Method for predicting settling amount of granulated sludge solidified by engineering filling

Abstract

The present application relates to a kind of engineering filling sludge solidified particle settlement quantity prediction method.Engineering filling sludge solidified particle is used as filling material, lack standard settlement quantity prediction method.This method prepares two samples of solidified particle;Through first sample, the specific gravity of solidified particle is calculated;First sample is treated by immersion, and the volume proportion of good solidified particle and poor solidified particle is obtained;The compression modulus of good solidified particle and the compression modulus of poor solidified particle are determined;Through second sample, the maximum porosity and minimum porosity of solidified particle are determined;Combined with filling engineering design load and design thickness, total settlement is calculated.This method comprehensively considers upper load and solidified particle gravity when engineering filling sludge solidified particle settlement quantity is predicted, and the compression settlement of good solidification and poor solidification particles is also considered, in addition, the volume reduction caused by the internal reduction of particle porosity, internal compression is also used in prediction calculation, and more real and reliable total settlement prediction value is obtained.

Description

Technical Field

[0001] This invention relates to the field of engineering material quality testing technology, specifically to a method for predicting the settling amount of solidified silt particles in engineering backfill. Background Technology

[0002] Excavation of silt is a common construction step in municipal, building, and water conservancy projects. The silt obtained is often just solid waste with high water content and poor engineering properties, making it difficult to use directly. Granulating the silt using a granulator significantly reduces its water content, yielding solidified granules with better engineering properties. Utilizing these solidified granules is an ideal method for reusing engineering silt. Solidified granules possess certain mechanical strength and stability, are uniform in size and shape, and can withstand filling pressure and deformation forces, thus making them suitable as filling materials in engineering projects.

[0003] When using solidified particles obtained from engineering sludge as engineering fill material, there are requirements for properties such as resistance to deformation and compression. Their own compression and settlement must meet certain standards; otherwise, the load-bearing capacity and stability of the fill structure will decrease, leading to safety accidents. Due to the complexity of engineering sludge itself, the solidified particles obtained from it may contain not only well-solidified portions but also poorly solidified portions. When mixed and used for filling, it is impossible to know the overall properties of the material in terms of resistance to deformation and compression, and there is a lack of methods for predicting the settlement of such fill materials. Summary of the Invention

[0004] The purpose of this invention is to provide a method for predicting the settlement of solidified sludge particles in engineering backfill, so as to solve the problem of the lack of methods for predicting and calculating the settlement of solidified sludge particles in engineering backfill.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for predicting the settling amount of solidified sludge particles in engineering backfill, the method comprising:

[0007] Prepare two samples of the solidified granules;

[0008] Calculate the density of the solidified particles using the first sample;

[0009] The first sample was immersed in water to obtain the volume ratio of good and bad solidified particles;

[0010] Determine the compressive modulus of well-cured particles and poorly cured particles;

[0011] The maximum and minimum porosity of the solidified particles were determined using the second sample.

[0012] Calculate the total settlement by combining the design load and design thickness of the filling project.

[0013] Furthermore, the first sample was immersed in water to obtain the volume ratio of good and bad solidified particles, including:

[0014] The first sample is a cured particle with a curing age of 3 days, and the volume V0 of the first sample is measured.

[0015] The first sample was completely immersed in water for 24 hours. After being removed, the volume V1 of the particles that could maintain their original shape was measured. The volume ratio of well-cured particles was R1 = V1 / V0, and the volume ratio of poorly cured particles was R2 = 1 - R1.

[0016] Further, the compression modulus of a good sample is determined, including:

[0017] The well-cured particles in the first sample were subjected to indoor compression consolidation tests at 3, 7, 14, 28 and 60 days of curing, and the compression modulus at each time point was measured.

[0018] For the compressive modulus at 3 days, 7 days, 14 days, 28 days, and 60 days, the value is taken directly; for the compressive modulus at other time points, the value is determined by the linear interpolation method; when it is greater than 60 days, the value is taken according to the 60-day time point.

[0019] Further, the compressive modulus of the defective solidified particles is determined, including;

[0020] Particles that cannot maintain their original shape after being soaked in water are considered defective solidified particles.

[0021] The compressive modulus of poorly solidified particles was determined by indoor compression consolidation test.

