CN113670771B - Variable pressure vibration maximum dry density measuring device - Google Patents
Variable pressure vibration maximum dry density measuring device Download PDFInfo
- Publication number
- CN113670771B CN113670771B CN202110808797.8A CN202110808797A CN113670771B CN 113670771 B CN113670771 B CN 113670771B CN 202110808797 A CN202110808797 A CN 202110808797A CN 113670771 B CN113670771 B CN 113670771B
- Authority
- CN
- China
- Prior art keywords
- sample
- sleeve
- disc
- pressure
- dry density
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims description 18
- 238000005096 rolling process Methods 0.000 claims description 6
- 238000001739 density measurement Methods 0.000 claims description 5
- 238000005259 measurement Methods 0.000 claims description 5
- 239000002689 soil Substances 0.000 abstract description 22
- 238000012360 testing method Methods 0.000 abstract description 18
- 239000004927 clay Substances 0.000 abstract description 2
- 239000002245 particle Substances 0.000 description 10
- 238000005056 compaction Methods 0.000 description 7
- 238000010276 construction Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- 238000007605 air drying Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
- G01N5/04—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder
- G01N5/045—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder for determining moisture content
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention relates to the technical field of geotechnical tests, in particular to a variable pressure vibration maximum dry density measuring device; the scheme is that a counter-force frame and a spring are combined to replace a counterweight to load the top of a sample, so that the loading pressure is adjustable; the maximum dry density rho dmax of the sample is calculated by checking the spring stiffness coefficient K, filling the sample in the sample cylinder, determining the top pressure p 0 of the applied sample, measuring the height H 0 of the sample after vibration; the invention applies pressure by adopting a spring, does not need a counterweight, and can adjust the top loading pressure according to the on-site preloading pressure; for determining the maximum dry densities of the non-clay soil free draining coarse-grained soil and the macro-grained soil; the device can be matched with a vibrating table to use the maximum dry density, and can also be used for measuring the maximum dry density by adopting a manual hammering method.
Description
Technical Field
The invention relates to engineering test equipment, in particular to geotechnical test equipment, and particularly relates to a variable pressure vibration maximum dry density measuring device.
Background
The existing coarse-grained soil and huge-grained soil dry density measuring method comprises a surface vibration compaction method and a vibrating table method. The loading pressures of the two methods are fixed loads, the loading pressures of different specifications are different in value, 18kPa is taken, such as highway geotechnical test regulations (JTG 3430-2020), 14kPa is taken, such as coarse-grained soil test regulations (DL/T5356-2006) of hydroelectric engineering, and the top loading of a sample, such as crushed stone pebbles for construction (GB/T14685-2011), is not needed for measuring the stacking compactness. For coarse-grained soil and huge-grained soil, the compaction dry density is related to factors such as grading, water content, loading pressure and the like, and the relation between the compaction dry density and the loading pressure is that the compaction dry density is increased and then decreased when the loading pressure is increased from 7kPa to 200 kPa. Thus, the following technical drawbacks occur in practical engineering: firstly, the fixed pressure adopted in the indoor test cannot be matched with the grounding pressure of different construction machines on site, and the indoor test result cannot guide the site construction well; secondly, the vibrating table method needs to balance weight at the top of the test sample, 18kPa is loaded according to the top, the inner diameter of the test sample cylinder is 152mm and 280mm, and the balance weight is 32kg and 111kg respectively; third, the high counterweight has potential safety hazards in vibration, and the labor intensity of testers is also increased.
Disclosure of Invention
The invention overcomes the defects of the prior art, and provides a variable pressure vibration maximum dry density measuring device which is used for measuring the free-draining coarse-grained soil and huge-grained soil of non-clay soil.
In order to achieve the above purpose, the present invention is realized by the following technical scheme.
The variable pressure vibration maximum dry density measuring device comprises a reaction frame, wherein a sleeve is fixed at the bottom of the reaction frame, a sample tube is fixed in the sleeve, an adjustable pressure device is arranged right above the sample tube, and the adjustable pressure device is used for loading pressure to a sample to be measured in the sample tube; the pressure-adjustable device comprises a hollow screw rod, and the hollow screw rod is in threaded connection with a cross beam of the reaction frame; the upper end of the hollow screw rod is connected with a rotary table, the lower end of the hollow screw rod is connected with an upper disc through a bearing, and the lower disc is connected under the upper disc through a spring; the diameters of the upper disc and the lower disc are the same, and the upper disc and the lower disc can extend into the inner wall of the sample cylinder; the number of the springs is more than or equal to 3, the springs are uniformly distributed on the periphery of the center of the upper disc and the lower disc and used for providing uniform pressure for the surface of the sample, and the pressure provided by the springs is more than or equal to 14 kPa; and the hollow screw is internally used for placing a vernier depth gauge for depth measurement.
