Preparation method of light filler, railroad bed structure and laying method of railroad bed structure

Abstract

The invention discloses a preparation method of a light filler, a railroad bed structure and a laying method of the railroad bed structure. The preparation method comprises the following steps: preparing raw materials according to a certain ratio, wherein the raw materials comprise Portland cement, fly ash, hollow glass beads, a polycarboxylic acid water reducing agent and a liquid foaming agent formed by compounding alkyl sulfonic acid alkali metal salt and hydrolyzed protein according to a mass ratio; the preparation process of the light filler comprises the following steps: diluting a foaming agent and preparing foams; mixing and stirring; forming and maintaining; the volume weight of the light filler is designed, specifically, the total volume of the mixed dry material, the total volume of needed water and the foam mass of the light filler are accurately calculated, and the design density of the light filler is determined. According to the invention, rapid first-aid repair and emergency response can be realized, extreme environments are adapted, structural stability is improved, durability is enhanced, heat and sound insulation performance is improved, balance of light weight and high strength is realized, and environment friendliness is realized.

Description

Technical Field

[0001] The invention relates to the technical field of high-speed railway subgrade engineering, and in particular to a method for preparing a lightweight filler, a railway subgrade structure and a laying method thereof. Background Art

[0002] Faster running speeds place higher demands on the smoothness and stability of the line. The structural vibration caused by high-speed rail vehicles propagates outward through the roadbed to the surrounding strata, which not only endangers the safety performance of the wheel-rail system itself, but also has an adverse effect on the durability of the high-speed rail roadbed structure. There are many types of vibration reduction measures for high-speed railway roadbeds, and the vibration reduction effects vary. Generally speaking, there are disadvantages of high cost and insufficient effect.

[0003] A large number of studies on roadbed fillers have shown that the deformation of the surface and bottom layers of the subgrade can account for more than 50% of the total deformation of the entire roadbed. With the rapid development of high-speed railways, the study of the strength and deformation characteristics of high-speed railway subgrade fillers has become a hot topic. The use of seismic reduction and isolation materials can effectively reduce the deformation behavior of high-speed railway subgrades under dynamic loads. If a new type of seismic reduction and isolation filler can be developed and widely applied to the subgrade materials of high-speed railways to achieve industrial promotion, this problem will be solved to a great extent. At present, prefabricated structures and construction technologies have become one of the important trends in the development of railway engineering construction. Existing lightweight high-strength concrete and other materials can play a role in strengthening the performance of the subgrade through mechanical foaming in the construction of high-speed railway subgrades. Good integrity and low permeability can reduce subgrade diseases. However, as a prefabricated mechanism filler, how to achieve a unified improvement in its basic mechanical properties, vibration reduction performance, corrosion resistance, durability and other properties still requires further research and demonstration.

[0004] Existing technical solutions:

[0005] (1) A construction method for municipal roads and bridge abutment backfill based on lightweight fillers (CN110219216B)

[0006] China Railway 16th Bureau Group Co., Ltd. invented and disclosed a construction method for municipal roads and bridge abutment backfill based on lightweight fillers, including the following steps: mixing cement, lightweight aggregate and water and stirring to obtain cement slurry; using a foaming machine to fully foam the foaming agent to obtain foam; mixing the obtained foam with cement slurry to obtain lightweight fillers; directly pumping the obtained lightweight fillers and pouring them in sections; within 3 to 12 hours after pouring the lightweight fillers, the lightweight fillers are maintained by covering with straw pulp, reed mats, sacks, sawdust, wet soil or wet sand and watering, and the maintenance time of the lightweight fillers is not less than 7 days. This construction method improves the problem of uneven settlement of roadbeds and bridges by applying lightweight fillers to municipal roads and bridge abutment backfills; installing a single layer of wire mesh in the lightweight fillers improves the integrity of the lightweight fillers.

