CN115492173B - On-site testing method for non-sticky coarse-grained soil relative density test - Google Patents
On-site testing method for non-sticky coarse-grained soil relative density test Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 214
- 239000002689 soil Substances 0.000 title claims abstract description 102
- 238000005096 rolling process Methods 0.000 claims abstract description 81
- 238000010276 construction Methods 0.000 claims abstract description 40
- 238000013461 design Methods 0.000 claims abstract description 21
- 238000005056 compaction Methods 0.000 claims abstract description 15
- 238000010998 test method Methods 0.000 claims abstract description 13
- 239000000463 material Substances 0.000 claims description 56
- 238000000034 method Methods 0.000 claims description 43
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 238000005259 measurement Methods 0.000 claims description 17
- 229910000831 Steel Inorganic materials 0.000 claims description 14
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- 239000004033 plastic Substances 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 6
- 239000008187 granular material Substances 0.000 claims description 5
- 230000002262 irrigation Effects 0.000 claims description 5
- 238000003973 irrigation Methods 0.000 claims description 5
- 238000003825 pressing Methods 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 3
- 239000000945 filler Substances 0.000 abstract description 9
- 239000002985 plastic film Substances 0.000 description 5
- 229920006255 plastic film Polymers 0.000 description 5
- 238000002347 injection Methods 0.000 description 4
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- 239000004746 geotextile Substances 0.000 description 3
- 238000006467 substitution reaction Methods 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
- E02D1/08—Investigation of foundation soil in situ after finishing the foundation structure
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
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- G01N1/04—Devices for withdrawing samples in the solid state, e.g. by cutting
- G01N1/08—Devices for withdrawing samples in the solid state, e.g. by cutting involving an extracting tool, e.g. core bit
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
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- G01N15/0806—Details, e.g. sample holders, mounting samples for testing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/082—Investigating permeability by forcing a fluid through a sample
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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
- G01N9/36—Analysing materials by measuring the density or specific gravity, e.g. determining quantity of moisture
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Abstract
The invention provides a field test method for a relative density test of non-sticky coarse-grained soil, which comprises the steps of carrying out different grading working conditions and different soil paving thicknesses H on a test field n And (3) carrying out a plurality of stages of rolling tests, wherein different grading conditions are represented by different design grading curves. According to the invention, rolling tests are carried out on site construction sites or special sites, so that the maximum dry density and the minimum dry density under different soil paving thicknesses and different grading working conditions are obtained, and then the site construction calculation is combined to calculate the actual measured relative density value of the appearance site, so that the compaction quality of the filler is truly reflected, and the work efficiency is greatly improved.
Description
Technical Field
The invention relates to the field of soil mechanics tests, in particular to a field test method for a relative density test of non-sticky coarse-grained soil.
Background
In engineering construction, the backfilling compaction quality of the non-cohesive coarse-grained soil is generally controlled by adopting a porosity or relative density index, a porosity or relative density control value is generally set by design, and the porosity or relative density after site filling and rolling is required to be not lower than the design requirement. The relative density after site filling compaction refers to the measured dry density after site filling compaction, and the minimum dry density and the maximum dry density obtained by the indoor relative density test are calculated by formulas. The minimum dry density of the indoor relative density test (minimum dry density and maximum dry density) is measured by a pouring loose fill method, the maximum dry density is usually measured by a vibrating table method, namely a phi 300 multiplied by 340mm volume barrel and a vibrating table with adjustable vibration frequency of 40 Hz-60 Hz and vibration amplitude of 0 mm-2 mm are adopted, the pressure is applied to be 14KPa, the vibration test is carried out, the maximum particle size of a sample is required to be not more than 60mm, and the ultra-diameter part in the original grading is generally treated by an equal substitution method and the like, so that the maximum dry density and the minimum dry density are determined.
