A backfill structure and construction method based on self-compacting vibration reduction backfill soil

Abstract

The application relates to a backfill structure based on self-compacting vibration-reducing backfill soil and a construction method, the backfill structure comprising a first self-compacting vibration-reducing backfill soil layer and a second self-compacting vibration-reducing backfill soil layer, and a vibration isolation layer arranged between the first self-compacting vibration-reducing backfill soil layer and the second self-compacting vibration-reducing backfill soil layer, wherein the vibration isolation layer comprises hollow bricks and rubber sheets arranged alternately. The backfill structure has good backfill effect, good compressive strength and good vibration isolation effect.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering technology, and in particular relates to a backfill structure and construction method based on self-compacting vibration-damping backfill soil. Background Technology

[0002] With the increasing scarcity of urban land, underground space construction projects are becoming more widespread. In the construction of subways, basements, and underground shopping malls, the open-cut method is often used. After the main structure is completed, backfilling of the foundation pit is necessary to serve as a force transfer zone between the main structure and the foundation. Patent application CN 113089747 A discloses a construction method for foundation pit backfilling based on self-compacting backfill soil. This method involves adding crushed soil in multiple groups according to the required mix proportions into a mixing chamber, along with corresponding curing agents, admixtures, and water to obtain self-compacting backfill soil. This self-compacting backfill soil is then used for layered backfilling of the foundation pit. A guide channel guides the self-compacting backfill soil into the pit, utilizing its self-leveling properties to fill and compact the pit until backfilling is complete. This results in good backfill strength and minimal settlement. Furthermore, no manual vibration is required after pouring, overcoming the limitations of insufficient construction space when backfilling narrow pits, and ensuring the strength and quality of the backfilled material.

[0003] However, with the development of backfill technology, application scenarios are becoming increasingly diversified, placing higher demands on backfilling. This is especially true in laboratories equipped with precision instruments, where vibration requirements are extremely stringent, with amplitude limits reaching the nm level and vibration velocities required to be at the μm / s level. With continuous urbanization and significant improvements in transportation infrastructure, the environmental vibrations generated by the constant flow of vehicles inevitably have a considerable impact on high-precision testing platforms. Therefore, the requirements for backfilling are becoming increasingly stringent, demanding not only sufficient strength, stability, and resistance to collapse, but also vibration isolation and resistance performance. Thus, it is necessary to improve existing backfilling technologies to enhance vibration resistance. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a backfill structure and construction method based on self-compacting vibration-damping backfill soil, which improves the vibration isolation and damping effect of the backfill while ensuring strength.

[0005] A first aspect of the present invention provides a backfill structure based on self-compacting vibration-damping backfill soil, comprising a first self-compacting vibration-damping backfill soil layer and a second self-compacting vibration-damping backfill soil layer, and a vibration isolation layer disposed between the first self-compacting vibration-damping backfill soil layer and the second self-compacting vibration-damping backfill soil layer, wherein the first self-compacting vibration-damping backfill soil layer and the second self-compacting vibration-damping backfill soil layer are formed by self-compacting vibration-damping backfill soil, the self-compacting vibration-damping backfill soil layer comprising soil material, rubber granules, curing agent, fly ash and water; the vibration isolation layer comprises hollow bricks and rubber sheets arranged alternately.

[0006] The backfill structure of this invention, by introducing a vibration isolation layer formed by alternating hollow bricks and rubber sheets, combined with a backfill vibration-damping soil layer containing rubber particles, can shield the propagation path of ground traffic vibrations, thus achieving vibration isolation. Furthermore, the backfill vibration-damping soil primarily uses undisturbed soil excavated from municipal engineering projects as raw material, combined with specific proportions of cement, curing agent, water, and fly ash. The vibration isolation layer uses hollow bricks and rubber sheets as raw materials; the raw materials are readily available and inexpensive, reducing backfill costs and project costs, while also providing good backfilling effect with good compressive strength and vibration isolation performance.

