CN111380778A - On-site relative density testing method for soil material - Google Patents
On-site relative density testing method for soil material Download PDFInfo
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- CN111380778A CN111380778A CN202010237381.0A CN202010237381A CN111380778A CN 111380778 A CN111380778 A CN 111380778A CN 202010237381 A CN202010237381 A CN 202010237381A CN 111380778 A CN111380778 A CN 111380778A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
- G01N9/02—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
- G01N9/02—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume
- G01N2009/022—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume of solids
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Abstract
The invention discloses a field relative density testing method for soil materials, which comprises the following steps: 1) making a test barrel with a volume V0It is known to bury test buckets underground in a test field; 2) weighing the mass M of the soil material, slowly pouring the soil material into a test barrel until the test barrel is filled with the soil material, wherein the minimum dry density is the mass M of the soil material/volume V of the test barrel0(ii) a 3) The soil sample in the test barrel is vibrated to be compact, a film is laid on the surface of the soil sample, then clear water is filled into the soil sample, and the volume V of the clear water filled into the test barrel is obtainedS1(ii) a 4) Digging out a soil sample, cleaning, and filling clear water again to obtain a volume V01The maximum dry density is the mass of the soil material M/(V)01‑VS1). The invention adopts the same soil materials, can measure the minimum dry density and the maximum dry density at one time, adopts the twice irrigation method, can accurately measure the subsidence volume of the soil sample, eliminates the influence of the shape change and the top inclination of the sample barrel under the action of vibration load, improves the test precision of the maximum dry density, and can be suitable for coarse-grained soil with different grain diameters.
Description
Technical Field
The invention relates to the field of physical property test research of soil bodies, in particular to a field relative density testing method for soil materials.
Background
The relative density of the soil refers to the ratio of the difference between the pore ratio of the non-cohesive soil in the most loose state and the pore ratio in the natural state to the difference between the pore ratio in the most loose state and the pore ratio in the most compact state. The relative density is generally obtained by measuring the maximum dry density and the minimum dry density of the cohesionless soil and converting the minimum pore ratio and the maximum pore ratio of the soil. The relative density can comprehensively reflect factors such as the particle shape, the gradation, the structural property and the like of the soil, can measure the compaction degree of the soil and is an important index for controlling the filling quality of the soil body.
The minimum dry density of the soil is generally determined by adopting a pouring loose filling method, and the method is simple and widely applied. The test method for measuring the maximum dry density of coarse-grained soil mainly comprises a vibration table method and a surface vibrator method. The former is adopted by the American national standard ASNI/ASTM, and the method is introduced by most countries such as Canada, Japan and the like; and national standards in uk, sweden, etc. adopt the latter. The national hydropower system 'hydropower and water conservancy project coarse soil test procedure' (DL/T5356-. The relative density test is generally carried out indoors and is generally applicable to soil with a maximum particle size of less than 60mm, due to limitations of equipment and economy.
In hydraulic and hydroelectric engineering, there is currently no standard method for determining the maximum dry density of ultra large particle size rockfill materials, since the particle size of the rockfill material is too large.
Disclosure of Invention
The invention aims to solve the problems that the existing method for measuring the relative density of soil is complex, and particularly the relative density of rockfill materials with large particle sizes is inaccurate to measure, and provides a field relative density measuring method for soil materials.
