Flow-state backfill material and preparation method thereof

Abstract

The invention provides a flow-state backfill material and a preparation method thereof, and relates to the technical field of building construction, the flow-state backfill material comprises the following components by weight: 1800-2000 parts of engineering slurry, 20-30 parts of demolition garbage, 20-30 parts of cement and 20-30 parts of calcium chloride. 200 to 800 parts of demolition garbage; 150 to 250 parts of cement; and 1-2 parts of calcium chloride. The method comprises the following steps: carrying out flocculent precipitation and dehydration treatment on the engineering slurry; the demolition garbage is gradually mixed into the treated dehydrated slurry; sequentially adding cement and calcium chloride into the mixture of the demolition garbage and the dehydrated slurry, and stirring by using a stirrer. The preparation method has the beneficial effects that the flow-state backfill material is prepared from the engineering slurry and the demolition garbage, and waste materials generated on a construction site can be converted into valuable backfill materials in situ, so that reutilization of resources is realized, the environment can be protected, and the building construction efficiency and economic benefits can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and particularly to a fluid backfill material and a preparation method thereof. Background Art

[0002] A fluid backfill material is a material with high fluidity. It can self-fill under its own weight without or with only a little vibration, forming a self-compacting structure of cemented backfill material. This material has high construction efficiency and is particularly suitable for backfilling in special-shaped, narrow spaces and deep foundation pits. It can solve the construction problems in limited spaces and ensure the safety of construction workers in narrow trenches.

[0003] Traditional backfill technologies mainly use materials such as sand and gravel, and lime-fly ash soil for layered rolling and ramming. However, this technology has problems such as cumbersome construction processes and unstable compaction quality of backfill soil. Especially when encountering working conditions such as narrow and special-shaped backfill spaces and large backfill depths, it is more difficult to ensure the quality of the backfill project. Therefore, a more efficient and stable backfill material and technology are needed to replace the traditional compaction process.

[0004] During the process of engineering construction, a large amount of engineering slurry will be generated. If this slurry is directly discharged, it will not only cause environmental pollution but also waste resources. Currently, the main treatment methods for engineering slurry include dehydration, solidification, etc., but the treatment effects are limited and the treatment costs are relatively high. During the process of urban renewal and old city reconstruction, a large amount of demolition waste will be generated. This waste contains a large amount of recyclable resources, such as bricks, concrete blocks, etc. However, due to limitations in treatment technology and costs, these demolition wastes are often directly landfilled or stacked, resulting in waste of resources and environmental pollution. Summary of the Invention

[0005] In view of this, the present invention provides a preparation method for a fluid backfill material, and the method includes the following steps:

[0006] S1: Carry out flocculation precipitation and dehydration treatment on the engineering slurry, and detect and determine the moisture content of the engineering slurry after dehydration treatment; determine the dosage of the engineering slurry according to the moisture content of the engineering slurry after dehydration treatment;

[0007] S2: Gradually incorporate demolition waste into the treated dewatered slurry to make the fluidity of the mixture of demolition waste and dewatered slurry reach the predetermined requirement;

[0008] S3: Add cement to the mixture of demolition waste and dewatered slurry in step S2;

[0009] S4: Add calcium chloride to the mixture of demolition waste, dewatered slurry and cement in step S3, and use a mixer to stir to make the finished product of the fluid backfill material.

[0010] Further, during the dehydration treatment of the engineering slurry in step S1, it is also necessary to adjust its moisture content to ensure that the moisture content range is 80%-100%.

[0011] Further, the demolition waste incorporated in step S2 is subjected to crushing and screening treatments, and the mesh number of its screening treatment is below 5 meshes.

[0012] Further, the dosage of the demolition waste in step S2 is obtained through the following formula:

[0013] W 1 = 1000(1 + w);

[0014]

[0015] where w is the dry basis moisture content of the engineering slurry after dehydration, and W 1 is the dosage of the engineering slurry; L 0 is the fluidity when the dosage of the demolition waste is 0, W 2 is the dosage of the demolition waste, a is the influence coefficient of the dosage of the demolition waste on the fluidity of the engineering slurry, and L is the predetermined fluidity.