[0007] (2) A lightweight filler for bridge arch filling (CN107265953B)

[0008] The invention of Southeast University relates to a lightweight filler for filling bridge arches. The lightweight filler is composed of the following parts by mass: 500-600 parts of PⅡ52.5 or 42.5 cement, 60-240 parts of lithium slag, 2-3 parts of foaming agent, 3-4 parts of water reducer, 10-30 parts of alkali-resistant glass fiber, 2-5 parts of emulsion waterproofing agent, 12-100 parts of styrene-acrylic latex powder, 1-3 parts of thickener, and 250-300 parts of water. After the lightweight filler is poured for 28 days, a silane hybrid silicone waterproof coating is impregnated on the surface of the lightweight filler concrete. This method uses cement, lithium slag, water, water reducing agent, styrene acrylic latex powder, alkali-resistant glass fiber, fluorosilicone acrylate emulsion waterproofing agent, etc. to prepare lightweight filler, and impregnates the surface of the lightweight filler with silane hybrid silicone waterproof coating. Compared with ordinary lightweight fillers, the lightweight filler has higher strength, greatly reduced water absorption and sedimentation rate, and significantly enhanced durability. It can be used as filler on bridge arches to solve the problems of high water absorption, severe sedimentation and poor durability of ordinary lightweight fillers.

[0009] There are still some defects and challenges in the actual application of these two lightweight filler roadbed structures. The following is an analysis of the main defects of the two technologies of lightweight filler full-bed roadbed and lightweight filler base bed bottom roadbed:

[0010] Crack problems caused by differences in structural stiffness:

[0011] When lightweight filler materials are used in highway bridge transition sections, when there are differences in stiffness or uneven deformation in the substructure, especially on foundations with weak bearing capacity, it is easy to cause instability in the overall structure. This instability first forms cracks in the lower part of the structure, and then the cracks extend to the top, which may lead to the destruction of the overall structure. Since the elastic modulus of lightweight fillers is lower than that of traditional concrete, this difference exacerbates the risk of uneven settlement.

[0012] Quality and laying requirements of graded crushed stone:

[0013] When using graded crushed stone as the surface layer of the lightweight filler subgrade, higher requirements are placed on the quality and laying technology of the crushed stone. The uniformity and thickness control of the crushed stone layer are crucial to the stability and drainage performance of the overall subgrade. If the crushed stone layer is unevenly laid or the drainage design is improper, it may cause moisture accumulation, thus affecting the stability and durability of the subgrade.

[0014] High cost issues:

[0015] Lightweight fill materials are generally more expensive to produce and transport than traditional concrete materials. In addition, the construction of these roadbed structures is technically demanding and requires specialized equipment and technicians. These factors combined can significantly increase the cost of the entire road project, especially in large-scale infrastructure construction.

[0016] Vulnerability to severe climatic conditions:

[0017] Lightweight fill roadbeds may be affected in harsh climates, especially in rainy and snowy weather, extreme low temperatures, and repeated freeze-thaw cycles. Under these conditions, the structural and functional integrity of the roadbed may be compromised, leading to cracks, settlement, or other roadbed diseases. Especially in winter, freeze-thaw cycles may cause microscopic damage to the lightweight fill structure, which in turn affects its macroscopic performance.

[0018] Insufficient ability to quickly clear the road:

[0019] When the roadbed suffers devastating damage such as collapse, washout, and flooding, the ability to quickly open and repair the roadbed is relatively weak due to the special structure and material properties of the lightweight filler roadbed. This type of roadbed structure requires precise material matching and construction technology. Once damaged, the repair process may be complicated and time-consuming, affecting the rapid resumption of use of the road.

[0020] In summary, although these two lightweight fill roadbed structures perform well in many aspects, there are also a series of challenges and limitations in practical applications. Summary of the invention

[0021] The purpose of the present invention is to provide a shock-absorbing lightweight filler for a fast-assembly block-type railway roadbed structure. This shock-absorbing lightweight filler mainly focuses on the scientific configuration of internal fillers and the layered design of the shock-absorbing lightweight filler roadbed. The first layer of the assembled block-type railway roadbed is filled with hollow glass microsphere lightweight fillers, and the second / third layers of the assembled block-type railway roadbed are filled with solid waste collaborative lightweight fillers. In this structure, the use of hollow glass microspheres is a key innovation. The uniform distribution of hollow glass microspheres in the lightweight filler can effectively absorb and disperse these vibration waves, thereby reducing the impact on the railway roadbed, extending the service life of the roadbed, and providing a smoother ride experience for train passengers. In addition, this design method also takes into account environmental sustainability. The use of hollow glass microspheres, rubber particles and fly ash not only improves the performance of the material, but is also an environmentally friendly choice because these materials can be recovered and reused from discarded glass materials, tires and slag, thereby reducing the burden on the environment.