Further, the bearing is secured within the central opening of the upper disc.
Further, the reaction frame is an H-shaped beam reaction frame, the H-shaped beam reaction frame comprises a beam and a double-head threaded rod, the upper end of the double-head threaded rod is connected with the beam, and the lower end of the double-head threaded rod is connected with the sleeve.
Further, the sleeve comprises an upper sleeve with an upper opening and a lower sleeve with an upper opening, the sample tube is sleeved between the upper sleeve and the lower sleeve, and the lower sleeve is fixed on the vibrating table; the upper sleeve and the lower sleeve are fixed through a full threaded rod after being assembled with the sample cylinder.
Further, the lower end of the double-head threaded rod is connected with the lower sleeve.
Furthermore, 360-degree dial is embedded around the reserved hole on the top surface of the beam of the H-shaped beam reaction frame, and the minimum graduation value is 1 degree.
Further, a guide rod is arranged in the center of the spring and used for controlling the vertical movement track of the lower disc in the vibration process, the lower end of the guide rod is fixed on the lower disc, and the upper end of the guide rod penetrates through the upper disc rolling shaft; the guide rod is in sliding contact with the upper disc through a rolling shaft and is used for reducing side friction of the guide rod; the rolling shaft is embedded in the reserved hole of the upper disc.
A variable pressure vibration maximum dry density measurement method comprising the steps of:
a) Checking the spring rate coefficient K: placing pressure detection device in the sample tube, rotating the carousel makes the lower wall closely adhere with pressure detection device surface, rotates the carousel and applys the uninstallation again after initial load, inserts the bottom contact lower wall top surface with vernier depth chi from hollow threaded rod top trompil, and the initial reading L 0 of record vernier depth chi rotates carousel n circles, obtains loading pressure p, inserts and contacts the lower wall top surface with the vernier depth chi from hollow threaded rod again, records the reading L of vernier depth chi, calculates spring rate K:
K=p/(L0-L)= p/（nx） （Ӏ）
wherein: x is the pitch of the hollow screw.
The relation formula (II) between the spring loading pressure and the number of turns n of the rotary table is obtained from Ӏ:
p=n（Kx）=K (L0-L) （Ⅱ）。
b) After the pressure detection device is taken out, a sample is filled in the sample cylinder, and the top pressure p of the applied sample is determined: recording an initial reading L 0 of the vernier depth scale according to the method of the step a, rotating the turntable for n circles, and measuring the reading L of the corresponding vernier depth scale after the spring is compressed; determining a sample top loading pressure p 1 from formula (ii); after the sample is vibrated, the average of the sample top loading pressures p 2;p1 and p 2 is determined as top loading pressure p according to step a.
C) Measuring the height H 0 of the vibration-finished sample; the maximum dry density ρ dmax is calculated.
Further, the maximum dry density ρ dmax is:
ρdmax=1.274Md/（D2×H0） （Ⅲ）
Wherein: m d is the mass of the sample; d is the inner diameter of the sample cylinder; h 0 is the specimen height.
Further, the vibration of the sample is performed by using a vibrating table or by hand.
Further, after measuring the height H 0 of the vibration-finished sample, the water content of the sample is measured; calculating the maximum dry density ρ dmax of the sample according to formula (IV):
ρdmax=1.274Mf/（H0×D2×（1+0.01ω）） （Ⅳ）
wherein: m f is the mass of the air-dried sample; omega is the water content of the sample; d is the inner diameter of the sample cylinder; h 0 is the specimen height.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention applies pressure by adopting a spring, does not need a counterweight, and can adjust the top loading pressure according to the on-site preloading pressure.
(2) The invention can be directly matched with the existing vibrating table in the laboratory, thereby saving the cost.
(3) According to the invention, the top loading of the sample replaces the counterweight by using the spring, so that the potential safety hazard existing in vibration is reduced, and the labor intensity of a tester is lightened.
(4) The invention has simple structure and light weight, is suitable for field construction test, and can realize the maximum dry density test of the granular soil without a vibrating table.
