Composite high-bearing platform back backfilling structure and construction method thereof

Abstract

The invention discloses a composite high-bearing abutment back backfilling structure and a construction method thereof, and belongs to the technical field of road backfilling. The abutment back backfilling structure comprises side sealing soil, large-size stone, an isolation layer and a flow state filling material, the side sealing soil is arranged between a lateral retaining wall of the bridge and culvert component and a roadbed, so that a backfilling area is formed among the bridge and culvert component, the side sealing soil and the roadbed, in the backfilling area, the large-size stone is filled in a layered mode, the isolation layer is arranged between the layers, and after filling is conducted to the designed height, the flow state filling material is filled. And flow state filling materials are injected in a layered mode through the pre-buried vertical guide pipes to complete backfilling. Compared with the prior art, the long-term bearing capacity, deformation stability and service toughness of the abutment back backfilling structure can be greatly improved, and the method has good application and popularization value.

Description

Technical Field

[0001] The invention relates to the field of road engineering, in particular to a composite high-bearing platform backfill structure and a construction method thereof. Background Art

[0002] With the high-quality development of my country's transportation infrastructure construction, higher requirements have been placed on the resilience and safety of engineering services. In previous high-grade highway projects, the transition section between rigid structures such as bridges and culverts and the roadbed is often prone to differential settlement and deformation, and vehicles passing at high speeds will experience obvious bumps and impacts, namely the "bridge head jump" phenomenon. The existence of this phenomenon not only directly affects the service life of bridges and roads, but also causes drivers to passively brake and slow down, and even causes safety accidents.

[0003] At present, cement-solidified soil, crushed stone soil, milling materials and other materials are mostly used for backfilling the transition sections of structures such as bridges and culverts. These materials have the characteristics of high strength and good water stability, which can reduce the occurrence of bridge head bounce disease to a certain extent. However, the above materials have high requirements on material quality, strict control of the construction process, and are not easy to obtain in some areas, resulting in certain limitations in practical applications. Stone materials have the characteristics of extremely high strength, strong compression resistance, and good durability. Therefore, it is of great practical significance to further develop high-load-bearing, low-deformation abutment backfill structures and construction methods based on the characteristics of stone materials. Summary of the invention

[0004] The technical task of the present invention is to provide a composite high-load-bearing platform backfill structure in view of the deficiencies of the above-mentioned prior art, which has the characteristics of large overall stiffness, high bearing capacity, small post-construction settlement and high construction efficiency.

[0005] The technical task of the present invention is achieved in the following way: a composite high-load-bearing platform backfill structure, including side sealing soil, large-size stones, isolation layers and fluid filling materials,

[0006] The side sealing soil is set between the lateral retaining wall of the bridge and culvert components and the roadbed, so that a backfill area is formed between the bridge and culvert components, the side sealing soil and the roadbed.

[0007] In the backfill area, large-size stones are filled in layers, and isolation layers are set between the layers. After filling to the designed height, the fluid filling material is injected in layers through the pre-buried vertical conduit to complete the backfill.

[0008] The particle size of the large-size stone is in the range of 30 cm to 80 cm, and the porosity after compaction is 15% to 35%;

[0009] The side sealing soil and the isolation layer are both made of clay fine-grained soil or silty clay fine-grained soil, with a compaction degree greater than 96%;

[0010] The vertical conduit comprises an inner tube and an outer tube which are sleeved together, and a grouting hole is opened on the inner tube or the outer tube.

[0011] Preferably, vertical conduits are pre-buried on one side of the backfill area close to the culvert components, and several transverse conduits are pre-buried on one side of the backfill area close to the roadbed. The transverse conduits are located on the top of each layer of large-size stones, and their outer ends extend to the outside of the side cover.

[0012] Preferably, a sealing member is provided between the outer wall of the inner tube and the inner wall of the outer tube of the vertical conduit, and the sealing member is preferably a sealing ring.

[0013] Preferably, the inner tube is a steel tube with openings at both ends, the upper end of which is used to connect to the grouting equipment, and the lower end is inserted into the outer tube. The outer tube is a steel tube with a closed lower end, and grouting holes are opened in the tube wall.

[0014] Preferably, the outer tube is a steel tube with openings at both ends, the upper end of which is used to connect to the grouting equipment, and the lower end is sleeved on the outside of the inner tube. The inner tube is a steel tube with a closed lower end, and grouting holes are opened on the tube wall.

