Flow-state backfill material based on high-stone-content earthwork crushed material and preparation method thereof

Abstract

The invention provides a flow-state backfill material based on a high-stone-content earthwork crushed material and a preparation method of the flow-state backfill material. The flow-state backfill material based on the high-stone-content earth-rock crushed material is prepared from the following components in parts by weight: 60-85 parts of an earth-rock mixture; 5-15 parts of a cementing material; 10 to 20 parts of water; the addition amount of the additive is 0.1-1% of the weight of the cementing material; the invention discloses a preparation method of a flow-state backfill material based on a high-stone-content earthwork crushed material. The preparation method comprises the following steps: S1, screening and crushing earthwork excavated on site; s2, weighing the soil-rock mixture, the cementing material, the water and the additive in parts by weight; s3, adding the soil-rock mixture, the cementing material, the water and the additive into stirring equipment, and stirring to form slurry; s4, the slurry is poured into the backfill area in a pumping or self-flowing mode; s5, curing and forming; according to the invention, resource utilization of earthwork is realized, outward transportation and disposal cost is reduced, and meanwhile, dual requirements of underground engineering on material fluidity and strength are met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of civil engineering, and particularly relates to a flowable backfill material based on high-stone-content earthwork broken materials and a preparation method thereof. BACKGROUND

[0002] In the process of urban construction, a large amount of earthwork (especially the mixture with high stone content) generated by site excavation is difficult to be resourceized on site, and often needs to be transported and disposed, resulting in high transportation cost, great difficulty in piling up and heavy environmental burden.

[0003] The commonly used flowable solidified soil is a backfill material that can be pumped and has self-compacting property, and is usually prepared by using construction waste soil, fly ash, sand, cementing material and water. The main advantages of the material are convenient construction, good flowability and dense filling. However, the material is not suitable for the mixture with large particle size and high stone content, and does not have the ability to treat earthwork. Therefore, how to use the earthwork with high stone content to prepare a backfill material that is flowable, pumpable and has structural strength is a big problem in current engineering technology.

[0004] In the prior art, the Chinese practical new type patent document with the authorization announcement number CN111268930B discloses a method for industrialized recycling of construction waste soil with high sand and stone content. The mud and stones in the construction waste soil are separated, and the mud is utilized after being sintered into building bricks. The separation and sintering processes consume a lot of energy and have poor environmental protection. SUMMARY

[0005] In view of the deficiencies in the prior art, the application provides a flowable backfill material based on high-stone-content earthwork broken materials and a preparation method thereof, which realizes the resourceization of earthwork, reduces the transportation and disposal cost, and meets the dual requirements of material flowability and strength for underground engineering.

[0006] The technical scheme of the application is as follows: the flowable backfill material based on high-stone-content earthwork broken materials is composed of the following components by weight:

[0007] 60-85 parts of earth-stone mixture;

[0008] 5-15 parts of cementing material;

[0009] 10-20 parts of water;

[0010] An additive, and the additive is added in an amount of 0.1-1% of the weight of the cementing material.

[0011] Further, the earth-stone mixture is prepared by crushing earthwork, and the earth-stone ratio of the earth-stone mixture is 1:4 to 2:3.

[0012] Further, the cementitious material comprises one or more combinations of cement, fly ash, and slag.

[0013] Further, the admixture comprises one or more combinations of water-reducing agent, retarder, and rheology control agent.

[0014] Further, the particle size of the stone in the soil-stone mixture is ≤ 40 mm.

[0015] Further, the initial slump of the fluid backfill material is 180-230 mm, and the 28-day compressive strength is 3-5 MPa.

[0016] The preparation method of the fluid backfill material based on high-stone-content soil-stone material, comprising the following steps:

[0017] S1, screening and crushing the soil-stone material excavated on site;

[0018] S2, weighing the soil-stone mixture, cementitious material, water, and admixture by weight fraction;

[0019] S3, adding the soil-stone mixture, cementitious material, water, and admixture to the mixing equipment for mixing to form a uniform flowable slurry;

[0020] S4, pumping or self-flowing the slurry into the backfill area;

[0021] S5, curing and forming.

[0022] Further, in S1, the particle size of the stone is controlled to be not greater than 40 mm.

[0023] The beneficial effects of the present application are:

[0024] (1) Cost savings, which can reduce or eliminate the transportation and disposal of soil, reduce transportation and disposal costs;

[0025] (2) Green and environmentally friendly, breaking through the limitations of traditional fluid solidified soil that cannot handle high-stone-content materials, realizing the resource utilization of soil-stone material with a stone content of up to 80%, and reducing the land occupation and environmental disturbance of discarded materials;

[0026] (3) Improved construction efficiency, even with a higher proportion of stone, it still has good fluidity and pumpability, meets the backfill construction of complex configurations of underground space, and saves labor and machinery costs;

[0027] (4) Excellent engineering performance, establishing the relationship between soil-stone ratio, slump, and strength, and developing standardized blending and proportioning methods, so that the material performance is highly controllable, and the stabilized structure has a strength of 3-5 MPa, meeting the backfill requirements of most underground projects. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The method flow chart of the preparation method of the flowable backfill material based on high-stone-content earthwork broken materials in the present application. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely meant to be illustrative in nature and is not meant to be limiting in any way on the present application and its uses or applications. The present application can be implemented in numerous ways, including, but not limited to, the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. It should be noted that the relative arrangement of components and steps, the numerical expressions, and the numerical values set forth in these embodiments are to be interpreted as merely exemplary and not as a limitation unless otherwise specifically stated.