[0007] Preferably, in the self-compacting vibration-damping backfill, the mass ratio of water to dry soil is 0.28-0.34, the mass ratio of cement to dry soil is 0.12-0.15, the mass ratio of curing agent to dry soil is 0.15%, and the mass ratio of fly ash to cement is 2:8. The cured sample block has high strength. Furthermore, this formula uses fly ash to replace part of the cement, which can save costs. Here, "dry soil" refers to soil completely free of moisture. In actual batching calculations, the amount used can be calculated based on the net weight of the soil after removing moisture from its moisture content.

[0008] More preferably, the self-compacting vibration-damping backfill soil comprises 100 parts of dry soil, 32 parts of water, 12 parts of cement, 0.15 parts of curing agent, 3 parts of fly ash, and 20-40 parts of rubber granules.

[0009] In the self-compacting vibration-damping backfill soil of this invention, the soil material used is the original soil excavated from municipal engineering earthwork. The cement is the type commonly used for backfill solidification in municipal engineering, such as general-purpose silicate cement or slag cement conforming to standard GB175-2007. The curing agent is a soil and rock curing agent, preferably Zhongyan Dadi ZYDD curing agent. The rubber granules can be crushed rubber granules from waste tires; preferably, the particle size of the rubber granules is 1-2.5 mm.

[0010] Preferably, the flow value of the self-compacting vibration-damping backfill soil is 180-200mm, which has good fluidity and is more conducive to construction.

[0011] The hollow brick is a commonly used hollow brick as a main wall material, and the rubber sheet can be made from materials such as waste tires. Preferably, the side of the rubber sheet that contacts the hollow brick is the same size and has a thickness of 15-25mm, which provides better vibration isolation.

[0012] A second aspect of the present invention provides a construction method for the aforementioned backfill structure based on self-compacting vibration-damping backfill soil, comprising the steps of:

[0013] S1: Clean the bottom of the fertilizer pit, removing loose garbage, mortar, stones and other debris;

[0014] S2: Preparation of self-compacting vibration-damping backfill soil;

[0015] S3: Self-compacting vibration-damping backfill soil is used for backfilling the fertilizer trench. When the volume reaches about 70%, the first vibration-damping backfill soil layer is formed. Then, a vibration isolation layer is laid, which is formed by alternating hollow bricks and rubber sheets. After that, the self-leveling property of the self-compacting vibration-damping backfill soil is used to fill the fertilizer trench densely to form the second vibration-damping backfill soil layer until the backfilling is completed.

[0016] S4: Cover the backfilled fertilizer trench with a film to retain moisture and maintain its strength.

[0017] Preferably, step S2 includes:

[0018] S21, Screening soil from the excavated soil of the foundation pit and removing impurities;

[0019] S22, Test the moisture content of the soil material and control the moisture content to 10%-15% through drying measures;

[0020] S23, the soil material is crushed to obtain soil material with a particle size of less than 40mm, which can facilitate the mixing of the mixture and increase the contact area between the soil material and cement.

[0021] S24, the crushed soil is added to the mixing container in multiple groups according to the mixing ratio requirements, and the corresponding curing agent, rubber granules, fly ash and water are added at the same time. The mixture is stirred to produce the self-compacting vibration-damping backfill soil.

[0022] Preferably, in step S3, the backfill soil is poured in layers, with the initial pouring height not exceeding 0.5m and each subsequent pouring height not exceeding 2m. The interval between each layer of backfill soil is less than 3 hours, which is more conducive to ensuring better strength after pouring.

[0023] Preferably, step S4 includes:

[0024] S41, after the backfilling is completed, the surface is smoothed and leveled. After the self-compacting and vibration-damping backfill soil has initially set, the surface of the backfill soil is covered with plastic film or geotextile for moisture retention and curing. When the temperature is below 4℃, insulation cotton is required. During the curing period, a dedicated person is responsible for sprinkling water to keep the soil moist. The curing time is not less than 7 days.

