Solidification improvement process and application of high-liquid-limit organic-matter-rich engineering residue soil

Abstract

The invention relates to the related technical field of recycling of recoverable waste muck, and discloses a solidification improvement process and application of high-liquid-limit organic-matter-rich engineering muck, and the solidification improvement process comprises the following steps: carrying out mechanical filter pressing on sludge engineering muck to obtain pretreated muck; the pretreated muck and a first mixing material are mixed, and the first mixing material is obtained; mixing the first mixed material with a second mixed material, and then crushing and mixing for the second time to obtain the second mixed material; and adding the mixed material into a third mixed material, and mixing to obtain the solidified and improved engineering residue soil. The high-liquid-limit organic-matter-rich engineering residue soil is improved by adopting a mixing material and a treatment method, the used material is low-carbon and environment-friendly, and the engineering defects of a traditional curing agent are effectively eliminated.

Description

Technical Field

[0001] The invention relates to the technical field related to the reuse of recyclable waste slag, and specifically to a solidification improvement process and application of high liquid limit organic-rich engineering slag. Background Art

[0002] Highly water-containing muddy waste soil generated by pile foundation excavation, shield excavation and municipal engineering usually has a high content of organic matter, generally exceeding 5%. The organic matter in the soil is mainly fulvic acid and humic acid. During the sludge solidification process, fulvic acid has strong reducing and complexing abilities, which has a strong impact on the solidification process. Therefore, the traditional silty waste soil improvement process is difficult to effectively treat such waste soil, resulting in these waste soils often being abandoned in the soil dump, which in turn causes problems such as occupation of arable land, environmental pollution and engineering disasters. In addition, engineering waste soil usually contains debris such as concrete blocks, bricks and stones, which increases the difficulty of using the waste soil.

[0003] At present, the utilization of muddy waste soil mainly relies on mixing it with a curing agent. However, when dealing with muddy engineering waste soil containing organic matter, the conventional mixing and curing process has problems such as being unable to solve the organic matter problem, high water content, and uneven mixing. These problems lead to low production efficiency and insufficient safety. Therefore, a more efficient curing and improved process is needed for the resource utilization of high-water-content and organic-rich muddy engineering waste soil. Summary of the invention

[0004] The object of the present invention is to provide a solidification improvement process and application of high liquid limit organic-rich engineering slag to overcome the above-mentioned defects in the prior art.

[0005] The present invention is achieved through the following technical solutions.

[0006] A solidification and improvement process for high liquid limit organic-rich engineering slag, comprising the following steps:

[0007] S1: Mechanically filter the muddy engineering slag to obtain pre-treated slag;

[0008] S2: Mixing the pretreated slag with a first mixing material to obtain a first mixing material;

[0009] S3: mixing the first mixing material with the second mixing material, crushing and mixing for the second time to obtain a second mixing material;

[0010] S4: Mixing the second mixing material and the third mixing material, and statically pressing and forming the mixed material to obtain solidified and improved engineering slag.

[0011] A further technical solution is to filter the silty engineering soil by pressure filtering, which specifically includes:

[0012] The silty engineering slag is filtered, dried, crushed and sieved to obtain pre-treated slag.

[0013] According to a further technical solution, the particle size of the pretreated slag is ≤2 mm.

[0014] According to a further technical solution, the mass of the first mixed material accounts for 2% to 12% of the mass of the pre-treated slag.

[0015] According to a further technical solution, the mass of the second mixed material accounts for 10-40% of the mass of the first mixed material.

[0016] According to a further technical solution, the mass of the third mixing material accounts for 1-5% of the mass of the first mixing material.

[0017] According to a further technical solution, in the static pressing molding, the weight ratio of the water to the three-stage mixed powder is (0.15-0.2):1.

[0018] The present invention also includes an application of a solidification improvement process for high liquid limit organic-rich engineering slag, which includes using the process as described in any one of claims 1 to 9 to prepare high liquid limit organic-rich engineering slag regeneration roadbed filler.

[0019] According to a further technical solution, the application further comprises: performing standardized curing on the solidified body.

