Backfill composed of mixed industrial waste applied to low load level

Abstract

The invention relates to the field of construction materials, in particular to a backfill material composed of mixed industrial waste applied to a low load level, the backfill material composed of the mixed industrial waste applied to the low load level comprises broken tempered glass, old plastic and waste tire rubber particles according to the volume ratio of 6: (1-1.5): (2.5-3), the water content of the backfill material is 0.7-1.2%, and the water content of the backfill material is 0.5-1.5%. And when the backfill material is dumped to the backfill area, the ground clearance of the backfill material is 1.5-2m. The backfill material composed of the mixed industrial waste materials applied to the low load level is composed of pure waste materials, the waste materials meet environmental safety, the backfill material only needs to be directly poured into a backfill area at a certain height during use, the compaction degree can be larger than 90% without being compacted, the vertical strain of a formed backfill body under the load of 6 kPa is smaller than 0.42%, and the vertical strain of the backfill body under the load of 6 kPa is smaller than 0.42%. And the method can be applied to low-load-level engineering parts such as municipal pipe gallery backfilling and park greenway lower cushion layers.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of construction materials, in particular to a backfill material composed of mixed industrial waste applied to low load levels. BACKGROUND

[0002] During construction, when facing the need for underground structure construction, underground pipeline laying, removal of poor soil, overall site leveling and other construction requirements, it usually involves soil excavation and backfilling operations.

[0003] When backfilling soil, for cost considerations, previously excavated soil or soil around the construction site is usually selected for backfilling, and for the purpose of ensuring construction quality and responding to environmental restrictions on the construction site, special backfilling materials are also selected for backfilling.

[0004] The inventor has found through extensive practice that when backfilling with backfilling soil, it is generally necessary to use large compaction equipment to compact the backfilling soil in layers to reduce the settlement that may occur after backfilling is completed; if a relatively more expensive backfilling material is used for backfilling, although the requirements for compaction equipment are reduced, a certain quality of compaction work on the backfilling material is still required; for some construction sites with restrictions, such as municipal pipe gallery foundation trench construction and park greenway foundation trench construction, which are generally less than 2m in width, large mechanical compaction equipment cannot enter the site, and only small compaction equipment and manual compaction can be used, making it difficult to meet the quality standards for compaction work, and often resulting in large settlements under pedestrian loads or even under self-weight after the project is completed, affecting normal road traffic. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a backfilling material composed of mixed industrial waste applied to low load levels, which is composed of pure waste material, meets environmental safety, and only needs to be poured directly into the backfilling area at a certain height without the need for compaction to achieve a compaction degree > 90%, and the vertical strain of the backfilling body formed under a load of 6kPa is < 0.42%, which can be applied to municipal pipe gallery backfilling, park greenway underpad and other low load level engineering sites.

[0006] The technical solution of the present application is achieved by the following way: A backfilling material composed of mixed industrial waste applied to low load levels, comprising broken tempered glass, old plastic and waste tire rubber particles, the volume ratio of the broken tempered glass, the old plastic and the waste tire rubber particles being 6: (1-1.5): (2.5-3), the water content of the backfilling material being 0.7-1.2%, and the ground clearance of the backfilling material when poured into the backfilling area being 1.5-2m.

[0007] The backfill material applied to the mixed industrial waste composition under low load level is composed of pure waste, the waste meets environmental safety, and only needs to be directly poured into the backfill area at a certain height during use, without compaction, so as to achieve a compaction degree > 90%, and the formed backfill body has a vertical strain < 0.42% under a load of 6kPa, and can be applied to municipal pipe gallery backfill, park greenway underlayer and other low load level engineering parts.

[0008] Further, the height of the backfill material from the ground when the backfill material is poured into the backfill area is 1.5m.

[0009] Further, the water content of the backfill material is 1%.

[0010] Further, the volume ratio of the broken tempered glass, the old plastic and the waste tire rubber particles is 6:1:3.

[0011] Further, the volume ratio of the broken tempered glass, the old plastic and the waste tire rubber particles is 6:1.5:2.5.

[0012] Further, the average particle specific gravity of the broken tempered glass is 2.45~2.55, the non-uniformity coefficient is 2.14~2.22, and the curvature coefficient is 1.18~1.26.

