A correction method for cement dosage detection in cement-stabilized soil based on moisture content deviation

Abstract

The present invention relates to the technical field of cement dosage detection, and provides a method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation, comprising the following steps: W 0 and designed cement dosage C 0 as the base, prepare multiple cement doses C Test the consumption of EDTA standard solution P i , determine the function P i = α + β · C i Parameters in α and β ; Cement dosage is C 0 conditions, prepare multiple different moisture contents W n samples, test EDTA standard solution consumption P k , determine the function R k = m + i · W k Parameters in m and i ; During the construction process, the cement dosage of cement-solidified soil C Test value by formula C =[ P – α – i ( W – W 0)] / β *100% correction; the correction method of the present invention can better reflect the influence of moisture content preparation deviation on cement dosage detection value in the construction of cement-solidified soil in roadbed engineering, and improve the reliability of engineering detection and engineering quality.

Description

Technical Field

[0001] The present invention relates to the technical field of cement dosage detection, and in particular to a correction method for cement dosage detection in cement-solidified soil based on water content deviation. Background Art

[0002] The mixing quality of cement-stabilized soil in roadbed engineering has a great impact on the safety of engineering structures. The cement blending amount, that is, the cement dosage (cement mass / dry raw soil mass) detection is an important part of engineering quality control. Among the various cement blending amount detection methods for cement-stabilized soil, the EDTA titration method is the recommended method in my country's engineering technical specifications.

[0003] The test specifications generally require reference to the engineering design parameter indicators of cement-stabilized soil, with cement dosage as the variable, and 5 samples with different cement contents prepared according to the cement blending ratio of 0~10%. An EDTA standard titration test is carried out in the laboratory to obtain the standard solution consumption (ml) of each sample, and a standard curve of the relationship between the standard solution consumption (ml) and the cement dosage (%) is plotted; then, representative samples of cement-stabilized soil fillers are selected from the engineering filling construction site, and an EDTA standard solution consumption (ml) test is carried out in the laboratory. According to the obtained standard curve of the cement dosage-standard solution consumption relationship, the cement dosage corresponding to the test sample is calculated, which is the cement blending amount reflected by the cement-stabilized soil sample taken from the engineering filling construction site.

[0004] EDTA titration is a chemical testing technique. The cement dosage in the solidified soil is mainly determined by titrating the Ca in the solution with a disodium standard solution. 2+ The hydration reaction in cement-stabilized soil is very complex, mainly due to the Ca in the cement hydration reaction product. 2+ , which is significantly affected by the moisture content of the cement-solidified soil mixture, showing that as the moisture content increases, the hydration reaction intensity decreases, and the soluble Ca 2+ It can be seen that the influence of the moisture content deviation of cement-solidified soil mixture should be considered in the EDTA titration test during the construction process of engineering filling.

[0005] Due to the complex environment, changeable climate and huge amount of earthwork in roadbed construction, tremendous pressure is placed on the control of parameter indicators in the preparation process such as mixing and blending of cement-solidified soil. It is inevitable that the moisture content of the mixture will deviate to a certain extent, which will have an adverse effect on the accurate determination of cement dosage. Summary of the invention

[0006] The purpose of the present invention is to provide a correction method for detecting cement dosage in cement-solidified soil based on water content deviation. On the basis of the existing EDTA standard titration method, the influence of water content preparation deviation on cement-solidified soil sampling and EDTA titration detection during large-scale engineering construction is further considered, so that the corrected method of the present invention can significantly improve the accuracy of EDTA titration method for detecting cement dosage in cement-solidified soil, and provide detection guarantee for the quality control of cement-solidified soil filling construction in roadbed engineering.

[0007] The embodiments of the present invention are implemented by the following technical solutions:

[0008] A correction method for cement dosage detection in cement-solidified soil based on moisture content deviation comprises the following steps:

[0009] It should be noted that i and k below are sample numbers.