[0030] The terms "first", "second", and similar terms in the present application do not denote any order, quantity, or importance, but are merely used to distinguish different parts. The terms "comprise", "comprising", and similar terms mean that the elements before the term encompass the elements listed after the term, and do not exclude the possibility of also encompassing other elements. The terms "upper", "lower", "left", "right", and the like are merely used to indicate relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships can also change accordingly.

[0031] The flowable backfill material based on high-stone-content earthwork broken materials consists of the following components by weight parts:

[0032] 60-85 parts of earth-rock mixture;

[0033] 5-15 parts of cementitious material;

[0034] 10-20 parts of water;

[0035] Admixtures, the amount of admixtures added is 0.1-1% of the weight of the cementitious material.

[0036] As an optional embodiment of the flowable backfill material based on high-stone-content earthwork broken materials, the flowable backfill material based on high-stone-content earthwork broken materials consists of the following components by weight parts:

[0037] 60 parts of earth-rock mixture;

[0038] 5 parts of cementitious material;

[0039] 10 parts of water;

[0040] Admixtures, the amount of admixtures added is 0.1% of the weight of the cementitious material.

[0041] As an optional embodiment of the flowable backfill material based on high-stone-content earthwork broken materials, the flowable backfill material based on high-stone-content earthwork broken materials is composed of the following components by weight parts:

[0042] earth-rock mixture 85 parts;

[0043] cementitious material 15 parts;

[0044] water 20 parts;

[0045] additive, the additive is added in an amount of 1% of the weight of the cementitious material.

[0046] As an optional embodiment of the flowable backfill material based on high-stone-content earthwork broken materials, the flowable backfill material based on high-stone-content earthwork broken materials is composed of the following components by weight parts:

[0047] earth-rock mixture 72.5 parts;

[0048] cementitious material 10 parts;

[0049] water 15 parts;

[0050] additive, the additive is added in an amount of 0.55% of the weight of the cementitious material.

[0051] In some embodiments, the earth-rock mixture is prepared after the earthwork is broken, and the stone-earth ratio of the earth-rock mixture is 1:4 to 2:3; as some optional examples, the stone-earth ratio of the earth-rock mixture is 1:4, the stone-earth ratio of the earth-rock mixture is 3:7, or the stone-earth ratio of the earth-rock mixture is 2:3.

[0052] In some embodiments, as a specific embodiment of the cementitious material, the cementitious material includes one or a combination of cement, fly ash, and mineral powder; as some optional examples, the cementitious material is cement, the cementitious material is a combination of cement and fly ash, the cementitious material is a combination of cement and mineral powder, or the cementitious material is a combination of cement, fly ash, and mineral powder.

[0053] In some embodiments, as a specific embodiment of the additive, the additive includes one or a combination of water reducing agent, retarder, and rheological control agent; as some optional examples, the additive is water reducing agent, the additive is a combination of water reducing agent and retarder, the additive is a combination of water reducing agent and rheological control agent, or the additive is a combination of water reducing agent, retarder, and rheological control agent.

[0054] In some embodiments, the particle size of the stone in the earth-rock mixture is ≤40mm.

[0055] In some embodiments, the initial slump of the flowable backfill material is 180-230mm, and the 28-day compressive strength is 3MPa to 5MPa.

[0056] In some embodiments, as shown in Figure 1 A preparation method of a flowable backfill material based on high-stone-content earthwork broken material is disclosed, comprising the following steps:

[0057] S1, screening and crushing the on-site excavated earthwork, controlling the stone particle size to be no more than 40 mm. The broken earthwork has high stone content, and the stone inside has a certain gradation, and the strength is higher than that of the flowable solidified soil;

[0058] S2, measuring the earth-stone mixture, cementing material, water, and additive by weight;

[0059] S3, adding the earth-stone mixture, cementing material, water, and additive into a stirring device to stir and form a uniform flowable slurry;

[0060] S4, pumping or self-flowing the slurry into the backfill area;

[0061] S5, curing and forming.

