Method and device for comprehensively evaluating durability of cemented sand gravel

Abstract

The invention provides a method and a device for comprehensively evaluating the durability of cemented sand gravel, which are characterized in that the configuration strength of the cemented sand gravel is calculated according to engineering to obtain a molded cemented sand gravel test piece, the molded cemented sand gravel test piece is subjected to workability test, compressive strength test and elastic modulus test, and the durability is comprehensively evaluated according to the configuration strength after the workability test, the compressive strength test and the elastic modulus test pass. Preparing a test piece, and respectively carrying out anti-permeability and anti-corrosion performance quantitative test, anti-abrasion performance test and anti-freezing performance test on the test piece and the actual piece to obtain a first test result, a second test result and a third test result. And carrying out weighted calculation on the three test results, and if the results are greater than a preset standard value, determining that the durability of the actual part meets the requirement. The method has the advantages that quantitative evaluation with specific numerical values can be carried out on the performance of the actually-used construction parts, and further, constructors can effectively screen the construction parts according to evaluation results instead of evaluation only according to experimental trends.

Description

Technical Field

[0001] This invention relates to the field of cemented gravel testing, and more particularly to a method and apparatus for comprehensive evaluation of the durability of cemented gravel. Background Technology

[0002] Cemented Sand Gravel and Rock (CSGR) is a dam construction technology that broadens the range of applicable raw materials. Its design philosophy is "suitable materials for suitable structures" and "suitable structures for suitable materials." Cemented sand gravel dams are a new type of dam that falls between earth-rock dams and roller-compacted concrete dams.

[0003] Based on existing research and practice on cemented gravel dams, they have the following characteristics: safety, economy, ease of construction, and environmental friendliness.

[0004] The structural design of cemented gravel dams makes full use of local materials and the principle of "suitable materials for suitable structures," that is, selecting the most suitable materials for different parts of the dam body to ensure structural performance. A functional gradient structure is constructed, and high-performance materials such as cemented gravel with rich grout or grout-mixed vibratory compaction and normal concrete are used in areas with tensile stress distribution and requirements for seepage prevention and frost resistance. Through structural design, the cemented gravel inside is kept under compression.

[0005] In actual construction, structural calculations are usually performed on the parts where cemented gravel materials are used to obtain stress distribution, temperature stress distribution, determine the foundation treatment method, dam cross-sectional dimensions, dam material zoning, dam jointing scheme, temperature control, cofferdam structure, water-stopping and drainage layout and detailed construction within the dam, pressure resistance design and seepage and erosion resistance durability design.

[0006] In the process of designing for durability, it is necessary to evaluate resistance to permeation, corrosion, abrasion, and frost. However, existing technologies can only predict the trends of these properties separately in combination with local environment and material characteristics, and estimate some possibilities based on these predictions. It is impossible to comprehensively and quantitatively evaluate these properties. Therefore, how to provide a method that can accurately evaluate the durability of cemented gravel has become an urgent problem to be solved. Summary of the Invention

[0007] This invention provides a method and apparatus for comprehensive evaluation of the durability of cemented gravel, which solves the problem that the existing technology can only predict the trend of these properties in combination with local environment and material characteristics, but cannot comprehensively and quantitatively evaluate these properties.

[0008] To achieve the above objectives, the present invention provides a comprehensive durability evaluation method for cemented gravel, comprising: calculating the configuration strength of cemented gravel based on engineering calculations, obtaining molded cemented gravel specimens, and conducting workability tests, compressive strength tests, and elastic modulus tests on the specimens. After passing all tests, a comprehensive durability evaluation is performed based on this configuration strength. The test specimens are configured, and quantitative tests of their impermeability and corrosion resistance are conducted. The impermeability and corrosion resistance of actual specimens are also quantitatively tested, and the two tests are compared to obtain a first test result. The test specimens are subjected to impact and abrasion resistance tests, and the actual specimens are also subjected to impact and abrasion resistance tests. The two tests are compared to obtain a second test result. The test specimens are subjected to frost resistance tests, and the actual specimens are also subjected to frost resistance tests. The two tests are compared to obtain a third test result. The first, second, and third test results are weighted and calculated. If the result is greater than a preset standard value, the durability of the actual specimen meets the requirements.

[0009] As a preferred embodiment of the above technical solution, the comprehensive durability evaluation based on the configured strength includes: grading the field material according to the configured strength, obtaining an average gradation based on the gradation results, and designing a gravel gradation envelope including the coarsest gradation, the finest gradation, and the average gradation. The test specimen is then configured according to the finest gradation, and quantitative tests are performed on its impermeability and corrosion resistance, abrasion resistance, and freeze-thaw resistance.

