Method for estimating particle crushing value of crushed gravel compacted soil of roadbed

Abstract

The invention provides a method for estimating the particle crushing value of roadbed crushed gravel compacted soil, and relates to the technical field of geotechnical engineering test.The method comprises the steps that crushed gravel soil filler is selected from a roadbed filling construction site and prepared into standard filler; then, preparing samples with different mass ratios of the fine aggregates, measuring a first crushing value, and fitting the relationship between the first crushing value and the mass ratios of the fine aggregates by adopting a first function to obtain parameters alpha, beta and delta; preparing the standard filler into samples with different relative densities, measuring a second crushing value, and fitting the relationship between the second crushing value and the relative densities by adopting a second function to obtain parameters lambda and eta; and determining the relative density of crushed gravel compacted soil after roadbed rolling and the mass ratio of fine particles, and estimating the particle crushing value according to the parameters alpha, beta, delta, lambda and eta. The method solves the problem that the traditional crushing value determination method cannot consider the influence of multiple factors such as fine-grained material filling in coarse-grained soil filler and roadbed filling compaction effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of geotechnical engineering testing, and particularly relates to a method for estimating the particle crushing value of crushed gravel compacted soil for subgrade, considering the filling effect of fine aggregate and the compaction effect of rolling. Background Technique

[0002] Crushed gravel soil is a kind of coarse-grained soil or boulder soil mainly composed of crushed stones (60 - 200 mm) or gravels (20 - 60 mm). When used for the subgrade filling of railways and highways, the main engineering problems faced are that there may be relatively serious particle crushing phenomena, resulting in the deterioration of physical and mechanical properties, causing subgrade deformation and settlement, and further affecting the service performance of railway tracks and highway pavements. Especially for soft rock fillers with relatively low particle strength, the particle crushing phenomenon of the subgrade under long-term load and adverse environmental effects is more prominent, and the engineering problems faced are more intractable. Conducting the evaluation of the particle crushing value of crushed gravel compacted soil for subgrade has technical significance and engineering value.

[0003] The soil structure of coarse-grained soil fillers for subgrade successively presents types such as "skeleton - pore structure", "skeleton - dense structure", "suspension - dense structure", etc. as the proportion of fine aggregate in the filler gradually increases. In terms of mechanical behavior, it shows that when the proportion of fine aggregate is relatively low and is not sufficient to fill the pore spaces formed by coarse aggregate, the load borne by the subgrade mainly acts on the skeleton formed by coarse aggregate, and the particle crushing phenomenon in the filler is more likely to occur; increasing the proportion of fine aggregate in the filler can weaken the particle crushing phenomenon in the filler. It can be seen that the content of fine soil in the crushed gravel soil filler for subgrade has an important influence on particle crushing.

[0004] The core of the construction quality of subgrade engineering filling is the compaction density. As the compaction density increases, the contact between particles in the filler becomes closer, and the number of contacts with adjacent surrounding particles increases. Under the same subgrade bearing conditions, the contact force between particles will decrease, and the risk of particle crushing will be correspondingly reduced. It can be seen that the compaction density of crushed gravel soil for subgrade also has an impact on particle crushing.

[0005] To ensure the good road performance of the subgrade filling body, railway and highway projects put forward the requirement of the crushing value CA index for the particle anti - crushing ability in coarse - grained soil fillers for subgrade. However, in the traditional crushing value test method, the test sample is composed of particles of a specified particle size group, and the crushing value CA index mainly reflects the influence of the rock block strength of the particles in the test particle size group, without considering the filling effect of fine aggregate in the coarse - grained soil filler and the compaction effect of subgrade filling. There are defects in the evaluation of the particle crushing phenomenon of crushed gravel compacted soil for subgrade. In the construction of coarse - grained soil filling for subgrade in railway and highway projects, the main engineering problem faced is the possible particle crushing phenomenon in the filler, and the crushing value CA index is mostly used for evaluation. However, the traditional crushing value test method only reflects the influence of the rock block strength of coarse aggregate, and there are obvious deficiencies, which affect the accuracy and reliability of the evaluation. Summary of the Invention

[0006] Aiming at the above deficiencies in the prior art, the present invention provides a method for estimating the particle crushing value of subgrade crushed gravel compacted soil. This method can improve the evaluation technology of the particle anti-crushing ability of coarse-grained soil fillers for subgrade, improve the accuracy and reliability of test data under the influence of multiple factors, and provide technical support for the efficient filling and safe construction of subgrade projects.