Drawings
Fig. 1 is a schematic structural view of a dry density measuring device according to the present invention.
Fig. 2 is a schematic view of the upper sleeve structure of the dry density measuring device according to the present invention.
Fig. 3 is a schematic structural view of a sample cartridge of the dry density measurement device according to the present invention.
Fig. 4 is a schematic view of the structure of the lower sleeve of the dry density measuring device according to the present invention.
FIG. 5 is a schematic view of a beam scale of the dry density measurement device of the present invention.
FIG. 6 is a schematic view of the connection part of the upper and lower trays of the dry density measuring device according to the present invention.
In the figure, 1 is a full threaded rod, 2 is a reserved threaded hole, 3 is a double-head threaded rod, 4 is a reserved hole, 5 is a nut, 6 is an upper beam, 7 is a turntable, 8 is a hollow threaded rod, 9 is a reserved threaded hole, 10 is a bearing, 11 is a top orifice of the hollow threaded rod, 12 is an upper disc, 13 is a spring, 14 is a rubber shield, 15 is a lower disc, 16 is a sample tube, 17 is an upper sleeve, 18 is a lower sleeve, 19 is a vibrating table, 20 is a guide rod, 21 is a rolling shaft, and 22 is a dial.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail by combining the embodiments and the drawings. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. The technical scheme of the present invention is described in detail below with reference to examples and drawings, but the scope of protection is not limited thereto.
Example 1
As shown in fig. 1, the present embodiment is a vibration pressure-adjustable maximum dry density measuring device for measuring free-draining coarse-grained soil and huge-grained soil of non-cohesive soil, the device mainly comprising: a vibration table 19, a sample tube 16, an upper sleeve 17, a lower sleeve 18, an adjustable pressure device and a vernier depth gauge.
Vibration table: the table surface of the vibration table 19 is not less than 500mm×500mm in size and has sufficient rigidity. The frequency of the vibrating table is 30 Hz-50 Hz, the double amplitude is 0-2 mm, the maximum load of the vibrating table meets the quality requirements of the sample cylinder 16, the upper sleeve 17, the lower sleeve 18, the sample, the adjustable pressure device and the like. The vibration table 19 is fixed to the concrete foundation.
As shown in FIG. 3, the sample tube 16 was a cylindrical metal tube having a wall thickness of not less than 5mm and the dimensions were selected as shown in Table 1. The cartridge 16 is sealed at the bottom but removable.
The sleeve comprises an upper sleeve 17 and a lower sleeve 18. As shown in fig. 2, the inner diameter of the upper sleeve 17 is matched with that of the sample tube 16, and is in linear connection with the inner wall of the sample tube 16 after being tightly fixed. As shown in fig. 4, the lower sleeve 18 is fixed on the table top of the vibration table 19, the inner diameter of the sleeve is matched with the outer diameter of the sample tube 16, the height is not less than 30mm, the wall thickness is equal to the sample tube 16, the upper sleeve 17 is connected with the sample tube 16 by adopting a gamma interface, and the upper sleeve and the lower sleeve are fixed through the full threaded rod 1 after being assembled with the sample tube 16.
An adjustable pressure device: the device comprises an H-shaped beam reaction frame, a turntable 7, a hollow threaded rod 8, a bearing 10, an upper disc 12, a spring 13, a rubber shield 14 and a lower disc 15. The H-shaped beam reaction frame consists of a double-head threaded rod 3, a nut 5 and a beam 6, wherein the double-head threaded rod 3 is fixed on a lower sleeve 18 through a reserved threaded hole 2. The lower sleeve 18 is secured to the vibration table 19 by a secure connection. The upper end of the double-head threaded rod 3 is connected with the cross beam 6 through bolts, the hollow threaded rod 8 passes through a reserved threaded hole 9 on the cross beam 6, the lower end is connected with a bearing 10, and the upper end is connected with the turntable 7. The bearing 10 is fixed in the central hole of the upper disc 12, the lower disc 15 is fixed below the upper disc through the springs 13, the springs 13 are uniformly distributed outside the centers of the upper disc and the lower disc and are 1/2 away from the center, the number of the springs 13 is not less than 3, the pressure of the springs 13 can be not less than 14kPa, and the springs 13 are connected with the upper disc and the lower disc through bolts. The spring 13 is internally provided with a guide rod 20 at the center, the lower end of the guide rod 20 is fixed on the lower disc, the upper end of the guide rod passes through an upper disc roller 21, the roller 21 is embedded in a reserved hole of the upper disc 12, and the guide rod 20 is in sliding contact with the upper disc 12 through the roller 21. The upper and lower discs have the same diameter and are slightly smaller than the inner diameters of the sample tube 16 and the sleeve, and the rigidity is enough that the lower disc 15 can freely move in the sample tube during loading.