[0010] As a preferred embodiment of the above technical solution, preferably, quantitative tests are performed on the permeability and corrosion resistance of the test specimen and on the actual specimen. The two tests are compared to obtain a first test result, including: measuring the permeability and corrosion resistance of the test specimen to obtain the cumulative permeability coefficient, segmented permeability coefficient, and calcium ion dissolution concentration. Actual production is conducted to obtain an actual specimen, which is then subjected to pressurized permeation using deionized water to obtain the cumulative permeability coefficient, segmented permeability coefficient, and calcium ion dissolution concentration of the actual specimen. The ratio of the actual specimen's calcium ion concentration at the same time / time period to the cumulative permeability coefficient, and the ratio of the actual specimen's calcium ion concentration to the segmented permeability coefficient, are used as the correlation coefficient. This correlation coefficient is then processed with the corresponding cumulative permeability coefficient and / or segmented permeability coefficient of the test specimen to obtain another calcium ion concentration in the actual specimen, thus obtaining the corrosion resistance measurement evaluation result of the actual specimen. If this calcium ion concentration is less than the calcium ion concentration in the test specimen, it meets the corrosion resistance measurement standard and can be used as the first test result. If the ratio is obtained based on the time period, and the corrosion resistance measurement evaluation result of the actual part during the 300d-600d time period is less than half of the average calcium ion concentration of the test part during the 300d-600d time period, then it meets the corrosion resistance measurement standard and can be used as the first test result.

[0011] As a preferred embodiment of the above technical solution, the test piece is subjected to an impact and abrasion resistance test, and the actual part is also subjected to an impact and abrasion resistance test. The two are compared to obtain a second test result, including: using an impact and abrasion resistance testing device to conduct impact and abrasion resistance tests on the test piece and the actual part respectively. If the test result of the actual part is better than the test result of the test piece, then the test result of the actual part is the second test result; otherwise, the actual part is reproduced.

[0012] As a preferred embodiment of the above technical solution, the test specimen is subjected to a frost resistance test, and the actual part is also subjected to a frost resistance test. The two tests are compared to obtain a third test result, including: adding slurry to the test specimen at different slurry addition rates and then sequentially performing a slurry addition vibration molding test and a frost resistance test to obtain test results including at least compressive strength, splitting tensile strength, and relative dynamic modulus of elasticity. Adding slurry to the actual part at the same slurry addition rate and then sequentially performing a slurry addition vibration molding test and a frost resistance test to obtain test results including at least compressive strength, splitting tensile strength, and relative dynamic modulus of elasticity. The two sets of test results are compared. If all test results of the actual part are better than those of the test specimen, the third test result is obtained; otherwise, the actual part is reproduced.

[0013] As a preferred embodiment of the above technical solution, preferably, the first test result, the second test result, and the third test result are weighted and calculated. If the result is greater than the standard value, the durability of the molded cemented gravel specimen meets the requirements. This includes: weighting the average of the two ratios of the correlation in the first test result, the impact abrasion strength value in the second test result, and the relative dynamic modulus of elasticity in the third test result. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0014] This invention also provides a comprehensive durability evaluation device for cemented gravel to implement the above method. The device includes: a test specimen production unit, used to calculate the configuration strength of cemented gravel based on engineering calculations, obtain molded cemented gravel specimens, and perform workability tests, compressive strength tests, and elastic modulus tests on them. After passing all tests, a comprehensive durability evaluation is performed based on the configuration strength. Then, based on the configuration strength, the on-site materials are graded, and an average gradation is obtained according to the gradation results. A gravel gradation envelope including the coarsest gradation, the finest gradation, and the average gradation is designed, and test specimens are configured according to the finest gradation. An actual measurement unit is used to quantitatively test the impermeability and corrosion resistance of the test specimens produced in the test specimen production unit, and also to quantitatively test the impermeability and corrosion resistance of actual specimens. The two tests are compared to obtain a first test result. The test specimens are also tested for impact and abrasion resistance, and the actual specimens are also tested for impact and abrasion resistance. The two tests are compared to obtain a second test result. Finally, the test specimens are tested for frost resistance, and the actual specimens are also tested for frost resistance. The two tests are compared to obtain a third test result. The calculation and evaluation unit is used to perform a weighted calculation based on the first test result, the second test result, and the third test result obtained by the actual measurement unit. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0015] As a preferred embodiment of the above technical solution, the actual measurement unit includes:

[0016] The test specimen measurement module is used to measure the permeability and corrosion resistance of the test specimens produced in the test specimen production unit, and to obtain the cumulative permeability coefficient, segmented permeability coefficient and calcium ion dissolution concentration; it is also used to test the impact and abrasion resistance of the test specimens to obtain the impact and abrasion resistance strength; and it is also used to test the freeze resistance of the test specimens by adding slurry to the test specimens at different slurry addition rates and then performing slurry addition vibration molding test and freeze resistance test in sequence, to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity.

[0017] The production module is used to produce actual components for construction based on the gradation results in the test component production unit, thus obtaining the actual components.

[0018] The first test result acquisition module is used to pressurize and permeate the actual part produced by the production module with deionized water to obtain the cumulative permeation coefficient, segmented permeation coefficient, and calcium ion dissolution concentration of the actual part; the ratio obtained by comparing the value / average of the calcium ion concentration of the actual part at the same time / time period with the value / average of the cumulative permeation coefficient, and the ratio obtained by comparing the value / average of the segmented permeation coefficient, are used as the correlation degree; the correlation degree is processed with the corresponding cumulative permeation coefficient and / or segmented permeation coefficient of the test part to obtain another calcium ion concentration of the actual part, thereby obtaining the corrosion resistance measurement evaluation result of the actual part. If this calcium ion concentration is less than the calcium ion concentration in the test part, it meets the corrosion resistance measurement standard and can be used as the first test result; wherein, if the ratio is obtained according to the time period, the corrosion resistance measurement evaluation result of the actual part in the 300d-600d time period is less than half of the average calcium ion concentration of the test part in the 300d-600d time period, then it meets the corrosion resistance measurement standard and can be used as the first test result.