[0007] In order to achieve the above objectives, the technical solution adopted by the present invention is: a method for estimating the particle crushing value of subgrade crushed gravel compacted soil, including the following steps:

[0008] S1. Filler preparation: Select crushed gravel soil filler from the subgrade filling construction site and prepare standard filler;

[0009] S2. Calibration of the influence of fine-grained material filling: Based on the standard filler, prepare specimens with different mass ratios of fine-grained materials, measure the first crushing value, and fit the relationship between the first crushing value and the mass ratio of fine-grained materials using a first function to obtain the parameter values of α, β, and δ;

[0010] S3. Calibration of the influence of filling and compaction: Prepare specimens with different relative densities from the standard filler, measure the second crushing value, and fit the relationship between the second crushing value and the relative density using a second function to obtain the parameter values of λ and η;

[0011] S4. Estimation of particle crushing value: Determine the relative density and the mass ratio of fine-grained materials of the crushed gravel compacted soil after subgrade compaction is completed, and estimate the particle crushing value according to the parameters α, β, δ, λ, and η.

[0012] The beneficial effects of the present invention are: Based on the existing crushing value test method in the current specification, the present invention further considers the influence of the fine-grained material filling effect and the subgrade filling and compaction effect in the actual engineering filling construction of coarse-grained soil fillers, improves the accuracy of particle crushing value evaluation and the reliability of engineering quality control. The present invention can further reflect the quantitative estimation method of the particle crushing value of subgrade crushed gravel compacted soil filler affected by multiple factors such as the content of fine-grained soil and the degree of compaction in coarse-grained soil fillers, and has reference value and guiding significance for the safe and high-quality construction of subgrade projects.

[0013] Furthermore, the specific content of S1 is as follows:

[0014] Select crushed gravel soil filler from the subgrade construction site. After air drying, sieve out particles with a particle size greater than 20 mm and less than 10 mm to prepare standard filler M0 for standby;

[0015] Adopt the loose stacking method test and the vibration method test to respectively measure the minimum dry density ρ d,min and the maximum dry density ρ d,max, the preparation of the filler is completed.

[0016] The beneficial effect of the above further solution is that by testing the minimum and maximum dry densities of the specimen, the loosest and densest states of the compaction degree of the filler are determined, and the change range of the compaction density of the filler is evaluated.

[0017] Furthermore, the maximum particle size of the crushed gravel soil filler is not greater than 75 mm, and the proportion of the dry mass of the fine aggregate with a particle size not greater than 2.5 mm in the total dry mass of the filler is less than 50%; the uniaxial saturated compressive strength of the crushed gravel particles is between 15 MPa and 45 MPa, and the proportion of acicular and flaky particles is not greater than 20%.

[0018] The beneficial effect of the above further solution is that by the index limits of the maximum particle size of the filler, the proportion of the dry mass of the fine aggregate, the uniaxial saturated compressive strength of the particles, and the proportion of acicular / flaky particles, the applicable range of the evaluation method proposed in the present invention is determined.

[0019] Furthermore, the specific content of S2 is as follows:

[0020] Based on the standard filler M0, air-dried fine aggregate with a particle size not greater than 2.5 mm is admixed to prepare specimens M0, M 15 = 0.15, P 30 = 0.30, P 45 = 0.45 of M 15 , M 30 and M 45 ;

[0021] For the prepared specimens M0, M 15 , M 30 and M 45 with different proportions of fine aggregate mass, carry out the crushing value test under the loose pile state with a relative density D r ≈ 0.25, and respectively measure the first crushing value and Draw the relationship curve between the first crushing value and the proportion of fine aggregate mass P0, P 15 , P 30 , P 45 ;

[0022] Use the first function to fit the test data of specimens M0, M 15 , M 30 and M 45 to obtain the parameter values of α, β, and δ. Among them, i is 0, 15, 30, and 45 respectively, represents the crushing value of the specimen under the condition of a relative density of 0.25 and a proportion of fine aggregate mass of i in the specimen, and P iIt is indicated that the mass proportion of fine aggregate in the specimen is i.