[0022] The technical solution disclosed in the present invention is as follows:

[0023] A method for preparing a vibration-damping lightweight filler, characterized by:

[0024] Step 1: Ingredients and Proportions

[0025] A liquid foaming agent comprising silicate cement, fly ash, hollow glass microspheres, polycarboxylic acid water reducer, alkali metal salt of alkyl sulfonic acid and hydrolyzed protein in a composite composition according to a mass ratio;

[0026] Step 2: The preparation process of the lightweight filler includes: dilution and foaming of the foaming agent; mixing and stirring; molding and curing;

[0027] Step 3: Lightweight filler bulk density design

[0028] Accurately calculate the total volume of mixed dry materials, the total volume of water required and the mass of lightweight filler foam, as well as determine the design density of the lightweight filler.

[0029] The present invention also discloses an assembled block type railway roadbed structure, which is characterized in that: the railway roadbed structure includes a waterproof layer, an assembled block type railway roadbed and a foundation from top to bottom; the assembled block type railway roadbed is located above the foundation, and a waterproof layer formed by pouring asphalt concrete is provided above the foundation; the railway roadbed is composed of a combination of prefabricated blocks made of the above-mentioned vibration-damping lightweight filler.

[0030] The present invention also discloses a railway roadbed, which is characterized by: it is composed of the above-mentioned assembly base block type railway roadbed structure, the base block structure is a rectangular parallelepiped or cube configuration; single-point mortise and tenon connection is adopted between adjacent assembly base blocks.

[0031] The present invention also discloses a method for laying a railway roadbed, wherein the railway roadbed is the above-mentioned railway roadbed, and the method is characterized in that the method comprises the following steps:

[0032] Laying of base blocks:

[0033] Use the third design bulk density blocks; use the corresponding lifting device to lay the bottom layer blocks one by one or in multiple pieces simultaneously along the line direction; the bottom layer blocks use the third design bulk density blocks; when laying the bottom layer blocks, pay attention to the flatness and stability of the blocks, and ensure that each block is correctly placed and aligned; after laying a certain distance of the bottom layer blocks, start laying the middle layer blocks;

[0034] Laying of middle layer blocks:

[0035] The middle-layer foundation blocks adopt the second design bulk density foundation blocks. The pre-assembled middle-layer foundation blocks are placed on the bottom-layer foundation blocks in the same number as the bottom-layer foundation blocks by using a lifting device. During the laying process, ensure that the lower concave platform of the middle-layer foundation blocks is correctly embedded with the upper convex platform of the bottom-layer foundation blocks. After the middle-layer foundation blocks are laid, continue to lay the upper-layer foundation blocks in the same way.

[0036] Laying of upper foundation blocks:

[0037] The upper foundation block uses the first type of designed bulk density foundation block, and assembles the bottom, middle and upper foundation blocks in a predetermined order and method; uses a lifting device to connect the assembled section of roadbed with the previously laid section of roadbed in a concave-convex fit of the front and rear foundation blocks;

[0038] The assembly of the overall roadbed is completed:

[0039] Repeat the above steps until the entire railway subgrade is laid; during the laying process, continuously check the fit quality and stability of each layer of base blocks to ensure the uniformity and continuity of the entire railway subgrade.

[0040] Beneficial Effects

[0041] 1. Rapid repair and emergency response: The addition of hollow glass beads makes lightweight fillers easier to lay and cure quickly in emergency situations, which is particularly important for repairing railway subgrades or emergency response in disaster situations.

[0042] 2. Adapt to extreme environments: The addition of hollow glass beads improves the stability of lightweight fillers under extreme temperature and humidity conditions, making them more suitable for use in changing environmental conditions.

[0043] 3. Improve structural stability: The addition of hollow glass beads can increase the overall stability of lightweight fillers. This stability is crucial for high-speed railway subgrades, especially when subjected to long-term vibration and impact from high-speed trains.

[0044] 4. Enhanced durability: The properties of hollow glass microspheres include chemical corrosion resistance and wear resistance, which makes the lightweight filler mixed with this material have better long-term durability. For railway roadbeds, this means less maintenance and longer service life.

[0045] 5. Improve thermal and sound insulation performance: Hollow glass microspheres have good thermal and sound insulation properties, which are particularly important for improving the environmental quality along the railway and reducing noise pollution.