[0025] S42. After construction, the self-compacting vibration-damping backfill soil shall be tested for 28-day and 90-day strength, including the compressive strength test of the test block, on-site core sampling and static cone penetration test. The strength shall be not less than 300 kPa. For projects without special requirements, the performance indicators of the self-compacting vibration-damping backfill soil shall be based on the test results at 90 days. For projects with special requirements, the performance indicators of the self-compacting vibration-damping backfill soil may be implemented according to the design requirements.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The backfill structure of the present invention introduces a vibration isolation layer formed by interleaved hollow bricks and rubber sheets in the backfill structure, combined with a backfill vibration damping soil layer with rubber particles. Since the hollow bricks are lightweight, high-strength, and porous, they can be filled with self-compacting vibration damping backfill soil during backfilling, thereby forming a vibration isolation zone with a certain strength, which can shield the propagation path of ground traffic vibration, play a good vibration isolation role, and at the same time ensure the strength of the backfill.

[0028] (2) The backfill vibration isolation layer uses the original soil excavated from the municipal engineering earthwork as the main raw material, combined with cement, water, curing agent, fly ash and other raw materials in a specific ratio. The vibration isolation layer uses hollow bricks and rubber sheets as raw materials. The raw materials are easy to obtain and the raw material cost is low, which reduces the backfill cost and project cost.

[0029] (3) The backfilling effect of the present invention is good, with good compressive strength and vibration isolation effect. The strength can reach 300-600KPa and the vibration isolation effect can reach 60%.

[0030] (4) The construction method of the present invention is simple. It can utilize the self-compacting properties of the vibration-damping backfill soil. After pouring, no manual vibration is required, which can overcome the disadvantage of insufficient construction space when backfilling narrow trenches. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the backfill structure of the present invention;

[0032] Figure 2 The structure of the vibration isolation layer of the present invention is shown in the schematic diagram.

[0033] Reference numerals: 100-First self-compacting vibration-damping backfill layer, 200-Vibration isolation layer, 300-Second self-compacting vibration-damping backfill layer; 1-Hollow brick, 2-Rubber sheet, 3-Soil material, 4-Rubber granules, 5-Fertilizer trench. Detailed Implementation

[0034] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0035] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0036] In the description of this invention, references to terms such as "some embodiments" and "examples" indicate that the specific methods or materials described in connection with that embodiment or example are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific methods and materials described may be combined in any suitable manner in one or more embodiments or examples.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0038] refer to Figure 1-2 A backfill structure based on self-compacting vibration-damping backfill soil includes a first self-compacting vibration-damping backfill soil layer 100; a vibration isolation layer 200; and a second self-compacting vibration-damping backfill soil layer 300.

[0039] The first self-compacting vibration-damping backfill layer 100 and the second self-compacting vibration-damping backfill layer 300 are formed by self-compacting vibration-damping backfill soil, which includes soil material 3, rubber granules 4, cement, curing agent, fly ash, and water. Soil material 3 refers to the original soil excavated from municipal engineering earthwork. Cement is the type of cement commonly used for backfill curing in municipal engineering, such as general-purpose silicate cement or slag cement conforming to standard GB175-2007. Curing agent is a soil and rock curing agent, preferably Zhongyan Dadi ZYDD curing agent. Rubber granules 4 can be crushed rubber granules from waste tires; preferably, the particle size of the rubber granules is 1-2.5 mm. Water can be fire-fighting water or tap water.

[0040] Preferably, in the self-compacting vibration-damping backfill, the mass ratio of water to dry soil is 0.28-0.34, the mass ratio of cement to dry soil is 0.12-0.15, the mass ratio of curing agent to dry soil is 0.15%, and the mass ratio of fly ash to cement is 2:8.

[0041] In some embodiments, the mass ratio of water to dry soil is 0.32, the mass ratio of cement to dry soil is 0.12, the mass ratio of curing agent to dry soil is 0.15%, and the mass ratio of fly ash to cement is 2:8.