[0023] The beneficial effect of the above further solution is that by conducting the crushing value calibration test of the filler specimens with different mass proportions of fine aggregate in the loose piled state, the functional relationship between the crushing value and the mass proportion of fine aggregate is established, and the quantitative influence of the content of fine aggregate in the filler on the crushing value of the filler is estimated.

[0024] Furthermore, the expression of the mass proportion of fine aggregate is as follows:

[0025]

[0026] Among them, P represents the mass proportion of fine aggregate in the specimen, m represents the dry mass of fine aggregate with a particle size not greater than 2.5 mm in the specimen, and M represents the total dry mass of the specimen.

[0027] The beneficial effect of the above further solution is that by establishing the functional expression of the mass proportion of fine aggregate, the calculation method of the mass proportion of fine aggregate in the filler is clarified.

[0028] Furthermore, for the crushing value test of specimens with different mass proportions of fine aggregate, the first crushing value CA is measured:

[0029]

[0030] Among them, m represents the dry mass of fine aggregate with a particle size not greater than 2.5 mm in the specimen, M represents the total dry mass of the specimen, and m0 represents the mass of air-dried fine aggregate with a particle size not greater than 2.5 mm admixed in the specimen.

[0031] The beneficial effect of the above further solution is that by establishing the functional expression of the crushing value of the filler specimens with different mass proportions of fine aggregate, the calculation method of the crushing value of the filler specimens containing fine aggregate is clarified.

[0032] Furthermore, the specific content of S3 is as follows:

[0033] Using the standard filler M0, standard filler specimens with relative densities and are respectively prepared;

[0034] For the prepared standard filler specimens with different compaction degrees, conduct the crushing value test, and respectively measure the second crushing values and Plot the relationship curve of the second crushing value of the standard filler specimen and the relative density of the specimen;

[0035] Based on the relationship curve, use the second function for the 4 kinds of specimen relative densities Fitting the test data of the compacted standard filler specimens to obtain the parameter values of λ and η. Among them, j is 0.25, 0.50, 0.75, and 1.00 respectively. represents the crushing value of the specimen under the condition that the relative density is j and the mass ratio of fine-grained materials is 0. represents that the relative density of the specimen is j under the condition that the mass ratio of fine-grained materials is 0.

[0036] The beneficial effect of the above further solution is: By carrying out the calibration test of the crushing value of the standard filler specimens under different compaction degrees, establishing the functional relationship between the crushing value and the relative density, and realizing the estimation of the quantitative influence of the compaction degree of the filler on its crushing value.

[0037] Still further, the expression of the relative density of the specimen is as follows:

[0038] D r =[ρ d,max (ρ d -ρ d,min )] / [ρ d (ρ d,max -ρ d,min )]

[0039] where D r represents the relative density of the specimen, and its value is not less than 0.25, ρ d,max represents the maximum dry density of the specimen, ρ d represents the dry density of the specimen, ρ d,min represents the minimum dry density of the specimen.

[0040] The beneficial effect of the above further solution is: Based on the functional expression of the relative density, by the position of the dry density of the specimen relative to its minimum and maximum dry densities, the estimation of the compaction degree of the filler is realized.

[0041] Still further, the specific content of S4 is as follows:

[0042] At the subgrade filling construction site, for the crushed gravel compacted soil after rolling, the water injection method test is adopted to measure the density ρ of the compacted soil, and the drying method test is adopted to measure the water content w of the compacted soil. From the relationship ρ = ρ d (1 + w), the dry density ρ d of the compacted soil is determined;

[0043] Taking samples of the crushed gravel compacted soil after rolling, using the loose stacking method test and the vibration method test, the minimum dry density ρ d,min and the maximum dry density ρ d,max are measured respectively, and the relative density of the compacted soil is determined where represents that the mass ratio of fine-grained materials in the compacted soil specimen is n and the relative density value is k;

[0044] Take samples of the crushed gravel compacted soil after rolling, conduct sieve analysis tests, determine the proportion of the dry mass of fine aggregates with a particle size not greater than 2.5 mm in the total dry mass, and determine the proportion P of the fine aggregate mass in the compacted soil. n ;

[0045] According to the relative density of the subgrade crushed gravel soil filler after rolling construction and the proportion P of the fine aggregate mass n , combined with the parameters α, β, δ, λ, η, estimate the particle crushing value of the compacted soil according to the following expression

[0046]

[0047] where represents the crushing value CA of the specimen under the conditions of relative density k and proportion n of the fine aggregate mass.