[0046] 6. Balance of light weight and high strength: The addition of hollow glass beads not only maintains the lightweight characteristics of lightweight fillers, but also improves their compressive strength. This is particularly critical for railway subgrades that need to carry heavy trains.

[0047] 7. Environmentally friendly: As an environmentally friendly material, the application of hollow glass microspheres meets the current demand for sustainable construction. The use of this material helps to reduce the impact on the environment while improving the overall sustainability of railway construction projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Sectional diagram of assembled block railway subgrade structure with rectangular and cube configurations;

[0049] Among them, 1-foundation, 1-1-foundation cut-off length 40m, 1-2-foundation width 30m, 1-3-foundation cut-off height 5m; 2-three-layer assembled block railway roadbed, 2-1-roadbed top layer block, 2-2-roadbed middle layer block, 2-3-roadbed bottom layer block, 3-waterproof layer. Rectangular and square components do not affect the selection of filler, and the filler is only related to the level. Among them, 2-1-roadbed top layer block uses the first design bulk density block, 2-2-roadbed middle layer block uses the second design bulk density block, and 2-3-roadbed bottom layer block uses the third design bulk density block. DETAILED DESCRIPTION

[0050] To achieve the above purpose, the vibration-damping lightweight filler for the assembled block type railway roadbed structural filler of the present invention is implemented by the following technical scheme:

[0051] A method for preparing a vibration-damping lightweight filler for an assembled block type railway roadbed structure, which aims to achieve an efficient and stable vibration reduction effect and ensure the long-term durability of the railway roadbed structure through a specific raw material ratio and production process. The following is a detailed description of the technical solution of the present invention:

[0052] 1. Raw materials and ratio design

[0053] (1): The raw materials include ordinary Portland cement (strength grade 42.5), fly ash, hollow glass microspheres of 15 to 85 μm, polycarboxylic acid water reducer (water reduction rate greater than 20%), and a liquid foaming agent composed of alkali metal salts of alkyl sulfonic acids and hydrolyzed protein in a mass ratio of 0.2% to 0.4%.

[0054] (2): Raw material weighing includes silicate cement, hollow glass microspheres and water to ensure accurate configuration of each component as required.

[0055] 2. Preparation process of lightweight filler

[0056] 1. Dilution and foaming of foaming agent: Use A01 foaming agent, mix it with water at the optimal dilution ratio and put it into the liquid storage tank. Use an air compressor to pressurize it to 0.5MPa, control the mixing ratio of foaming agent and air, and generate foam with ideal density.

[0057] 2. Mixing and stirring: Put the well-proportioned cement into the mixing pot and stir for 2 minutes, then add the dissolved water reducer and water, and continue stirring for 3-5 minutes. Then add the pre-made foam and stir until the foam and slurry are evenly mixed.

[0058] 3. Molding and curing: Pour the mixed foam lightweight soil into test pieces, cover them with film and transfer them to the curing room (control the temperature at 20±2.0℃) for natural curing until the strength requirements for demolding are met.

[0059] 3. Lightweight filler bulk density design

[0060] Mix the total volume of dry materials, the total volume of water required and 1m 3 Accurate calculation of lightweight fill foam mass and determination of lightweight fill design density.

[0061] Bulk density design of lightweight fillers:

[0062] (1) Calculate the total volume of mixed dry materials

[0063] (2) Calculate the total volume of water required

[0064] (3) Calculate 1m 3 The foam quality of lightweight fillers is measured as follows:

[0065]

[0066] (4) Calculate the bulk density of lightweight fillers

[0067] ρ s =S a m c

[0068] m w =Bm c

[0069] ρ s —Design density of lightweight filler;

[0070] S a --The mass of lightweight filler determined by the total amount of dry material and the total amount of non-evaporable matter of the product after the specified age of curing.

[0071] The coefficient for ordinary Portland cement is 1.2;

[0072] m c —Cement mass (kg);

[0073] m w —The mass of water (kg);

[0074] B—Water-cement ratio.

[0075] 4. Design of assembled block railway subgrade structure

[0076] The railway subgrade structure of the present invention includes a waterproof layer, an assembled block railway subgrade and a foundation from top to bottom. The assembled block railway subgrade is located above the foundation, and a waterproof layer formed by pouring asphalt concrete is arranged on the top. The railway subgrade is composed of blocks made of foamed lightweight soil materials prefabricated in the factory, and the structural form of the blocks can be a rectangular or cubic configuration. The assembled block railway subgrade adopts a simple and fast single-point mortise and tenon connection method, that is, the blocks are directly connected as a whole by concave and convex fittings, without the need for additional processing.