[0016] Further, the dosage of the cement in step S3 is obtained through the following formula:

[0017]

[0018] where UCS 28d is the unconfined compressive strength at 28 days, k is the strength influence coefficient of the dosage of the demolition waste, and m and n are the strength influence coefficients related to the dosage of the cement.

[0019] Further, the dosage of calcium chloride in step S4 is W 4 , where W 4 = 0.01W 3 .

[0020] Further, the mixing treatment time of the mixer in step S4 is 20 to 30 minutes.

[0021] Further, the specific weight ratio of each component material in the preparation of this method is:

[0022] Engineering slurry: 1800 to 2000 parts;

[0023] Demolition waste: 200 to 800 parts;

[0024] Cement: 150 to 250 parts;

[0025] Calcium chloride: 1 to 2 parts;

[0026] The demolition waste is one of the materials such as muck, concrete blocks, crushed stones, brick and tile fragments, waste mortar, slurry, asphalt blocks, waste plastics, waste metals, and waste bamboo and wood, or a mixture of multiple of these materials.

[0027] Furthermore, the engineering slurry is derived from the waste slurry in bored pile foundations, diaphragm walls, slurry shield tunneling, horizontal directional drilling, slurry pipe jacking construction, and muck washing and sand washing projects. The cement is 425 ordinary Portland cement, and the calcium chloride is industrial-grade calcium chloride in white powder form.

[0028] The present invention also provides a fluid backfill material, which is the fluid backfill material prepared by the preparation method of the fluid backfill material. The beneficial effects of a fluid backfill material and its preparation method according to the present invention are as follows:

[0029] 1. Resource reuse: The main components of the fluid backfill material are engineering slurry and demolition waste. Through this preparation method, the waste materials generated at the construction site (i.e., engineering slurry and demolition waste) can be recycled and transformed into valuable backfill materials, thus achieving resource reuse.

[0030] 2. Environmental benefits: The fluid backfill material can reduce the dependence on traditional backfill materials, thereby reducing the exploitation and consumption of natural resources. At the same time, due to the characteristics of self-compaction and no need for vibration of the material itself, the problems of noise, vibration, and air pollution during the construction process that affect residents are effectively solved.

[0031] 3. Economic benefits: The preparation method of the fluid backfill material using engineering slurry and demolition waste to prepare the fluid backfill material can reduce the backfill cost and improve the construction efficiency. At the same time, due to the controllable strength characteristics of the material, it can also be designed and adjusted according to the engineering needs to meet different backfill requirements.

[0032] In summary, preparing a fluid backfill material using engineering slurry and demolition waste is a new backfill technology with broad application prospects and significant advantages. Through the popularization and application of this technology, not only can resource reuse and environmental protection be achieved, but also the construction efficiency and economic benefits can be improved. Description of the Drawings

[0033] Figure 1 is a flowchart of a preparation method of a fluid backfill material according to an embodiment of the present invention.

[0034] Figure 2 is a graph showing the relationship between the number of demolition waste parts and the fluidity in an embodiment of the present invention

[0035] Figure 3 is a graph showing the relationship between the number of demolition waste parts and the unconfined compressive strength in an embodiment of the present invention

[0036] Figure 4 This is a graph showing the relationship between the ratio of the number of parts of engineering slurry to the number of parts of cement and the unconfined compressive strength in the embodiments of the present invention. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0038] The present invention provides a fluid backfill material and a preparation method thereof, which make full use of two common waste materials generated at construction sites, namely engineering slurry and demolition waste.

[0039] A fluid backfill material of the present invention comprises the following components: engineering slurry, demolition waste, cement and calcium chloride. The specific weight ratio of engineering slurry, demolition waste, cement and calcium chloride is as follows:

[0040] Engineering slurry: 1800 to 2000 parts;

[0041] Demolition waste: 200 to 800 parts;

[0042] Cement: 150 to 250 parts;

[0043] Calcium chloride: 1 to 2 parts.