[0015] Preferably, the fluid filling material is formed by uniformly mixing powder and water in a proportion, the mass ratio of powder to water is 1:(0.70-1.20), and the powder includes the following raw materials in weight proportion:

[0016]

[0017] In the fluid filling material, stone powder and / or tailings powder and / or fine soil are used as the main carriers, which are fully dispersed with water to form a homogeneous slurry. Titanium gypsum has fine particles and contains a large amount of Ca 2+ , can be fully dispersed in the slurry and adsorbed on the solid particles, and the colloidal structure of the Fe, Al and other elements contained in it further enhances the cohesiveness and cementation of the slurry. Steel slag powder and / or volcanic ash powder contain a large amount of Ca, Si, Al, Fe and other compounds, which react with SO4 contained in titanium gypsum. 2+ The reaction forms low-solubility calcium aluminum sulfate minerals, which give the slurry hardening strength. The sulfonic acid group and allyl functional group contained in sodium α-olefin sulfonate (white or light yellow powder, purity greater than 99%) can accelerate the dissolution of solid particles in the slurry with the aqueous solution, as well as Ca 2+ 、Si 4+ The dispersion of high-valent ions such as iodine and iodine can reduce the segregation of solid particles due to differences in particle size and weight. Sodium cocoyl glycinate (white powder, active ingredient content greater than 95%, pH value 7-9) can neutralize the electrostatic interaction between solid particles and reduce frictional resistance. In the later stage of the reaction, a film is formed on the surface of solid particles, which effectively improves the early stability and flowability of the slurry, and improves the long-term durability against water-air circulation. Sodium tripolyphosphate (white powder, purity greater than 98%) and Ca in the slurry 2+、Al 3+ Calcium aluminum phosphate crystals are formed in the cations, further filling the micropores of the gel structure, which can improve the water resistance and anti-penetration performance of the hardened filling material.

[0018] The weight ratio of each raw material in the powder is further preferably:

[0019]

[0020] Preferably, the fluidity of the fluid filling material is 200 mm to 260 mm, the strength after hardening is not less than 500 kPa, the 28d softening coefficient is greater than 0.8, and the 28d permeability coefficient is less than 1.5×10 -6 cm / s, 28d shrinkage coefficient is less than 2.5×10 -4 .

[0021] Preferably, the maximum particle size of the clay fine-grained soil or silty clay fine-grained soil does not exceed 1 mm, the liquid limit is not higher than 50%, and the plasticity index is greater than 17.

[0022] Preferably, the compacted thickness of the side sealing soil and large-size stones is 30 cm to 80 cm, and the width of the side sealing soil is 1 to 2 m;

[0023] The compacted thickness of the isolation layer is 5 cm to 10 cm.

[0024] A further technical task of the present invention is to provide a construction method for the above-mentioned pavement structure.

[0025] The construction method of the composite high-bearing platform backfill structure is characterized by comprising the following steps:

[0026] a. Level and compact the foundation of the backfill structure of the platform;

[0027] b. Pre-embed a number of vertical conduits on one side of the bridge culvert component;

[0028] c. Carry out the first layer of filling construction

[0029] c1. Spread large-sized stones between the bridge and culvert components and the roadbed, spread side covering soil between the lateral retaining wall of the bridge and culvert components and the roadbed, level them, and bury transverse guide pipes on the side close to the roadbed and compact them;

[0030] c2. Spread a layer of isolation material on the compacted large-size stones and side sealing soil and compact it;

[0031] d. Follow step c to fill and construct until the designed height is reached;

[0032] e. Preparation of fluid filling material;

[0033] f. Adjust the relative height of the inner and outer tubes of the vertical conduit, and use pressure grouting equipment to fill the large-sized stones with fluid filling materials in layers until the filling materials flow out of the horizontal conduit at the filled layer and then seal it;

[0034] g. Follow step f to perform grouting and filling construction until the top layer is reached.

[0035] Preferably, in step a, the compaction degree of the foundation of the backfill structure of the platform is greater than 90%, and the rebound modulus is greater than 30 MPa.

[0036] Preferably, the lateral spacing between adjacent vertical conduits in step b is 1.5 m to 3.0 m. The length of the vertical conduit can be slightly higher than the filling height, for example, the length of the vertical conduit is 10 to 40 cm higher than the filling height.

