data acquired by the measuring mechanism and controlling the pressurizing mechanism.
2. The rockfill testing apparatus according to claim 1, wherein the bottom of the side wall of the container is further provided with at least three positioning bolts in a circumferential direction, the positioning bolts penetrating the side wall of the container in a radial direction of the circular cylinder, the positioning bolts being threadedly coupled with the side wall of the container; the positioning bolt can be switched between a positioning position and a non-positioning position in a screwing mode, when the positioning bolt is screwed to the positioning position, the bottom of the circular cylinder is supported at the top of the positioning bolt, the bottom of the circular cylinder is not higher than the upper surface of the water-permeable bottom plate, and when the positioning bolt is screwed to the non-positioning position, the positioning bolt is located on the outer side of the circular cylinder.
3. The rockfill testing apparatus according to claim 1, wherein the pressurizing mechanism includes a motor for driving a screw of the screw mechanism to move up and down, a screw mechanism, and a bearing plate located above the water-permeable top plate.
4. The rockfill testing apparatus according to claim 3, wherein the lower end of the screw is further provided with a thrust bearing.
5. The rockfill material testing device according to claim 3, wherein the measuring mechanism includes a data acquisition module, a dynamometer and a dial indicator for measuring displacement of the permeable top plate; the top center of the pressure bearing plate is provided with the dynamometer, and the dynamometer and the dial indicator are respectively communicated with the data acquisition module.
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| CN201922244842.2U CN211978534U (en) | 2019-12-13 | 2019-12-13 | Rockfill material testing device |
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| CN201922244842.2U CN211978534U (en) | 2019-12-13 | 2019-12-13 | Rockfill material testing device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114414375A (en) * | 2022-01-21 | 2022-04-29 | 武汉大学 | Drainage rate controllable type rockfill material lateral confinement compression test device and method |
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2019
- 2019-12-13 CN CN201922244842.2U patent/CN211978534U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114414375A (en) * | 2022-01-21 | 2022-04-29 | 武汉大学 | Drainage rate controllable type rockfill material lateral confinement compression test device and method |
| CN114414375B (en) * | 2022-01-21 | 2024-01-12 | 武汉大学 | Device and method for lateral limit compression test of rock-fill material with controllable drainage rate |
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