[0048] The beneficial effect of the above further solution is: By carrying out the calibration test data of the crushing values of fillers with different proportions of fine aggregates and degrees of compaction, establish the functional relationship between the crushing value and the proportion of the fine aggregate mass and the relative density, and realize the quantitative influence estimation of multiple factors such as the content of the fine aggregate in the filler and the degree of compaction on the crushing value of the subgrade crushed gravel soil compacted filler. Brief Description of the Drawings

[0049] Figure 1 is the method flow chart of the present invention.

[0050] Figure 2 is a schematic diagram of the change curve of the crushing value CA with the proportion P of the fine aggregate mass and the relative density D r of the change curve. Detailed Embodiments

[0051] The following describes the detailed embodiments of the present invention to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the detailed embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions made using the concept of the present invention are within the scope of protection.

[0052] Embodiment

[0053] As Figure 1 shown, the present invention provides a method for estimating the particle crushing value of subgrade crushed gravel compacted soil, and the implementation method is as follows:

[0054] S1. Filler preparation: Select crushed gravel soil filler from the subgrade filling construction site and prepare standard fillers, and the implementation method is as follows:

[0055] Select the crushed gravel soil filler from the subgrade construction site. After air-drying, sieve out the particles with a particle size greater than 20 mm and less than 10 mm to prepare the standard filler M0 for standby;

[0056] Adopt the loose stacking method test and the vibration method test to respectively measure the minimum dry density ρ d,min and the maximum dry density ρ d,max of the standard filler M0 to complete the preparation of the filler.

[0057] In this embodiment, the maximum particle size of the crushed gravel soil filler is not greater than 75 mm, and the proportion of the dry mass of the fine particles with a particle size not greater than 2.5 mm in the total dry mass of the filler is less than 50%; the uniaxial saturated compressive strength of the crushed gravel particles is between 15 MPa and 45 MPa, and the proportion of needle-shaped and flaky particles is not greater than 20%.

[0058] S2. Calibration of the influence of fine particle filling: Based on the standard filler, prepare specimens with different proportions of fine particle mass, measure the first crushing value, and fit the relationship between the first crushing value and the proportion of fine particle mass with the first function to obtain the parameter values of α, β, and δ. The implementation method is as follows:

[0059] Based on the standard filler M0, admix air-dried fine particles with a particle size not greater than 2.5 mm to respectively prepare specimens M0, M 15 =0.15, M 30 =0.30, M 45 =0.45 with the fine particle mass ratios of P0, P 15 , M 30 and M 45 ;

[0060] For the prepared specimens M0, M 15 , M 30 and M 45 with different fine particle mass ratios, conduct the crushing value test under the loose stacking state with a relative density D r ≈0.25, and respectively measure the first crushing value and Draw the relationship curve between the first crushing value and the fine particle mass ratios P0, P 15 , P 30 , P 45 of the specimen;

[0061] Use the first function to fit the test data of specimens M0, M 15 , M 30 and M 45 to obtain the parameter values of α, β, and δ, where i is 0, 15, 30, 45 respectively, It represents the crushing value of the specimen under the condition that the relative density is 0.25 and the mass ratio of the fine aggregate in the specimen is i, P i It represents that the mass ratio of the fine aggregate in the specimen is i.

[0062] In this embodiment, the expression of the mass ratio of the fine aggregate is as follows:

[0063]

[0064] Among them, P represents the mass ratio of the fine aggregate, m represents the dry mass of the fine aggregate with a particle size not greater than 2.5 mm in the specimen, and M represents the total dry mass of the specimen.

[0065] In this embodiment, for the crushing value test of the filler specimens with different mass ratios of the fine aggregate, the first crushing value CA is measured by calculating the fine aggregate with a particle size not greater than 2.5 mm generated by the crushing of the standard filler particles, that is, CA = the dry mass of the fine aggregate with a particle size not greater than 2.5 mm generated by the crushing of the standard filler particles / the dry mass of the standard filler particles.