[0042] In some embodiments, the self-compacting vibration-damping backfill soil includes 100 parts soil, 32 parts water, 12 parts cement, 0.2 parts curing agent, 3 parts fly ash, and 20-40 parts rubber granules.

[0043] Preferably, the flow value of the self-compacting vibration-damping backfill soil is 180-200mm, which has good fluidity and is more conducive to construction.

[0044] The vibration isolation layer 200 includes hollow bricks 1 and rubber sheets 2 arranged alternately. The hollow bricks 1 are commonly used hollow bricks in wall construction, such as cement hollow bricks, clay hollow bricks, and shale hollow bricks, with dimensions typically 390×190×190mm. The rubber sheets can be made from materials such as waste tires. The side of the rubber sheet in contact with the hollow bricks is the same size, and its thickness is 15-25mm, such as 15mm, 18mm, 20mm, or 25mm, resulting in better vibration isolation. The hollow bricks are lightweight, high-strength, and porous, allowing for the filling of self-compacting vibration-damping backfill soil during backfilling, thus forming a vibration isolation zone and providing good vibration isolation while ensuring the strength of the backfill.

[0045] The construction method for backfill structures based on self-compacting vibration-damping backfill soil includes the following steps:

[0046] S1: Clean the bottom of the fertilizer tank 5 pit, removing loose garbage, mortar, stones and other debris;

[0047] S2: Preparation of self-compacting vibration-damping backfill soil;

[0048] S21, Screening soil from the excavated soil of the foundation pit and removing impurities;

[0049] S22, test the moisture content of the soil and control the moisture content to 10%-15% through drying measures;

[0050] S23 involves crushing the soil to obtain soil with a particle size of less than 40mm, which facilitates the mixing of the mixture and increases the contact area between the soil and cement.

[0051] S24, the crushed soil is added to the mixing container in multiple groups according to the above-mentioned mix proportions, along with the corresponding curing agent, rubber granules, cement, fly ash, and water. The mixture is then stirred to produce the self-compacting vibration-damping backfill soil.

[0052] S3: Self-compacting vibration-damping backfill soil is used for backfilling the fertilizer trench. When the volume reaches about 70%, the first vibration-damping backfill soil layer is formed. Then, a vibration isolation layer is laid, which is formed by alternating hollow bricks and rubber sheets. After that, the self-leveling property of the self-compacting vibration-damping backfill soil is used to fill the fertilizer trench densely to form the second vibration-damping backfill soil layer until the backfilling is completed.

[0053] S4: Cover the backfilled fertilizer trench with a film to retain moisture and maintain its strength.

[0054] In some embodiments, in step S3, the backfill soil is poured in layers, with the initial pouring height not exceeding 0.5m and each subsequent pouring height not exceeding 2m. The interval between each layer of backfill soil is less than 3 hours, which is more conducive to ensuring better strength after pouring.

[0055] In some embodiments, step S4 includes:

[0056] S41, after the backfilling is completed, the surface is smoothed and leveled. After the self-compacting and vibration-damping backfill soil has initially set, the surface of the backfill soil is covered with plastic film or geotextile for moisture retention and curing. When the temperature is below 4℃, insulation cotton is required. During the curing period, a dedicated person is responsible for sprinkling water to keep the soil moist. The curing time is not less than 7 days.

[0057] S42. After construction, the self-compacting vibration-damping backfill soil shall be tested for 28-day and 90-day strength, including the compressive strength test of the test block, on-site core sampling and static cone penetration test. The strength shall not be less than 300 kPa. For projects without special requirements, the performance indicators of the self-compacting vibration-damping backfill soil shall be based on the test results at 90 days. For projects with special requirements, the performance indicators of the self-compacting vibration-damping backfill soil may be implemented according to the design requirements.