Vernier depth gauge: the length satisfies the distance of +3cm from the lower disc 15 to the top surface of the turntable 7, and the precision is 0.02mm.
Example 2
Is a maximum dry density measurement method using the measurement apparatus described in example 1: the maximum dry density of the granular soil was measured in conjunction with a vibrating table.
The test procedure is described in "Highway geotechnical test protocol" (JTG 3430-2020) by the shaking table method in T0132-1996.
1. The table top size is selected to be not less than 500mm multiplied by 500mm of the vibrating table 19, the frequency of the vibrating table 19 is 30 Hz-50 Hz, the double amplitude is 0-2 mm, the table top of the vibrating table 19 has enough rigidity, and the vibrating table 19 is fixed on a concrete foundation.
2. Representative samples are collected, the particle percentage of each particle group is measured by adopting a standard screening method (T0115-2007), the 20mm standard square-hole sieve is utilized to screen out the particle soil with the particle size larger than 20mm, and the mass percentage of dry particles passing through the 0.075mm standard sieve is limited to be not more than 15%, so that the particle soil with the particle size of 20 mm-0.075 mm is obtained, and the particle soil is properly stored for standby. Before the test, the prepared granular soil is put into an oven, the soil sample is dried at 105-110 ℃, cooled to room temperature, uniformly stirred, roughly divided into three parts and kept dry.
3. The sample tube 16 with the inner diameter phi 152mm is selected, and the lower sleeve 18 matched with the outer diameter of the sample tube 16 is selected, so that the mass of the sample tube 16 is weighed. The lower sleeve 18 is fixed with the vibrating table 19, the sample tube 16 is placed in the lower sleeve 18, the bottom of the sample tube 16 is closely attached to the lower sleeve 18, then the upper sleeve 17 is placed on the top, and the whole is fixed through the full threaded rod 1.
4. The top loading pressure of the sample is selected and an adjustable pressure device is installed. The H-shaped beam reaction frame of the adjustable pressure device is fixed in the reserved threaded hole 2 of the lower sleeve 18 through the double-head threaded rod 3, and the lower sleeve 18 and the vibrating table 19 are fixed in a reliable connection mode. The upper end of the double-head threaded rod 3 is connected with the cross beam 6 through bolts, the hollow threaded rod 8 penetrates through the cross beam 6 to reserve threaded holes 9, the lower end of the hollow threaded rod is connected with a bearing 10, and the upper end of the hollow threaded rod is connected with the turntable 7. The upper disc 12 and the lower disc 15 which are matched with the inner diameter of the sample tube 16 are selected, the diameters of the upper disc and the lower disc are slightly smaller than 2mm of the inner diameter of the sample tube 16, the bearing 10 is fixed in a central opening of the upper disc 12, the lower disc 15 is fixed below the upper disc 12 through the springs 13, the springs 13 are uniformly distributed outside the center of the upper disc and the outside of the center of the lower disc and are 1/2 of the center, the number of the springs is not less than 3, the springs 13 are connected with the upper disc and the lower disc through bolts, and the center of the springs 13 is provided with the guide rod 20. The stiffness of the spring 13 is selected in accordance with the on-site loading pressure such that the loading pressure of the spring 13 meets the on-site precompaction pressure. The pitch of the hollow threaded rod 8 is x, in mm.
5. The stiffness coefficient K of the spring 13 is checked. Placing a force transducer at the center of the sample tube 16, rotating the turntable 7 to enable the lower disc 15 to be closely attached to the surface of the sample force transducer, rotating the turntable 7 clockwise for 2 circles to apply initial load, then rotating anticlockwise for 2 circles to unload, enabling the reading of the force transducer to return to zero, enabling the vernier depth gauge to be inserted into an opening at the top of the hollow threaded rod 8 to be in bottom contact with the top surface of the lower disc, recording initial reading L 0 of the vernier depth gauge, enabling the vernier depth gauge to be in unit mm, and taking out the vernier depth gauge. The rotary table 7 rotates clockwise for N circles, the reading p of the load cell is recorded, the loading pressure p is not smaller than the unit N of the on-site preloading pressure, the vernier depth gauge is inserted into the top orifice 11 of the hollow threaded rod 8 again to contact the top surface of the lower disc from the bottom, and the reading L of the vernier depth gauge is recorded in mm. The spring rate K was calculated as an average value in N/mm from this measurement 3 times.