[0037] Preferably, in step c1, the large-sized stones and side sealing soil are compacted 4 to 6 times by a 4t to 8t vibratory roller or 1 to 2 times by a 14t or higher vibratory roller.

[0038] Preferably, in step c2, the isolation layer material is compacted 2-3 times by a 4-8 t vibratory roller and statically pressed once, or compacted 1 time by a ≥14 t vibratory roller and statically pressed once;

[0039] Preferably, the grouting pressure in step f is 0.2 MPa to 1.0 MPa.

[0040] Compared with the prior art, the composite high-load-bearing platform backfill structure and the construction method thereof of the present invention have the following outstanding beneficial effects:

[0041] (I) Based on the material compression characteristics and the principle of macroscopic deformation coordination, the present invention strengthens the ability of the transition section between the rigid bridge and culvert components and the roadbed to resist deformation under short-term and long-term effects, thereby realizing the long-term deformation continuous gradual transition of "bridge and culvert components-transition section-roadbed", and solving the bridge head jumping disease caused by local subsidence, uneven settlement, etc.

[0042] (II) The present invention adopts a new structural design method, using high-strength large-size stone as the main load-bearing skeleton, and using self-hardening, anti-penetration high-fluidity materials for filling and further stabilizing support, thereby forming an overall reinforced structure. Compared with the existing backfill structure based on mechanical compaction and physical compaction, the long-term bearing capacity, deformation stability and service toughness of the structure are greatly improved.

[0043] (III) The present invention uses clay fine-grained soil or silty clay fine-grained soil as an isolation layer, which can effectively reduce the spatial discreteness of large-sized stones in the vertical dimension and improve the overall bearing uniformity of the backfill structure. At the same time, it serves as an isolation measure for the layered construction of fluidized filling materials, greatly improving the pouring and filling effect and ensuring the internal integrity of the backfill structure.

[0044] (IV) The present invention adopts a new structural construction method, through the construction technology of "filling complementation" and "module control", which effectively solves the practical problems commonly existing in the existing traditional platform backfill technology, such as high material standards, high compaction requirements, high project costs, difficult to control construction quality, poor long-term toughness, and difficult maintenance and repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Attached Figure 1 It is a schematic diagram of the position relationship between the bridge and culvert components and the roadbed before backfilling;

[0046] Attached Figure 2 This is a three-dimensional diagram of the composite high-load-bearing platform backfill structure of the first embodiment;

[0047] Attached Figure 3 This is a schematic diagram of the composite high-load-bearing platform backfill structure of the first embodiment;

[0048] Attached Figure 4 Figure 3 AA section view of the backfill structure shown

[0049] Attached Figure 5 It is a schematic diagram of the vertical conduit structure in the composite high-load-bearing platform backfill structure of Example 1.

[0050] Attached Figure 6 It is a structural schematic diagram of a vertical duct.

[0051] The symbols in the accompanying drawings represent:

[0052] 1. Bridge and culvert components, 11. Lateral retaining wall, 2. Roadbed, 3. Lateral sealing soil, 4. Large-sized stone, 5. Flowing filling material, 6. Isolation layer, 7. Vertical duct, 71. Inner pipe, 72. Outer pipe, 73. Grouting hole, 74. Sealing ring, 8. Horizontal duct, DETAILED DESCRIPTION

[0053] The composite high-load-bearing platform backfill structure and the construction method thereof of the present invention are described in detail below with reference to the accompanying drawings of the specification by using specific embodiments.

[0054] Since the bridge and culvert components are in various forms, and the cross-section of the lateral retaining wall is rectangular, trapezoidal, etc., in combination with common forms in practical applications, each embodiment is simplified uniformly. The structure of the bridge and culvert component 1 and its positional relationship with the roadbed 2 are shown in FIG. Figure 1 shown.

[0055] Embodiment 1:

[0056]

Backfill structure

[0057] As attached Figure 2-4As shown, the composite high-bearing platform backfill structure of this embodiment is mainly composed of side sealing soil 3, large-size stones 4, fluid filling materials 5 and isolation layer 6 filled between the bridge culvert component 1 and the roadbed 2.

[0058] The side sealing soil 3 is filled between the lateral retaining wall 11 of the bridge culvert component 1 and the roadbed 2, so that a backfill area is formed between the bridge culvert component 1, the side sealing soil 3 and the roadbed 2. The total filling height of the backfill area is 3.5m, which can be divided into 5 layers.

[0059] In the backfill area, the large-size stones 4 are filled in five layers, and the top surfaces of the interlayers and the uppermost layer are filled with isolation layers 6. In addition, six vertical pipes 7 are pre-buried on the side of the backfill area close to the bridge culvert component 1, and ten transverse pipes 8 are pre-buried on the side close to the roadbed 2. The ten transverse pipes 8 are respectively located on both sides of the top of each layer of large-size stones 4, and their outer ends extend to the outside of the side sealing soil 3.

[0060] In this embodiment, the filling thickness of a single layer of large-size stones is 60 cm, and natural stones with a particle size of 30 cm to 60 cm are used, and the uniaxial saturated compressive strength of the stones is 80 MPa.

[0061] The width of the side sealing soil in this embodiment is 1m, and clay fine-grained soil is used, with a maximum particle size of no more than 1mm, a liquid limit of 39.2%, and a plasticity index of 22.1.

[0062] The filling thickness of the isolation layer in this embodiment is 10 cm, and clay fine-grained soil is used, with a maximum particle size of no more than 1 mm, a liquid limit of 39.2%, and a plasticity index of 22.1.

[0063] The fluid filling material of this embodiment is made by uniformly mixing powder and water. The mass ratio of stone powder, titanium gypsum, steel slag powder, sodium α-olefin sulfonate, sodium cocoyl glycinate and sodium tripolyphosphate in the powder is 55:18:14:0.9:0.7:0.5.

[0064] As attached Figure 5 As shown, the vertical conduit 7 of this embodiment is mainly composed of an inner tube 71 and an outer tube 72. The inner tube 71 is a steel tube with two ends open, an outer diameter of 9.5 cm, and a wall thickness of 2 mm. Its upper end is used to connect the grouting equipment, and the lower end is inserted into the outer tube 72.

[0065] The outer tube 72 is a steel tube with a closed lower end, an inner diameter of 10 cm, a wall thickness of 3 mm, and a grouting hole 73 with a diameter of 1.2 cm. The filling height of the fluid filling material can be adjusted by adjusting the relative positions of the inner tube 71 and the outer tube 72.

[0066] A sealing ring 74 is installed between the outer wall of the inner tube 71 and the inner wall of the outer tube 72 .

[0067] The transverse conduit 8 is a steel pipe with openings at both ends, a wall thickness of 2 mm and an inner diameter of 8 cm.

[0068]

Construction steps

[0069] The construction method of the composite high-load bearing platform backfill structure of this embodiment is as follows:

[0070] a. Level and compact the foundation of the backfill structure of the platform, with a compaction degree of 93% and a rebound modulus of 40MPa;

[0071] b. A row of vertical conduits 7 is pre-buried on one side of the culvert component 1. The lateral spacing between adjacent vertical conduits 7 is 1.6m, and the length is greater than the filling height by 30cm (wherein the inner tube is 3.8 and the outer tube is 3.6m).

[0072] c. Carry out the first layer of filling construction

[0073] c1. Spread large-size stones between the bridge culvert component 1 and the roadbed 2, spread 1-meter-wide side sealing soil 3 between the lateral retaining wall 11 of the bridge culvert component 1 and the roadbed 2, level it, and bury two transverse guide tubes 8 on the side close to the roadbed.

[0074] An 8t vibratory roller was used to perform vibration compaction for 5 times, with a compaction thickness of 60 cm. After compaction, the porosity of the large-size stone 4 was 32%, and the compaction degree of the side sealing soil 3 was 96.5%.

[0075] c2. Spread a layer of clayey fine-grained soil on the compacted large-size stones 4 and side sealing soil 3, and use an 8t vibratory roller to vibrate and compact 3 times and statically compact 1 time to form an isolation layer 6. The compaction thickness is 10 cm and the on-site compaction degree is 97.4%.

[0076] d. Follow step c to fill and construct until the designed height is reached;

[0077] e. Preparation of fluid filling materials

[0078] The powder and water were mixed in a ratio of 1:0.9 and stirred for 120 seconds using a forced stirring device to prepare a homogeneous fluid filling material with a fluidity of 240 mm ± 10 mm, a strength of 600 kPa to 650 kPa after hardening, a 28-day softening coefficient of 0.83, and a 28-day permeability coefficient of 1.26 × 10 -6 cm / s, and the shrinkage coefficient at 28 days is 1.85×10 -4 .