The invention is realized by the following technical scheme:
an on-site relative density testing method for soil materials comprises the following steps: 1) manufacturing a test barrel meeting the standard requirements, wherein the volume V of the test barrel0As known, a test barrel is buried underground in a test field, so that the top of the barrel is flush with the ground surface; 2) determination of the minimum dry density of the soil material: weighing the mass M of the soil material, slowly pouring the soil material into a test barrel until the test barrel is filled with the soil material, wherein the minimum dry density is the mass M of the soil material/volume V of the test barrel0(ii) a 3) Determining the maximum dry density of the soil material: applying dynamic load on the upper part of the soil material body by using a vibration roller, vibrating the soil sample in the test barrel to be compact, paving a thin film on the surface of the soil sample after the rolling is finished, and then filling clear water until the test barrel is filled to obtain the volume V of the clear water filled in the test barrelS1(ii) a 4) Digging out the soil sample in the test barrel, cleaning up, and filling clear water again to obtain the volume V01The maximum dry density is the mass of the soil material M/(V)01-VS1)。
The method for measuring the relative density of the soil material adopts the completely same soil material, can measure the minimum dry density and the maximum dry density at one time, wherein the maximum dry density is measured by adopting a twice irrigation method, the subsidence volume of the soil sample can be accurately measured, the influences of the shape change and the top inclination of the sample barrel under the action of vibration load are eliminated, the measuring precision of the maximum dry density is improved, and the method can be suitable for coarse-grained soil with different grain diameters. After the minimum dry density test is completed, the soil sample can be used for testing the maximum dry density after being tamped; the test barrels are buried underground, and the ground surface is flush with the barrel top, so that on a large enough field, the tamping of soil samples with different particle sizes in a plurality of test barrels can be completed by one-time rolling through vibration grinding, a plurality of groups of relative density tests can be simultaneously carried out, batch operation can be realized, and manpower, machinery and resources are saved; wherein, first watering can obtain the volume that the soil sample subsided after the tamping, and after accomplishing with the soil material of experimental bucket clear away totally, irritate the water for the second time, volume in the experimental bucket of measurement department this moment can obtain the volume of the soil sample after being tamped through twice difference of watering the volume, has eliminated the shape change and the top slope of the sample bucket under the vibration load effect influence to soil sample volume test, has improved the measuring accuracy of maximum dry density.
In the step 1), broken gravels flush with the test barrel are filled around the test barrel, so that the damage to the barrel top of the test barrel in the movement process of the vibration roller can be avoided.
Step 2), mixing the prepared soil sample into a rubber frame, weighing the mass mi of the soil sample filled into the rubber frame, slightly putting the soil sample in the rubber frame into a test barrel, enabling the rubber frame to be close to the barrel bottom, slowly pouring the soil sample, repeating the steps until the sample barrel is quickly filled with the sample, leveling the top of the test barrel by using a square aluminum alloy pipe, and filling the rubber frame soil sample with the minimum dry density of the mass mi of the soil sample in the rubber frame/the volume V of the test barrel to the minimum dry density of the mass mi of the soil sample in the sigma0And by continuously adding the soil sample into the test barrel for a small number of times, the soil sample can be uniformly kept in a loose state to the maximum degree when the minimum dry density is tested.
In the step 3), before vibrating the soil sample, covering a geotextile on the leveled soil sample, covering a soil cushion layer on the geotextile, wherein the soil cushion layer comprises a gravel layer which is 5-6cm thick and has a particle size smaller than 20mm and covers the geotextile, the gravel layer is covered with 20-30 cm thick gravel soil with a particle size of 20-60 mm, the upper layer of the geotextile is covered with the gravel layer and the gravel soil, and the gravel layer and the gravel soil are subjected to vibration rolling to transmit load, so that the energy loss caused by the fact that vibration force directly acts on the top of the test barrel can be avoided; meanwhile, the geotextile is used for separating the soil sample and the soil body for transferring the load, so that the completely same and same batch of soil materials can be used for testing the maximum dry density and the minimum dry density, the comprehensive settlement and the breakage rate of the soil materials under the action of the vibration load can be measured, and important parameters are provided for engineering.
The method can adapt to rainy day operation, and the maximum dry density can be directly measured through the change of the water content when the maximum dry density is measured as long as a dry soil sample is adopted during sample preparation.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the on-site relative density testing method for the soil material adopts the completely same soil material, can determine the minimum dry density and the maximum dry density at one time, wherein the maximum dry density is tested by adopting a twice irrigation method, the subsidence volume of the soil sample can be accurately measured, the influences of the shape change and the top inclination of a sample barrel under the action of vibration load are eliminated, the testing precision of the maximum dry density is improved, and the method can be suitable for coarse-grained soil with different grain diameters;
2. according to the on-site relative density testing method for the soil material, the test barrels are buried underground, and the ground surface is flush with the barrel top, so that on a large enough field, the soil samples with different particle sizes in a plurality of test barrels can be tamped by one-time rolling through vibration rolling, a plurality of groups of relative density tests can be simultaneously carried out, batch operation can be realized, and manpower, machinery and resources are saved;
3. according to the field relative density testing method for the soil material, the maximum dry density is tested by adopting a twice irrigation method, so that the influence of the shape change and the top inclination of the sample barrel on the volume test of the soil sample under the action of vibration load can be eliminated, and the testing precision of the maximum dry density is improved;
4. according to the field relative density testing method for the soil material, the load of the vibration roller is transmitted by the gravel layer and the gravel soil, so that the energy loss caused by the direct action of the vibration force on the top of the test barrel can be avoided;
5. the invention relates to a field relative density testing method for soil materials, which utilizes geotextile to separate a soil sample and a soil body for transferring load, can ensure that the soil materials in the same batch are completely the same in the test of the maximum dry density and the minimum dry density, can measure the comprehensive settlement and the breakage rate of the soil materials under the action of vibration load, and provides important parameters for engineering.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic diagram of the test of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
As shown in fig. 1, an on-site relative density testing method for soil material includes the following steps: 1) manufacturing a test barrel meeting the standard requirements, wherein the volume V of the test barrel0As known, a test barrel is buried underground in a test field, so that the top of the barrel is flush with the ground surface; 2) determination of the minimum dry density of the soil material: weighing the mass M of the soil material, slowly pouring the soil material into a test barrel until the test barrel is filled with the soil material, wherein the minimum dry density is the mass M of the soil material/volume V of the test barrel0(ii) a 3) Determining the maximum dry density of the soil material: applying dynamic load on the upper part of the soil material body by using a vibration roller, vibrating the soil sample in the test barrel to be compact, paving a thin film on the surface of the soil sample after the rolling is finished, and then filling clear water until the test barrel is filled to obtain the volume V of the clear water filled in the test barrelS1(ii) a 4) Digging out the soil sample in the test barrel, cleaning up, and filling clear water again to obtain the volume V01The maximum dry density is the mass of the soil material M/(V)01-VS1)。
The method for measuring the relative density of the soil material adopts the completely same soil material, can measure the minimum dry density and the maximum dry density at one time, wherein the maximum dry density is measured by adopting a twice irrigation method, the subsidence volume of the soil sample can be accurately measured, the influences of the shape change and the top inclination of the sample barrel under the action of vibration load are eliminated, the measuring precision of the maximum dry density is improved, and the method can be suitable for coarse-grained soil with different grain diameters. After the minimum dry density test is completed, the soil sample can be used for testing the maximum dry density after being tamped; the test barrels are buried underground, and the ground surface is flush with the barrel top, so that on a large enough field, the tamping of soil samples with different particle sizes in a plurality of test barrels can be completed by one-time rolling through vibration grinding, a plurality of groups of relative density tests can be simultaneously carried out, batch operation can be realized, and manpower, machinery and resources are saved; wherein, first watering can obtain the volume that the soil sample subsided after the tamping, and after accomplishing with the soil material of experimental bucket clear away totally, irritate the water for the second time, volume in the experimental bucket of measurement department this moment can obtain the volume of the soil sample after being tamped through twice difference of watering the volume, has eliminated the shape change and the top slope of the sample bucket under the vibration load effect influence to soil sample volume test, has improved the measuring accuracy of maximum dry density.
Preferably, in the step 1), gravel stones flush with the test barrel are filled around the test barrel, so that the damage to the top of the test barrel caused by the vibration roller in the movement process can be avoided.
Preferably, in the step 2), the prepared soil sample is mixed into the rubber frame, the mass mi of the soil sample filled into the rubber frame is weighed, the soil sample in the rubber frame is gently placed into the test barrel, the rubber frame is close to the barrel bottom, the soil sample is slowly poured into the rubber frame, the steps are repeated until the sample barrel is quickly filled with the sample, the top of the test barrel is leveled by using a square aluminum alloy pipe, and the minimum dry density sigma is equal to the mass mi of the soil sample filled into the rubber frame/the volume V of the test barrel0And by continuously adding the soil sample into the test barrel for a small number of times, the soil sample can be uniformly kept in a loose state to the maximum degree when the minimum dry density is tested.
Preferably, in the step 3), before vibrating the soil sample, covering a geotextile on the leveled soil sample, covering a gravel layer with the thickness of 5-6cm and the particle size of less than 20mm on the geotextile, covering 20-30 cm of gravels with the particle size of 20-60 mm on the gravel layer, covering the gravel layer and the gravels on the geotextile, and carrying out vibration rolling on the gravel layer and the gravels to transmit load, so that the energy loss caused by the direct action of vibration force on the top of the test barrel can be avoided; meanwhile, the geotextile is used for separating the soil sample and the soil body for transferring the load, so that the completely same and same batch of soil materials can be used for testing the maximum dry density and the minimum dry density, the comprehensive settlement and the breakage rate of the soil materials under the action of the vibration load can be measured, and important parameters are provided for engineering.