K=p/(L0-L)= p/（nx） （1）
Wherein: x is the pitch, mm.
The relation formula (2) between the spring-loaded pressure and the number of turns n of the rotary dial 7 is thus obtained:
p=n（Kx）=K (L0-L) （2）
6. filling the sample. Taking a part of prepared dried sample, slowly filling the prepared sample into a test cylinder by using a small shovel or a funnel, and taking care to minimize the particle separation degree (the filling amount is preferably such that the sample after shaking is equal to or slightly lower than 1/3 of the height of the cylinder); the surface of the sample was smoothed. Then, the cylinder wall may be knocked with a rubber hammer or the like several times to sink the specimen.
7. And applying the top pressure p 0 of the sample according to the pre-applied pressure in the field, and determining the estimated rotation number n of the turntable 7 according to a formula (2). The upper sleeve 17 is arranged on the upper part of the sample tube 16, the rotary turntable 7 enables the lower disc 15 to be closely attached to the surface of the sample, the rotary turntable 7 rotates clockwise for 2 circles, an initial load is applied, then the rotary turntable is rotated anticlockwise for 2 circles to unload, the vernier depth gauge is inserted into the opening 11 at the top of the hollow threaded rod 8 and the bottom of the vernier depth gauge is contacted with the top surface of the lower disc 15, and the initial reading L 0 of the vernier depth gauge is recorded. The rotary disk 7 is rotated clockwise for n times, and then the length L corresponding to the compressed spring is measured by using a vernier depth gauge. The actual loading pressure p 1 at the top of the sample can be determined by the formula (2).
8. And (5) turning on a vibrating table switch to start vibrating for 6min.
9. And after the vibration is finished, measuring the expansion and contraction amount of the spring again, determining the top loading pressure p 2, of the sample after the vibration by using the formula (2), taking the average value of p 1 and p 2 as the top actual loading pressure p Real world , calculating the absolute value of the polar difference of p Real world and p 0 not to exceed 10%, meeting the requirement, and carrying out the next step, otherwise, retesting. .
10. And repeating the steps 6 to 8, and carrying out vibration compaction on the samples of the second layer and the third layer.
11. The upper sleeve 17 is removed. The height of the sample after vibration was measured by placing a straight steel bar on the diameter of the sample cylinder 16. The readings are preferably measured from four locations uniformly distributed on the surface of the sample at least 15mm from the wall of the cylinder and are accurate to 0.5mm, and the height H 0 of the sample is recorded and calculated.
12. The sample tube 16 and the sample are taken out, and the mass is weighed. The mass of the sample tube 16 was subtracted to obtain a sample mass M d, and the maximum dry density ρ dmax was calculated to 0.001 according to the formula (3).
ρdmax=1.274Md/（D2×H0） （3）
Wherein: m d is the mass of the dried sample, kg; d is the inner diameter of the sample tube, m; h 0 is the sample height, m.
13. And taking out the dried sample again, repeating the steps 6-12 for 2 times, and measuring the maximum dry density rho dmax. In the test, a sufficient representative sample must be prepared, and the vibration compaction of the individual samples must not be repeated.
14. The maximum dry density measured in three times was averaged as the maximum dry density value reported in the test.
Example 3
On-site determination of maximum dry density by manual hammering method
The method is identical to the loading device used in the vibrating table method of examples 1 and 2, and the measurement steps are also basically identical, except for the following points:
1. In order to adapt to the tight packing density of the test soil particles without a vibrating table on site, the H-shaped beam reaction frame of the adjustable pressure device is directly connected with the lower sleeve 18 through the double-headed threaded rod 3.
2. The sample impact compaction method refers to a method for measuring the maximum dry density of crushed stone pebbles (GB/T14685-2011) for construction. In example 2, after the first charge was completed, a round steel 16mm in diameter was placed under the lower sleeve 18, and the cylinder 16 and the adjustable pressure device were pressed together, and the strokes were alternately reversed 25 times. And then the second layer is filled, the second layer is overturned in the same way after being filled (but the direction of the round steel is perpendicular to the direction of the first layer when the lower sleeve 18 is filled), and then the third layer is filled, and the third layer is overturned in the same way after being filled (but the direction of the round steel is parallel to the direction of the first layer when the lower sleeve is filled).