[0079] f. Adjust the height of the lower end of the inner tube 71 of the vertical conduit 7 to the corresponding filling layer, and use the pressure grouting equipment to fill the large-sized stones 4 layer by layer. The pressure during grouting is controlled at 0.4-0.6MPa until the horizontal conduit 8 at the filled layer flows out the filling material and then seals it.

[0080] g. Follow step f to perform grouting and filling construction until the top layer is reached.

[0081] Embodiment 2:

[0082] The backfill structure and construction method of this embodiment are basically the same as those of the first embodiment, the only difference being the size of the large-size stones and the layer thickness: the filling thickness of a single layer of large-size stones is 40 cm, and natural stones with a particle size of 30 cm to 40 cm are used. The uniaxial saturated compressive strength of the stones is 80 MPa, and the porosity after compaction is 28%.

[0083] The second embodiment is implemented simultaneously with the first embodiment, and is constructed and tested in sections.

[0084] Embodiment three:

[0085] The backfill structure and construction method of this embodiment are basically the same as those of the first embodiment, except that the mixing ratio of the components of the fluid filling material is 58:13:15:0.8:0.6:0.4 in the powder, and the mass ratio of the powder to water is 1:1.

[0086] The fluidity of the prepared fluid filling material is 250mm±10mm, the strength after hardening is 530kPa~570kPa, the 28d softening coefficient is 0.81, and the 28d permeability coefficient is 1.37×10 -6 cm / s, and the shrinkage coefficient at 28 days is 2.01×10 -4 .

[0087] The third embodiment is implemented simultaneously with the first embodiment, and is constructed and tested in sections.

[0088] Embodiment 4:

[0089] The backfill structure and construction method of this embodiment are basically the same as those of the first embodiment, and the only difference is the selection of raw materials for each component of the fluid filling material: the mass ratio of fine-grained soil, titanium gypsum, volcanic ash powder, sodium α-olefin sulfonate, sodium cocoyl glycinate, and sodium tripolyphosphate in the powder is 55:18:14:0.9:0.7:0.5. The mass ratio of powder to water is 1:0.9.

[0090] The fluidity of the prepared fluid filling material is 235mm±10mm, the strength after hardening is 610kPa~630kPa, the 28d softening coefficient is 0.82, and the 28d permeability coefficient is 1.29×10 -6 cm / s, and the shrinkage coefficient at 28 days is 1.94×10 -4 .

[0091] The fourth embodiment is implemented simultaneously with the first embodiment, and is constructed and tested in sections.

[0092] Embodiment five:

[0093] As attached Figure 6 As shown, the vertical conduit 7 of this embodiment is mainly composed of an inner tube 71 and an outer tube 72.

[0094] The outer tube 72 is a steel tube with openings at both ends, an inner diameter of 10 mm and a wall thickness of 3 mm. Its upper end is used to connect to the grouting equipment, and its lower end is sleeved on the outside of the inner tube 71.

[0095] The inner tube 71 is a steel tube with a closed lower end, an outer diameter of 9.5 cm, a wall thickness of 2 mm, and a grouting hole 73 with a diameter of 1.1 cm. The filling height of the fluid filling material can be adjusted by adjusting the relative positions of the inner tube 71 and the outer tube 72.

[0096] A sealing ring 74 is installed between the outer wall of the inner tube 71 and the inner wall of the outer tube 72 .

[0097] [Comparative Example]

[0098] Each comparative example adopts the construction method described in Example 1, changes the filling material or the structure layer setting, and measures the service performance indexes of the platform backfill structure of each example and comparative example, as shown in the following table:

[0099]

[0100] It can be seen from the comparison results that the composite high-load-bearing platform backfill structure of the present invention realizes the long-term deformation continuous gradual transition of "structure-transition section-roadbed" through the organic combination of large-size stones and fluidized fillers in the structure, the water-proof and anti-seepage functions of the fluidized fillers in the material, and the "filling complementation" and "module control" processes in the construction. It solves the bridge head jumping disease caused by local subsidence, uneven settlement, etc., reduces construction and maintenance costs, and can greatly improve the long-term bearing capacity, deformation stability and service toughness function of the backfill structure.