Preferably, the method of the invention can adapt to rainy day operation, and the maximum dry density can be directly measured through the change of the water content when the maximum dry density is measured as long as a soil sample in a dry state is adopted during sample preparation.
The following table is a table of the results of testing the maximum and minimum dry densities of two samples using the method of the present invention:
wherein, the method is specified according to 'hydropower hydraulic engineering coarse soil test regulations' (DL/T5356-: the maximum dry density and the minimum dry density of the coarse-grained soil are subjected to two parallel tests respectively, and the difference between the densities of the two tests is not more than 0.03g/cm3. As can be seen from the results in the table, for the same sample, 2 sets of field relative density tests conducted in parallel each had a difference in the maximum dry density and a difference in the minimum dry density of less than 0.03g/cm3And meets the requirement of the specification. Comparing the results of the on-site relative density test and the indoor relative density test, the difference between the results is less than 0.03g/cm3The specification requirements are met, which shows that the experimental results are met by the method of the invention.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (4)
1. An on-site relative density testing method for soil materials is characterized by comprising the following steps: 1) knowing the volume as V0The test barrel is buried underground in a test field, so that the top of the barrel is flush with the ground surface; 2) determination of the minimum dry density of the soil material: weighing the mass M of the soil material, slowly pouring the soil material into a test barrel until the test barrel is filled with the soil material, wherein the minimum dry density is the mass M of the soil material/volume V of the test barrel0(ii) a 3) Determining the maximum dry density of the soil material: applying dynamic load on the upper part of the soil material body by using a vibration roller, vibrating and compacting the soil sample in the test barrel, paving a thin film on the surface of the soil sample after the rolling is finished, and then pouring clear water until the test barrel is filled to obtain the poured materialVolume V of test barrel clear waterS1(ii) a 4) Digging out the soil sample in the test barrel, cleaning up, and filling clear water again to obtain the volume V01The maximum dry density is the mass of the soil material M/(V)01-VS1)。
2. The field relative density test method for the soil material as claimed in claim 1, wherein in the step 1), the periphery of the test barrel is filled with crushed gravels which are flush with the test barrel.
3. The on-site relative density testing method for soil material according to claim 1, wherein in step 2), the prepared soil sample is mixed into the rubber frame, the mass mi of the soil sample loaded into the rubber frame is weighed, the soil sample in the rubber frame is lightly placed into the testing barrel, the rubber frame is attached to the barrel bottom, the soil sample is slowly poured into the rubber frame, the steps are repeated until the testing barrel is filled with the sample, the leveling is performed on the top of the testing barrel by using a square aluminum alloy pipe, and the minimum dry density is sigma and the mass mi of the soil sample loaded into the rubber frame/the volume V of the testing barrel0。
4. The on-site relative density testing method for soil material according to claim 1, wherein in the step 3), before vibrating the soil sample, the leveled soil sample is covered with geotextile, the geotextile is covered with gravel layer with thickness of 5-6cm and particle size of less than 20mm, and the gravel layer is covered with 20-30 cm of gravel soil with particle size of 20mm-60 mm.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111896717A (en) * | 2020-09-22 | 2020-11-06 | 兰州理工大学 | Soil seepage-settlement testing method |
| CN112255064A (en) * | 2020-10-26 | 2021-01-22 | 中国电建集团成都勘测设计研究院有限公司 | Method for testing relative density of coarse soil and measuring and calculating rolling parameters |
| CN117169049A (en) * | 2023-09-21 | 2023-12-05 | 中国水利水电科学研究院 | Method and device for testing relative density of field original grading blasting pile material |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111896717A (en) * | 2020-09-22 | 2020-11-06 | 兰州理工大学 | Soil seepage-settlement testing method |
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| CN112255064A (en) * | 2020-10-26 | 2021-01-22 | 中国电建集团成都勘测设计研究院有限公司 | Method for testing relative density of coarse soil and measuring and calculating rolling parameters |
| CN112255064B (en) * | 2020-10-26 | 2023-04-07 | 中国电建集团成都勘测设计研究院有限公司 | Method for testing relative density of coarse soil and measuring and calculating rolling parameters |
| CN117169049A (en) * | 2023-09-21 | 2023-12-05 | 中国水利水电科学研究院 | Method and device for testing relative density of field original grading blasting pile material |
| CN117169049B (en) * | 2023-09-21 | 2024-05-28 | 中国水利水电科学研究院 | Method and device for testing relative density of field original grading blasting pile material |
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