Example 4:
the other matters in this case are the same as those in embodiment cases 1 and 2 except that: (1) air-drying the sample; (2) After the vibration stacking density test is finished, drying the sample, and measuring the water content of the sample; (3) The maximum dry density ρ dmax of the sample is calculated according to equation (4).
ρdmax=1.274Mf/（H0×D2×（1+0.01ω）） (4)
Wherein: m f is the mass of the air-dried sample, kg; omega is the water content of the sample,%; the other symbols are as above.
While the invention has been described in detail in connection with specific preferred embodiments thereof, it is not to be construed as limited thereto, but rather as a result of a simple deduction or substitution by a person having ordinary skill in the art to which the invention pertains without departing from the scope of the invention defined by the appended claims.
Claims (3)
1. The variable pressure vibration maximum dry density measuring device comprises a reaction frame, wherein a sleeve is fixed at the bottom of the reaction frame, and a sample tube (16) is fixed in the sleeve, and is characterized in that an adjustable pressure device is arranged right above the sample tube (16) and is used for loading pressure to a sample to be measured in the sample tube (16); the pressure-adjustable device comprises a hollow screw rod (8), and the hollow screw rod (8) is in threaded connection with a cross beam (6) of the reaction frame; the upper end of the hollow screw rod (8) is connected with a rotary table (7), the lower end of the hollow screw rod is connected with an upper disc (12) through a bearing (10), and a lower disc (15) is connected under the upper disc (12) through a spring (13); the diameters of the upper disc (12) and the lower disc (15) are the same, and the upper disc and the lower disc can extend into the inner wall of the sample cylinder (16); the number of the springs (13) is more than or equal to 3, the springs (13) are uniformly distributed at the periphery of the center of the upper disc and the lower disc and used for providing uniform pressure for the surface of a sample, and the pressure provided by the springs (13) is more than or equal to 14 kPa; a guide rod (20) is arranged at the center of the spring (13) and used for controlling the vertical movement track of the lower disc (15) in the vibration process, the lower end of the guide rod (20) is fixed on the lower disc (15), and the upper end of the guide rod passes through the upper disc rolling shaft (21); the guide rod (20) is in sliding contact with the upper disc (12) through a roller (21) and is used for reducing side friction of the guide rod (20); the rolling shaft (21) is embedded in the reserved hole of the upper disc (12);
The reaction frame is an H-shaped beam reaction frame, the H-shaped beam reaction frame comprises a beam (6) and a double-head threaded rod (3), the upper end of the double-head threaded rod (3) is connected with the beam (6), and the lower end of the double-head threaded rod is connected with the sleeve;
The sleeve comprises an upper sleeve (17) with an upper opening and a lower sleeve (18) with an upper opening, the sample tube (16) is sleeved between the upper sleeve (17) and the lower sleeve (18), and the lower sleeve (18) is fixed on the vibrating table; the upper sleeve, the lower sleeve and the sample tube (16) are fixed through a full threaded rod (1) after being assembled; the lower end of the double-head threaded rod (3) is connected with a lower sleeve (18);
The hollow screw rod (8) is internally used for placing a vernier depth gauge for depth measurement.
2. A variable pressure vibration maximum dry density measurement device according to claim 1, characterized in that the bearing (10) is fixed in the central opening of the upper disc (12).