[0020] Beneficial effects of the present invention:

[0021] The present invention provides a method for solidifying and improving high liquid limit organic-rich engineering slag as a road base, which specifically refers to first mechanically dehydrating the engineering slag, and then sequentially adding three mixing materials to the high liquid limit and high organic matter engineering slag. This method not only strengthens the dehydration of the slag, but also utilizes a unique mixing material to further dehydrate the slag, and at the same time combines with a unique curing agent (the third mixing material) to improve the overall stability of the slag and reduce the environmental risks in the process of resource utilization of the slag. According to the above method, a variety of materials are synergistically used with the engineering slag, and the resource utilization goal of the roadbed soil is achieved through the interaction between different materials. The high liquid limit slag is improved in an all-solid waste manner, and the materials used are low-carbon and environmentally friendly, and the engineering defects caused by traditional curing agents are effectively eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0024] Figure 1 This is a flow chart of the improved process for solidification of engineering slag in the present invention;

[0025] Figure 2 It is a schematic diagram of factors and levels of orthogonal test in the present invention;

[0026] Figure 3 It is a schematic diagram of the scheme and results of the orthogonal experiment in the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the embodiments.

[0028] The solidification improvement process and application of a high liquid limit organic-rich engineering slag comprises the following steps:

[0029] S1, mechanically filter-pressing the muddy engineering slag to obtain pre-treated slag;

[0030] The step S1 specifically includes:

[0031] S101, filtering, drying, crushing and screening the muddy engineering slag to obtain pre-treated slag;

[0032] S102, the particle size of the pre-treated slag is ≤ 2 mm

[0033] In the above technical solution, the particle size of the pre-treated slag is ≤2mm because if the particle size is greater than 2mm, there will be adverse effects such as large material differences and uneven mixing, which will affect the stability of the road base in the later stage;

[0034] S2, mixing the pretreated soil and the first mixing material, performing a mixing once, to obtain a first mixing material; the mass of the first mixing material accounts for 2% to 8% of the mass of the pretreated soil;

[0035] S3, mixing the first mixing material with the second mixing material, crushing and mixing for the second time to obtain a second mixing material; the mass of the second mixing material is 3 times the mass of the first mixing material;

[0036] S4, mixing the second mixing material with the third mixing material, and statically pressing and forming to obtain solidified and improved engineering slag; the mass of the third mixing material is 30% of the mass of the first mixing material;

[0037] Preferably, in the static pressing molding, the weight ratio of the water to the three-stage mixed powder is (0.15-0.2):1.

[0038] The present invention also includes the application of a solidification improvement process for high liquid limit organic-rich engineering slag, and the application includes using the process in the preparation of high liquid limit organic-rich engineering slag regeneration roadbed filling material.

[0039] Preferably, the application further comprises: performing standardized curing on the solidified body.

[0040] Example 1

[0041] S1, filtering, drying, crushing and screening the muddy engineering slag to obtain pre-treated slag, wherein the particle size of the pre-treated slag is ≤2 mm;

[0042] S2, mixing the pretreated soil and the first mixing material, performing a mixing once, to obtain a first mixing material; the mass of the first mixing material accounts for 2% of the mass of the pretreated soil;

[0043] S3, mixing the first mixing material with the second mixing material, crushing and mixing for the second time to obtain a second mixing material; the mass of the second mixing material is 3 times the mass of the first mixing material;

[0044] S4, mixing the second mixing material with the third mixing material, statically pressing and forming, to obtain solidified and improved engineering slag; the mass of the third mixing material is 30% of the mass of the first mixing material;

[0045] In the static pressure molding, the weight ratio of the water to the weight of the three-stage mixed powder is 0.15:1.

[0046] Example 2

[0047] In this example, the mass ratio of the pre-treated soil, the first mixing material, the second mixing material, and the third mixing material is 100:5:10:2, which is used as the liquid limit index; the weight ratio of the added water to the weight of the powder is 0.15:1; static pressure is used to obtain a solidified body for standard curing. The particle size of the pre-treated soil is ≤2mm. The other steps are the same as in Example 1.

[0048] Example 3

[0049] In this example, the mass ratio of the pre-treated soil, the first mixing material, the second mixing material, and the third mixing material is 100:8:24:2.4, which is used as the liquid limit index; the weight ratio of the added water to the weight of the powder is 0.16:1; static pressure is used to obtain a solidified body for standard curing. The particle size of the pre-treated soil is ≤2mm. The other steps are the same as in Example 1.