[0013] Further, the average particle specific gravity of the old plastic is 0.9~0.98, the non-uniformity coefficient is 2.01~2.09, and the curvature coefficient is 0.84~0.92.

[0014] Further, the average particle specific gravity of the waste tire rubber particles is 1.08~1.16, the non-uniformity coefficient is 3.88~3.96, and the curvature coefficient is 1.31~1.39.

[0015] Further, the average particle specific gravity of the backfill material is 1.93, the non-uniformity coefficient is 4.54, and the curvature coefficient is 1.54.

[0016] Further, the average particle specific gravity of the backfill material is 1.92, the non-uniformity coefficient is 4.1, and the curvature coefficient is 1.33.

[0017] In order to better understand and implement, the present application is described in detail below in combination with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a schematic diagram of the test device for sand rain test; Figure 2 It is a schematic diagram of the test device for consolidation test; Figure 3A schematic diagram of the particle size distribution curve of the broken tempered glass, old plastic, and waste tire rubber particles; Figure 4 A schematic diagram of the particle size distribution curve of the backfill material of Examples 1-2 and Comparative Examples 1-2; Figure 5 A schematic diagram of the standard compaction test results; Figure 6 A schematic diagram of the sand column test results of the backfill material having the composition and ratio of Example 1; Figure 7 A schematic diagram of the sand column test results of the backfill material having the composition and ratio of Example 2; Figure 8 A schematic diagram of the sand column test results of the backfill material having the composition and ratio of Comparative Example 1; Figure 9 A schematic diagram of the sand column test results of the backfill material having the composition and ratio of Comparative Example 2; Figure 10 A schematic diagram of the one-dimensional consolidation test results of the backfill material of Examples 1-2 and Comparative Examples 1-2; Figure 11 A schematic diagram of the one-dimensional consolidation test results of the backfill material of Examples 1-2 and Comparative Example 3; Figure 12 A schematic diagram of the collapsibility test results of the backfill material of Example 2. DETAILED DESCRIPTION

[0019] It should be clear that the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0020] The terms used in the present application are merely for the purpose of describing particular embodiments, and are not intended to limit the present application. The singular forms "a," "an," and "the" used in the present application and the appended claims are intended to include plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0021] The following description refers to the accompanying drawings. Unless otherwise noted, like elements in different drawings have the same or similar reference numerals. The following description of illustrative embodiments is not meant to limit or restrict the scope of the application, but is to enable any person skilled in the art to make or use the application. Numerous specific details are described to provide a thorough understanding of the present application. However, in the interest of not obscuring the application, the principles and aspects of the application can be practiced with not all specific details described. Conjunctions, when used, are to be understood to cover the intended correlative meaning of "one", "or" and "another".

[0022] In addition, in the description of the present application, "a plurality of" means two or more, unless otherwise specified. "And / or", describes the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean: A exists alone, A and B exist together, and B exists alone. The character " / " generally represents that the associated objects before and after are in an "or" relationship.

[0023] It should be understood that the embodiments of the present application are not limited to the precise structures described and shown in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the embodiments of the present application is only limited by the appended claims.

[0024] Please refer to Figure 1 As an embodiment of the present application, the present embodiment provides a backfill material composed of mixed industrial waste applied to a low load level, comprising broken tempered glass, old plastic, and waste tire rubber particles. The volume ratio of the broken tempered glass, the old plastic, and the waste tire rubber particles is 6: (1-1.5): (2.5-3). The water content of the backfill material is 0.7-1.2%. When the backfill material is poured into a backfill area, the ground clearance of the backfill material is 1.5-2 m.

[0025] Further, when the backfill material is poured into a backfill area, the ground clearance of the backfill material is 1.5 m.

[0026] Further, the water content of the backfill material is 1%.

[0027] Further, the volume ratio of the broken tempered glass, the old plastic, and the waste tire rubber particles is 6:1:3.

[0028] Further, the volume ratio of the broken tempered glass, the old plastic, and the waste tire rubber particles is 6:1.5:2.5.

[0029] Further, the broken tempered glass has an average particle specific gravity of 2.45-2.55, a non-uniformity coefficient of 2.14-2.22, and a curvature coefficient of 1.18-1.26.