[0077] Through this series of carefully designed process flows and structural designs, the vibration-damping lightweight filler of the present invention not only provides the advantages of light weight and high vibration reduction in the railway roadbed structure, but also greatly improves the construction efficiency and structural stability through the assembly base block design. In addition, considering the environmental impact and cost-effectiveness, the present invention provides a railway infrastructure construction solution that is both economical and environmentally friendly. Through the precise proportion of materials, strict control of the preparation process, and meticulous maintenance and performance testing, the present invention can effectively improve the overall performance of the railway roadbed and provide an innovative technical solution for modern railway construction.

[0078] This embodiment provides three types of vibration-damping lightweight fillers, including the following raw materials by weight: the first type has a design bulk density of 800 (Kg / m 3 ), composed of the following parts by weight: cement 600-616 (kg / m 3 ), hollow glass beads 49~50(kg / m 3 ), water 308 (kg / m 3 ), foaming agent 12~18(g / m 3 ), water reducing agent 30~40(g / m 3 ), foam 1.746(m 3 / m 3 ).

[0079] The second design density is 400 (Kg / m 3 ), composed of the following parts by mass: cement 316 (kg / m 3 ), rubber particles 16 (kg / m 3 ), water 166 (kg / m 3 ), foam 0.873(m 3 / m 3 ), foaming agent 6~9(g / m 3 ), water reducing agent 15~20(g / m 3 ).

[0080] The third design density is 400 (Kg / m 3 ), composed of the following parts by mass: cement 266 (kg / m 3 ), fly ash 67 (kg / m 3), water 133 (kg / m 3 ), foam 0.873(m 3 / m 3 ), foaming agent 10~15(g / m 3 ), water reducing agent 25~35(g / m 3 ).

[0081] The requirements for the base block mold are as follows:

[0082] After the specimens are poured, they are covered with a film and moved into a curing room (20 ± 2.0°C) for natural curing. When the strength reaches the demolding requirement, the demolding is performed.

[0083] The laying method of the assembled block type railway subgrade structure aims to achieve efficient assembly and stability of the railway subgrade structure by using prefabricated blocks of different bulk densities and a specific laying sequence and method. The following are the detailed construction steps for laying prefabricated blocks:

[0084] Laying of base blocks:

[0085] Use the corresponding lifting device to lay the bottom foundation blocks one by one or in multiple pieces simultaneously along the line direction. The bottom foundation blocks adopt the third design bulk density blocks, which have higher stability and bearing capacity. When laying the bottom foundation blocks, pay attention to the flatness and stability of the blocks to ensure that each block is correctly placed and aligned. After laying a certain distance of the bottom foundation blocks, start laying the middle foundation blocks.

[0086] Laying of middle layer blocks:

[0087] The middle-layer foundation blocks adopt the second design bulk density blocks, which are balanced in lightness and strength. The pre-assembled middle-layer foundation blocks are placed on the bottom-layer foundation blocks in the same number as the bottom-layer foundation blocks using a lifting device. During the laying process, ensure that the lower concave platform of the middle-layer foundation blocks is correctly embedded with the upper convex platform of the bottom-layer foundation blocks to ensure the tight connection and overall stability of the structure. After the middle-layer foundation blocks are laid, continue to lay the upper-layer foundation blocks in the same way.

[0088] Laying of upper foundation blocks:

[0089] The upper layer blocks use the first type of design bulk density blocks, which are usually light in weight and easy to lay and adjust. The bottom, middle and upper layers of blocks are assembled in a predetermined order and method. A lifting device is used to connect the assembled section of roadbed with the previously laid section of roadbed in a way that the front and rear concave and convex fit of the blocks.

[0090] The assembly of the overall roadbed is completed:

[0091] Repeat the above steps until the entire railway subgrade is laid. During the laying process, the fit quality and stability of each layer of base blocks are constantly checked to ensure the uniformity and continuity of the entire railway subgrade.