[0050] The curing performance of each example was analyzed, and the results are shown in the following table. (The test plan was carried out in accordance with the "Standard for Geotechnical Test Methods", and the unconfined compressive strength complies with the "Technical Specifications for Roadbed with Recycled Engineering Muck Filling")

[0051]

[0052] Sample experiment:

[0053] The preparation method of the unconfined compressive strength specimen is to add curing agent and water to the sludge according to the designed proportion, and then forcefully stir it with a mechanical mixer, and then load it into a steel mold with an inner diameter of 39.1mm and a height of 80.0mm in 3 layers. After each layer is compacted to a specific height by a small compacting hammer, it is scraped with a geotechnical knife and then loaded into the next layer until it is full. A layer of vaseline is first applied to the inner wall of the test film for demoulding. After the soil sample is loaded into the mold, it is wrapped and sealed with a polyethylene plastic bag and placed in a curing box at (20±2)℃ and humidity>90% for curing for 24h before demoulding. After demoulding, the sample is wrapped and sealed with a plastic bag and continues to be cured in the curing box to 3d, 7d and 28d. The unconfined compressive strength test is carried out, and the initial moisture content of the sludge is set to 80%.

[0054] All tests were conducted in accordance with the Geotechnical Test Method Standard (GB / T50123-1999). The unconfined compressive strength test instrument used a strain triaxial shear instrument with a compression rate of 0.83 mm / min. Three parallel samples were tested for each mix ratio, and the average value was taken as the unconfined compressive strength of the group of samples. When the difference between the test value of a sample and the average value exceeded ±20% of the average value, the test value of the sample was removed, and the average value was calculated according to the test values ​​of the remaining samples.

[0055] Orthogonal test:

[0056] The orthogonal test was conducted based on the test results of solidifying sludge with cement alone and two solidifying materials. The ratios of three composite solidifying materials were studied. The orthogonal analysis factor values ​​were obtained based on the above test results. The cement addition ratio was 8%, 10% and 12%, the gypsum was 20%, 30% and 40% of the cement content, and the solidifying agent was 2%, 3% and 4% of the cement content. The factors and levels of the orthogonal test are shown in Figure 2 , the experimental plan and results are shown in Figure 3 .

[0057] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology in this field to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A solidification and improvement process for high liquid limit organic-rich engineering slag, characterized in that: include: S1: Mechanically filter the muddy engineering slag to obtain pre-treated slag; S2: Mixing the pretreated slag with a first mixing material to obtain a first mixing material; S3: mixing the first mixing material with the second mixing material, crushing and mixing for the second time to obtain a second mixing material; S4: Mixing the second mixing material and the third mixing material, and statically pressing and forming the mixed material to obtain solidified and improved engineering slag.

2. The solidification and improvement process of a high liquid limit organic-rich engineering slag according to claim 1, characterized in that: In the above S1, the mechanical filtration of the muddy engineering soil specifically includes: The silty engineering slag is filtered, dried, crushed and sieved to obtain pre-treated slag.

3. The solidification and improvement process of a high liquid limit organic-rich engineering slag according to claim 2, characterized in that: The particle size of the pretreated slag is ≤2mm.

4. The solidification and improvement process of a high liquid limit organic-rich engineering slag according to claim 1, characterized in that: In the above S2, the mass of the first mixing material accounts for 2% to 12% of the mass of the pre-treated slag.

5. The solidification and improvement process of high liquid limit organic-rich engineering slag according to claim 1, characterized in that: In the above S3, the mass of the second mixed material accounts for 10-40% of the mass of the first mixed material.

6. The solidification and improvement process of high liquid limit organic-rich engineering slag according to claim 1, characterized in that: In the above S4, the mass of the third mixing material accounts for 1-5% of the mass of the first mixing material.

7. The solidification and improvement process of high liquid limit organic-rich engineering slag according to claim 1, characterized in that: In the above S4, in the static pressing molding, the weight ratio of the water to the weight of the three-stage mixed powder is (0.15-0.2):

1.

8. An application of a solidification improvement process for high liquid limit organic-rich engineering slag, the application comprising using the process as described in any one of claims 1 to 9 in the preparation of high liquid limit organic-rich engineering slag regeneration roadbed filler.

9. The application of the solidification improvement process of high liquid limit organic-rich engineering slag according to claim 8 is characterized by: The application further comprises: performing standardized curing on the solidified body.

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