[0030] Further, the old plastic has an average particle specific gravity of 0.9-0.98, a non-uniformity coefficient of 2.01-2.09, and a curvature coefficient of 0.84-0.92.

[0031] Further, the waste tire rubber particle has an average particle specific gravity of 1.08-1.16, a non-uniformity coefficient of 3.88-3.96, and a curvature coefficient of 1.31-1.39.

[0032] Further, the backfill material has an average particle specific gravity of 1.93, a non-uniformity coefficient of 4.54, and a curvature coefficient of 1.54.

[0033] Further, the backfill material has an average particle specific gravity of 1.92, a non-uniformity coefficient of 4.1, and a curvature coefficient of 1.33.

[0034] The physical property indexes of the embodiments or the comparative examples of the present application and the test methods thereof are as follows: The particle specific gravity Gs, the non-uniformity coefficient Cu and the curvature coefficient Cc are obtained by testing according to GB / T 50145-2007 "Engineering Classification Standard for Soil".

[0035] The pollutant leaching test is performed according to HJ 557-2010 "Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillation Method". The specification limit is determined according to GB 5085.3-2007 "Hazardous Waste Identification Standard Leaching Toxicity Identification".

[0036] The standard compaction test is performed according to GB / T 50123-2019 "Soil Test Method Standard".

[0037] From a certain height, the granular material is accumulated in the form of free fall, which is a common sample preparation method and is called "sand-rain technique". In indoor tests, this sand-rain test is often used to simulate the process of backfilling soil in a field trench or pipe gallery. In the embodiments of the present application, the mixed waste with different proportions, different water contents and different drop distances is subjected to sand-rain test to study and analyze the influence on the accumulation characteristics. The test device is shown in Figure 1 Before the sand-rain test, the required water amount is calculated according to the predetermined water content, and then the mixed waste is added and stirred uniformly in the customized funnel at the top of the support frame; then the mixed waste is allowed to fall freely by opening the bottom pin of the funnel and pouring into the organic glass container below; finally, the weight of the waste in the metal barrel and the water content thereof are measured, and the dry density of the mixed waste accumulation body is calculated. The drop distance is the distance from the lowermost part of the funnel to the middle height of the metal cylinder.

[0038] The consolidation test includes the following steps: placing the broken tempered glass, old plastic, and waste tire rubber particles in an oven at 60°C for 6 hours to dry, drying the moisture, then mixing the broken tempered glass, old plastic, and waste tire rubber particles in a proportion, pouring them into the cutting ring of the test equipment, and hitting the side with a rubber hammer during the process to make the sample surface flush with the surface of the cutting ring and reach the required dry density, complete the sample preparation, then install the cutting ring sample on the consolidation instrument, and then perform the staged loading to test the vertical strain under different loads. The consolidation test equipment is shown in Figure 2 .

[0039] The wetting test includes the following steps: mixing the broken tempered glass, old plastic, and waste tire rubber particles in a proportion, pouring them into the cutting ring, and preparing a sample with a diameter of 100mm*height of 128mm, the initial moisture content of the sample is 1%, a vertical load of 6kPa is applied to the sample, after the deformation is stable, the vertical load of 6kPa is maintained on the sample, water is sprayed on the surface of the sample until the sample is completely saturated, and the vertical displacement (i.e. settlement) of the sample during the water spraying process is measured.

[0040] The broken tempered glass of the embodiment is obtained by crushing the tempered glass (physical tempered glass) of the building curtain wall, the old plastic of the embodiment is obtained by crushing the waste plastic boxes of the market, and is specifically composed of high-density polyethylene (HDPE), the natural rubber in the main layer of the tire tread is used as the waste tire rubber particles, the particle size curve of the broken tempered glass, old plastic, and waste tire rubber particles is shown in Figure 3 , and the pollutant leaching test results of the three materials are shown in Table 1, the heavy metal content in the leaching liquid of the three materials does not exceed the standard, and meets the environmental requirements.

[0041] Table 1

[0042] Example 1 The embodiment provides a backfill material composed of mixed industrial waste applied to a low load level, which includes 60wt% broken tempered glass, 10wt% old plastic, and 30wt% waste tire rubber particles, and the moisture content of the backfill material is 1%.