[0019] The second test result acquisition module is used to perform impact and abrasion performance testing on the actual part using an impact and abrasion testing device, and compare the impact and abrasion performance test result of the actual part with the impact and abrasion performance test result obtained by the test part measurement module. If the test result of the actual part is better than the test result of the test part, then the test result of the actual part is the second test result; otherwise, the actual part is reproduced.

[0020] The third test result acquisition module is used to add slurry to the actual part according to the slurry addition rate adopted by the test part measurement module, and then conduct slurry addition vibration molding test and frost resistance test in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity; it is also used to compare the two sets of test results. If all the test results of the actual part are better than the test results of the test part, then the third test result is obtained; otherwise, the actual part is reproduced.

[0021] As a preferred embodiment of the above technical solution, the calculation and evaluation unit is specifically used to: calculate the weight of the average of the two ratios of the correlation obtained by the first test result acquisition module; calculate the weight of the impact and abrasion resistance value in the second test result obtained by the second test result acquisition module; calculate the weight of the relative dynamic elastic modulus in the third test result obtained by the third test result acquisition module; and add the three weighted results together.

[0022] As a preferred embodiment of the above technical solution, it is preferable to determine whether the sum of the three weights is greater than a preset standard value; if so, the requirement is met.

[0023] This invention provides a comprehensive durability evaluation method for cemented gravel. Based on engineering calculations of the cemented gravel's configuration strength, molded cemented gravel specimens are obtained. These specimens undergo workability, compressive strength, and elastic modulus tests. Once all tests are passed, the configuration strength is used for a comprehensive durability evaluation. The method involves configuring test specimens and quantitatively testing their impermeability and corrosion resistance. A second test result is obtained by comparing the first and second test results on the test specimens and the actual specimen. A third test result is obtained by comparing the first, second, and third test results. A weighted calculation is performed on the first, second, and third test results. If the result exceeds a preset standard value, the durability of the actual specimen meets the requirements.

[0024] The advantage of this invention is that it can solve the problem that the existing technology can only predict the trend of these properties in combination with the local environment and material characteristics, but cannot comprehensively and quantitatively evaluate these properties. By combining the results of three tests, it can make a quantitative evaluation of the construction parts actually used with specific values. Furthermore, construction personnel can effectively screen construction parts based on the evaluation results, rather than just evaluating them based on experimental trends. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A simplified flowchart of a comprehensive durability evaluation method for cemented gravel provided by the present invention.

[0027] Figure 2 A detailed flowchart of a comprehensive durability evaluation method for cemented gravel provided by the present invention.

[0028] Figure 2a for Figure 2 The flowchart for step 204.

[0029] Figure 3 This refers to the gradation envelope of the cemented gravel mentioned in the embodiments of the present invention.

[0030] Figure 4 This is a line graph of the cumulative permeability coefficient.

[0031] Figure 5This is a line graph of the segmented permeability coefficient.

[0032] Figure 6 This is a trend graph of the concentration of dissolved calcium ions.

[0033] Figure 7 This is a schematic diagram of a device for comprehensively evaluating the durability of cemented gravel. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] First, a brief description of the technical solution of this invention is provided, as shown in the flowchart below. Figure 1 As shown:

[0036] Step 101: Calculate the strength configuration and perform a strength test on the corresponding cemented gravel. If the test is passed, proceed to step 102; otherwise, reconfigure the strength.

[0037] Specifically, based on the engineering calculations of the cemented gravel configuration strength, molded cemented gravel specimens are obtained, and their workability, compressive strength, and elastic modulus are tested. After all tests are passed, the configuration strength is used to perform gradation, thereby conducting a comprehensive durability evaluation.

[0038] Step 102: Perform gradation, design the sand and gravel gradation envelope, and then produce test pieces.

[0039] Specifically, based on the configuration strength determined in step 101, the on-site materials are graded, and the average gradation is obtained according to the gradation results. A gravel gradation envelope, including the finest gradation, the finest gradation, and the average gradation, is designed. Test specimens are configured based on the finest gradation, and subsequent quantitative tests on their impermeability and corrosion resistance, abrasion resistance, and frost resistance are conducted.

[0040] Step 103: Conduct actual production and obtain actual parts.

[0041] Step 104: Conduct quantitative tests on impermeability and corrosion resistance to obtain the first test results.

[0042] Specifically, the test specimens were subjected to permeability and corrosion resistance measurements to obtain the cumulative permeability coefficient, segmented permeability coefficient, and calcium ion dissolution concentration.

[0043] The actual component was subjected to pressurized permeation using deionized water to obtain the cumulative permeation coefficient, segmented permeation coefficient, and calcium ion dissolution concentration. The correlation coefficient was obtained by comparing the value / average of the calcium ion concentration of the actual component at the same time / time period with the value / average of the cumulative permeation coefficient and by comparing the value / average of the segmented permeation coefficient.

[0044] The correlation coefficient and / or segmented permeability coefficient of the test specimen are processed to obtain another or more calcium ion concentrations of the actual specimen, thereby obtaining the corrosion resistance measurement evaluation result of the actual specimen. If this calcium ion concentration is less than the calcium ion concentration in the test specimen, it meets the corrosion resistance measurement standard and can be used as the first test result.

