CN115876607A - Friction type loaded rock-soil in-situ large shear test system and method - Google Patents
Friction type loaded rock-soil in-situ large shear test system and method Download PDFInfo
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- CN115876607A CN115876607A CN202211518578.7A CN202211518578A CN115876607A CN 115876607 A CN115876607 A CN 115876607A CN 202211518578 A CN202211518578 A CN 202211518578A CN 115876607 A CN115876607 A CN 115876607A
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Abstract
The invention discloses a friction type loaded rock-soil in-situ large shear test system and method. According to the invention, the rubber plate is arranged between the sample and the vertical force application module, the vertical force application module bears the horizontal force provided by the horizontal force application module and then transmits the horizontal force to the sample through the rubber plate, when the horizontal force is large enough, the sample is sheared to test the shearing strength of the sample, and the rubber plate and the sample are uniformly contacted to uniformly distribute the shearing stress generated in the sample, so that the tested shearing stress can truly reflect the shearing strength of the sample.
Description
Technical Field
The invention relates to the technical field of civil engineering tests, in particular to a friction type loaded rock-soil in-situ large shear test system and method.
Background
In the existing large shear test, as shown in fig. 1, a vertical force application module is used for applying normal stress to a sample, a jack is used for applying shear stress to the test through a pressure bearing plate, the sample is extruded by the pressure bearing plate and is firstly pressed at a part in contact with the pressure bearing plate to deform, the central part of the sample is far away from the pressure bearing plate, and the disturbance is small, so that the shear stress distributed on a shear surface is not uniform, the measured shear stress cannot truly reflect the shear strength characteristics of the sample, and the measurement of the shear strength of the sample is influenced.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, the embodiment of the invention provides a friction type loaded rock-soil in-situ large shear test system and method.
On one hand, the invention provides a friction type loaded rock-soil in-situ large shear test system, which comprises:
the rubber plate is laid on the top surface of the sample;
the vertical force application module is placed on the upper portion of the rubber plate and used for generating normal stress, and the rubber plate, the vertical force application module and the sample are in close contact;
one end of the horizontal force application module is abutted against the vertical force application module, and the horizontal force application module is used for generating shear stress;
and the horizontal ruler is used for testing the horizontal displacement of the vertical force application module.
In some embodiments, the rubber plate has a coefficient of friction of 1-4 in contact with the vertical force application module and the test specimen.
In some embodiments, the blanket has a thickness of 2-5mm.
In some embodiments, the vertical force application module applies a positive stress with a weight.
In some embodiments, the horizontal forcing module is a jack.
In some embodiments, one end of the jack abuts against the vertical force application module, and the other end of the jack is connected with the force measurement ring.
In some embodiments, the jack force is controlled by a manual pump.
In some embodiments, the force ring is used to test the shear stress applied by the jack, and one end of the force ring, which is far away from the jack, abuts against a support.
In some embodiments, when the sample is soft rock soil, the top surface of the sample is modified by cement slurry.
On the other hand, the invention provides a friction type loaded rock-soil in-situ large shear test method, which comprises the following steps:
recording the shear plane cross-sectional area A j ；
Digging a sample in rock soil to be tested, wherein the bottom of the sample and the rock soil of an original stratum are kept complete, and an expected shear plane is higher than that of the surrounding original rock;
treating the surface of the sample to be flat and free of debris;
sequentially placing a rubber plate and a vertical force application module on the surface of a sample to make the rubber plate and the vertical force application module closely contact with each other;
applying a vertical force F on the vertical force application module to keep the vertical force F unchanged;
applying a horizontal direction displacement sequence U from small to large on a horizontal force application module i And recording the horizontal force T corresponding to the force i Stopping applying the displacement when the sample is damaged or deformed too much;
drawing a horizontal force and displacement curve and determining a peak horizontal force T max Calculating the normal stress at failure σ j And shear stress tau j ；
After the samples are completely finished, the adhesive force c and the internal friction angle phi are finished by a least square method.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the rubber plate is arranged between the sample and the vertical force application module, the vertical force application module bears the horizontal force provided by the horizontal force application module and then transmits the horizontal force to the sample through the rubber plate, when the horizontal force is large enough, the sample is sheared to test the shearing strength of the sample, and the rubber plate and the sample are uniformly contacted to uniformly distribute the shearing stress generated in the sample, so that the tested shearing stress can truly reflect the shearing strength of the sample.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of a rock-soil in-situ large shear test system in the prior art;
FIG. 2 is a schematic diagram of a friction-type loaded rock-soil in-situ large shear test system according to the present invention;
description of the reference numerals:
the device comprises a sample 1, a rubber plate 2, a vertical force application module 3, a heavy object 4, a jack 5, a force measurement ring 6 and a support 7.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are illustrative and intended to explain the present invention and should not be construed as limiting the present invention.