[0043] Example 2 The embodiment provides a backfill material composed of mixed industrial waste applied to a low load level, which includes 60wt% broken tempered glass, 15wt% old plastic, and 25wt% waste tire rubber particles, and the moisture content of the backfill material is 1%.

[0044] Comparative Example 1 This comparative example provides a backfill material composed of mixed industrial waste for use under low load levels, comprising 50 wt% broken tempered glass, 20 wt% old plastics and 30 wt% waste tire rubber granules, with a moisture content of 1%.

[0045] Comparative Example 2 This comparative example provides a backfill material composed of mixed industrial waste for use under low load levels, comprising 50 wt% broken tempered glass, 10 wt% old plastics and 40 wt% waste tire rubber granules, with a moisture content of 1%.

[0046] Comparative Example 3 This comparative example provides a backfill material composed of mixed industrial waste for use under low load levels, comprising 70 wt% broken tempered glass, 10 wt% old plastics and 20 wt% waste tire rubber granules, with a moisture content of 1%.

[0047] The particle specific gravity Gs, uniformity coefficient Cu, and curvature coefficient Cc of the backfill material in Examples 1-2 and Comparative Examples 1-2 are shown in Table 2 below. For particle size distribution curves, please refer to [reference needed]. Figure 4 .

[0048] Table 2

[0049] Based on the composition and proportion of the backfill material in Examples 1-2 and Comparative Examples 1-2, samples with moisture contents of 0%, 1%, 3%, 5%, 7%, and 9% were prepared and subjected to standard compaction tests. Please refer to the test results for details. Figure 5 .

[0050] Based on the backfill composition and proportions of Examples 1-2 and Comparative Examples 1-2, samples with moisture contents of 0%, 1%, 3%, 5%, 7%, and 9% were prepared. Sandfall tests were conducted at four drop heights of 0.5m, 1m, 1.5m, and 2m. The test results are available in the [reference needed]. Figures 6 to 9 , Figures 5 to 8 The test results of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 are presented in sequence. Some experimental results of the standard compaction test and the sand rain test are shown in Table 3 below, where the compaction degree is the ratio of the maximum dry density measured by the sand rain test to the maximum dry density measured by the standard compaction test.

[0051] Table 3

[0052] Therefore, it can be seen that the bulk density of the mixed waste increases with the increase of the drop height at a certain moisture content, but the increase in bulk density is not significant when the drop height increases from 1.5 m to 2 m. Furthermore, for the packing curve at a certain drop height, it can be seen that the bulk density of the mixed waste is the highest at a moisture content of 1%, and an increase or decrease in moisture content will lead to a decrease in its bulk density. The proportions of this invention can meet the compaction requirements of some non-stressed or low-load-bearing areas, such as: compaction degree ≥85%~90% below the subbase of greenways and ground surfaces; compaction degree ≥85% for backfilling pipe trenches (within 500 mm of the pipe top).

[0053] Uniaxial consolidation tests were conducted on the backfill materials of Examples 1-2 and Comparative Examples 1-3. The maximum dry density of the accumulated material formed by a 1.5m drop height during sand rain testing was used as the sample density. The sample density of Comparative Example 3 was the same as that of Example 2. The sample size was 100 mm in diameter and 128 mm in height. The load was applied in stages: 6 kPa, 12.5 kPa, 25 kPa, 50 kPa, 100 kPa, and 200 kPa. The next load level was applied when the deformation was less than 0.01 mm per hour. Three parallel tests were conducted for each mix design, and the average value was used to output the vertical strain percentage. For the test results of Examples 1-2 and Comparative Examples 1-2, please refer to [link to relevant documentation]. Figure 10 Please refer to the test results of Comparative Example 3. Figure 11 .