[0045] If the ratio is obtained based on the time period, and the corrosion resistance measurement evaluation result of the actual part during the 300d-600d time period is less than half of the average calcium ion concentration of the test part during the 300d-600d time period, then it meets the corrosion resistance measurement standard and can be used as the first test result.

[0046] Step 105: Conduct an impact and abrasion resistance test to obtain the second test result.

[0047] Specifically, an impact and abrasion resistance testing device is used to test the impact and abrasion resistance of the test piece and the actual piece respectively. If the test result of the actual piece is better than the test result of the test piece, then the test result of the actual piece is the second test result; otherwise, the actual piece is reproduced.

[0048] Step 106: Conduct antifreeze performance test and obtain the third test result.

[0049] After adding slurry to the test specimens at different slurry addition rates, slurry addition vibration molding test and frost resistance test were carried out in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity.

[0050] After adding slurry to the actual part at the same slurry addition rate as described above, slurry addition vibration molding test and frost resistance test were carried out in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity.

[0051] The two sets of test results are compared. If the test results of the actual part are better than those of the test part, then the third test result is obtained; otherwise, the actual part is reproduced.

[0052] Step 107: Perform a weighted calculation on the first test result, the second test result, and the third test result. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0053] Specifically, the average of the two ratios of correlation in the first test result, the impact and abrasion resistance value in the second test result, and the relative dynamic modulus of elasticity in the third test result are weighted. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0054] The technical solution of this invention will now be described in conjunction with a specific implementation scenario, specifically:

[0055] Step 201: Calculate the strength configuration and perform a strength test on the corresponding cemented gravel. If the test passes, proceed to step 202; otherwise, reconfigure the strength.

[0056] According to the "Technical Guidelines for Dam Construction with Cemented Granular Materials" SL678-2014, the strength of cemented sand and gravel mix design is as follows: f cu,o =f cu,k +tσ, where: fcu,o—the prepared strength of cemented gravel, MPa; the strength age is taken as 180d; f cu,k —Standard strength value of cemented gravel at the design age, MPa; t —Probability coefficient, selected based on the guarantee rate P. In this embodiment, P is taken as 80%, and the corresponding t value is 0.84; σ —Standard deviation of compressive strength of cemented gravel, MPa.

[0057] The dam body design strength in this embodiment is C. 180 10. The standard deviation is taken as 4.0 MPa according to the "Technical Guidelines for Dam Construction with Cemented Granular Materials". Therefore, the design strength is C. 180 The strength of cemented sand and gravel with a grade of 10 should be 13.4 MPa. That is, the minimum strength of the average graded cemented sand and gravel specimen should be 13.4 MPa, and the minimum strength of the finest graded cemented sand and gravel specimen (taking the maximum sand ratio of 35%) should be 10.0 MPa.

[0058] The design strength of components such as cofferdams is C. 180 6. The standard deviation is 2.4 MPa, the design strength is 6.0 MPa, and the formulation strength is 8.0 MPa.

[0059] The design strength and formulation strength of cemented gravel in different parts are shown in Table 1.

[0060] Table 1 Design strength and mix design strength of cemented gravel in different zones

[0061]

[0062] Test methods for cemented gravel

[0063] Cemented sand and gravel specimens (wet-sieved two-stage mix) were molded according to the relevant test methods for roller-compacted concrete in the Technical Guidelines for Cemented Granular Concrete Dam Construction (SL678-2014) and the Test Procedures for Hydraulic Concrete (DL / T5150-2017), and workability, compressive strength and modulus of elasticity were tested.

[0064] Cemented gravel wet sieving specimens were prepared by mixing gravel with a maximum aggregate size of 150 mm, then passing it through a 40 mm sieve, and compacting it in two layers under pressure. The wet sieving compressive strength test specimen was a cube with a side length of 150 mm, and the elastic modulus test specimen was a cylinder with a diameter of 150 mm and a height of 300 mm.

[0065] The full-graded compressive strength test specimen was a cube with a side length of 450 mm. The maximum aggregate size of the sand and gravel used was 150 mm. After mixing, the aggregate was compacted in layers.

[0066] Referring to the mixing time of the special mixing equipment for cemented sand and gravel, the preferred mixing time is controlled at 30 seconds.

[0067] Step 202: Design the cemented gravel envelope and produce test pieces.

[0068] Mix proportion tests were conducted with different gradations and amounts of cementitious materials to obtain the compressive strength and VC value for each mix proportion, and the mix proportion that meets the design requirements was selected. The test scheme is shown below:

[0069] (1) Sand ratio: 35% (finest gradation) and 25% (average gradation). Generally, cemented sand and gravel materials prepared with the coarsest gradation tend to have higher performance than those with the average and finest gradations. Therefore, evaluating the performance of cemented sand and gravel with only the finest gradation is sufficient to assess its durability. The gradation envelope is shown in the figure. Figure 3 As shown.

[0070] (2) Coarse aggregate gradation ratio:

[0071] ①Fineest gradation: 35% sand ratio, coarse aggregate gradation ratio is 11.50% extra-large stone, 23.80% large stone, 25.00% medium stone, and 39.70% small stone;

[0072] ② Average gradation: 25% sand ratio, coarse aggregate gradation ratio is 35.02% extra-large stone, 30.64% large stone, 20.80% medium stone, and 13.54% small stone (the coarse aggregate gradation ratio of the finest gradation and the average gradation is obtained according to the sand and gravel sieve gradation provided in the design).

[0073] (3) Adhesive usage: 60~140kg / m 3 The mixture consists of half cement and half fly ash;

[0074] (4) The dosage of the special admixture is 0.6-1.0%, and the amount of water is adjusted to the VC value of the mixture to be 2-5 seconds;

[0075] (5) Form wet screening specimens at four ages: 14d, 28d, 90d, and 180d, where d represents the number of days.

[0076] In this embodiment, three pieces of SPA100 cemented sand and gravel with the finest gradation of 180d were used as test specimens.

[0077] Step 203: Actual production and obtaining actual parts.

[0078] Step 204: Conduct quantitative tests on impermeability and corrosion resistance to obtain the first test results of the actual part.

[0079] Specifically, the measurement results of the test piece are as follows: Figure 4-6 As shown:

[0080] Step 2041: Perform penetration and corrosion resistance measurements on the test specimen to obtain the test specimen measurement results.

[0081] Specifically, the test specimen measurement results include cumulative permeability coefficient, segmented permeability coefficient, and calcium ion dissolution concentration. The Ca in the cemented gravel test specimen... 2+ The dissolution amount was determined by chemical titration, using EDTA as the standard reagent solution with a concentration of 0.0271 mol / L and CMP mixed indicator as the titration indicator. The cumulative dissolution amount of Ca(OH)2 in the solution was calculated by titration using the following formula: C(Ca 2+ )for

[0082] c(Ca 2+ )=V1C×40.08×1000 / V

[0083] The concentration of dissolved calcium ions is mg / L; C is the concentration of EDTA standard reagent solution is mol / L; V1 is the volume of EDTA standard solution is ml; V is the volume of water consumed is mL.

[0084] The formula for calculating the permeability coefficient is as follows:

[0085]

[0086] Q is the infiltration flow rate, m 3 / s; L is the height of the standard specimen, m; A is the cross-sectional area of ​​the infiltration, m². 2 H represents the applied head, in meters (m); K represents the permeability coefficient of the specimen, in m / s. The permeability test was conducted using a stepwise pressurization method.

[0087] Step 2042: Perform penetration and corrosion resistance measurements on the actual part and obtain the measurement results.

[0088] The method for obtaining the permeability coefficient is as described in step 2041, and will not be repeated here.

[0089] In this embodiment, three test pieces are used to acquire data to ensure the accuracy of the test results.

[0090] Step 2043: Calculate the segmental permeability coefficients of the test specimen and the actual specimen.

[0091] For step 2041, the permeability coefficient for different time periods can be calculated according to the above formula (starting from 0d, calculate the permeability coefficient for the time period from 0 to nd (day)). The results are as follows: Figure 4 As shown. From Figure 4 It can be seen that the cumulative permeability coefficient of cemented gravel gradually decreases with time, and the maximum cumulative permeability coefficient is approximately 7 × 10⁻⁶. -10 m / s, the permeability coefficient decreased to 1~2×10 in the later stage. -10 m / s.

[0092] The permeability coefficient is not only related to the amount of infiltration but also affected by the calculation time. Using cumulative infiltration to calculate the permeability coefficient yields a cumulative permeability coefficient over a single period, which cannot accurately represent the change in permeability of cemented gravel over time. The influence of infiltration time on the properties of cemented gravel should be considered when calculating the permeability coefficient at different times. The smaller the time interval, the more accurately the calculation results reflect the change in permeability of cemented gravel over time. Therefore, this invention uses 50-day intervals, and the calculated segmented permeability coefficients are shown in Table 2 and... Figure 5 As shown in Table 2 and Figure 5 It can be seen that the permeability coefficient of cemented gravel first decreases and then increases with increasing infiltration time, with its segmented permeability coefficient ranging from 0.5 to 5.0 × 10⁻⁶. -10 Between m / s.

[0093] Table 2. Segmented permeability coefficients (×10) -10 m / s)

[0094]

[0095] Step 2044: Calculate the correlation degree.

[0096] Specifically, taking 300d as an example, the average calcium ion concentration at time 300d of the actual part is compared with the cumulative permeability coefficient after summing and averaging to obtain the first ratio. This value is also compared with the segmented permeability coefficients after summing and averaging to obtain the second ratio.

[0097] The first ratio is calculated using the cumulative permeability coefficient from the test specimen measurement results to obtain the corresponding calcium ion concentration; the second ratio is calculated using the same method using the segmented permeability coefficient from the test specimen measurement results to obtain another calcium ion concentration.

[0098] Step 2045: Determine whether it meets the standard.

[0099] The two calcium ion concentrations of the actual part obtained by calculation in step 2044 are compared with the measurement results of the test part. If the calcium ion concentration of the actual part is less than the calcium ion concentration of the test part, it meets the corrosion resistance measurement standard.

[0100] If the time interval calculation method is used, the calcium ion concentration, cumulative permeability coefficient and segmented permeability coefficient of the three test specimens within the time interval are added together and averaged before being calculated using the method in step 207.

[0101] When using time interval calculations, the corrosion resistance measurement evaluation results of the test specimen within the 300d-600d time period are preferred as the evaluation standard. If the results are lower than half of the average calcium ion concentration within the 300d-600d time period in the theoretical experiment, then the corrosion resistance measurement standard is met.