[0022] Furthermore, using a second sample, the maximum and minimum porosity of the solidified particles were determined, including:

[0023] Pour a portion of the second sample into a graduated cylinder, smooth the surface, and measure the volume V2.

[0024] Pour in water and make the water surface level with the surface of the solidified particles to obtain the volume V of water added. w1 The maximum porosity n was calculated. max =V w1 / V2;

[0025] Pour another portion of the second sample into a graduated cylinder, shake the cylinder up and down to compact the solidified particles as much as possible, and measure the volume V3. Pour in water and make the water surface level with the surface of the solidified particles to obtain the volume V of water added. w2 Calculate the minimum porosity n min =V w2 / V3.

[0026] Furthermore, combining the design load and design thickness of the filling project, the total settlement is calculated, including:

[0027] Determine the design load p0 and design thickness H0 of the filling project;

[0028] Calculate the compression amount S1 of well-cured particles:

[0029]

[0030] in:

[0031] γ0 is the density of the solidified particles;

[0032] E st For good compressive modulus of solidified particles;

[0033] Calculate the compression amount S2 of the poorly cured particles:

[0034]

[0035] in:

[0036] E s The compressive modulus of poorly cured particles;

[0037] Calculate the compression S3 caused by the change in porosity:

[0038] S3=H0(n max -n min )

[0039] Calculate the total settlement S:

[0040] S = S1 + S2 + S3.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] This method comprehensively considers the superstructure load and the weight of the solidified particles when predicting the settlement of silt solidification particles in engineering backfill. It also takes into account the compression settlement caused by well-solidified and poorly solidified particles. In addition, the volume reduction and internal compression caused by the reduction of particle pores are also used in the prediction calculation to obtain a more realistic and reliable total settlement prediction value. It can provide objective and reliable parameter design guidance for actual engineering projects and fill the gap in the settlement prediction method for this type of backfill material. Attached Figure Description

[0043] 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 only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0045] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0046] In the description of this patent, it should be understood that all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which this patent pertains. In case of any contradiction, the definitions in this specification shall prevail. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art, and the devices used in the embodiments are existing devices. The limitation of the means or devices shall not be construed as a limitation of this patent, and means or devices of the same type that solve the same technical problem are all within the protection scope of this patent.

[0047] In the description of this patent, it should be understood that the method involves multiple steps, which should not be interpreted as a limitation on the order of the steps. Technical solutions obtained by changing the order of steps when solving the same technical problem are also within the scope of protection of this patent.

[0048] Granulation of engineering sludge using a granulator can significantly reduce its moisture content, resulting in solidified sludge granules for engineering fill. These granules possess certain mechanical strength and stability and can be used as filling materials. When these solidified sludge granules are used in filling projects, both well-solidified and poorly solidified particles undergo compression and settling under the combined load of the superstructure and the particle's own weight. Additionally, the reduced pore size within the particles causes internal compression. Therefore, the total settlement is caused by these three compression components.

[0049] like Figure 1 This invention provides a method for predicting the settlement of solidified sludge particles used in engineering backfilling. When these solidified sludge particles are used in backfilling construction, they can be used as a method for predicting their performance. The method includes:

[0050] S1: Prepare two samples of the solidified particles, namely the first sample and the second sample. The two samples should be as similar as possible in terms of weight, volume, and particle number, for the purpose of testing different parameters.

[0051] S2: Calculate the density of the solidified particles using the first sample.

[0052] The first sample is poured into a graduated cylinder, and its volume and mass are measured. The mass is divided by the volume to obtain its density, and then multiplied by the gravitational acceleration to obtain its specific weight γ0.

[0053] S3: Immerse the first sample in water to obtain the volume ratio of good and bad cured particles, including:

[0054] S301: The first sample is a cured particle with a curing age of 3 days. The volume V0 of the first sample is measured.

[0055] S302: Immerse the first sample completely in water for 24 hours.

[0056] After removal, particles that can maintain their original shape are considered well-cured particles, and their volume V1 is measured. The volume ratio of well-cured particles is R1 = V1 / V0. The remaining particles that cannot maintain their original shape are considered poorly cured particles, and the volume ratio of poorly cured particles is R2 = 1 - R1.

[0057] S4: Determine the compressive modulus of well-cured particles and the compressive modulus of poorly cured particles.