Because the existing vibration rolling equipment technology is faster in development, the exciting force is larger, the actual maximum particle size of field fillers can reach more than 300mm, the grading range is wide, the limiting particle size of an indoor relative density test (minimum dry density, maximum dry density) device is smaller, the maximum dry density and the minimum dry density measured by the original grading treatment by using an equal substitution method and other methods are obviously smaller than those of a construction site, so that the calculated relative density after field filling rolling is far greater than the relative density required by design, even an overstock phenomenon occurs, the actual compaction relative density is lower than the calculated relative density, or the relative density value required by design possibly does not reach yet, the actual compaction quality real condition of an engineering site cannot be reflected, a false qualification phenomenon is caused, and hidden danger is left for the engineering construction quality; in addition, after each compaction degree detection, an indoor relative density test needs to be carried out, which is labor-consuming and time-consuming, has low work efficiency and affects the construction period.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide a field test method for a relative density test of non-sticky coarse-grained soil. According to the invention, rolling tests are carried out on site construction sites or special sites, so that the maximum dry density and the minimum dry density under different soil paving thicknesses and different grading working conditions are obtained, and then the site construction calculation is combined to calculate the actual measured relative density value of the appearance site, so that the compaction quality of the filler is truly reflected, and the work efficiency is greatly improved.
In order to solve the technical problems, the invention is realized by the following technical scheme:
a field test method for a relative density test of non-sticky coarse-grained soil is characterized in that: different grading working conditions and different soil paving thicknesses H are carried out on a test field n The rolling test comprises the following steps of:
s1, dividing a test field into a rolling test field and a relative density test field; paving and compacting the non-sticky coarse-grained soil for engineering construction as backfill material to serve as a base layer;
s2, presetting soil paving thickness H of first-stage test layer 1 Placing multiple sample cylinders on the backfilled base layer of the relative density test field to obtain the volume V of each sample cylinder Cartridge The method comprises the steps of carrying out a first treatment on the surface of the On the backfill base layer of the test site according to a predetermined thickness H 1 Paving and filling non-viscous coarse-grained soil, wherein the top surface elevation of the first-stage test layer is the same as the top surface elevation of the sample cylinder;
s3, respectively filling a test material prepared under a grading working condition curve into each sample tube, wherein the mass of the test material is M Cartridge By volume V of the cartridge Cartridge Calculating the minimum wet density rho of the test material under the current grading working condition curve min The method comprises the steps of carrying out a first treatment on the surface of the Rolling the first-stage test layer of the relative density test field and the test material until the settlement amount is unchanged, and rolling the first-stage test layer of the rolling test field until the preset rolling pass number is reached;
s4, randomly selecting test points in a rolling test field, measuring the mass M and the volume V of the non-cohesive coarse-grained soil of the test points, calculating the wet density rho of the compacted non-cohesive coarse-grained soil in the current rolling test field, detecting the moisture content of the non-cohesive coarse-grained soil in the area, and calculating the dry density rho of the non-cohesive coarse-grained soil of a first-stage test layer in the rolling test field d The method comprises the steps of carrying out a first treatment on the surface of the The actual grain composition of the non-cohesive coarse-grained soil of the first-stage test layer in the rolling test field is tested while the density is tested, and an actual measurement grading curve is drawn;
s5, testing the relative densityThe compacted non-adhesive test materials in each sample cylinder of the test field are measured to obtain the compacted volume V Pressing And according to the mass M of the test material Cartridge Calculating to obtain the maximum wet density rho of the compacted non-cohesive coarse-grained soil test material under the current grading working condition curve max The method comprises the steps of carrying out a first treatment on the surface of the Then the water content of the non-cohesive coarse-grained soil test material in the sample cylinder is detected, and the minimum dry density rho of the non-cohesive coarse-grained soil test material under the current grading working condition curve in the first-stage test layer of the relative density test field is obtained through calculation dmin And maximum dry density ρ dmax ；
S6, repeating the steps S2 to S5 until all the different soil paving thicknesses H are completed n Several stages of rolling test of different stage distribution working condition curves to obtain different soil paving thickness H n Minimum dry density and maximum dry density of the lower different level of distribution working condition curves;
and (3) controlling compaction quality of the non-sticky coarse-grained soil in the construction period: determining the paving thickness and the rolling pass number according to the rolling test result, performing layer-by-layer filling construction, and calculating the actual dry density and the actual grain composition of the layer of non-cohesive coarse-grained soil according to the step S4 after each layer of paving and rolling; and comparing the actual measurement grading curve with different grading working condition curves, and calculating an actual measurement relative density value of the appearance field.
Further: when the actual measurement grading curve is compared with different grading working condition curves, if the actual measurement grading curve is close to one of the grading working condition curves, the maximum dry density value rho of the grading working condition curve under the corresponding soil paving thickness is adopted in the calculation of the relative density dmax And a minimum dry density value ρ dmin The method comprises the steps of carrying out a first treatment on the surface of the If the actually measured grading curve is positioned near the middle of any two grading working condition curves, the maximum dry density rho of the two grading working condition curves under the corresponding soil paving thickness is adopted in the calculation of the relative density dmax Average and minimum dry density ρ of dmin Average value of (2).
Further: the test material configuration in the step S3:
s3-1: and (3) carrying out particle group screening on the non-sticky coarse granules meeting the design requirements: classifying and screening according to the grain composition of 600-400 mm, 400-200 mm, 200-100 mm, 100-80 mm, 80-60 mm, 60-40 mm, 40-20 mm, 20-10 mm, 10-5 mm and less than 5 mm;
s3-2: preparing different levels of the compound Kuang Jipei curve: volume V of the cartridge Cartridge Multiplying the maximum dry density of the estimated non-viscous coarse-grained soil, multiplying the maximum dry density by a margin coefficient to obtain the total amount of test materials required by a test, multiplying the total amount of the test materials by the percentage of each grain group in the grading working condition curve respectively to obtain the quality of each grain group, and fully mixing and uniformly mixing the test materials of each grain group for standby.
Further: in the step S2, the bottom part of the sample cylinder is buried in the backfill foundation layer or the test layer, the main body part of the cylinder body of the sample cylinder is a steel cylinder or a plastic cylinder, and the upper part of the sample cylinder is lapped by geotechnical cloth
Further: the different level distribution Kuang Jipei curves comprise a design level distribution upper envelope, a design level distribution lower envelope, an average line, a large value average line and a small value average line
Further: and the rolling test and the construction period adopt the same construction rolling machine to roll.
Further: the test site is a site construction site or a special site, the site test is carried out on the site construction site, the soil paved after the rolling test in a plurality of periods is not excavated, and the engineering construction is continued above the soil paved in the rolling test in a plurality of periods
Further: in step S2, each cartridge volume V Cartridge Obtaining by a sand filling method; in the step S4, measuring the mass M and the volume V of the non-viscous coarse-grained soil at the test point by adopting a density test method of an irrigation method; in step S5, the compacted volume V of the non-adhesive test material in each sample cylinder is measured by adopting a density test method by a water filling method Pressing 。
Compared with the prior art, the invention has the following advantages:
the invention considers the actual condition of site construction, does not need to adopt the technology treatment such as grading substitution to the original grading, does not need to carry out an indoor relative density test, can combine the productive rolling process test before formal construction to carry out the site test, and obtains the maximum dry density and the minimum dry density under different grading working conditions under different soil paving thicknesses, and the actual measured grading curve is compared with different grading working conditions (different grading working condition curves) in construction, and the calculated value of the site actual measured relative density is obtained by adopting the maximum dry density and the minimum dry density under the closer grading working conditions, thereby calculating the site actual measured relative density value after the filler compaction. The measured minimum dry density and maximum dry density values can represent the actual construction condition, and the relative density test is not needed to be carried out for many times in real time in the construction, so that the work efficiency is greatly improved, and the backfill compaction quality can be ensured to meet the design requirement.
Drawings
FIG. 1 is a schematic structural view of a cartridge field arrangement of the present invention;
FIG. 2 is a schematic illustration of a non-sticky coarse soil grade distribution curve of the present invention.
Reference numerals: 1-a sample cylinder; 2-geotextile; 3-test material; 4-backfilling.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present invention, preferred embodiments of the present invention will be described below with reference to specific examples, but it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the present invention; for the purpose of better illustrating the embodiments, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the actual product dimensions; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationship described in the drawings are for illustrative purposes only and are not to be construed as limiting the invention.
The invention is further illustrated by the following figures and examples, which are not intended to be limiting.
As shown in figures 1 to 2, the non-sticky coarse-grained soil relative density test site test method is used for carrying out different grading working conditions and different soil paving thicknesses H on a test site n The rolling test in a plurality of stages is carried out, and different stage matching working conditions adopt different modesThe grading working condition curve shows that the rolling test comprises the following steps:
s1, dividing a test field into a rolling test field and a relative density test field; paving and compacting the non-sticky coarse-grained soil for engineering construction as backfill material to serve as a base layer;
s2, presetting soil paving thickness H of first-stage test layer 1 Placing multiple sample cylinders on the backfilled base layer of the relative density test field to obtain the volume V of each sample cylinder Cartridge The method comprises the steps of carrying out a first treatment on the surface of the On the backfill base layer of the test site according to a predetermined thickness H 1 Paving and filling non-viscous coarse-grained soil, wherein the top surface elevation of the first-stage test layer is the same as the top surface elevation of the sample cylinder;
s3, respectively filling a test material 3 prepared under a grading working condition curve into each sample tube, wherein the mass of the test material is M Cartridge By volume V of the cartridge Cartridge Calculating to obtain the minimum wet density rho of the test material 3 under the current grading working condition curve min The method comprises the steps of carrying out a first treatment on the surface of the Rolling the first-stage test layer of the relative density test field and the test material 3 until the settlement amount is unchanged, and rolling the first-stage test layer of the rolling test field until the preset rolling pass number is reached;
s4, randomly selecting test points in a rolling test field, measuring the mass M and the volume V of the non-cohesive coarse-grained soil of the test points, calculating the wet density rho of the compacted non-cohesive coarse-grained soil in the current rolling test field, detecting the moisture content of the non-cohesive coarse-grained soil in the area, and calculating the dry density rho of the non-cohesive coarse-grained soil of a first-stage test layer in the rolling test field d The method comprises the steps of carrying out a first treatment on the surface of the The actual grain composition of the non-cohesive coarse-grained soil of the first-stage test layer in the rolling test field is tested while the density is tested, and an actual measurement grading curve is drawn;
s5, measuring the compacted non-adhesive test material 3 in each sample cylinder of the relative density test field to obtain the compacted volume V Pressing And according to the mass M of the test material Cartridge Calculating to obtain the maximum wet density rho of the compacted non-cohesive coarse-grained soil test material 3 under the current grading working condition curve max The method comprises the steps of carrying out a first treatment on the surface of the Then testing the non-viscous coarse-grained soil in the sample cylinder 1The water content of the test material 3 is detected, and the minimum dry density rho of the non-cohesive coarse-grained soil test material 3 under the current grading working condition curve in the first-stage test layer of the relative density test field is obtained through calculation dmin And maximum dry density ρ dmax ；
S6, repeating the steps S2 to S5 until all the different soil paving thicknesses H are completed n Several stages of rolling test of different stage distribution working condition curves to obtain different soil paving thickness H n Minimum dry density and maximum dry density of the lower different level of distribution working condition curves;
and (3) controlling compaction quality of the non-sticky coarse-grained soil in the construction period: determining the paving thickness and the rolling pass number according to the rolling test result, performing layer-by-layer filling construction, and calculating the actual dry density and the actual grain composition of the layer of non-cohesive coarse-grained soil according to the step S4 after each layer of paving and rolling; and comparing the actual measurement grading curve with different grading working condition curves, and calculating an actual measurement relative density value of the appearance field.
When the actual measurement grading curve is compared with different grading working condition curves, if the actual measurement grading curve is close to one of the grading working condition curves, the maximum dry density value rho of the grading working condition curve under the corresponding soil paving thickness is adopted in the calculation of the relative density dmax And a minimum dry density value ρ dmin The method comprises the steps of carrying out a first treatment on the surface of the If the actually measured grading curve is positioned near the middle of any two grading working condition curves, the maximum dry density rho of the two grading working condition curves under the corresponding soil paving thickness is adopted in the calculation of the relative density dmax Average and minimum dry density ρ of dmin Average value of (2).
In step S2, each cartridge volume V Cartridge Obtaining by a sand filling method; in the step S4, measuring the mass M and the volume V of the non-viscous coarse-grained soil at the test point by adopting a density test method of an irrigation method; in step S5, the compacted volume V of the non-adhesive test material in each sample cylinder is measured by adopting a density test method by a water filling method Pressing 。
In the step S1:
when planning a test field, firstly planning a rolling test field, and dividing a plurality of small fields (each small field is designed with different rolling passes) in each large field (with the same soil paving thickness); the relative density test field is planned again, i.e. a small field is additionally added next to the large field.
The non-sticky coarse-grained soil for engineering construction is adopted as backfill 4 for paving and compacting the test site, the backfill is paved to be 80cm (layered backfill can be carried out), and the test site can be used after compacting and qualified detection, wherein the surface unevenness is not more than +/-5 cm.
And arranging fixed control points around the test field, measuring the elevation, and marking settlement monitoring points on the test field according to a 1.5m multiplied by 1.5m square grid, and measuring the elevation.
In the step S2, the bottom part of the sample tube is embedded into the backfill layer or the test layer, the main body part of the tube body of the sample tube 1 is a steel tube or a plastic tube, and the upper part of the sample tube is lapped by geotechnical cloth 2.
The diameter of the sample tube 1 is at least 3 times of the maximum particle diameter of the filler, and the height is the predetermined thickness H of the test layer pavement in the period n Adding a 40cm bottomless and uncovered steel cylinder or plastic cylinder, and pasting geotextile with the steel cylinder or plastic cylinder (bonding overlap joint part is not less than 5 cm) at 20cm of the upper part of the sample cylinder 1. The purpose of the geotechnical cloth adopted at the upper 20cm of the sample tube 1 is to avoid the consumption of vibration exciting force of the vibration mill due to the support of the steel tube or the plastic tube in the vibration milling process, thereby affecting the compaction effect and enabling the test result to deviate.
Embedding sample tube 1:
and excavating a circular groove with the diameter consistent with that of the sample tube 1, placing the sample tube into the circular groove (the sample tube is buried into the lower layer solid soil body of the test layer in the period, and the sample tube is kept vertical and horizontal), and manually backfilling the outer periphery of the bottom of the sample tube 1 tightly, so that the sample tube is prevented from shaking. When the sample tube is buried, the filler at the bottom of the sample tube 1 is not disturbed as much as possible, the filler at the bottom of the sample tube 1 is flattened, the filler at the bottom of the sample tube 1 is hit by a sample hitting hammer to be compact, and a little lime is spread at the bottom to be used as a mark.
After the sample tube 1 is buried, the volume V of the sample tube is measured by adopting a sand filling method Cartridge (bottom of sample in cartridge 1 to top of geotextile). A layer of soft gauze is placed along the inner wall of the sample cylinder 1, and standard sand is slowly injected into the sample cylinder1, weighing the mass of the standard sand to be injected, and calculating to obtain the volume V of the sample cylinder Cartridge 。
The steps are adopted to embed the rest 4 sample cylinders, the embedding directions of the 5 sample cylinders are consistent with the advancing direction of the vibration compactor, and the rest 4 sample cylinders are kept in a straight line and are spaced at least more than 3.0 m.
In the step S2, backfill paving is carried out in a rolling test:
and transporting the non-viscous coarse-grained soil from the stock ground to the test field by adopting a dump truck, paving by a spreading-withdrawing method, and leveling by using a bulldozer.
The embedded sample cylinder 1 is assisted by artificial pavement, so that the sample cylinder 1 is prevented from being damaged or toppled obliquely by touching, and the pavement thickness is according to the preset pavement thickness H n And (5) controlling.
The paving thickness error is + -10% of the paving layer thickness, and the elevation is measured to ensure the fill loose paving thickness.
The different level fitter Kuang Jipei curves specifically include a design level fitted upper envelope, a design level fitted lower envelope, an average (averaged from the design level fitted upper envelope and the design level fitted lower envelope), a large value average (the average of the upper envelope and the average), and a small value average (the average of the lower envelope and the average). The average line, the large value average line and the small value average line are obtained through interpolation calculation of the design grading upper envelope line and the design grading lower envelope line.
And the rolling test and the construction period adopt the same construction rolling machine to roll.
The test site is a site construction site or a special site, the site test is carried out on the site construction site, the soil is not excavated after the rolling test in a plurality of periods is finished, and the engineering construction is continued above the soil in the rolling test in a plurality of periods.
The test material configuration in the step S3:
sampling according to the source (sand gravel, stone yard) of design planning or the source produced by a manual processing system, testing, judging whether the requirements of the design technical requirements on the non-sticky coarse-grained soil are met, and judging whether the requirements of strength, mud content, maximum grain size and the like are met. The non-sticky coarse granules meeting the requirements enter a special storage yard for storage. The non-tacky coarse pellets meeting these requirements should be hard and clean. If the mud content is too large, the mud can be washed out if the requirements are not met. The non-sticky coarse granules are subjected to airing and air-drying treatment.
S3-1: and (3) carrying out particle group screening on the non-sticky coarse granules meeting the design requirements: classifying and screening according to the grain composition of 600-400 mm, 400-200 mm, 200-100 mm, 100-80 mm, 80-60 mm, 60-40 mm, 40-20 mm, 20-10 mm, 10-5 mm and less than 5mm, and ensuring that the quantity of test materials in each grain grade is enough;
s3-2: preparing different levels of the compound Kuang Jipei curve: volume V of the cartridge Cartridge Multiplying the maximum dry density of the estimated non-viscous coarse-grained soil, multiplying the maximum dry density by a margin coefficient to obtain the total amount of test materials required by a test, multiplying the total amount of the test materials by the percentage of each grain group in the grading working condition curve respectively to obtain the quality of each grain group, and fully mixing and uniformly mixing the test materials of each grain group for standby.
In the step S3, the test material in the sample tube is filled with:
the test materials 3 arranged according to the test material arrangement step are slowly filled into 5 sample cylinders respectively by adopting a manual filling mode, and when the test materials are filled, a filling shovel is 10-20 cm away from the surface of the filled sample, and the test materials are slowly poured in, so that the thickness separation of the sample is avoided.
When the test piece is filled to a position 20cm away from the surface of the sample cylinder (namely, when the geotechnical cloth is partially filled), the upper edge of the geotechnical cloth is manually lifted and tensioned to avoid the geotechnical cloth from wrinkling, and then the test piece 3 is filled to the same height as the upper edge of the geotechnical cloth, namely, the backfill material for the peripheral rolling test, and is leveled.
And 5-6 settlement monitoring points are selected on the surface of the test material 3 in the filled and leveled sample cylinder, and the initial elevation is measured and recorded.
In the step S3, vibration rolling construction:
rolling test field rolling pass number: and performing rolling construction according to the preset rolling pass number of the rolling test, and stopping rolling after the preset rolling pass number is reached.
Relative density test field rolling pass: and (3) rolling by adopting a rolling machine, a travelling speed and exciting force which are the same as those of a rolling test field, carrying out settlement monitoring on 5-6 settlement monitoring points arranged in each sample tube every time of rolling until the settlement of the last 6 times is unchanged, and considering that the non-viscous coarse-grained soil reaches the tightest state. If the test material still has sedimentation in one of the test cylinders (such as the design-level distribution covered wire), the test cylinder can be singly and continuously vibrated and rolled until the sedimentation amount of the last 6 times is unchanged.
In the step S4, the volume V and the mass M of the non-viscous coarse-grained soil of a randomly selected test point in a rolling test field are measured by using a water irrigation method; the wet density calculation formula of the compacted non-cohesive coarse grained soil in the current rolling test field is as follows:
the calculation formula for converting wet density to dry density is as follows:
wherein ω is expressed as the moisture content of the non-cohesive coarse-grained soil.
In the step S3, the minimum wet density calculation formula of the compacted non-cohesive coarse-grained soil under the current grading working condition curve is as follows:
the calculation formula for converting the minimum wet density into the minimum dry density is as follows:
wherein ω is expressed as the moisture content of the non-cohesive coarse-grained soil.
In the step S5, the volume V of the non-viscous coarse-grained soil test material 3 in each sample barrel after compaction is performed by using a water filling method Pressing The maximum wet density calculation formula of the compacted non-cohesive coarse grained soil under the current designed grading working condition curve is measured as follows:
the calculation formula for converting the maximum wet density into the maximum dry density is as follows:
wherein ω is expressed as the moisture content of the non-cohesive coarse-grained soil.
The expression of the on-site measured relative density value is as follows:
relative density test field: in the irrigation test, a steel collar is adopted, and the diameter of the steel collar is at least 1.5 times of that of the sample cylinder. The steel collar is placed flat on the cartridge with the center points substantially centered.
Surface volume measurement V 1 : paving a white soft plastic film on the inner side of the steel ring to enable the white soft plastic film to be clung to the soil surface and the inner side wall of the steel sleeve ring, injecting the weighed water into the steel sleeve ring, performing primary water injection until the set initial scale is reached, and recording the mass M of the primary water injection 1 I.e. the surface volume.
Pit volume measurement V 2 : taking out the water and plastic film filled in the steel sleeve ring, manually excavating the filler in the sample tube until the next filling layer is excavated (slowly excavating when approaching the layer and stopping when white lime is seen), and weighing the excavated sample (and M) Cartridge Whether there is a change in mass). All samples in the sample tubeAfter taking out, laying the plastic film in the sample cylinder again, ensuring that the plastic film is closely adhered to the pit bottom, the cylinder wall and the inner wall of the steel sleeve ring, then injecting water for the second time, stopping injecting water when the water level is equal to the first initial injection water level, and recording the quality M of the injected water 2 (total volume) of the difference between the two water injections (M 2 -M 1 ) I.e. the volume V of the excavated test pit 2 ， V 2 Namely V Pressing 。
Based on the description of the invention and the drawings, one skilled in the art can easily make or use a non-sticky coarse-grained soil relative density test field test method of the invention and can produce the positive effects described in the invention.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present invention fall within the scope of the present invention.
Claims (6)
1. A field test method for a relative density test of non-sticky coarse-grained soil is characterized in that: different grading working conditions and different soil paving thicknesses H are carried out on a test field n The rolling test comprises the following steps of:
s1, dividing a test field into a rolling test field and a relative density test field; paving and compacting the non-sticky coarse-grained soil for engineering construction as backfill material to serve as a base layer;
s2, presetting soil paving thickness H of first-stage test layer 1 Placing multiple sample cylinders on the backfilled base layer of the relative density test field to obtain the volume V of each sample cylinder Cartridge The method comprises the steps of carrying out a first treatment on the surface of the On the backfill base layer of the test site according to a predetermined thickness H 1 Paving and filling non-viscous coarse-grained soil, wherein the top surface elevation of the first-stage test layer is the same as the top surface elevation of the sample cylinder;
s3, respectively filling a grading working condition in each sample cylinderTest material (3) prepared under the curve, the mass of the test material is M Cartridge By volume V of the cartridge Cartridge Calculating the minimum wet density rho of the test material (3) under the current grading working condition curve min The method comprises the steps of carrying out a first treatment on the surface of the Rolling the first-stage test layer of the relative density test field and the test material (3) until the settlement amount is unchanged, and rolling the first-stage test layer of the rolling test field until the preset rolling pass number is reached;
s4, randomly selecting test points in a rolling test field, measuring the mass M and the volume V of the non-cohesive coarse-grained soil of the test points, calculating the wet density rho of the compacted non-cohesive coarse-grained soil in the current rolling test field, detecting the moisture content of the non-cohesive coarse-grained soil in the area, and calculating the dry density rho of the non-cohesive coarse-grained soil of a first-stage test layer in the rolling test field d The method comprises the steps of carrying out a first treatment on the surface of the The actual grain composition of the non-cohesive coarse-grained soil of the first-stage test layer in the rolling test field is tested while the density is tested, and an actual measurement grading curve is drawn;
s5, measuring the compacted volume V of the non-adhesive test material (3) in each sample cylinder of the relative density test field Pressing And according to the mass M of the test material The cylinder is provided with a cylinder body, calculating the maximum wet density rho of the compacted non-cohesive coarse-grained soil test material (3) under the current grading working condition curve max The method comprises the steps of carrying out a first treatment on the surface of the Then the water content of the non-cohesive coarse-grained soil test material (3) in the sample cylinder (1) is detected, and the minimum dry density rho of the non-cohesive coarse-grained soil test material (3) under the current grading working condition curve in the first-stage test layer of the relative density test field is obtained through calculation dmin And maximum dry density ρ dmax ；
S6, repeating the steps S2-S5 until all the different soil paving thicknesses H are completed n Several stages of rolling test of different stage distribution working condition curves to obtain different soil paving thickness H n Minimum dry density and maximum dry density of the lower different level of distribution working condition curves;
and (3) controlling compaction quality of the non-sticky coarse-grained soil in the construction period: determining the paving thickness and the rolling pass number according to the rolling test result, performing layer-by-layer filling construction, and calculating the actual dry density and the actual grain composition of the layer of non-cohesive coarse-grained soil according to the step S4 after each layer of paving and rolling; comparing the actual measurement grading curve with different grading working condition curves, and calculating an actual measurement relative density value of the appearance field;
when the actual measurement grading curve is compared with different grading working condition curves, if the actual measurement grading curve is close to one of the grading working condition curves, the maximum dry density value rho of the grading working condition curve under the corresponding soil paving thickness is adopted in the calculation of the relative density dmax And a minimum dry density value ρ dmin The method comprises the steps of carrying out a first treatment on the surface of the If the actually measured grading curve is positioned near the middle of any two grading working condition curves, the maximum dry density rho of the two grading working condition curves under the corresponding soil paving thickness is adopted in the calculation of the relative density dmax Average and minimum dry density ρ of dmin Average value of (2);
in step S2, each cartridge volume V Cartridge Obtaining by a sand filling method; in the step S4, measuring the mass M and the volume V of the non-viscous coarse-grained soil at the test point by adopting a density test method of an irrigation method; in step S5, the compacted volume V of the non-adhesive test material (3) in each sample cylinder is measured by adopting a density test method of a water filling method Pressing 。
2. The method for testing the relative density of the non-sticky coarse-grained soil on site according to claim 1, wherein the method comprises the following steps: the test material configuration in the step S3:
s3-1: and (3) carrying out particle group screening on the non-sticky coarse granules meeting the design requirements: classifying and screening according to the grain composition of 600-400 mm, 400-200 mm, 200-100 mm, 100-80 mm, 80-60 mm, 60-40 mm, 40-20 mm, 20-10 mm, 10-5 mm and less than 5 mm;
s3-2: preparing different levels of the compound Kuang Jipei curve: volume V of the cartridge Cartridge Multiplying the maximum dry density of the estimated non-viscous coarse-grained soil, multiplying the maximum dry density by a margin coefficient to obtain the total amount of test materials required by a test, multiplying the total amount of the test materials by the percentage of each grain group in the grading working condition curve respectively to obtain the quality of each grain group, and fully mixing and uniformly mixing the test materials of each grain group for standby.
3. The method for testing the relative density of the non-sticky coarse-grained soil on site according to claim 1, wherein the method comprises the following steps: in the step S2, the bottom part of the sample cylinder is buried in a backfill base layer or a test layer, the main body part of the cylinder body of the sample cylinder is a steel cylinder or a plastic cylinder, and the upper part of the sample cylinder (1) is lapped by geotechnical cloth (2).
4. The method for testing the relative density of the non-sticky coarse-grained soil on site according to claim 1, wherein the method comprises the following steps: the different level fitter Kuang Jipei curves specifically comprise a design level fitter upper envelope, a design level fitter lower envelope, an average line, a large value average line and a small value average line.
5. The method for testing the relative density of the non-sticky coarse-grained soil on site according to claim 1, wherein the method comprises the following steps: and the rolling test and the construction period adopt the same construction rolling machine to roll.
6. The method for testing the relative density of the non-sticky coarse-grained soil on site according to claim 1, wherein the method comprises the following steps: the test site is a site construction site or a special site, the site test is carried out on the site construction site, the soil is not excavated after the rolling test in a plurality of periods is finished, and the engineering construction is continued above the soil in the rolling test in a plurality of periods.
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| CN107543775A (en) * | 2017-05-12 | 2018-01-05 | 河海大学 | The method that stockpile fills standard and live filled soils detect is determined based on fractal theory |
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| CN107543775A (en) * | 2017-05-12 | 2018-01-05 | 河海大学 | The method that stockpile fills standard and live filled soils detect is determined based on fractal theory |
| CN107807520A (en) * | 2017-09-11 | 2018-03-16 | 南京亿海水利工程技术有限公司 | A kind of determination Coarse Aggregate fills index and the method for Site quality control |
| CN108844852A (en) * | 2018-04-17 | 2018-11-20 | 南京亿海水利工程技术有限公司 | A kind of determining coarse-grained soil relative density index and the method for live filled soils detection |
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