[0102] Step 205: Conduct impact and abrasion resistance tests, compare the results, and obtain the second test results.

[0103] Specifically, the impact and abrasion resistance of SPA100 cemented gravel (test specimen) was tested using an impact and abrasion resistance testing device, and its impact and abrasion resistance strength was found to be 1.9 h / (kg / m²). 2 It already possesses high impact and abrasion resistance (the impact and abrasion resistance of C20 concrete is 2-3 h / (kg / m²)). 2 Then, the impact and abrasion resistance of the actual part is tested using an impact and abrasion resistance testing device. If the test result of the actual part is better than the test result of SPA100 cemented gravel, the impact and abrasion resistance test result of the actual part is the second test result for subsequent evaluation; otherwise, the actual part is reproduced.

[0104] Step 206: Conduct antifreeze performance tests, compare the results, and obtain the third test result.

[0105] Specifically, after adding slurry to SPA100 cemented gravel (test specimen) at slurry addition rates of 6% and 7%, slurry addition vibration molding test and frost resistance test were carried out in sequence to obtain test results including at least compressive strength, splitting tensile strength, and relative dynamic modulus of elasticity.

[0106] Table 3. Test results of cemented gravel with grouting and vibration (kg / m³) 3 )

[0107]

[0108] With grouting ratios of 6% and 7%, the compressive strength of grout-bonded gravel at 180 days can reach 21.7 MPa and 24.2 MPa, respectively, meeting the design requirements for the seepage prevention protective layer (generally C15 to C20). At 90 days, the splitting tensile strength of the specimen with a grouting ratio of 7% is 1.58 MPa, and the elastic modulus is above 30 GPa. Further testing was conducted on specimens with a grouting ratio of 7%.

[0109] The results of the frost resistance test of specimens with a 7% sizing rate at 180 days are shown in Table 4. It can be seen that the frost resistance grade of the sizing-added specimens is greater than F225.

[0110] Table 4. Freeze-thaw resistance of slurry-added specimens (180 days)

[0111]

[0112] This shows that grout-mixed vibratory cemented gravel has good frost resistance and can be used in dam sections with frost resistance design requirements.

[0113] In practice, the same slurry addition rate as described above can be applied to the actual part, and then the slurry addition vibration molding test and the frost resistance test can be carried out in sequence to obtain test results including at least compressive strength, splitting tensile strength, relative dynamic modulus of elasticity and weight loss rate.

[0114] The two sets of test results are compared. If the test results of the actual part are better than those of the test part, then the third test result is obtained; otherwise, the actual part is reproduced.

[0115] Step 207: Perform a weighted calculation on each test result. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0116] Specifically, the average of the two ratios of correlation in the first test result obtained in step 204, the impact and abrasion resistance value in the second test result obtained in step 205, and the relative dynamic modulus of elasticity in the third test result obtained in step 206 are weighted. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0117] This invention also provides a comprehensive durability assessment device for cemented gravel to achieve the above-mentioned method, such as... Figure 7 As shown, the device includes:

[0118] Test specimen production unit 31 is used to calculate the configuration strength of cemented gravel based on engineering calculations, obtain molded cemented gravel specimens, and conduct workability tests, compressive strength tests, and elastic modulus tests on them. After passing all tests, the durability is comprehensively evaluated based on the configuration strength. Then, based on the configuration strength, the on-site materials are graded, and the average gradation is obtained according to the gradation results. The gravel gradation envelope, including the finest gradation, the finest gradation, and the average gradation, is designed, and the test specimens are configured according to the finest gradation.

[0119] The actual measurement unit 32 is used to quantitatively test the impermeability and corrosion resistance of the test pieces produced by the test piece production unit 31, and also to quantitatively test the impermeability and corrosion resistance of the actual pieces. The two tests are compared to obtain a first test result. The test pieces are also tested for impact and abrasion resistance, and the actual pieces are also tested for impact and abrasion resistance. The two tests are compared to obtain a second test result. The test pieces are also tested for freeze resistance, and the actual pieces are also tested for freeze resistance. The two tests are compared to obtain a third test result.

[0120] The calculation and evaluation unit 33 is used to perform weighted calculations based on the first test result, the second test result, and the third test result obtained by the actual measurement unit 32. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0121] The calculation evaluation unit 33 is specifically used to weight the average of the two ratios of the correlation obtained by the first test result acquisition module, the impact and abrasion resistance value in the second test result obtained by the second test result acquisition module, and the relative dynamic modulus of elasticity in the third test result obtained by the third test result acquisition module, respectively, and to add the three weighted results. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

[0122] like Figure 7 As shown, the actual measurement unit 32 includes:

[0123] The test piece measurement module 321 is used to measure the permeability and corrosion resistance of the test pieces produced in the test piece production unit 31 to obtain the cumulative permeability coefficient, segmented permeability coefficient and calcium ion dissolution concentration; it is also used to test the impact and abrasion resistance of the test pieces to obtain the impact and abrasion resistance strength; it is also used to test the freeze resistance of the test pieces by adding slurry to the test pieces at different slurry addition rates and then performing slurry addition vibration molding test and freeze resistance test in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity.

[0124] Production module 322 is used to produce actual components for construction based on the gradation results in test component production unit 31, thereby obtaining actual components.