The friction type loaded rock-soil in-situ large shear test system and method provided by the embodiment of the invention are described below with reference to the accompanying drawings.
As shown in figure 2, the friction type loaded rock-soil in-situ large shear test system comprises a rubber plate 2, a vertical force application module 3, a horizontal force application module and a level ruler.
One end of the horizontal force application module is abutted against the vertical force application module 3, and the horizontal force application module is used for generating shear stress.
Specifically, horizontal force application module is used for applying the horizontal direction's power, and horizontal force application module is used for producing shear stress promptly, and the one end of horizontal force application module supports and leans on vertical force application module 3, and vertical force application module 3 bears the horizontal force that horizontal force application module provided, and the rethread rubber slab 2 transmits for sample 1.
In some embodiments, the horizontal force application module provides a jack 5, that is, a force in a horizontal direction is provided by the jack 5.
When the horizontal force application module is a jack 5, one end of the jack 5 is abutted against the vertical force application module 3, and the other end of the jack 5 is connected with the force measurement ring 6.
Specifically, one end of the jack 5 abuts against the vertical force application module 3 to provide a force in the horizontal direction for the vertical force application module 3, one end, far away from the vertical force application module 3, of the jack 5 is connected with the force measurement ring 6, and the force measurement ring 6 is used for testing the force in the horizontal direction, namely the shear stress, applied by the jack 5.
In addition, the magnitude of the horizontal force applied by the jack 5 is controlled by a manual pump, that is, the magnitude of the horizontal force is adjusted by the manual pump.
The end of the force measuring ring 6 away from the jack 5 abuts against a support 7, the support 7 provides a supporting point for the whole test system, and the support 7 provides the function of a counter force module in the system, namely the support 7 is used for providing counter force. It will be appreciated that the support 7 may be a wall or a box of steel plate having a certain self weight.
Rubber slab 2 is laid at 1 top surface of sample, and vertical force application module 3 is placed on rubber slab 2 upper portion, and vertical force application module 3 is used for producing normal stress, and between rubber slab 2 and vertical force application module 3 and the sample 1 in close contact with.
Specifically, rubber slab 2 is placed to the top surface of sample 1, and vertical force application module 3 is placed on the upper portion of rubber slab 2, the lower surface of rubber slab 2 and the top surface in close contact with of sample 1, the upper surface of rubber slab 2 and the lower surface in close contact with of vertical force application module 3 to make equal in close contact with between rubber slab 2 and vertical force application module 3 and the sample 1, vertical force application module 3 is used for producing the normal stress to sample 1.
In some embodiments, the vertical force module 3 applies a certain positive stress with the weight 4. Specifically, a weight 4 of known gravity is applied to the vertical force application module 3, and the gravity of the weight 4 and the gravity of the vertical force application module 3 itself are used to provide a positive stress.
In some embodiments, the vertical force application module 3 is a steel plate box, the weight 4 is a weight, the weight with a certain gravity is placed in the steel plate box, the gravity of the weight and the self weight of the steel plate box are used for providing a positive stress, and meanwhile, the vertical force application module 3 bears the horizontal force provided by the jack 5.
In some embodiments, the rubber plate 2 has a thickness of 2-5mm. It will be appreciated that the thickness of the rubber plate 2 can be chosen according to the actual circumstances. Preferably, the thickness of the rubber plate 2 is 3mm.
The friction coefficient of the rubber plate 2, the vertical force application module 3 and the sample 1 is 1-4. Because the friction coefficient of the rubber plate 2 and most of solids can reach 1 to 4, enough static friction force can be generated between the vertical force application module 3 and the rubber plate 2 and between the rubber plate 2 and the sample 1. When the horizontal force is sufficiently large, the test piece 1 is sheared, and the shear strength of the test piece 1 is tested. Since the contact between the rubber plate 2 and the sample 1 is uniform, it is ensured that the shear stress generated in the sample 1 is also uniform.
The level bar is used for testing the horizontal displacement of the vertical force application module 3, and the level bar can be placed on the horizontal ground in the testing process.
When the sample 1 is a soft rock sample, the top surface of the sample 1 needs to be modified. In some embodiments, cement slurry may be used to secure the top surface of sample 1, thereby allowing good contact between rubber plate 2 and the top surface of sample 1. After the top surface of sample 1 was modified with grout, the shear plane appeared below the grout treatment range.
The invention discloses a friction type loaded rock-soil in-situ large shear test method, which utilizes a friction type loaded rock-soil in-situ large shear test system and comprises the following steps:
(1) Preparing a site and equipment;
(2) Recording the shear plane cross-sectional area A j Wherein j is the serial number of the sample 1, usually three samples 1 are taken, and the number of the samples 1 can be determined according to the actual situation;
(3) Digging a sample 1 in rock soil to be tested, wherein the bottom of the sample 1 and the rock soil of an original stratum are kept complete, and an expected shear plane is higher than that of the surrounding original rock;
(4) Treating the surface of the sample 1 to be flat without scraps, and treating the sample 1 with cement slurry to be firm when the sample is soft rock soil, wherein the treatment depth cannot reach an expected shear plane, and the surface is firm enough, and then carrying out subsequent test steps;
(5) Sequentially placing a rubber plate 2 and a vertical force application module 3 on the surface of a sample 1 to enable the rubber plate and the vertical force application module to be in close contact;
(6) Applying a vertical force F on the vertical force application module 3 to keep the vertical force F unchanged;
(7) Applying a horizontal direction displacement sequence U from small to large on a horizontal force application module i And recording the horizontal force T corresponding to the force i Stopping applying the displacement when the sample 1 is damaged or excessively deformed, wherein i is a recording serial number and starts from 1;
(8) Drawing a horizontal force and displacement curve and determining a peak horizontal force T max Calculating the normal stress at failure σ j And shear stress tau j ；
(9) After the sample 1 is completely finished, the adhesive force c and the internal friction angle phi are finished by a least square method.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms may be directed to different embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (10)
1. The utility model provides a big test system that cuts of ground normal position of friction type loading which characterized in that includes:
the rubber plate is laid on the top surface of the sample;
the vertical force application module is placed on the upper portion of the rubber plate and used for generating normal stress, and the rubber plate, the vertical force application module and the sample are in close contact;
one end of the horizontal force application module is abutted against the vertical force application module, and the horizontal force application module is used for generating shear stress;
and the horizontal ruler is used for testing the horizontal displacement of the vertical force application module.
2. The system of claim 1, wherein the rubber plate has a coefficient of friction of 1-4 in contact with the vertical force application module and the test specimen.
3. The system of claim 1, wherein the blanket has a thickness of 2-5mm.
4. The system of claim 1, wherein the vertical force application module applies a positive stress with a weight.
5. The system of claim 1, wherein the horizontal force application module is a jack.
6. The system of claim 5, wherein one end of the jack abuts against the vertical force application module and the other end of the jack is connected with a force measurement ring.
7. The system of claim 5, wherein the jack force is controlled by a manual pump.
8. The system of claim 6, wherein the force ring is configured to test the shear stress applied by the jack, and wherein an end of the force ring distal from the jack rests on a support.
9. The system of claim 1, wherein the top surface of the sample is modified with cement slurry when the sample is soft rock.
10. A friction type loaded rock-soil in-situ high shear test method, characterized in that the system according to any one of claims 1-9 is used, comprising the following steps:
recording the shear plane cross-sectional area A j ；
Digging a sample in rock soil to be tested, wherein the bottom of the sample and the original stratum rock soil are kept complete, and the expected shearing surface is higher than the surrounding original rock;
treating the surface of the sample to make it flat and free of debris;
sequentially placing a rubber plate and a vertical force application module on the surface of a sample to make the rubber plate and the vertical force application module closely contact with each other;
applying a vertical force F on the vertical force application module to keep the vertical force F unchanged;
applying a horizontal direction displacement sequence U from small to large on a horizontal force application module i And recording the horizontal force T corresponding to the force i Stopping applying the displacement when the sample is damaged or deformed too much;
drawing a horizontal force and displacement curve and determining a peak horizontal force T max Calculating the normal stress at failure σ j And shear stress tau j ；
After all the samples are finished, the adhesive force c and the internal friction angle phi are finished by a least square method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211518578.7A CN115876607A (en) | 2022-11-30 | 2022-11-30 | Friction type loaded rock-soil in-situ large shear test system and method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211518578.7A CN115876607A (en) | 2022-11-30 | 2022-11-30 | Friction type loaded rock-soil in-situ large shear test system and method |
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| Publication Number | Publication Date |
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| CN115876607A true CN115876607A (en) | 2023-03-31 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211518578.7A Pending CN115876607A (en) | 2022-11-30 | 2022-11-30 | Friction type loaded rock-soil in-situ large shear test system and method |
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| CN (1) | CN115876607A (en) |
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- 2022-11-30 CN CN202211518578.7A patent/CN115876607A/en active Pending
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