[0058] Vibration reduction effect simulation experiment:

[0059] Through calculation and simulation, as shown in Table 1, under the same filling conditions, based on the plain backfill soil (i.e., soil material, curing agent, admixture, and water) and the traditional structure (without a vibration isolation layer), the self-compacting vibration-damping backfill soil and vibration isolation strip design of the present invention, which incorporates rubber particles, achieves a vibration isolation effect of 60%, far exceeding that of existing plain backfill soil structures. If only rubber particles are added to improve the backfill soil without introducing vibration isolation strips, the vibration isolation effect of the self-compacting vibration-damping soil is improved by 36.8% (Comparative Example 2). This demonstrates that the backfill structure of the present invention significantly improves the vibration isolation effect through the combination of vibration isolation strips and rubber particles. Although the soil may experience freeze-thaw damage, and the final strength may differ from the simulation calculation due to different construction environments, resulting in an error of about 10% in the vibration isolation effect, it still reflects the good vibration resistance of the backfill structure of the present invention after construction.

[0060] Table 1 Simulation results of vibration reduction effect

[0061]

[0062] Backfill structure strength test:

[0063] In one experimental example, a 70.7mm × 70.7mm × 70.7mm cubic mold was used in the laboratory. The self-compacting vibration-damping backfill soil was prepared from 100 parts dry soil, 32 parts water, 12 parts cement, 0.2 parts Zhongyan Dadi ZYDD curing agent, 3 parts fly ash (particle size 1-2.5mm), and 40 parts rubber granules, with a flow value of 180-200mm. Following the above construction method, post-construction curing tests were conducted.

[0064] In step S3, the backfill soil is poured in layers. The initial pouring height does not exceed 0.5m, and the height of each subsequent pour does not exceed 2m. The interval between pouring layers of backfill soil is less than 3 hours.

[0065] Step S4 includes:

[0066] S41. After the backfill is poured, the surface is smoothed and leveled. After the self-compacting and vibration-damping backfill soil has initially set, the surface of the backfill soil is covered with plastic film or geotextile for moisture retention and curing. When the temperature is below 4℃, insulation cotton is required. During the curing period, a designated person is responsible for sprinkling water to keep the soil moist. The curing time is not less than 7 days.

[0067] Unconfined compressive strength was studied on the cured specimens. Specifically, the specimen was placed at the center of the lower bearing plate of the universal testing machine, ensuring that the bearing surface of the solidified soil specimen was perpendicular to the molding surface. The universal testing machine was started, and the upper bearing plate was gradually adjusted to slowly approach the specimen until the upper bearing plate made light contact with the specimen and no force was generated. In this experiment, a loading speed of 1 mm / min was selected to begin loading, and the test ended when the specimen failed after the pressure peak was reached. The peak pressure was recorded, and the ultimate compressive strength was calculated. The strength can reach 300-600 kPa. This demonstrates that the backfill structure of this invention can have good strength after construction.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] (1) The backfill structure of the present invention introduces a vibration isolation layer in the backfill structure, and rubber particles are introduced into the backfill vibration damping soil layer, which can shield the propagation path of ground traffic vibration and play a vibration isolation role.

[0070] (2) The backfill vibration isolation layer uses the original soil excavated from the municipal engineering earthwork as the main raw material, combined with cement, water, curing agent, fly ash and other raw materials in a specific ratio. The vibration isolation layer uses hollow bricks and rubber sheets as raw materials. The raw materials are easy to obtain and the raw material cost is low, which reduces the backfill cost and project cost.

[0071] (3) It has good backfilling effect, good compressive strength and vibration isolation effect. The strength can reach 300-600KPa, and the vibration isolation effect can reach 60%.

[0072] (4) The construction method of the present invention is simple. It can utilize the self-compacting properties of the vibration-damping backfill soil. After pouring, no manual vibration is required, which can overcome the disadvantage of insufficient construction space when backfilling narrow trenches.

