CN111766363A - High-precision soil dilatometer for roadbed filling - Google Patents
High-precision soil dilatometer for roadbed filling Download PDFInfo
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- CN111766363A CN111766363A CN201910254300.5A CN201910254300A CN111766363A CN 111766363 A CN111766363 A CN 111766363A CN 201910254300 A CN201910254300 A CN 201910254300A CN 111766363 A CN111766363 A CN 111766363A
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Abstract
The invention relates to a high-precision soil dilatometer for roadbed filling, which comprises a double-layer test cylinder, a loading frame, a test cylinder top plate ring, a test cylinder bottom plate, a displacement measuring device, a force sensor, a moisture content measuring device, a porous top plate sleeve and a single-degree-of-freedom iron ring, and is characterized in that the test cylinder top plate ring is arranged above the double-layer test cylinder, the test cylinder bottom plate is arranged below the double-layer test cylinder, the porous top plate sleeve is arranged at the top of a sample, the single-degree-of-freedom iron ring is arranged in the double-layer test cylinder, the displacement measuring device is arranged on the test cylinder top plate ring and is contacted with the porous top plate, a tensiometer contact is embedded in the sample to form a basic module, the basic module is arranged on the loading frame and is integrated with the force sensor, so that an expansive force test and a load expansive test can be carried out, the invention aims at, and the experimental result is measured and output more accurately.
Description
Technical Field
The invention relates to the technical field of geotechnical engineering geotechnical tests, in particular to a high-precision soil dilatometer for roadbed fillers, which is suitable for testing fillers with different grain compositions and process swelling capacity of soil under different water content control and overlying load control.
Background
The expansive soil is special clay which is formed in natural geological transition and has multiple cracks, easy weathering, obvious expansion and contraction and repeated damage, the clay particle components of the expansive soil mainly comprise hydrophilic minerals of montmorillonite and illite, the expansive soil is sensitive to the damp and hot change of the environment, and the soil body is easy to damage when meeting water. China is one of the countries with the widest distribution of expansive rock soil in the world, and the regional distribution of expansive rock soil in 26 provincial and municipal autonomous regions in China has been found out. The damage of the expansive soil to the engineering construction is reflected on surface buildings and underground engineering. It includes not only all slopes, road surfaces and beddings of railways, highways and channels, but also house foundations and terraces, underground chambers and tunnel surrounding rocks, linings and even stability measures adopted in these projects. The expansive soil has multiple repeatability and long-term potential danger on the damage effect of the expansive soil on the engineering, the problem of the road bed diseases of the expansive soil is solved to different degrees in railway engineering of China, such as the southern Kunmu line, the Kyoho line, the southwest line and other railway main lines, and due to the above, the railway engineering industry puts forward a statement that the cutting is slippery and does not collapse when summarizing the experience of constructing the railway in the expansive soil area.
The existing traditional WZ-2 type dilatometer is small in volume, a cutting ring sample with the diameter of 58mm and the height of 20mm is adopted, the discrete sample needs to be screened and the whole block sample needs to be polished and trimmed before the instrument is used for carrying out a dilatometric test, the test process is complex, and the disturbance on the original soil structure is excessive. Therefore, the dilatometer has limited application range and insufficient data accuracy. Meanwhile, the dilatometer needs to be immersed in a water tank in the test process, so that the dilatometer can only measure the expansion rate of the soil body in the saturated state, but the roadbed filler and the foundation soil in the actual engineering construction often do not reach the saturated state because of the water prevention and drainage measures, so the obtained test result is inconsistent with the actual situation.