[0058] S401: Determine the compressibility modulus of a good sample, including:

[0059] The well-cured particles from the first sample were subjected to indoor compression consolidation tests at 3, 7, 14, 28, and 60 days of curing, and the compression modulus at each time point was measured as basic data for reference.

[0060] For the compressive modulus at 3 days, 7 days, 14 days, 28 days, and 60 days, the value is taken directly; for the compressive modulus at other time points, the value is determined by the linear interpolation method; when it is greater than 60 days, the value is taken according to the 60-day time point.

[0061] S402: Determine the compression modulus of defective cured particles, including;

[0062] Particles that cannot maintain their original shape after soaking in water are considered defective solidified particles. The top water can be poured off, and the good solidified particles can be removed. The remaining defective solidified particles can then be gently blotted with filter paper to remove the surface moisture, thus obtaining pure defective solidified particles. The compression modulus of the defective solidified particles can be tested through an indoor compression consolidation test.

[0063] Defective solidified granules can also be re-prepared. According to the design requirements, when the content of the curing agent is lower than a certain critical value, it is called the critical content. Using a granulator and in combination with the formulation scheme, solidified granules with a content lower than the critical content can be prepared, which are then called defective solidified granules.

[0064] S5: Determine the maximum and minimum porosity of the solidified particles using the second sample.

[0065] S501: Pour a portion of the second sample into a graduated cylinder, smooth the surface, and measure the volume V2;

[0066] S502: Pour in water and make the water surface flush with the surface of the solidified particles to obtain the volume V of water added. w1 The maximum porosity n was calculated. max =V w1 / V2;

[0067] S503: Pour another portion of the second sample into a graduated cylinder, shake the cylinder up and down to compact the solidified particles as much as possible, and measure the volume V3. Pour in water and make the water surface level with the surface of the solidified particles to obtain the volume V of water added. w2 Calculate the minimum porosity n min =V w2 / V3.

[0068] S6: Calculate the total settlement by combining the design load and design thickness of the filling project.

[0069] S601: Determine the design load p0 and design thickness H0 of the filling project;

[0070] S602: Calculate the compression amount of well-cured particles. S1:

[0071]

[0072] in:

[0073] γ0 is the density of the solidified particles;

[0074] E st For good compressive modulus of solidified particles;

[0075] S603: Calculate the compression amount of poorly cured particles. S2:

[0076]

[0077] in:

[0078] E s The compressive modulus of poorly cured particles;

[0079] S604: Calculate the compression caused by porosity changes. S3:

[0080] S3=H0(nmax -n min )

[0081] S605: Calculate the total settlement S:

[0082] S = S1 + S2 + S3.

[0083] Example:

[0084] Taking the solidified silt from a river in southeastern coastal my country as an example for road foundation filling, the method of this invention is used to predict the settlement of the solidified particles in the filling.

[0085] A certain amount of solidified granules was taken and poured into a graduated cylinder. Its volume and mass were measured. The mass was divided by the volume to obtain its density, which was then multiplied by the gravitational acceleration to obtain the specific gravity γ0 of the solidified granules, which was 18.4 kN / m³. 3 .

[0086] Take a certain number of cured granules, and when the curing age reaches 3 days, measure its volume V0 as 520ml using a measuring cup. Immerse it completely in water and soak for 24 hours. Take out the granules that can maintain their original shape and measure their volume V1 as 478ml. Then the volume ratio R1 of good cured granules is 0.919, and the volume ratio R2 of poor cured granules is 0.081.

[0087] Well-cured granules were subjected to indoor compression consolidation tests at 3, 7, 14, 28 and 60 days of curing, and their compression modulus was measured. The results are shown in Table 1.

[0088] Table 1. Compression modulus of well-cured particles at several curing times.

[0089] Time / day 3 7 14 28 60 Compression modulus / MPa 7.24 10.51 12.77 13.90 14.02

[0090] The defective cured particles were removed, and their compressive modulus E was determined using an indoor compression test. s It is 1.28 MPa.