[0062] As a more specific embodiment of the above-mentioned flowable backfill material based on high-stone-content earthwork broken material, the flowable backfill material based on high-stone-content earthwork broken material comprises: 1000 kg of broken earth-stone mixture, with a soil-stone ratio of 1:4; 100 kg of P.O42.5 cement; 160 kg of water; and 0.6 kg of polycarboxylate superplasticizer. After stirring the above-mentioned raw materials for 3 minutes, the slump is measured to be 210 mm; the 1d compressive strength is 1.2 MPa; the 28d compressive strength is 4.6 MPa; the material has no pipe blocking phenomenon within a pumping distance of 30 meters, and is dense after pouring.

[0063] As a more specific embodiment of the above-mentioned flowable backfill material based on high-stone-content earthwork broken material, the flowable backfill material based on high-stone-content earthwork broken material comprises: 1000 kg of broken earth-stone mixture, with a soil-stone ratio of 3:7; 120 kg of 42.5 cement; 30 kg of fly ash; 170 kg of water; and 0.8 kg of superplasticizer. After stirring the above-mentioned raw materials for 3 minutes, the slump is measured to be 190 mm; the 28d compressive strength is 3.9 MPa.

[0064] As a more specific embodiment of the above-mentioned flowable backfill material based on high-stone-content earthwork broken material, the flowable backfill material based on high-stone-content earthwork broken material comprises: 1000 kg of broken earth-stone mixture, with a soil-stone ratio of 2:3; 130 kg of cement; 180 kg of water; and 1.2 kg of additive combination, wherein the additive includes 0.8 kg of superplasticizer and 0.4 kg of retarder. After stirring the above-mentioned raw materials for 3 minutes, the slump is measured to be 185 mm; the 28d compressive strength is 3.4 MPa.

[0065] In the above embodiments, the flowable backfill material based on high-stone-content earthwork broken material and the preparation method thereof have the following characteristics:

[0066] Cost saving, which can reduce or eliminate the transportation and disposal of earthwork, reduce transportation and disposal costs;

[0067] Green and environmentally friendly, breaking the limitation of traditional flowable solidified soil that cannot handle high-stone-content materials, realizing the resource utilization of earthwork with a stone content as high as 80%, reducing the land occupation and environmental disturbance of abandoned earthwork;

[0068] Construction efficiency improvement, even at a higher stone ratio, it still has good fluidity and pumpability, meets the backfill construction of complex underground space configuration, saves manpower and mechanical cost;

[0069] Excellent engineering performance, the relationship between soil-stone ratio, slump, and strength is established, and standardized deployment ratio and method are developed, so that the material performance is highly controllable, and after solidification, a stable structure is formed, with a strength of 3-5MPa, meeting the backfill requirements of most underground projects.

[0070] The application scenarios of the flowable backfill material based on high-stone-content earthwork broken material include airport flight zones, parking aprons, and airport maintenance sites. It is a material between concrete and flowable solidified soil, combining the advantages of both.

[0071] Thus, the embodiments of the present application have been described in detail. In order to avoid obscuring the concept of the present application, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0072] The above-described embodiments only express some implementation manners of the present application, which are described in detail and specifically, but should not be understood as limitations to the scope of the patent. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A fluid backfill material based on high-stone-content earthwork broken material, characterized in that, consists of the following components by weight parts: earth-rock mixture 60-85 parts; cementing material 5-15 parts; water 10-20 parts; additive, the additive is added in an amount of 0.1-1% by weight of the cementing material.

2. The fluidized backfill material based on high-stone-content earthwork broken material according to claim 1, characterized in that: The earth-rock mixture is prepared after crushing of earth-rock, and the earth-rock ratio of the earth-rock mixture is 1:4 to 2:

3.

3. The fluidized backfill material based on high-stone-content earthwork crushing material according to claim 1, characterized in that: The cementing material includes one or more combinations of cement, fly ash, and mineral powder.

4. The flowable backfill material based on high-stone-content earthwork broken material according to claim 1, characterized in that: The additive includes one or more combinations of water reducing agent, retarder, and rheology control agent.

5. The flowable backfill material based on high-stone-content earthwork crushing material according to claim 1, characterized in that: The particle size of the stone in the earth-rock mixture is ≤40mm.

6. The flowable backfill material based on high-stone-content earthwork broken material according to claim 1, characterized in that: The initial slump of the flowable backfill material is 180-230mm, and the 28-day compressive strength is 3MPa to 5MPa.

7. A method for producing a fluid backfill material based on high-stone-content earthwork broken material, characterized in that, The method comprises the following steps: S1, screening and crushing the earth-rock excavated on site; S2, measuring the earth-rock mixture, cementing material, water, and additive by weight parts; S3, adding the earth-rock mixture, cementing material, water, and additive into a mixing device to mix and form a uniform flowable slurry; S4, pouring the slurry into the backfill area by pumping or gravity flow; S5, curing and forming.

8. The method for preparing a fluid backfill material based on high-stone-content earthwork crushing material according to claim 7, characterized in that: In S1, the particle size of the stone is controlled to be not greater than 40mm.

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