3. The variable-pressure vibration maximum dry density measuring device according to claim 1, wherein the periphery of the top surface reserved hole (9) of the cross beam (6) of the H-shaped cross beam reaction frame is embedded with a 360-degree dial (22), and the minimum graduation value is 1 degree.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110808797.8A CN113670771B (en) | 2021-07-16 | 2021-07-16 | Variable pressure vibration maximum dry density measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110808797.8A CN113670771B (en) | 2021-07-16 | 2021-07-16 | Variable pressure vibration maximum dry density measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113670771A CN113670771A (en) | 2021-11-19 |
| CN113670771B true CN113670771B (en) | 2024-07-30 |
Family
ID=78539448
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110808797.8A Active CN113670771B (en) | 2021-07-16 | 2021-07-16 | Variable pressure vibration maximum dry density measuring device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113670771B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108760428A (en) * | 2018-06-07 | 2018-11-06 | 中交公局厦门检测技术有限公司 | A kind of pervious concrete specimen molding device and its forming method |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6912903B2 (en) * | 1996-02-01 | 2005-07-05 | Bbnt Solutions Llc | Soil compaction measurement |
| JP3368535B2 (en) * | 2000-05-18 | 2003-01-20 | 西日本地研株式会社 | Simple compaction tester and compaction test method by compaction using the same |
| CN104777016B (en) * | 2015-01-14 | 2017-10-24 | 南京工业大学 | Slurry consolidation sample preparation equipment and use method thereof |
| CN104655463B (en) * | 2015-02-09 | 2017-02-22 | 浙江大学 | Vibration table-based sample preparation device and vibration table-based sample preparation method for large-scale triaxial test of coarse grained soil |
| JP6762257B2 (en) * | 2017-03-31 | 2020-09-30 | 鹿島建設株式会社 | Soil measurement method and soil measurement device |
| CN209387368U (en) * | 2018-10-30 | 2019-09-13 | 陈正汉 | A kind of unsaturated soil multifunctional triaxial instrument and its sample preparation device |
| CN111103185B (en) * | 2020-01-13 | 2023-11-21 | 石河子大学 | Spinning coarse-grained soil triaxial experiment sample preparation device and sample preparation method |
| CN112067500B (en) * | 2020-09-09 | 2022-08-30 | 中国铁道科学研究院集团有限公司铁道建筑研究所 | Railway coarse-grained soil filler vibration compaction experimental device and experimental method |
-
2021
- 2021-07-16 CN CN202110808797.8A patent/CN113670771B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108760428A (en) * | 2018-06-07 | 2018-11-06 | 中交公局厦门检测技术有限公司 | A kind of pervious concrete specimen molding device and its forming method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113670771A (en) | 2021-11-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Kim | Deformational characteristics of soils at small to intermediate strains from cyclic tests | |
| CN107389449B (en) | A kind of filling in mine material compression property experimental provision and its experimental method | |
| DeGregorio | Loading systems, sample preparation, and liquefaction | |
| US7191664B2 (en) | Testing of mechanical properties of materials | |
| Phillips | Centrifuge modelling: practical considerations | |
| JP4345942B2 (en) | Horizontal consolidation test equipment for ground materials | |
| CN113670771B (en) | Variable pressure vibration maximum dry density measuring device | |
| CN113686728B (en) | Variable pressure vibration maximum dry density measurement method | |
| KR200269540Y1 (en) | Large Cyclic Triaxial Testing Apparatus | |
| CN113686727B (en) | Variable pressure internal vibration close packing density measuring method | |
| CN113686729B (en) | Variable pressure internal vibration close packing density measuring method | |
| JP4260997B2 (en) | Method and apparatus for consolidation test of ground material | |
| Nielsen et al. | Scale errors in model tests on granular media with special reference to silo models | |
| CN102759493A (en) | Frequency modulation type surface vibratory compaction test instrument | |
| CN117388055A (en) | Device for measuring pressure coefficient of calcareous sand static soil and use method | |
| Muhanna | A testing procedure and a model for resilient modulus and accumulated plastic strain of cohesive subgrade soils | |
| Gilboy | Soil mechanics research | |
| Gilboy | Improved soil testing methods | |
| CN114935524A (en) | Method for testing maximum compression ratio and maximum molding density of stone filling material | |
| CN212300872U (en) | Test device for simulating subway tunnel train operation vibration | |
| Allard | Soil stress field around driven piles | |
| CN113252550B (en) | Roadbed filler compression tester and use method thereof | |
| EP1338704B1 (en) | Measurement of the compaction rate of granular material layers | |
| Abrantes¹ et al. | Effect of strain rate in cohesionless soil | |
| Pettibone et al. | Research on vibratory maximum density test for cohesionless soils |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20240617 Address after: 510000, 1st Floor, No. 49 Yuan'an New Street, Binjiang East Road, Haizhu District, Guangzhou City, Guangdong Province, China, Self made 1F Applicant after: Guangzhou Zhenghe Engineering Testing Co.,Ltd. Country or region after: China Address before: 030051 No. 15, unit 2, building 33, Xueyuan Road, Jiancaoping District, Taiyuan City, Shanxi Province Applicant before: Li Jianjun Country or region before: China |
|
| TA01 | Transfer of patent application right | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |