Sand silt cake roadbed filler and construction method

Abstract

This invention relates to a sand pit mud cake roadbed filler and its construction method, belonging to the field of civil engineering construction technology. The sand pit mud cake roadbed filler proposed in this invention comprises the following components: 40-50 parts of waste sand pit mud cake, 15-20 parts of clay, 45-30 parts of pond slag, and 0.3-0.5 parts of sawdust. The construction method of the sand pit mud cake roadbed filler includes the following steps: mixing the various component materials, followed by compaction and curing. This invention uses waste mud cake as the fine-grained soil component in the roadbed filler, reusing waste, avoiding environmental pollution, saving land resources, and reducing the sensitivity of the improved sand pit waste mud cake roadbed filler to the optimum moisture content, making construction quality easier to control.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering construction technology, and relates to a sand pit mud cake roadbed filler and construction method. Background Technology

[0002] Sand and gravel, as important building materials and concrete raw materials, are widely used in civil engineering construction. However, due to the depletion of natural sand and river sand resources, their production capacity has also decreased sharply. Manufactured sand has emerged as a replacement for natural sand and gravel, and its application has become a common trend worldwide. Currently, many regions utilize local rock resources or waste rock from engineering projects to produce manufactured sand. However, during the mining and processing of manufactured sand, the powder from the sedimentation of waste slurry is generally left in the open or buried nearby, forming large amounts of waste mud cakes that are difficult to reuse. Due to the huge demand for sand and gravel caused by infrastructure projects, many regions in my country generate a large amount of such waste mud cakes every year. The continuous accumulation of large amounts of waste mud cakes not only occupies a large amount of land resources but also affects the sustainable development of cities, making resource utilization impossible. In addition, the related stockpiles are usually loosely structured and prone to collapse. During the rainy season, this can trigger various geological disasters such as dam breaks, landslides, and debris flows, leading to significant maintenance costs for the stockpiles. Therefore, the proper disposal of mud cakes has both economic and social benefits. Under the influence of rainwater, mud cake will damage the soil, pollute groundwater, and seriously affect the health of surrounding plants, animals, and humans. After the surface of the dumping site dehydrates and weathers, the dust pollutes the air, which will harm people and animals near the dumping site. Therefore, it also brings environmental problems, and the proper disposal of mud cake has significant environmental benefits. How to make reasonable use of waste mud cake has become an urgent problem to be solved.

[0003] Currently, there is a lack of targeted research on the mud cake formed from waste slurry at sand and gravel quarries. Using waste mud cake as roadbed filler is the simplest and most convenient treatment method at present, and it also has the largest usage volume, which is more conducive to improving the comprehensive resource utilization of stone powder waste. Furthermore, road construction requires numerous borrow pits and sand and gravel quarries, consuming large amounts of land, sand, and other non-renewable resources, causing serious damage to the environment and ecology. Replacing traditional road construction materials with waste mud cake would be a win-win situation. Therefore, it is necessary to specifically explore the utilization methods of waste mud cake, providing a reference for solving the problem of waste accumulation in sand quarries and using different wastes for roadbed filling, and better serving large-scale engineering construction. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a sand pit mud cake roadbed filler and construction method, which avoids environmental pollution, saves land resources, improves the sand pit mud cake roadbed filler, and improves construction quality.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A type of roadbed filler made from sand pit mud cake includes waste mud cake from sand pits, clay, pond slag, and wood chips.

[0007] Optionally, the mass ratio of the waste mud cake, clay, pond slag and sawdust from the sand pit is as follows: 40-50 parts waste mud cake, 15-20 parts clay, 45-30 parts pond slag and 0.3-0.5 parts sawdust.

[0008] Optionally, the wood chips are air-dried fir sawdust.

[0009] Optionally, the particle size of the wood chips is less than 2 mm.

[0010] Optionally, the moisture content of the wood chips is <10%.

[0011] Optionally, the wood chips have a mass content >95%.

[0012] A construction method for sand pit mud cake roadbed filler, applied to the aforementioned sand pit mud cake roadbed filler,

[0013] Includes the following steps:

[0014] S1, determine the components of the sand pit mud cake roadbed filler, determine the mass ratio of each component, and mix the components according to the mass ratio;

[0015] S2, the mixed subgrade fill is evenly laid on the road surface and then compacted;

[0016] S3 is used to cure the compacted roadbed fill material.

[0017] Optionally, the mixing process in step S1 includes on-site mixing and road mixing. The appropriate mixing process is selected according to the filling method. For example, if it is a borrow filling, on-site mixing is the main method; if it is a roadbed earthwork mixing method, road mixing is the main method.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) Effectively utilize industrial solid waste sand pit waste mud cake as building material, avoid environmental pollution, save land resources, achieve the purpose of waste reuse, and deal with the backlog of waste materials in a fast and convenient way.

[0020] (2) It solved the long-term strength and stability problem of roadbed with waste mud cake from a single sand pit, reduced the hidden dangers of the roadbed, and improved the engineering utilization value of waste mud cake from the sand pit.

[0021] (3) Clay and ordinary pond slag are readily available, abundant, and inexpensive, which significantly reduces the cost of using waste mud cake from sand pits as roadbed filler.

[0022] (4) The construction process is simple and easy to promote and apply. Furthermore, since the sensitivity of the improved waste mud cake roadbed filler to the optimum moisture content is reduced, the construction quality is easier to control.

[0023] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0025] Figure 1 A flowchart illustrating the construction method for using waste mud cakes from sand pits as roadbed filling materials. Detailed Implementation

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0028] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0029] Please see Figure 1 This is a type of roadbed filler made from waste mud cake from sand pits, composed of waste mud cake from sand pits, clay, pond slag, and sawdust. Clay and pond slag are used as improving components, while sawdust is used as reinforcing components. The mass ratio of each component is as follows: 40-50 parts waste mud cake from sand pits, 15-20 parts clay, 45-30 parts pond slag, and 0.3-0.5 parts sawdust.

[0030] In this embodiment, the pond slag is ordinary pond slag, a commonly used local material; the clay is a local material; and the wood chips are air-dried fir sawdust with a particle size of less than 2 mm.

[0031] Waste mud cake from sand pits originates from crushed stone and contains a large amount of silt particles. Although it is sticky when dry, it is easily broken and tends to become fluid when soaked in water. When used alone as roadbed filler, waste mud cake from sand pits often causes a large capillary rise due to strong capillary action, which can easily lead to frost heave and frost heave in seasonally freezing areas. However, the cost of solidification treatment with cement and lime is relatively high. Therefore, it is necessary to add other materials to optimize the treatment of waste mud cake from sand pits.

[0032] This invention uses clay and pond slag as modifying materials to treat waste mud cake from sand pits. The clay and pond slag are sourced from local building materials. The mechanism is as follows: the clay and pond slag adjust the particle size distribution of the waste mud cake from sand pits, changing the engineering properties of the roadbed filler. By influencing the particle composition and structure of the waste mud cake, the strength of the roadbed filler is no longer determined by a dense structure, but rather by a dense-skeleton structure. This makes the roadbed strength dependent on the magnitude of internal friction and cohesion. The modified roadbed filler contains sufficient fine particles to fill the gaps between particles, and can achieve higher strength and stability through particle contact. It also has the advantages of low permeability and easy compaction during construction.

[0033] This invention also incorporates sawdust into the roadbed fill material. The sawdust serves two purposes: firstly, in the early stages, it works with materials such as clay to absorb excess moisture from the waste mud cake in the sand pit, bringing the overall moisture content of the roadbed fill material close to the optimum moisture content; secondly, it plays a role in humidity regulation in the roadbed fill material, reducing the dry-wet deformation of the roadbed; and thirdly, it serves to reinforce and stabilize the roadbed fill material, reducing the impact of water saturation and dry-wet cycles on the mechanical properties of the improved roadbed fill material.

[0034] Example 1:

[0035] The industrial solid waste sand pit waste mud cake roadbed filling material in this embodiment is composed of sand pit waste mud cake, clay, ordinary pond slag and wood chips. Among them, clay, ordinary pond slag and wood chips are used as soil improvement components. The mass ratio of each component is: 40 parts sand pit waste mud cake, 20 parts clay, 40 parts ordinary pond slag and 0.5 parts wood chips.

[0036] Example 2:

[0037] The industrial solid waste sand pit waste mud cake roadbed filling material in this embodiment is composed of sand pit waste mud cake, clay, ordinary pond slag and wood chips. Among them, clay, ordinary pond slag and wood chips are used as soil improvement components. The mass ratio of each component is: 50 parts sand pit waste mud cake, 15 parts clay, 35 parts ordinary pond slag and 0.3 parts wood chips.

[0038] Example 3:

[0039] The industrial solid waste sand pit waste mud cake roadbed filling material in this embodiment is composed of sand pit waste mud cake, clay, ordinary pond slag and wood chips. Among them, clay, ordinary pond slag and wood chips are used as soil improvement components. The mass ratio of each component is: 50 parts sand pit waste mud cake, 20 parts clay, 30 parts ordinary pond slag and 0.4 parts wood chips.

[0040] In Examples 1-3, the quality control parameters of the raw materials for the roadbed filling material made from waste mud cake from industrial solid waste sand pits were controlled. The clay and ordinary pond slag were both taken from Ningbo. The sawdust was air-dried fir sawdust with a moisture content of <10%, a particle size of less than 2 mm, and a mass content of >95% (mass content refers to the ratio of the mass contained in a substance to the mass contained in a unit mass of a reference substance).

[0041] The construction method for the above-mentioned industrial solid waste sand pit waste mud cake roadbed filler includes the following steps:

[0042] S1, mix the components according to a certain mass ratio;

[0043] The mixing process can be either on-site mixing or road mixing. The appropriate mixing process should be selected according to the filling method. For example, if it is a borrow filling, on-site mixing should be the main method, and if it is a roadbed earthwork mixing method, road mixing should be the main method.

[0044] Borrowing refers to the process of excavating soil (or rock) from a borrow pit for roadbed filling. During the filling process, the soil needs to be transported from outside to the construction site, and then filled and compacted in layers to achieve the design elevation.

[0045] The on-site mixing method refers to a construction method in which the mixture is prepared at a fixed mixing plant or a mobile mixing station.

[0046] The allocation of roadbed earthwork is carried out after the earthwork quantity has been calculated and verified. Before allocation, the locations of bridges and culverts, steep slopes, ditches, etc. that may affect transportation allocation should be marked next to the table for reference during allocation.

[0047] Road mixing is a construction method that uses machinery (such as tractors) or manual labor to mix the mixture on-site in the roadbed or along the road surface. Stabilized soil mixing machines can also be used for related mixing.

[0048] S2, the mixed subgrade fill is evenly laid on the road surface and then compacted;

[0049] During the compaction process, the moisture content of the filler should be controlled and a suitable compaction process should be selected.

[0050] S3 involves curing the compacted subgrade fill material to ensure the subgrade and its ancillary equipment are in a firm and stable state; the curing standards refer to relevant subgrade curing technical specifications.

[0051] Soil samples of waste mud cake from industrial solid waste sand pits (Examples 1-3) were taken as roadbed filler. Compacted specimens near the optimum moisture content were prepared using the dry soil method. The CBR (Carrier Bearing Ratio) value was tested according to the "Specifications for Geotechnical Testing of Highways" to evaluate the roadbed strength. The CBR of the specimens was further evaluated using a three-cycle dry-wet test to reflect the soil strength stability under real-world conditions. The test results are shown in Table 1 below.

[0052]

[0053] Table 1

[0054] It is evident that the undisturbed waste mud cakes used in the experiment cannot meet the minimum strength (2%) requirement for subgrade fill in lower-grade roads (Class III and IV highways). After wet-dry cycles, the strength of the subgrade fill material further decreases, making it unsuitable for direct application and requiring solidification treatment. However, the waste mud cakes from sand pits modified with clay, ordinary pond slag, and sawdust can meet the requirements for subgrade fill materials for all levels of highways, and the impact of wet-dry cycles is significantly reduced. This indicates that the strength and stability have been improved to a certain extent, demonstrating that the waste mud cake subgrade fill materials from sand pits in Examples 1-3 can be applied in practical engineering.

[0055] The present invention provides a roadbed filler material made from waste mud cake from sand pits, an industrial solid waste, which effectively utilizes waste mud cake from sand pits as a building material, avoiding environmental pollution, saving land resources, and achieving the goal of waste reuse. It also provides a fast and convenient way to process accumulated waste materials. Furthermore, it solves the long-term strength and stability problems of roadbeds made solely from waste mud cake from sand pits, reduces roadbed hazards, and increases the engineering utilization value of waste mud cake from sand pits. The clay and ordinary pond slag used in this invention are readily available, abundant, and inexpensive, significantly reducing the cost of using waste mud cake from sand pits as roadbed filler material. The construction process of this invention is simple and easy to promote and apply. Moreover, because the improved waste mud cake roadbed filler material has reduced sensitivity to the optimum moisture content, the construction quality is easier to control.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A type of mud cake roadbed filler, characterized in that: It includes waste mud cakes from sand pits, clay, pond slag, and wood chips; the mass ratio of the waste mud cakes from sand pits, clay, pond slag, and wood chips is as follows: 40-50 parts waste mud cakes from sand pits, 15-20 parts clay, 45-30 parts pond slag, and 0.3-0.5 parts wood chips.

2. The sand pit mud cake roadbed filler according to claim 1, characterized in that: The wood chips are air-dried fir sawdust.

3. The sand pit mud cake roadbed filler according to claim 1, characterized in that: The particle size of the wood chips is less than 2 mm.

4. The sand pit mud cake roadbed filler according to claim 1, characterized in that: The moisture content of the wood chips is <10%.

5. The sand pit mud cake roadbed filler according to claim 1, characterized in that: The wood chips have a mass content of >95%.

6. A construction method for sand pit mud cake roadbed filler, applied to the sand pit mud cake roadbed filler as described in any one of claims 1 to 5, characterized in that: Includes the following steps: S1, determine the components of the sand pit mud cake roadbed filler, determine the mass ratio of each component, and mix the components according to the mass ratio; S2, the mixed subgrade fill is evenly laid on the road surface and then compacted; S3 is used to cure the compacted roadbed fill material.

7. The construction method for sand pit mud cake roadbed filler according to claim 6, characterized in that: The mixing process in step S1 includes field mixing and road mixing.

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