[0091] Take a certain amount of solidified granules and gently drop them into a graduated cylinder using the sand rain method. Smooth the surface and measure its volume V2, which is 860.0 ml. Pour in an appropriate amount of tap water until the water surface is level with the surface of the solidified granules, and measure the volume V of the added tap water. w1 The volume is 132.2 ml. The maximum porosity n is calculated. max The volume is 0.15. Similarly, pour the solidified granules into a graduated cylinder, shake the cylinder up and down to make the solidified granules as compact as possible, and measure its volume V3 as 654.4 ml. Pour in an appropriate amount of tap water so that the water surface is level with the surface of the solidified granules, and measure the volume V of the added tap water. w2 The volume is 77.8 ml. The minimum porosity n is calculated.min It is 0.12.

[0092] Based on the engineering design scheme, the engineering load p0 on the solidified granules is determined to be 76.6 kPa. The thickness H0 of the solidified granules is also determined to be 2.81 m. Due to the tight schedule, the engineering load is applied 3 days after the solidified granules have cured. According to Table 1, the compression modulus E of well-cured granules is obtained. st The pressure was 7.24 MPa. Further, the compression S1 of well-cured particles was determined to be 36.5 mm. The compression S2 of poorly cured particles was determined to be 18.2 mm. The compression S3 caused by porosity changes was determined to be 84.3 mm. Finally, the total settlement S after filling with cured particles was determined to be 139 mm.

[0093] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A method for predicting the settlement amount of a granular material formed by filling with sludge, the method comprising: preparing two samples of the granular material; calculating the specific gravity of the granular material using the first sample; immersing the first sample in water to obtain the volume proportions of good and poor granular material, and determining the compression modulus of the good and poor granular material; determining the maximum and minimum porosities of the granular material using the second sample; and calculating the total settlement amount based on the design load and thickness of the filling project, including: determining the design load p0 and thickness H0 of the filling project; calculating the compression amount S1 of the good granular material: S1 = p0 * H0 * R1 / γ0, wherein: γ0 is the specific gravity of the granular material; and R1 is the volume proportion of the good granular material; calculating the compression amount S2 of the poor granular material: S2 = p0 * H0 * R2 / γ0, wherein: R2 is the volume proportion of the poor granular material; calculating the compression amount S3 caused by changes in porosity: S3 = p0 * H0 * (1 - R1 - R2) / γ0; and calculating the total settlement amount S: S = S1 + S2 + S3.

2. The method of claim 1, wherein: obtaining the volume proportions of good and poor granular material by immersing the first sample in water includes: measuring the volume V0 of the first sample, which has a curing age of 3 days; immersing the first sample completely in water for 24 hours; and measuring the volume V1 of the granular material that maintains its original shape after being removed from the water, wherein the volume proportion of good granular material is R1 = V1 / V0, and the volume proportion of poor granular material is R2 = 1 - R1.

3. The method of claim 2, wherein: determining the compression modulus of the good sample includes: performing indoor compression consolidation tests on the good granular material in the first sample at curing ages of 3 days, 7 days, 14 days, 28 days, and 60 days to obtain the compression modulus at each time point; and directly taking the values of the compression modulus at the time points of 3 days, 7 days, 14 days, 28 days, and 60 days, and using linear interpolation to determine the values of the compression modulus at other time points, with the value at 60 days being taken as the value at more than 60 days.

4. The method of claim 3, wherein: determining the compression modulus of the poor granular material includes: identifying the poor granular material as the granular material that does not maintain its original shape after being immersed in water; and testing the compression modulus of the poor granular material using an indoor compression consolidation test.

5. The method of claim 4, wherein: determining the maximum and minimum porosities of the granular material using the second sample includes: pouring a portion of the second sample into a graduated cylinder, smoothing the surface, and measuring the volume V2. ​ ​ ​ ​ ​ ​ E st For good compression modulus of the cured particles; ​ ​ ​ E s Compression modulus of poorly cured particles; ​ ​ S3 = H0(n max - n min ) ​ n max For maximum porosity; n min For minimum porosity; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pouring water and bringing the water surface to the level of the surface of the solidified granules, obtaining the volume V of water added w1 , calculating the maximum porosity n max = V w1 / V2; Pour another portion of the second sample into a graduated cylinder, shake the graduated cylinder up and down to make the solidified particles as compact as possible, measure the volume V3, pour in water and make the water surface level with the solidified particle surface, obtain the volume V of water added w2 , calculate the minimum porosity n min = V w2 / V3.

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