[0073] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A backfill structure based on self-compacting vibration-damping backfill soil, characterized in that, It includes a first self-compacting vibration-damping backfill layer and a second self-compacting vibration-damping backfill layer, and a vibration isolation layer disposed between the first self-compacting vibration-damping backfill layer and the second self-compacting vibration-damping backfill layer. The first and second self-compacting vibration-damping backfill layers are formed from self-compacting vibration-damping backfill soil. The self-compacting vibration-damping backfill soil includes soil, rubber granules, cement, curing agent, fly ash and water; The vibration isolation layer comprises hollow bricks and rubber sheets arranged alternately.

2. The backfill structure according to claim 1, characterized in that, In the self-compacting vibration-damping backfill soil The mass ratio of water to dry soil is 0.28-0.

34. The mass ratio of cement to dry soil is 0.12-0.

15. The mass ratio of the curing agent to the dried soil is 0.15%. The fly ash to cement mass ratio is 2:

8.

3. The backfill structure according to claim 2, characterized in that, The self-compacting vibration-damping backfill soil comprises 100 parts dry soil, 32 parts water, 12 parts cement, 0.15 parts curing agent, 3 parts fly ash, and 20-40 parts rubber granules.

4. The backfill structure according to claim 1, characterized in that, The thickness of the rubber sheet is 15-25mm.

5. The backfill structure according to claim 1, characterized in that, The flow value of the self-compacting vibration-damping backfill soil is 180-200mm.

6. A construction method for a backfill structure based on self-compacting vibration-damping backfill soil as described in any one of claims 1-5, characterized in that, Including the following steps: S1: Clean the bottom of the fertilizer pit, removing loose garbage, mortar, stones and other debris; S2: Preparation of self-compacting vibration-damping backfill soil; S3: Self-compacting vibration-damping backfill soil is used for backfilling the fertilizer trench. When the volume reaches about 70%, the first self-compacting vibration-damping backfill soil layer is formed. Then, a vibration isolation layer is laid, which is formed by alternating hollow bricks and rubber sheets. After that, the self-leveling property of the self-compacting vibration-damping backfill soil is used to fill the fertilizer trench densely to form the second self-compacting vibration-damping backfill soil layer until the backfilling is completed. S4: Cover the backfilled fertilizer trench with a film to retain moisture and maintain its strength.

7. The construction method according to claim 6, characterized in that, Step S2 includes: S21, Screening soil from the excavated soil of the foundation pit and removing impurities; S22, Test the moisture content of the soil material and control the moisture content to 10%-15% through drying measures; S23, the soil material is crushed to obtain soil material with a particle size of less than 40mm; S24, the crushed soil is added to the mixing container in multiple batches according to the mixing ratio requirements, along with the corresponding cement, curing agent, rubber granules, fly ash and water, and mixed to produce the self-compacting vibration-damping backfill soil.

8. The construction method according to claim 6, characterized in that, In step S3, the backfill soil is poured in layers. The initial pouring height does not exceed 0.5m, and the height of each subsequent pouring does not exceed 2m. The interval between each layer of backfill soil is less than 3 hours.

9. The construction method according to claim 6, characterized in that... Step S4 includes: S41, after the backfilling is completed, the surface is smoothed and leveled. After the self-compacting and vibration-damping backfill soil has initially set, the surface of the backfill soil is covered with plastic film or geotextile for moisture retention and curing. When the temperature is below 4℃, insulation cotton is required. During the curing period, a dedicated person is responsible for sprinkling water to keep the soil moist. The curing time is not less than 7 days. S42. After construction, the self-compacting vibration-damping backfill soil shall be tested for 28-day and 90-day strength, including the compressive strength test of the test block, on-site core sampling and static cone penetration test. The strength shall be not less than 300 kPa. For projects without special requirements, the performance indicators of the self-compacting vibration-damping backfill soil shall be based on the test results at 90 days. For projects with special requirements, the performance indicators of the self-compacting vibration-damping backfill soil may be implemented according to the design requirements.

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