[0010] A. Raw material preparation

[0011] According to the composition of cement-solidified soil mixture designed by the project, the raw soil samples were taken from the construction filling site; after being air-dried, they were ground and passed through a 2 mm geotechnical sieve for use, and then a curing agent and mixing water were added to mix. The curing agent was ordinary Portland cement; the mixing water was laboratory tap water;

[0012] B. Cement dosage calibration

[0013] B1. Design moisture content of cement-solidified soil mixture W 0, based on the designed cement dosage C 0 as the reference, at least n groups of mixing ratios were set according to the cement dosage of C0, C0±2%, C0±4% gradient, and mixed to obtain various cement dosages C i ; Specifically in this scheme, 5 kinds of mixing ratios can be set, namely: C0-4%, C0-2%, C0, C0+2%, C0+4% for mixing and sampling; Among them, the moisture content of the solidified soil mixture is: water mass / (dry raw material soil mass+cement mass); The cement dosage of the solidified soil mixture is: cement mass / dry raw material soil mass;

[0014] B2. Dosage of the prepared n types of cement C i For the solidified soil mixture, the EDTA standard titration test is carried out before the initial setting of cement to obtain the standard solution consumption of the corresponding solidified soil mixture sample. Ρ i , draw cement dosage C i Consumption of standard solution Ρ i Relationship curve;

[0015] B3. Use function P i = α + β · C i The test data of n groups of EDTA standard titration tests with different cement dosages were fitted to obtain the parameters α , β value;

[0016] C. Moisture content deviation calibration

[0017] C1. Design cement dosage in cement-solidified soil mixture C 0, with the designed moisture content W 0 as the basis, at least the moisture content is W 0±2%, W The stabilized soil mixtures with n moisture contents were prepared with a gradient of 0 ± 4%;

[0018] C2, for the prepared n kinds of moisture content W k ) Solidified soil mixture, before the initial setting of cement, the EDTA standard titration test was carried out to obtain the standard solution consumption of the corresponding solidified soil mixture samples. Ρ k , plot the moisture content W k Consumption of standard solution Ρ k Relationship curve;

[0019] C3. Test data of EDTA standard titration test for n groups of solidified soil mixture samples ( Ρ k , W k ) and step B according to the designed moisture content W 0 and designed cement dosage C Test data of EDTA standard titration test of stabilized soil mixture samples prepared by 0 P 0, using function Ρ k = μ + θ · W k The test data of n groups of EDTA standard titration tests with different water contents were fitted to obtain the parameters μ , θ value;

[0020] D. Cement dosage detection and correction

[0021] D1. Take cement-solidified soil samples at the construction site and conduct moisture content test and EDTA standard titration test to measure the moisture content.W And standard solution consumption P ;

[0022] D2. Correction value of cement dosage test for cement-solidified soil mixture C =[ P – α – θ ( W – W 0)] / β* 100%.

[0023] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0024] The present invention proposes a correction method for cement dosage detection in cement-solidified soil based on moisture content deviation. On the basis of the existing EDTA standard titration method, the method further considers the influence of moisture content preparation deviation of cement-solidified soil sampling for EDTA titration detection during large-scale engineering construction, and corrects the cement dosage detection data obtained by EDTA titration detection of samples taken from the construction site, and obtains that when the moisture content preparation of the actual detection mixture deviates from the design value by 5.5%, it will cause a cement dosage detection value deviation of about 1.0%. Based on this, the corrected method of the present invention can significantly improve the accuracy of cement dosage in cement-solidified soil detection by EDTA titration, and provide detection guarantee for the quality control of cement-solidified soil filling construction in roadbed engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 The cement dosage provided for the experimental example of the present invention is C (%) and moisture content W (%) and EDTA standard solution consumption P (ml) relationship curve diagram. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0028] Example

[0029] A correction method for cement dosage detection in cement-solidified soil considering moisture content preparation deviation comprises the following steps:

[0030] A. Raw material preparation: According to the composition of cement-solidified soil mixture designed by the project, the raw soil samples are taken from the construction filling site, crushed and dried to pass through a 2 mm geosieve; the curing agent is ordinary Portland cement; the mixing water is laboratory tap water.

[0031] B. Cement dosage calibration

[0032] B1. Design moisture content of cement-solidified soil mixture W 0, based on the designed cement dosage C 0 as the base, and the cement dosage is C 0-4%, C 0-2%, C 0. C 0+2%, C 0+4%, prepare five cement dosages of stabilized soil mixtures, each sample is not less than 300 g;

[0033] B2. Dosage of the five prepared cements C i ：C 0-4%, C 0-2%, C 0. C 0+2%, C 0+4% solidified soil mixture, before the initial setting of cement, the EDTA standard titration test was carried out to obtain the standard solution consumption of the corresponding solidified soil mixture samples. Ρ i : Ρ 0-4%, Ρ 0-2%, Ρ 0. Ρ 0+2%, Ρ 0+4%, draw cement dosage C i Consumption of standard solution Ρ i Relationship curve;

[0034] B3. Use function P i = α + β · C i The test data of 5 groups of EDTA standard titration tests with different cement dosages were fitted to obtain the parameters α , β value.