[0066] S3. Calibration of the influence of filling and compaction: Prepare specimens with different relative densities from the standard filler, measure the second crushing value, and fit the relationship between the second crushing value and the relative density with a second function to obtain the parameter values of λ and η. The implementation method is as follows:

[0067] Use the standard filler M0 to prepare standard filler specimens with relative densities and respectively;

[0068] For the prepared standard filler specimens with different compaction degrees, carry out the crushing value test, and measure the second crushing values and respectively. Plot the relationship curve between the second crushing value of the standard filler specimen and the relative density of the specimen;

[0069] Based on the relationship curve, use the second function to fit the test data of the compacted standard filler specimens with 4 kinds of specimen relative densities to obtain the parameter values of λ and η. Among them, j is 0.25, 0.50, 0.75, and 1.00 respectively, represents the crushing value of the specimen under the condition that the relative density is j and the mass ratio of the fine aggregate is 0, represents that the relative density of the specimen is j under the condition that the mass ratio of the fine aggregate is 0.

[0070] In this embodiment, the expressions of the relative density in S2 and S3 are as follows:

[0071] Dr = [ρ d,max (ρ d - ρ d,min )] / [ρ d (ρ d,max - ρ d,min )]

[0072] where D r represents the relative density of the specimen, with a value not less than 0.25, ρ d,max represents the maximum dry density of the specimen, ρ d represents the dry density of the specimen, ρ d,min represents the minimum dry density of the specimen.

[0073] S4. Estimation of particle crushing value: Determine the relative density of the crushed gravel compacted soil after subgrade compaction and the proportion of fine-grained material mass, and estimate the particle crushing value according to the parameters α, β, δ, λ, η. The implementation method is as follows:

[0074] At the subgrade filling construction site, for the crushed gravel compacted soil after compaction, use the water injection method test to measure the compacted soil density ρ, and use the drying method test to measure the compacted soil moisture content w. From the relationship ρ = ρ d (1 + w), determine the dry density ρ d of the compacted soil;

[0075] Take samples of the crushed gravel compacted soil after compaction, and use the loose stacking method test and the vibration method test to measure the minimum dry density ρ d,min and the maximum dry density ρ d,max , and determine the relative density of the compacted soil where represents that the proportion of fine-grained material mass in the compacted soil specimen is n and the relative density value is k;

[0076] Take samples of the crushed gravel compacted soil after compaction, and use the sieving method test to measure the proportion of the dry mass of fine-grained material with a particle size not greater than 2.5 mm in the total dry mass, and determine the proportion of fine-grained material mass P n in the compacted soil;

[0077] According to the relative density and the proportion of fine-grained material mass P n of the subgrade crushed gravel soil filler after compaction, combined with the parameters α, β, δ, λ, η, estimate the particle crushing value of the compacted soil according to the following expression

[0078]

[0079] where represents the crushing value CA of the specimen under the conditions of relative density k and proportion of fine-grained material mass n.

[0080] The present invention is experimentally verified as follows.

[0081] The stone materials after blasting and size reduction in a certain railway engineering cutting are used, and gravelly sandy soil is admixed to prepare the embankment crushed gravel soil filler. Particles with oversized particle sizes in the filler are removed through a 75-mm side-length sieve. According to the "Code for Geotechnical Tests of Railway Engineering" (TB10102-2023), the proportion of the dry mass of fine particles with particle sizes less than 2.5 mm in the total dry mass of the filler is about 30.4%. The uniaxial saturated compressive strength of the parent rock of the coarse particles in the filler is about 31.2 MPa, and the proportion of needle-shaped and flaky particles is less than 20%. The maximum dry density ρ d,max = 1.935 g / cm 3 and the minimum dry density ρ d,min = 1.508 g / cm 3 .

[0082] According to the method of the above embodiment, the prepared crushed gravel soil filler selected from the subgrade construction site is air-dried, and particles with particle sizes greater than 20 mm and less than 10 mm are sieved out to prepare the standard filler M0. The minimum dry density ρ d,min = 1.319 g / cm 3 and the maximum dry density ρ d,max = 1.692 g / cm 3 of the standard filler M0 are tested.

[0083] Based on the standard filler M0, filler specimens M0, M 15 = 0.15, P 30 = 0.30, P 45 = 0.45 with the proportion of fine particle mass P0 = 0, P 15 , M 30 , M 45 are prepared, and the crushing value test is carried out under the condition of relative density D r ≈ 0.25. The first crushing value is measured respectively Draw relationship curve, and use the first function to fit, and the parameters α = 13.778, β = -18.440, δ = 13.089 are obtained, as Figure 2 shown; i is 0, 15, 30, 45 respectively; represents the crushing value of the specimen under the condition of relative density 0.25 and the proportion of fine particle mass i, and P i represents the proportion of fine particle mass i of the specimen.

[0084] At the same time, using the standard filler M0, the relative density is prepared Standard filler specimens were used to conduct crushing value tests, and the second crushing values were measured respectively. Plot relationship curves, and use the second function for fitting, and obtain the parameters λ = -4.424 and η = 14.275, as Figure 1 shown; j are 0.25, 0.50, 0.75, and 1.00 respectively; represents the crushing value of the specimen under the condition of relative density j and fine-grained material mass ratio of 0, represents the relative density j of the specimen under the condition of fine-grained material mass ratio of 0.

[0085] Finally, at the subgrade filling construction site, for the crushed gravel compacted soil after compaction, the "water injection method" test was used to measure the density of the compacted soil ρ = 1.795 g / cm 3 , and the "drying method" test was used to measure the water content of the compacted soil w = 0.63%. From the relationship ρ = ρ d (1 + w), the dry density ρ d of the compacted soil was determined to be 1.784 g / cm 3 , and from the relationship D r = [ρ d,max (ρ d - ρ d,min )] / [ρ d (ρ d,max - ρ d,min )], the relative density of the compacted soil was determined From the function the estimated value of particle crushing was obtained Compared with the test-verified test value of 5.87%, the deviation is only 0.89%; while the test detection value of the traditional method is 12.57%, with a large deviation; the particle crushing value estimation method proposed by the present invention is closer to the engineering reality and more reliable.

[0086] In summary, the construction and quality inspection tests of coarse-grained soil filling in the subgrade project carried out show that, based on the particle crushing value estimation method of subgrade crushed gravel compacted soil proposed by the present invention, the obtained crushing value estimation data are closer to the measured values than the traditional method, the test efficiency is greatly improved, it can better reflect the influence of fine-grained material filling and compaction effect in coarse-grained soil fillers, and the accuracy of particle crushing value evaluation is improved.

Claims

1. A method for estimating the particle crushing value of crushed gravel compacted soil of subgrade, characterized in that It includes the following steps: S1. Filler preparation: Select gravelly soil filler from the subgrade filling construction site and prepare standard filler; S2. Calibration of the influence of fine-grained material filling: Based on the standard filler, prepare specimens with different mass ratios of fine-grained materials, measure the first crushing value, and fit the relationship between the first crushing value and the mass ratio of fine-grained materials using a first function to obtain the parameter values of α, β, and δ; S3. Calibration of the influence of filling and compaction: Prepare specimens with different relative densities from the standard filler, measure the second crushing value, and fit the relationship between the second crushing value and the relative density using a second function to obtain the parameter values of λ and η; S4. Estimation of particle crushing value: Determine the relative density and the mass ratio of fine-grained materials of the compacted gravelly soil after subgrade compaction, and estimate the particle crushing value according to the parameters α, β, δ, λ, and η.

2. The method for estimating the particle crushing value of the subgrade crushed gravel compacted soil according to claim 1, characterized in that, The specific content of S1 is as follows: Select gravelly soil filler from the subgrade construction site. After air-drying, sieve out particles with a particle size greater than 20 mm and less than 10 mm to prepare standard filler M0 for standby; The loose stockpiling method test and the vibration method test are adopted to respectively test the minimum dry density ρ d,min and the maximum dry density ρ d,max of the standard filler M0, and the preparation of the filler is completed.

3. The method for estimating the particle crushing value of the subgrade crushed gravel compacted soil according to claim 2, wherein The maximum particle size of the gravelly soil filler is not greater than 75 mm, the dry mass ratio of fine-grained materials with a particle size not greater than 2.5 mm to the total dry mass of the filler is less than 50%; the uniaxial saturated compressive strength of gravel particles is between 15 MPa and 45 MPa, and the proportion of needle-shaped and flaky particles is not greater than 20%.

4. The method for estimating the particle crushing value of the crushed gravel compacted soil of the roadbed according to claim 1, characterized in that, The specific content of S2 is as follows: Based on the standard filler M0, air-dried fine aggregate with a particle size not greater than 2.5 mm was admixed to prepare specimens M0, M 15 , M 30 , and M 45 with the mass ratio of fine aggregate P0 = 0, P 15 = 0.15, P 30 = 0.30, and P 45 = 0.45; For the prepared specimens M0, M 15 , M 30 and M 45 with different mass ratios of fine aggregates, carry out the crushing value test under the loose state with a relative density D r ≈0.25, and measure the first crushing value and respectively. Plot the relationship curve between the first crushing value and the mass ratios P0, P 15 , P 30 , P 45 of the fine aggregates in the specimens; Adopt the first function For the test data of specimens M0, M 15 , M 30 and M 45 perform fitting to obtain the parameter values of α, β, and δ. Among them, i is 0, 15, 30, and 45 respectively, represents the crushing value of the specimen under the conditions of a relative density of 0.25 and a fine-grained material mass ratio of i for the specimen, and P i represents the fine-grained material mass ratio of i for the specimen.

5. The method for estimating the particle crushing value of the subgrade crushed gravel compacted soil according to claim 4, wherein, The expression for the mass ratio of fine-grained materials in the specimen is as follows: Where P represents the mass ratio of fine-grained materials in the specimen, m represents the dry mass of fine-grained materials with a particle size not greater than 2.5 mm in the specimen, and M represents the total dry mass of the specimen.

6. The method for estimating the particle crushing value of the subgrade crushed gravel compacted soil according to claim 4, characterized in that Conduct crushing value tests on specimens with different mass ratios of fine-grained materials to measure the first crushing value CA: Where m represents the dry mass of fine-grained materials with a particle size not greater than 2.5 mm in the specimen, M represents the total dry mass of the specimen, and m0 represents the dry mass of air-dried fine-grained materials with a particle size not greater than 2.5 mm admixed in the specimen.

7. The method for estimating the particle crushing value of the subgrade crushed gravel compacted soil according to claim 4, characterized in that, The specific content of S3 is as follows: Using the standard filler M0, standard filler specimens with relative densities and were prepared respectively; For the prepared standard filler specimens with different compaction degrees, conduct the crushing value test and measure the second crushing value respectively and Plot the relationship curve of the second crushing value of the standard filler specimen and the relative density of the specimen; Based on the relationship curve, the second function is adopted For the relative densities of 4 kinds of specimens The test data of the compacted standard filler specimens are fitted to obtain the values of parameters λ and η. Among them, j is 0.25, 0.50, 0.75, and 1.00 respectively, indicating the crushing value of the specimen under the condition that the relative density is j and the mass ratio of fine aggregate is 0, indicating that the relative density of the specimen is j under the condition that the mass ratio of fine aggregate is 0.

8. The method for estimating the particle crushing value of the crushed gravel compacted soil of the subgrade according to claim 7, characterized in that, The expression for the relative density of the specimen is as follows: D r = [ρ d,max (ρ d - ρ d,min )] / [ρ d (ρ d,max - ρ d,min )] Among them, D r represents the relative density of the specimen, and its value is not less than 0.25, ρ d,max represents the maximum dry density of the specimen, ρ d represents the dry density of the specimen, ρ d,min represents the minimum dry density of the specimen.

9. The method for estimating the particle crushing value of the crushed gravel compacted soil of the roadbed according to claim 8, wherein The specific content of S4 is as follows: At the subgrade filling construction site, for the crushed gravel compacted soil after compaction, the water injection method test is adopted to measure the density ρ of the compacted soil, and the drying method test is adopted to measure the moisture content w of the compacted soil. From the relationship ρ = ρ d (1 + w), the dry density ρ d of the compacted soil is determined; Samples of the crushed gravel compacted soil after rolling are taken, and the minimum dry density ρ d,min and the maximum dry density ρ d,max are measured respectively by the loose stacking method test and the vibration method test to determine the relative density of the compacted soil Among them, It means that the proportion of the fine-grained material mass in the compacted soil sample is n and the relative density value is k; Take samples of the crushed gravel compacted soil after rolling, conduct sieve analysis tests, determine the proportion of the dry mass of the fine aggregate with a particle size not greater than 2.5 mm in the total dry mass, and determine the proportion P of the fine aggregate mass in the compacted soil n ; According to the relative density after the rolling construction of the subgrade crushed gravel soil filler and the proportion P of the fine aggregate quality n , combined with the parameters α, β, δ, λ, η, estimate the particle crushing value of the compacted soil according to the following expression Among them, represents the crushing value CA of the specimen under the conditions of relative density k and fine aggregate mass ratio n.

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