[0044] Among the above components, the engineering slurry is derived from waste slurry in projects such as bored pile foundations, diaphragm walls, slurry shield tunneling, horizontal directional drilling, slurry pipe jacking construction, and washing sand of muck. The dry basis moisture content before dehydration exceeds 100%. After sedimentation and dehydration treatment, the dry basis moisture content is adjusted to between 80% and 100%. The demolition waste is construction waste generated at construction sites, including but not limited to muck, concrete blocks, crushed stones, brick and tile fragments, waste mortar, slurry, asphalt blocks, waste plastics, waste metals, and waste bamboo and wood. The demolition waste needs to be pulverized and screened before use. The cement is commercially available 425# ordinary Portland cement, and the calcium chloride is commercially available industrial grade calcium chloride, which is a white powdery mud.

[0045] In a preferred embodiment, the dosage of calcium chloride is 1% of the weight of the cement.

[0046] The above fluid backfill material is made from waste materials generated at the construction site, and has the characteristics of low strength, self-leveling, self-filling and self-compacting. The fluid backfill material can effectively solve the limitations of traditional backfill materials in specific construction environments, such as narrow operation space and difficulty in ramming. The fluid backfill material is an environmentally friendly and efficient construction backfill material.

[0047] Reference Figures 1-4, the present invention also provides a method for preparing a fluid backfill material, which is used to prepare the above-mentioned fluid backfill material. The method for preparing the fluid backfill material of the present invention includes the following steps:

[0048] S1: Carry out flocculation precipitation and dehydration treatment on the engineering slurry, and detect and determine the water content of the engineering slurry after dehydration treatment; determine the dosage of the engineering slurry according to the water content of the engineering slurry after dehydration treatment;

[0049] S2: Gradually incorporate demolition waste into the treated dewatered slurry to make the fluidity of the demolition waste and dewatered slurry mixture reach the predetermined requirements;

[0050] S3: Add cement to the demolition waste and dewatered slurry mixture in step S2;

[0051] S4: Add calcium chloride to the demolition waste, dewatered slurry and cement mixture in step S3, and stir with a mixer to make the finished product of the fluid backfill material.

[0052] In a preferred embodiment, the water content of the engineering slurry needs to be adjusted during the dehydration treatment in step S1 to ensure that its water content range is 80%-100%. The dosage of the engineering slurry is determined through the following process:

[0053] W 1 = 1000(1 + w);

[0054] wherein, w is the dry basis water content of the engineering slurry after dehydration (in the range of 80% to 100%), and W1 is the dosage of the engineering slurry (in the range of 1800 to 2000 parts).

[0055] The dosage of the demolition waste in step S2 is obtained through the following formula:

[0056] W 1 = 1000(1 + w);

[0057]

[0058] wherein, w is the dry basis water content of the engineering slurry after dehydration, W 1 is the dosage of the engineering slurry; L 0 is the fluidity when the dosage of the demolition waste is 0, W 2 is the dosage of the demolition waste, a is the influence coefficient of the dosage of the demolition waste on the fluidity of the engineering slurry, and L is the predetermined fluidity. The influence coefficient of the dosage of the demolition waste on the fluidity of the engineering slurry is obtained by fitting test data, Figure 2 is the relationship diagram of the number of parts of the demolition waste and the fluidity obtained by fitting in this embodiment. In this embodiment, the value of a is -0.024. The value of L is determined according to the actual construction needs.

[0059] The parameter of cement in step S3 is obtained by the following formula:

[0060]

[0061] where UCS 28d is the unconfined compressive strength at 28 days, k is the strength influence coefficient of the demolition waste content, and m and n are the strength influence coefficients related to the cement content. The strength influence coefficient k of the demolition waste content, and the strength influence coefficients m and n related to the cement content are all obtained by fitting experimental data. Figure 3 is the relationship diagram between the number of parts of demolition waste and the unconfined compressive strength in the embodiment, Figure 4 is the relationship diagram between the project (number of parts of slurry / number of parts of cement) and the unconfined compressive strength in the embodiment. In this embodiment, k is 0.2635, m is 974.05, n is 589.46, and UCS 28d is determined according to the actual construction needs.

[0062] In a preferred embodiment, the dosage of calcium chloride in step S4 is W 4 , where W 4 = 0.01W.