Another commonly used coarse particle immersion dilatometer, other than WZ-2, uses a CBR test cartridge as the instrument body, which tests cylindrical samples 151mm in diameter and 116mm in height, the size of which takes into account the larger particle size particles that may be encountered by the road-based filler. The maximum particle size of the filler sample adopted by the soaking expansion test device cannot exceed 20mm or 40mm according to the current JTG E40-2007 Highway soil engineering test regulation and TB10102-2010 railway engineering soil engineering test regulation. However, the device still adopts a water supply mode that the device is immersed in water, and water enters the sample through the porous bottom plate at the bottom and the porous top plate at the top of the device, so that only the immersion expansion test can be carried out, and the test type is limited. In addition, since the water supply mode of the device permeates into the sample from the top and the bottom, if the permeability of the sample is poor, the expansion time distribution of the expansion change of the sample in the height direction is uneven.
Disclosure of Invention
Aiming at the defects of the test equipment, the invention provides a high-precision soil dilatometer for roadbed fillers, which can solve the problems of damage to the original soil body structure and filler gradation caused by the fact that the filler has overlarge particle size and needs to be screened due to the small sample amount while considering the swelling amounts of actual soil and filler samples at different water content stages.
The invention solves the problems through the following technical scheme.
The utility model provides a high accuracy soil dilatometer that can be used to road bed filler, includes double-deck test section of thick bamboo, loading frame, test section of thick bamboo roof ring, test section of thick bamboo bottom plate, displacement measuring device, force transducer, moisture content measuring device, porous roof suit, single degree of freedom hoop, its characterized in that single degree of freedom hoop is arranged in inside the double-deck test section of thick bamboo, the sample is then laid when testing inside the single degree of freedom hoop, inside the sample is buried in to the tensiometer contact.
The porous top plate is sleeved on the top of the sample, and the displacement measuring device is arranged on the top plate ring of the test cylinder and is in contact with the porous top plate, so that the basic test module is formed.
The basic test module is coaxially arranged on a loading frame, and the loading frame is connected with the porous top plate by utilizing a force sensor.
The high-precision soil dilatometer for roadbed filling of claim 1, wherein the test cylinder is an internal and external double-layer structure, comprising an internal cylinder and an external cylinder, which are coaxially adhered and fixed by organic glass strips; and water permeable holes are uniformly drilled in the wall of the inner cylinder.
The device is characterized in that the loading frame comprises a metal cross beam, a counter-force bolt rod, an instrument base, a screw loading device and a smooth metal round rod which can be used for replacement.
The metal beam is connected with the base through a counter-force bolt rod, the screw loading device comprises a knob and a screw, the screw moves downwards to push the force sensor to be in contact with the porous top plate when the knob is rotated, and the screw and the knob combination can be used for an expansive force test.
The screw rod and the knob combination can be replaced by smooth metal round steel, and the upper end of the round steel is connected with a disc and can be used for a load expansion test.
Furthermore, because the invention can carry out the no-load expansion test, the load expansion test and the expansion force test in the four soil expansibility tests proposed in the current geotechnical test regulations, the invention can be assembled according to the specific requirements when carrying out different tests, and only needs to be assembled into the basic test module when carrying out the no-load expansion test, namely, a loading frame is not needed; when a load expansion test is carried out, a loading frame is needed, namely a basic test module is placed on the loading frame, and the loading device is replaced by the smooth round steel and the disc; when performing the expansion force test, similar to the load expansion test, it is necessary to place the basic test module on the loading frame, and use the loading device, i.e. the loading screw, the knob, and the force sensor.
Compared with the prior device, the invention has the following outstanding effects.
1. According to the invention, the inner and outer double-layer test cylinder structure is adopted, water enters the interlayer between the inner and outer cylinders and then infiltrates from the periphery of the sample through the water permeable holes on the inner wall, the infiltration path is short and is uniformly distributed, and the nonuniform expansion time distribution of expansion change in the height direction caused by nonuniform infiltration in the traditional equipment is avoided.
2. The test cylinder adopted by the invention has larger volume, can adapt to coarse particles in the filler, and avoids the original grading damage of the filler caused by screening.