Claims

1. A composite high-load-bearing platform backfill structure, characterized in that: Including side sealing soil, large-size stones, isolation layer and fluid filling material, The side sealing soil is set between the lateral retaining wall of the bridge and culvert components and the roadbed, so that a backfill area is formed between the bridge and culvert components, the side sealing soil and the roadbed. In the backfill area, large-size stones are filled in layers, and isolation layers are set between layers. After filling to the designed height, fluid filling materials are injected in layers through the pre-buried vertical conduits to complete the backfill. The particle size of the large-size stone is in the range of 30 cm to 80 cm, and the porosity after compaction is 15% to 35%; The side sealing soil and the isolation layer are both made of clay fine-grained soil or silty clay fine-grained soil, with a compaction degree greater than 96%; The vertical conduit comprises an inner tube and an outer tube which are sleeved together, and a grouting hole is opened on the inner tube or the outer tube.

2. The composite high-load-bearing platform backfill structure according to claim 1 is characterized in that: The vertical duct is pre-buried on one side of the backfill area close to the bridge culvert components, and several transverse ducts are pre-buried on one side of the backfill area close to the roadbed. The transverse ducts are located on the top of each layer of large-size stones, and their outer ends extend to the outside of the side cover soil.

3. The composite high-load-bearing platform backfill structure according to claim 1 is characterized in that: A sealing member is arranged between the outer wall of the inner tube and the inner wall of the outer tube of the vertical conduit.

4. The composite high-load bearing platform backfill structure according to claim 1, 2 or 3, characterized in that: The inner tube is a steel tube with two ends open, the upper end of which is used to connect the grouting equipment, and the lower end is inserted into the outer tube. The outer tube is a steel tube with a closed lower end and a grouting hole is opened on the tube wall; or, The outer tube is a steel tube with openings at both ends. Its upper end is used to connect to the grouting equipment, and its lower end is sleeved on the outside of the inner tube. The inner tube is a steel tube with a closed lower end, and grouting holes are opened on the tube wall.

5. The composite high-load bearing platform backfill structure according to claim 1, 2 or 3, characterized in that: The fluid filling material is formed by uniformly mixing powder and water in proportion, the mass ratio of powder to water is 1:(0.70-1.20), and the powder includes the following raw materials in weight proportion:

6. The composite high-load-bearing platform backfill structure according to claim 5 is characterized in that: The fluidity of the fluid filling material is 200 mm to 260 mm, the strength after hardening is not less than 500 kPa, the 28d softening coefficient is greater than 0.8, and the 28d permeability coefficient is less than 1.5×10 -6 cm / s, 28d shrinkage coefficient is less than 2.5×10 -4 .

7. The composite high-load bearing platform backfill structure according to claim 1, 2 or 3, characterized in that: The maximum particle size of clay fine-grained soil or silty clay fine-grained soil shall not exceed 1 mm, the liquid limit shall not be higher than 50%, and the plasticity index shall be greater than 17.

8. The composite high-load-bearing platform backfill structure according to claim 7 is characterized in that: The compaction thickness of the side cover soil and large-size stones is 30cm to 80cm, and the width of the side cover soil is 1 to 2m; The compacted thickness of the isolation layer is 5 cm to 10 cm.

9. The method for constructing the composite high-load bearing platform backfill structure according to claim 1, characterized in that: The following steps are involved: a. Level and compact the foundation of the backfill structure of the platform; b. Pre-embed a number of vertical conduits on one side of the bridge culvert component; c. Carry out the first layer of filling construction c1. Spread large-sized stones between the bridge culvert structure and the roadbed, spread side sealing soil between the lateral retaining wall of the bridge culvert component and the roadbed, level it, and bury a transverse guide tube close to the roadbed and compact it; c2. Spread a layer of isolation material on the compacted large-size stones and side sealing soil and compact it; d. Follow step c to fill and construct until the designed height is reached; e. Preparation of fluid filling material; f. Adjust the relative height of the inner and outer tubes of the vertical conduit, and use pressure grouting equipment to fill the large-sized stones with fluid filling materials in layers until the filling materials flow out of the horizontal conduit at the filled layer and then seal it; g. Follow step f to perform grouting and filling construction until the top layer is reached.

10. The method for constructing a composite high-load bearing platform backfill structure according to claim 9, characterized in that: In step c1, the large-sized stones and side sealing soil are compacted 4 to 6 times by a 4t to 8t vibratory roller or 1 to 2 times by a 14t or higher vibratory roller; In step c2, the isolation layer material is compacted 2-3 times by a 4-8 t vibratory roller and statically pressed once, or compacted 1 time by a 14 t vibratory roller and statically pressed once; The grouting pressure in step f is 0.2MPa~1.0Mpa.

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