[0063] In a preferred embodiment, the mixing treatment time of the mixer in step S4 is 20 to 30 minutes.

[0064] By resourcefully utilizing engineering slurry and demolition waste, the above method can convert them into valuable backfill materials, thus realizing the reuse of resources. And the above method also obtains multiple fitting formulas by means of fitting experimental data. According to this fitting formula, fillers with different unconfined compressive strengths can be obtained by adjusting the ratio of each raw material, so as to meet different backfill requirements. This method for preparing the fluid backfill material has broad application prospects. Through the popularization and application of this technology, not only can the reuse of resources and environmental protection be achieved, but also the construction efficiency and economic benefits can be improved.

[0065] In this article, the front, back, up, down and other orientation words are defined based on the positions of the components in the drawings and the positions of the components relative to each other, only for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the orientation words should not limit the scope of protection claimed in this application.

[0066] Without conflict, the above embodiments and the features in the embodiments in this article can be combined with each other.

[0067] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a fluid backfill material, characterized in that: The method comprises the following steps: S1: flocculating and settling the engineering mud and dehydrating it, and testing and determining the water content of the engineering mud after the dehydration treatment; and determining the dosage of the engineering mud according to the water content of the engineering mud after the dehydration treatment; S2: gradually adding demolition waste into the treated dewatered slurry to make the fluidity of the mixture of demolition waste and dewatered slurry reach a predetermined requirement; S3: adding cement to the mixture of demolition waste and dewatered slurry in step S2; S4: adding calcium chloride to the demolition waste, dewatered water slurry and cement mixture in step S3, and stirring with a mixer to prepare a fluid backfill material product.

2. A method for preparing a fluid backfill material according to claim 1, characterized in that: In step S1, during the dehydration process of the engineering mud, its moisture content needs to be adjusted to ensure that its moisture content is within the range of 80%-100%.

3. A method for preparing a fluid backfill material according to claim 1, characterized in that: The demolition waste mixed in step S2 is crushed and sieved, and the mesh number of the sieved waste is less than 5 meshes.

4. A method for preparing a fluid backfill material according to claim 1, characterized in that: The amount of demolition waste in step S2 is obtained by the following formula: W1=1000(1+w); Among them, w is the moisture content of the engineering mud on dry basis after dehydration, W1 is the engineering mud dosage; L0 is the fluidity when the demolition waste dosage is 0, W2 is the demolition waste dosage, a is the influence coefficient of the demolition waste dosage on the fluidity of the engineering mud, and L is the predetermined fluidity.

5. A method for preparing a fluid backfill material according to claim 4, characterized in that: The parameters of cement in step S3 are obtained by the following formula: Among them, UCS 28d is the 28-day unconfined compressive strength, k is the strength influence coefficient of demolition waste content, and m and n are the strength influence coefficients related to cement content.

6. A method for preparing a fluid backfill material according to claim 5, characterized in that: The dosage of calcium chloride in step S4 is W4, where W4=0.01W3.

7. A method for preparing a fluid backfill material according to claim 1, characterized in that: The stirring time of the mixer in step S4 is 20 to 30 minutes.

8. The method for preparing a fluid backfill material according to claim 1, characterized in that: The specific weight ratio of each component material in the preparation method is: Engineering mud: 1800 to 2000 parts; Demolition waste: 200 to 800 pieces; Cement: 150 to 250 parts; Calcium chloride: 1 to 2 parts; The demolition waste is one of the following materials: slag, concrete blocks, broken stones, brick and tile fragments, waste mortar, mud, asphalt blocks, waste plastics, waste metals, waste bamboo and wood, or a mixture of multiple materials thereof.

9. A method for preparing a fluid backfill material according to claim 8, characterized in that: The engineering mud is derived from waste mud in bored pile foundation, underground continuous wall, slurry shield, horizontal directional drilling and slurry jacking construction, and slag sand washing engineering. The cement is No. 425 ordinary Portland cement, and the calcium chloride is white powdery industrial grade calcium chloride.

10. A fluid backfill material, characterized in that: The fluid backfill material is the fluid backfill material prepared by the method for preparing the fluid backfill material according to any one of claims 1 to 9.

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