[0092] Through the above steps, the assembled block type railway roadbed structure of the present invention can be assembled efficiently while ensuring the stability and durability of the structure. This laying method not only improves construction efficiency, but also reduces construction costs and time. In addition, the method provides a flexible construction solution that is suitable for different types of railway infrastructure construction, especially in complex terrain or where rapid construction is required. Through precise design and strict construction management, the long-term stability and reliability of the railway roadbed can be ensured, providing an innovative technical solution for modern railway construction.

[0093] The addition of hollow glass microspheres in the present invention plays a positive role in the application of lightweight fillers in many aspects, especially in the construction and maintenance of railway subgrades. First, the lightweight nature of this material makes it easier to quickly lay and cure lightweight fillers in emergency situations, such as disaster response or rapid repair. This is particularly critical for maintaining the integrity and function of the railway subgrade in emergencies. At the same time, hollow glass microspheres also improve the stability of concrete in extreme temperature and humidity conditions, making it more suitable for coping with changing environmental conditions, which is particularly important for railway construction and maintenance in complex climates.

[0094] In addition, hollow glass microspheres have a positive impact on the structural stability and durability of lightweight fillers. Lightweight fillers with this material show higher stability when subjected to long-term vibration and impact from high-speed trains, which is crucial to the safety and reliability of high-speed railway subgrades. In addition, the chemical corrosion and wear resistance of hollow glass microspheres provide lightweight fillers with longer service life and less maintenance requirements, which is a major advantage for long-term railway subgrade maintenance and economic benefits.

[0095] Finally, the application of hollow glass microspheres is also conducive to improving the thermal insulation and sound insulation performance of lightweight fillers, which is very important for improving the environmental quality along the railway and reducing noise pollution. At the same time, as an environmentally friendly material, the application of hollow glass microspheres in railway construction meets the current demand for sustainable development and helps to reduce the impact of construction projects on the environment. By adding hollow glass microspheres to lightweight fillers, a balance between lightness and high strength can be achieved, which is crucial for railway subgrades that carry heavy trains, while also improving the environmental friendliness and sustainability of the entire railway construction project.

[0096] The present invention proposes a new type of vibration-damping lightweight filler for use in the base block of a fast-assembled railway roadbed structure. This vibration-damping lightweight filler mainly focuses on achieving effective absorption and mitigation of railway operation vibrations through the scientific configuration of internal fillers. In this structure, the use of hollow glass microspheres is a key innovation. These microspheres have unique structural properties, namely, they have specific hollowness at the microscopic level. This property can provide excellent shock-absorbing function for lightweight fillers. The lightweight characteristics of hollow glass microspheres not only reduce the weight of the overall structure, but also because of the presence of their internal cavities, it brings better elasticity and compression rebound capabilities to lightweight fillers. The above advantages show that the use of hollow glass microspheres can reduce the performance loss of the material described in the present invention under dynamic loads, and provide new ideas for the performance optimization design of roadbed materials and the performance improvement of structures.

[0097] In summary, the design method of vibration-damping lightweight fillers in the prefabricated roadbed structure described in the present invention, by introducing hollow glass microspheres as key fillers, can not only improve the shock-absorbing performance of the material, but also take into account the economy and environmental sustainability, providing an innovative and practical solution for the high-quality, green and sustainable development of modern railway engineering.

[0098] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a vibration-damping lightweight filler, characterized by: Step 1: Ingredients and Proportions A liquid foaming agent comprising silicate cement, fly ash, hollow glass microspheres, polycarboxylic acid water reducer, alkali metal salt of alkyl sulfonic acid and hydrolyzed protein in a composite composition according to a mass ratio; Step 2: The preparation process of the lightweight filler includes dilution of the foaming agent and foaming; mixing and stirring; molding and curing; Step 3: Lightweight filler bulk density design Accurately calculate the total volume of mixed dry materials, the total volume of water required and the mass of lightweight filler foam, as well as determine the design density of the lightweight filler.

2. The method for preparing a vibration-damping lightweight filler according to claim 1, characterized in that: The ordinary Portland cement has a strength grade of 42.5, fly ash, hollow glass microspheres of 15 to 85 μm, a polycarboxylic acid water reducer with a water reduction rate greater than 20%, and a liquid foaming agent composed of alkali metal salts of alkyl sulfonic acids and hydrolyzed protein in a mass ratio of 0.2% to 0.4%.