3. The loading frame replaces the method of stacking loading plates above the samples, which is commonly used in the traditional experimental equipment, so that the loading frame can continuously control the size of the applied load while outputting the applied load during the expansion force test, and the problems of discontinuous loading increment and insufficient control precision during the use of the loading plates are avoided.
4. According to the invention, by integrating the force sensor and the tensiometer, the change condition of the water content can be monitored in the experimental process, and the water content of the sample can be controlled more accurately, so that the expansion test of the sample in a non-saturated state can be carried out, and the force sensor can output the change of the size of the overlying load more accurately, thereby achieving the purpose of higher precision.
Drawings
FIG. 1 is a schematic view of the structure of the present invention.
FIG. 2 is a cross-sectional view of the present invention.
Fig. 3 is a loading frame with smooth round steel and discs replacing the loading knob and screw.
Shown in the figure: the device comprises a loading screw 1, a loading knob 2, a loading frame beam 3, a force sensor 4, a loading frame counterforce bolt 5, a displacement meter support 6, a displacement meter 7, a force sensor contact 8, a porous top plate contact 9, a displacement meter contact 10, a test cylinder top plate ring 11, a porous top plate 12, a double-layer test cylinder inner cylinder 13, a double-layer test cylinder outer cylinder 14, a single-degree-of-freedom metal lantern ring 15, a test cylinder bottom plate 16, a loading frame base 17, a permeable stone 18, a sample 19, a tensiometer probe 20, a loading frame smooth metal round rod 21, a loading frame disc 22, a loading frame 23 and a double-layer test cylinder 24.
Detailed Description
The following describes embodiments of the present invention with reference to the drawings.
As shown in fig. 1, 2 and 3, a high-precision soil dilatometer for roadbed filling comprises a double-layer test cylinder 24, a loading frame 23, a test cylinder top plate ring 11, a test cylinder bottom plate 16, a displacement meter 7, a force sensor 4, a tensiometer 20, a porous top plate 12 and a single-degree-of-freedom iron ring 15, and is characterized in that the specific structure and connection relationship are as follows: the test cylinder top plate ring 11 is arranged above the double-layer test cylinder 24, and the test cylinder bottom plate 16 is arranged below the double-layer test cylinder 24; the single-degree-of-freedom iron ring 15 is arranged inside the double-layer test cylinder 24, a test sample 19 is arranged inside the single-degree-of-freedom iron ring during testing, and a tension meter measuring head 20 is embedded inside the test sample 19; the porous top plate 12 is arranged on the top of a test sample 19, and the displacement meter 20 is arranged on the top plate ring 11 of the test cylinder and is in contact with the porous top plate contact 9, so that a basic test module of the invention is formed; the basic test module is coaxially placed on a loading frame 23 and the perforated top plate 12 are connected by a force sensor 8.
The test cylinder 24 is of an inner-outer double-layer structure and comprises an inner cylinder 13 and an outer cylinder 14 which are coaxially adhered and fixed through organic glass strips, water permeable holes are uniformly drilled in the wall of the inner cylinder 13, the width of an interlayer between the inner cylinder 13 and the outer cylinder 14 is 5mm, and small openings are reserved at the bottom end of the test cylinder when the inner-outer cylinder interlayer is uniformly divided into four parts, so that the liquid level heights of the four parts of interlayers can be guaranteed to be consistent after water enters the interlayer.
The loading frame 23 comprises a metal beam 3, a counter-force bolt rod 5, an instrument base 17, a loading screw rod 1 and a smooth metal round rod 21 which can be replaced, the metal beam 3 is connected with the base 17 through the counter-force bolt rod 5, a threaded round hole is formed in the middle of the metal beam, the loading screw rod 1 and a loading knob 2 jointly form a loading device, the screw rod 1 penetrates through the round hole, the knob 2 is fixed at the upper end of the screw rod 1, the screw rod 1 moves downwards to enable a driving force sensor 4 to be in contact with a porous top plate contact 9 when the knob 2 is rotated, and the screw rod 1 and the knob 2 are combined for an expansion force test; the screw rod 1 and the knob 2 can be combined and replaced by a smooth metal round rod 21, and the upper end of the round rod 22 is connected with a disc 22 which can be used for a load expansion test.