[0125] The first test result acquisition module 323 is used to perform pressurized permeation of the actual parts produced by the production module 322 with deionized water to obtain the cumulative permeation coefficient, segmented permeation coefficient, and calcium ion dissolution concentration of the actual parts; the ratio obtained by comparing the value / average of the calcium ion concentration of the actual parts at the same time / time period with the value / average of the cumulative permeation coefficient, and the ratio obtained by comparing the value / average of the segmented permeation coefficient, are used as the correlation degree; the correlation degree is processed with the corresponding cumulative permeation coefficient and / or segmented permeation coefficient of the test parts obtained by the test parts measurement module 321 to obtain another calcium ion concentration of the actual parts, thereby obtaining the corrosion resistance measurement evaluation result of the actual parts. If this calcium ion concentration is less than the calcium ion concentration in the test parts, it meets the corrosion resistance measurement standard and can be used as the first test result; wherein, if the ratio is obtained according to the time period, the corrosion resistance measurement evaluation result of the actual parts in the 300d-600d time period is less than half of the average calcium ion concentration of the test parts in the 300d-600d time period, then it meets the corrosion resistance measurement standard and can be used as the first test result.

[0126] The second test result acquisition module 324 is used to perform impact and abrasion performance tests on the actual parts produced by the production module 322 using an impact and abrasion test device, and compare the impact and abrasion performance test results of the actual parts with the impact and abrasion performance test results acquired by the test part measurement module 321. If the test result of the actual parts is better than the test result of the test parts, then the test result of the actual parts is the second test result; otherwise, the actual parts are reproduced.

[0127] The third test result acquisition module 325 is used to add slurry to the actual part produced by the production module 322 according to the slurry addition rate adopted by the test part measurement module 321, and then conduct slurry addition vibration molding test and frost resistance test in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity; it is also used to compare the two sets of test results. If all the test results of the actual part are better than the test results of the test part, then the third test result is obtained; otherwise, the actual part is reproduced.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A comprehensive durability evaluation method for cemented gravel, characterized in that, The method includes: Based on the engineering calculations, the configuration strength of cemented gravel was determined, and molded cemented gravel specimens were obtained. Workability tests, compressive strength tests, and elastic modulus tests were then conducted on these specimens. Once all tests were passed, the overall durability was evaluated based on this configuration strength. Configure test specimens and conduct quantitative tests on the impermeability and corrosion resistance of the test specimens. Also conduct quantitative tests on the impermeability and corrosion resistance of actual specimens. Compare the two results to obtain the first test result. The impact and abrasion resistance of the test piece and the actual part were tested, and the two were compared to obtain a second test result. The test specimen was subjected to an antifreeze performance test, and the actual specimen was also subjected to an antifreeze performance test. The two tests were compared to obtain a third test result. The first test result, the second test result, and the third test result are weighted and calculated. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

2. The evaluation method according to claim 1, characterized in that, The subsequent comprehensive durability assessment based on this strength configuration includes: Based on the configured strength, the field materials are graded, and the average gradation is obtained according to the gradation results. The gravel gradation envelope, including the coarsest gradation, the finest gradation, and the average gradation, is designed. The test specimens are configured according to the finest gradation, and quantitative tests are conducted on the impermeability and corrosion resistance, abrasion resistance, and freeze resistance.

3. The evaluation method according to claim 1, characterized in that, The quantitative test of the impermeability and corrosion resistance of the test specimen is performed, and the quantitative test of the impermeability and corrosion resistance of the actual specimen is also performed. The two tests are compared to obtain the first test result, including: The test specimen was subjected to permeability and corrosion resistance measurements to obtain the cumulative permeability coefficient, segmented permeability coefficient, and calcium ion leaching concentration. Actual production is carried out to obtain actual parts. Deionized water is used for pressurized permeation to obtain the cumulative permeation coefficient, segmented permeation coefficient, and calcium ion dissolution concentration of the actual parts. The ratio obtained by comparing the value / average of calcium ion concentration of the actual parts at the same time / time period with the value / average of the cumulative permeation coefficient, and the ratio obtained by comparing the value / average of the segmented permeation coefficient, are used as the correlation degree. The correlation degree is processed with the cumulative permeability coefficient and / or segmented permeability coefficient of the test piece to obtain another calcium ion concentration of the actual piece, thereby obtaining the corrosion resistance measurement evaluation result of the actual piece. If this calcium ion concentration is less than the calcium ion concentration in the test piece, it meets the corrosion resistance measurement standard and can be used as the first test result. If the ratio is obtained based on the time period, and the corrosion resistance measurement evaluation result of the actual part during the 300d-600d time period is less than half of the average calcium ion concentration of the test part during the 300d-600d time period, then it meets the corrosion resistance measurement standard and can be used as the first test result.

4. The evaluation method according to claim 1, characterized in that, The impact and abrasion resistance test is performed on the test piece, and the impact and abrasion resistance test is also performed on the actual part. The two tests are compared to obtain a second test result, including: The impact and abrasion resistance performance of the test piece and the actual piece are tested using an impact and abrasion resistance testing device. If the test result of the actual piece is better than that of the test piece, then the test result of the actual piece is the second test result; otherwise, the actual piece is reproduced.