3. The method for preparing a vibration-damping lightweight filler according to claim 1, characterized in that: The dilution and foaming process of the foaming agent is as follows: A01 type foaming agent is used, mixed with water according to the dilution ratio and then loaded into a liquid storage tank; the air compressor is used to pressurize to 0.5MPa, and the mixing ratio of the foaming agent and air is controlled to generate foam with an ideal density.

4. The method for preparing a vibration-damping lightweight filler according to claim 3, characterized in that: The mixing and stirring is as follows: putting the well-proportioned cement into a mixing pot and stirring for 2 minutes, then adding the dissolved water reducer and water, and continuing to stir for 3-5 minutes; then adding the prefabricated foam, and stirring until the foam and the slurry are evenly mixed.

5. The method for preparing a vibration-damping lightweight filler according to claim 4, characterized in that: The molding and curing are as follows: the mixed foam lightweight soil is cast into a test piece, and after covering, it is transferred to a curing room, the temperature is controlled at 20±2.0° C., and natural curing is performed until the strength requirement for demolding is reached.

6. An assembled block type railway roadbed structure, characterized by: The railway subgrade structure comprises a waterproof layer, an assembled block railway subgrade and a foundation from top to bottom; the assembled block railway subgrade is located above the foundation, and a waterproof layer made of asphalt concrete is provided on the top; the railway subgrade is composed of a combination of prefabricated blocks made of vibration-damping lightweight fillers as described in any one of claims 1-5.

7. A railway roadbed characterized by: It is composed of the assembly block type railway roadbed structure as described in claim 6, the block structure is in the shape of a cuboid or cube; adjacent assembly blocks are connected by a single-point mortise and tenon connection.

8. A method for laying a railway roadbed, wherein the railway roadbed is the railway roadbed according to claim 7, characterized in that: The steps include: Laying of base blocks: Use the third design bulk density blocks; use the corresponding lifting device to lay the bottom layer blocks one by one or in multiple pieces simultaneously along the line direction; the bottom layer blocks use the third design bulk density blocks; when laying the bottom layer blocks, pay attention to the flatness and stability of the blocks, and ensure that each block is correctly placed and aligned; after laying a certain distance of the bottom layer blocks, start laying the middle layer blocks; Laying of middle layer blocks: The middle-layer foundation blocks adopt the second design bulk density foundation blocks. The pre-assembled middle-layer foundation blocks are placed on the bottom-layer foundation blocks in the same number as the bottom-layer foundation blocks by using a lifting device. During the laying process, ensure that the lower concave platform of the middle-layer foundation blocks is correctly embedded with the upper convex platform of the bottom-layer foundation blocks. After the middle-layer foundation blocks are laid, continue to lay the upper-layer foundation blocks in the same way. Laying of upper foundation blocks: The upper foundation block uses the first type of designed bulk density foundation block, and assembles the bottom, middle and upper foundation blocks in a predetermined order and method; uses a lifting device to connect the assembled section of roadbed with the previously laid section of roadbed in a concave-convex fit of the front and rear foundation blocks; The assembly of the overall roadbed is completed: Repeat the above steps until the entire railway subgrade is laid; during the laying process, continuously check the fit quality and stability of each layer of base blocks to ensure the uniformity and continuity of the entire railway subgrade.

9. The method for laying a railway roadbed according to claim 8, characterized in that: The present embodiment provides three types of vibration-damping lightweight fillers, including the following raw materials by weight: the first type has a design bulk density of 800 (Kg / m 3 ), composed of the following parts by weight: cement 600-616 (kg / m 3 ), hollow glass beads 49~50(kg / m 3 ), water 308 (kg / m 3 ), foaming agent 12~18(g / m 3 ), water reducing agent 30~40(g / m 3 ), foam 1.746(m 3 / m 3 ); The second design density is 400 (Kg / m 3 ), composed of the following parts by mass: cement 316 (kg / m 3 ), rubber particles 16 (kg / m 3 ), water 166 (kg / m 3 ), foam 0.873(m 3 / m 3 ), foaming agent 6~9(g / m 3 ), water reducing agent 15~20(g / m 3 ); The third design density is 400 (Kg / m 3 ), composed of the following parts by mass: cement 266 (kg / m 3 ), fly ash 67 (kg / m 3 ), water 133 (kg / m 3 ), foam 0.873(m 3 / m 3 ), foaming agent 10~15(g / m 3 ), water reducing agent 25~35(g / m 3 ).

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