[0035] C. Moisture content deviation calibration

[0036] C1. Design cement dosage in cement-solidified soil mixture C 0, with the designed moisture content W 0 as the basis, respectively according to the moisture content W 0-4%, W 0-2%, W 0+2%, W 0+4%, prepare four kinds of stabilized soil mixtures with different moisture contents, each sample shall be no less than 300 g;

[0037] C2, the prepared 4 kinds of moisture content of For the solidified soil mixture, the EDTA standard titration test is carried out before the initial setting of cement to obtain the sodium standard solution consumption of the corresponding solidified soil mixture sample. Ρ k , plot the moisture content W k Consumption of standard solution Ρ k Relationship curve;

[0038] C3. Test data of EDTA standard titration test on 4 groups of solidified soil mixture samples ( Ρ k , W k ) and step B according to the designed moisture content W 0 and designed cement dosage C Test data of EDTA standard titration test of stabilized soil mixture samples prepared by 0 P 0, using function Ρ k = μ + θ · W k The test data of 5 groups of EDTA standard titration tests with different water contents were fitted to obtain the parameters μ , θ value.

[0039] D. Cement dosage detection and correction

[0040] D1. At the construction site, take cement-solidified soil samples for moisture content test and EDTA standard titration test to measure the moisture content. W And standard solution consumption P ;

[0041] D2. Correction value of cement dosage test for cement-solidified soil mixture C =[ P – α – θ ( W –W 0)] / β* 100%.

[0042] Experimental example - test verification

[0043] For the preparation and filling construction site of fully (strongly) weathered soft rock cement-stabilized soil for a roadbed project, ordinary silicate cement was used as the curing agent, and the mixing water was laboratory tap water. According to the specific gravity bottle method in the "Railway Engineering Geotechnical Test Code" (TB 10102-2023), the particle density of the fully (strongly) weathered soft rock raw soil was measured to be 2.69g / cm 3 The liquid limit and plastic limit measured by the combined liquid and plastic limit determination method are 31.5% and 17.1% respectively, and the moisture content measured by the drying method is 4.9%; according to the heavy compaction II-2 test in the Highway Geotechnical Test Code JTG 3430-2020, the maximum dry density of the fully (strongly) weathered soft rock raw soil is 1.95 g / cm 3 , the optimal moisture content is 10.65%.

[0044] According to the above embodiment method, the designed cement dosage of the fully (strongly) weathered soft rock cement-solidified soil filler is C 0=10% and design moisture content W 0=44%, prepare cement dosage with a moisture content of 44% C i Five mixture samples with 6%, 8%, 10%, 12% and 14% respectively were subjected to EDTA standard titration test before initial setting of cement to obtain the corresponding standard solution consumption Ρ i The cement dosage is 11.5 ml, 13.7 ml, 15.6 ml, 17.9 ml and 20.3 ml respectively. C i Consumption of standard solution Ρ i Relationship curve, such as Figure 1 As shown, the function P i = α + β · C i Parameters in α =4.940, β =1.085; that is, cement dosage C Consumption of standard solution Ρ The relationship curve is: P =4.940+1.085 C .

[0045] At the same time, according to the designed cement dosage C 0=10% and design moisture contentW 0=44%, the moisture content of the prepared cement at a dosage of 10% W k Four fully (strongly) weathered soft rock cement-stabilized soil samples with concentrations of 40%, 42%, 46%, and 48% were prepared, and an EDTA standard titration test was performed before the initial setting of the cement to obtain the corresponding standard solution consumption. Ρ k 16.5 ml, 16.2 ml, 15.2 ml, 15.0 ml respectively; the test data of EDTA standard titration test on 4 fully (strongly) weathered soft rock stabilized soil mixture samples ( Ρ k , W k ) and the designed cement dosage C 0 and design moisture content W Test data of EDTA standard titration test of fully (strongly) weathered soft rock stabilized soil mixture prepared by 0 before initial setting of cement P 0, plot moisture content W k Consumption of standard solution Ρ k Relationship curve, such as Figure 1 As shown, the function Ρ k = μ + θ · W k Parameters in μ =24.350, θ =–0.198; i.e. moisture content W Consumption of standard solution Ρ The relationship curve is: P =24.350–0.198 W .