Furthermore, because the invention can carry out the no-load expansion test, the load expansion test and the expansion force test of the four soil expansion tests proposed in the current geotechnical test regulations, the invention can be assembled according to the specific requirements when carrying out different tests, and only needs to be assembled into the basic test module when carrying out the no-load expansion test, namely the loading frame 23 is not needed; when a load expansion test is carried out, a loading frame 23 is needed, namely, a basic test module is placed on the loading frame 23, and the loading screw rod 1 and the loading knob 2 are replaced by the smooth round rod 21 and the round disc 22; when performing the expansion force test, similar to the load expansion test, it is necessary to place the basic test module on the loading frame, and use the loading device, i.e. the loading screw 1, the knob 2 and the force sensor 4.
In view of the foregoing, it is intended that the present invention cover the best mode and the technical features of the invention, but those skilled in the art should understand that they can make various substitutions and modifications without departing from the spirit of the invention.
Claims (5)
1. A high-precision soil dilatometer for roadbed filling comprises a double-layer test cylinder, a loading frame, a test cylinder top plate ring, a test cylinder bottom plate, a displacement measuring device, a force sensor, a moisture content measuring device, a porous top plate sleeve and a single-degree-of-freedom iron ring, and is characterized in that the single-degree-of-freedom iron ring is arranged in the double-layer test cylinder, a sample is arranged in the single-degree-of-freedom iron ring during testing, and a tensiometer contact is embedded in the sample;
the porous top plate is sleeved on the top of the sample, and the displacement measuring device is arranged on the top plate ring of the test cylinder and is in contact with the porous top plate, so that a basic test module is formed;
the basic test module is coaxially arranged on a loading frame, and the loading frame is connected with the porous top plate by utilizing a force sensor.
2. The high-precision soil dilatometer for roadbed filling of claim 1, wherein the test cylinder is an internal and external double-layer structure, comprising an internal cylinder and an external cylinder, which are coaxially adhered and fixed by organic glass strips; and water permeable holes are uniformly drilled in the wall of the inner cylinder.
3. The high-precision soil dilatometer for roadbed filling of claim 1, wherein said loading frame comprises metal beam, reaction bolt shaft, instrument base, screw loading device and smooth metal round bar for replacement.
4. The metal beam of claim 3 connected to the base by a counter bolt shaft, the screw loading device comprising a knob and a screw, wherein rotation of the knob moves the force sensor downward into contact with the porous top plate, and the screw and knob combination is used for an expansive force test.
5. The screw and knob combination of claim 3 can be replaced by a smooth metal round bar, and a disc is connected to the upper end of the round bar and can be used for a load expansion test.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910254300.5A CN111766363A (en) | 2019-03-31 | 2019-03-31 | High-precision soil dilatometer for roadbed filling |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910254300.5A CN111766363A (en) | 2019-03-31 | 2019-03-31 | High-precision soil dilatometer for roadbed filling |
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| Publication Number | Publication Date |
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| CN111766363A true CN111766363A (en) | 2020-10-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201910254300.5A Pending CN111766363A (en) | 2019-03-31 | 2019-03-31 | High-precision soil dilatometer for roadbed filling |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113138111B (en) * | 2021-04-28 | 2023-07-21 | 山东省公路桥梁建设有限公司 | Indoor test method and device for water stability of roadbed filler |
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2019
- 2019-03-31 CN CN201910254300.5A patent/CN111766363A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113138111B (en) * | 2021-04-28 | 2023-07-21 | 山东省公路桥梁建设有限公司 | Indoor test method and device for water stability of roadbed filler |
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