5. The evaluation method according to claim 1, characterized in that, The test involves performing a freeze-thaw resistance test on the test specimen and also on the actual specimen. A third test result is obtained by comparing the two results, including: After adding slurry to the test specimens at different slurry addition rates, slurry addition vibration molding test and frost resistance test were carried out in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity. After adding slurry to the actual part at the same slurry addition rate as described above, slurry addition vibration molding test and frost resistance test were carried out in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity. The two sets of test results are compared. If all test results of the actual part are better than those of the test part, then the third test result is obtained; otherwise, the actual part is reproduced.

6. The evaluation method according to claim 1, characterized in that, The first, second, and third test results are weighted and calculated. If the result is greater than the standard value, the durability of the molded cemented gravel specimen meets the requirements, including: The average of the two ratios of correlation in the first test result, the impact and abrasion resistance value in the second test result, and the relative dynamic modulus of elasticity in the third test result are weighted. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

7. A comprehensive durability assessment device for cemented gravel, used to implement the method described in any one of claims 1-6, characterized in that, The device includes: The test specimen production unit is used to obtain molded cemented gravel specimens based on the configuration strength of cemented gravel calculated by the engineering project. After the specimens pass the workability test, compressive strength test, and elastic modulus test, the durability is comprehensively evaluated based on the configuration strength. Then, based on the configuration strength, the on-site materials are graded, and the average gradation is obtained according to the gradation results. The gravel gradation envelope including the coarsest gradation, the finest gradation, and the average gradation is designed, and the test specimens are configured according to the finest gradation. The actual measurement unit is used to quantitatively test the impermeability and corrosion resistance of the test pieces produced in the test piece production unit, and also to quantitatively test the impermeability and corrosion resistance of the actual pieces. The two tests are compared to obtain a first test result. The unit also tests the impact and abrasion resistance of the test pieces and the actual pieces, and the two tests are compared to obtain a second test result. Finally, the unit tests the freeze resistance of the test pieces and the actual pieces, and the two tests are compared to obtain a third test result. The calculation and evaluation unit is used to perform a weighted calculation based on the first test result, the second test result, and the third test result obtained by the actual measurement unit. If the result is greater than the preset standard value, the durability of the actual part meets the requirements.

8. The evaluation apparatus according to claim 7, characterized in that, The actual measurement unit includes: The test specimen measurement module is used to measure the permeability and corrosion resistance of the test specimens produced in the test specimen production unit, and to obtain the cumulative permeability coefficient, segmented permeability coefficient and calcium ion dissolution concentration; it is also used to test the impact and abrasion resistance of the test specimens to obtain the impact and abrasion resistance strength; and it is also used to test the freeze-thaw resistance of the test specimens by adding slurry to the test specimens at different slurry addition rates and then performing slurry addition vibration molding test and freeze-thaw resistance test in sequence, to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity. The production module is used to produce actual components for construction based on the gradation results in the test component production unit, thus obtaining actual components; The first test result acquisition module is used to pressurize and permeate the actual part produced by the production module with deionized water to obtain the cumulative permeation coefficient, segmented permeation coefficient, and calcium ion dissolution concentration of the actual part; the ratio obtained by comparing the value / average of the calcium ion concentration of the actual part at the same time / time period with the value / average of the cumulative permeation coefficient, and the ratio obtained by comparing the value / average of the segmented permeation coefficient, are used as the correlation degree; the correlation degree is processed with the corresponding cumulative permeation coefficient and / or segmented permeation coefficient of the test part to obtain another calcium ion concentration of the actual part, thereby obtaining the corrosion resistance measurement evaluation result of the actual part. If this calcium ion concentration is less than the calcium ion concentration in the test part, it meets the corrosion resistance measurement standard and can be used as the first test result; wherein, if the ratio is obtained according to the time period, and the corrosion resistance measurement evaluation result of the actual part in the 300d-600d time period is less than half of the average calcium ion concentration of the test part in the 300d-600d time period, it meets the corrosion resistance measurement standard and can be used as the first test result. The second test result acquisition module is used to perform impact and abrasion performance testing on the actual part using an impact and abrasion testing device, and compare the impact and abrasion performance test result of the actual part with the impact and abrasion performance test result obtained by the test part measurement module. If the test result of the actual part is better than the test result of the test part, then the test result of the actual part is the second test result; otherwise, the actual part is reproduced. The third test result acquisition module is used to add slurry to the actual part according to the slurry addition rate adopted by the test part measurement module, and then conduct slurry addition vibration molding test and frost resistance test in sequence to obtain test results including at least compressive strength, splitting tensile strength and relative dynamic modulus of elasticity; it is also used to compare the two sets of test results. If all the test results of the actual part are better than the test results of the test part, then the third test result is obtained; otherwise, the actual part is reproduced.

9. The evaluation apparatus according to claim 8, characterized in that, The calculation and evaluation unit is specifically used to calculate the weight of the average of the two ratios of the correlation obtained by the first test result acquisition module, calculate the weight of the impact and abrasion resistance value in the second test result obtained by the second test result acquisition module, calculate the weight of the relative dynamic elastic modulus in the third test result obtained by the third test result acquisition module, and add the three weighted results together.

10. The evaluation apparatus according to claim 9, characterized in that, The calculation and evaluation unit is also used to determine whether the sum of the three weights is greater than a preset standard value; if so, the requirement is met.

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