[0046] During the construction of fully (strongly) weathered soft rock cement-stabilized soil, samples are taken on site before the initial setting of cement to conduct moisture content determination and EDTA standard titration test to obtain the moisture content of the sample. W =48.13%, standard solution consumption P =14.8 ml, the cement dosage test value of fully (strongly) weathered soft rock cement-stabilized soil after considering the water content preparation deviation correction:

[0047] C =[ P – α – θ ( W – W 0)] / β*100%=[14.8–4.940+0.198(48.13–44)] / 1.085 * 100%=9.84%, which is only about 0.16% lower than the design value; the uncorrected detection value is 9.09%, which is 0.91% lower than the design value; the deviation of the corrected detection value is reduced by 82% compared with the uncorrected value.

[0048] It can be seen that the correction method of the present invention can better reflect the influence of moisture content preparation deviation on cement dosage detection value in large-scale construction of cement-solidified soil in roadbed engineering, thereby improving the accuracy of engineering detection data and the reliability of engineering quality control.

[0049] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A correction method for cement dosage detection in cement-solidified soil based on moisture content deviation, comprising the following steps: S1. Cement dosage calibration, including the following steps: S11. Design moisture content of cement-solidified soil mixture W 0, based on the designed cement dosage C 0 as the benchmark, at least multiple groups of cement dosages of solidified soil mixture C are set according to the cement dosage of C0, C0±2%, C0±4% gradient. i ; S12, the dosage of the prepared n types of cement C i For the solidified soil mixture, the EDTA standard titration test is carried out before the initial setting of cement to obtain the standard solution consumption of the corresponding solidified soil mixture samples. P i , draw cement dosage C i Consumption of standard solution P i Relationship curve; S13, using function P i = α + β · C i The test data of n groups of EDTA standard titration tests with different cement dosages were fitted to obtain the parameters α , β Value; where i is the sample number; S2. Moisture content deviation calibration, including the following steps: S21. Design cement dosage in cement-stabilized soil mixture C 0, with the designed moisture content W 0 as the basis, at least the moisture content is W 0±2%, W The stabilized soil mixtures with n moisture contents were prepared with a gradient of 0 ± 4%; S22, the prepared n kinds of moisture content W k For the solidified soil mixture, the EDTA standard titration test is carried out before the initial setting of cement to obtain the standard solution consumption of the corresponding solidified soil mixture samples. P k , plot the moisture content W k Consumption of standard solution P k Relationship curve; S23. Test data of EDTA standard titration test for n groups of solidified soil mixture samples ( P k , W k ) and according to the designed moisture content W 0 and designed cement dosage C Test data of EDTA standard titration test of stabilized soil mixture samples prepared by 0 P 0, using function P k = μ + θ · W k Fit the test data of n groups of titration tests with different water contents to obtain the parameters μ , θ Value; where k is the sample number; S3. Cement dosage test correction: During the construction process of engineering filling, the cement dosage of cement-solidified soil C Test value by formula C =[ P – α – θ ( W – W 0)] / β* 100% correction.

2. The method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation according to claim 1, characterized in that: Before step S1, the process also includes the step of raw material preparation: according to the engineering design of cement-solidified soil mixture, raw soil is selected from the construction site, ground and sieved for standby use after air drying, and a curing agent and mixing water are added to mix.

3. The method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation according to claim 1, characterized in that: Step S3 includes the following steps: S31. Take cement-solidified soil samples at the construction site and conduct moisture content test and EDTA standard titration test to measure the moisture content. W And standard solution consumption P ; S32. The cement dosage test correction value of cement-solidified soil mixture is corrected according to the following formula: C =[ P – α – θ ( W – W 0)] / β .

4. The method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation according to claim 2, characterized in that: When preparing raw materials: the curing agent is silicate; the mixing water is tap water.

5. The method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation according to claim 1, characterized in that: In step S1, the cement dosage is: cement mass / dry raw material soil mass.

6. The method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation according to claim 1, characterized in that: In step S1, the moisture content is: water mass / (dry raw soil mass+cement mass).

7. The method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation according to claim 3, characterized in that: The deviation between the moisture content of the sample taken in step S3 and the designed moisture content W0 in step S1 does not exceed 1%.

8. The method for correcting cement dosage detection in cement-solidified soil based on moisture content deviation according to claim 3, characterized in that: In step S3, at the cement-solidified soil construction site, the time for sampling and conducting the EDTA standard titration test should be before the initial setting of the cement.

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