[0054] Based on the results of the uniaxial consolidation test, it can be seen that under the same vertical stress, the vertical strain of Examples 1-2 is significantly smaller than that of Comparative Examples 1-2, and the vertical strain of Examples 1-2 is also smaller than that of Comparative Example 3. This indicates that the strain of mixed waste with a larger glass content is not necessarily smaller, but rather there is an optimal ratio. The backfill material in Examples 1 and 2, when subjected to a vertical stress of 6 kPa (slightly higher than the 3.5 kPa of the crowd load), exhibited vertical strains of 0.42% and 0.30%, respectively. This means that if a 1 m thick layer of mixed waste is piled on-site, the settlement under the crowd load would be less than 4.2 mm and 3.0 mm, respectively, which meets the requirements for backfill materials in low-load scenarios such as pedestrian greenway cushion layers. This is less than the vertical strain of 0.6% corresponding to the settlement of 30 mm of backfill soil overlying the EA1 integrated utility tunnel structure in the Xiong'an New Area Start-up Zone EA1 Integrated Utility Tunnel Project under its own weight. (Li Fengting, Luo Tao, Sun Zhanyong, et al. Study on settlement characteristics of backfill soil layer in deep foundation pit of underground utility tunnel [J]. Transportation Science and Engineering, 2024, 40(3): 82-90).

[0055] A wet collapse test was conducted on the backfill material of Example 2, and the dry density of the sample was 1.2 g*cm³. -3 Please refer to the test results. Figure 12As can be seen, after the vertical load of the backfill material in Example 2 increased from 0 kPa to 6 kPa, the sample produced a vertical displacement of 0.385 mm, with a corresponding vertical strain of 0.301%. Keeping the vertical stress constant at 6 kPa, after the sample was fully saturated with water, the vertical displacement increased to 0.391 mm, with a corresponding vertical strain of 0.305%. This indicates that after backfilling as required, within a 6 kPa load, subsequent changes in the moisture content of the backfill material have little impact on the vertical strain of the backfill material. Changes in moisture content caused by external factors such as heavy rain and water immersion will not significantly affect the bearing capacity of the completed backfill material.

[0056] Since the initial dry density of the backfill material in Example 2 is lower than that in Example 1 at a drop height of 1.5m, and the vertical strain is also lower than that in Example 1 under the same load, Example 2 is the preferred formulation.

[0057] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A backfill material composed of mixed industrial waste for use under low load levels, characterized in that, The backfill material includes broken tempered glass, old plastics, and waste tire rubber granules. The volume ratio of the broken tempered glass, the old plastics, and the waste tire rubber granules is 6:(1~1.5):(2.5~3). The moisture content of the backfill material is 0.7~1.2%. When the backfill material is dumped into the backfill area, the height of the backfill material above the ground is 1.5m~2m.

2. The backfill material composed of mixed industrial waste under low load levels according to claim 1, characterized in that, When the backfill material is dumped into the backfill area, the height of the backfill material above the ground is 1.5m.

3. The backfill material composed of mixed industrial waste under low load levels according to claim 1, characterized in that, The moisture content of the backfill material is 1%.

4. The backfill material composed of mixed industrial waste under low load levels according to claim 1, characterized in that, The volume ratio of the broken tempered glass, the old plastic, and the waste tire rubber particles is 6:1:

3.

5. The backfill material composed of mixed industrial waste under low load levels according to claim 1, characterized in that, The volume ratio of the broken tempered glass, the old plastic, and the waste tire rubber particles is 6:1.5:2.

5.

6. The backfill material composed of mixed industrial waste under low load levels according to claim 1, characterized in that, The average particle specific gravity of the broken tempered glass is 2.45~2.55, the non-uniformity coefficient is 2.14~2.22, and the curvature coefficient is 1.18~1.

26.

7. The backfill material composed of mixed industrial waste under low load levels according to claim 1, characterized in that, The average particle weight of the old plastic is 0.9~0.98, the non-uniformity coefficient is 2.01~2.09, and the curvature coefficient is 0.84~0.

92.

8. The backfill material composed of mixed industrial waste under low load levels according to claim 1, characterized in that, The waste tire rubber granules have an average particle weight of 1.08~1.16, a non-uniformity coefficient of 3.88~3.96, and a curvature coefficient of 1.31~1.

39.

9. The backfill material composed of mixed industrial waste under low load levels according to claim 4, characterized in that, The backfill material has an average particle density of 1.93, a non-uniformity coefficient of 4.54, and a curvature coefficient of 1.

54.

10. The backfill material composed of mixed industrial waste under low load levels according to claim 5, characterized in that, The backfill material has an average particle density of 1.92, a non-uniformity coefficient of 4.1, and a curvature coefficient of 1.33.

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