Bearing platform foundation backfilling structure and construction method

Abstract

The invention discloses a bearing platform foundation backfilling structure and a construction method, and belongs to the technical field of building construction.The bearing platform foundation backfilling structure comprises a foundation layer and a bearing platform structure, two pile foundations are fixedly arranged at the bottom end of the bearing platform structure, and the bottoms of the two pile foundations are both embedded into the foundation layer; a steel structure frame set is arranged above the foundation layer and located on the pile foundation, the upper portion of the steel structure frame set is filled with lower-layer backfill soil, a fixed concrete layer is arranged in the steel structure frame set, upper-layer backfill soil is arranged above the lower-layer backfill soil, the lower-layer backfill soil and the upper-layer backfill soil are tightly attached to the outer side face of the pile foundation after being tamped, and the lower-layer backfill soil and the upper-layer backfill soil are tightly attached to the outer side face of the pile foundation after being tamped. The upper end face of the upper-layer backfill soil is tightly attached to the lower end face of the bearing platform structure after being tamped, and a surface concrete layer is backfilled on the bearing platform structure. The working time of single backfilling can be effectively shortened, meanwhile, the backfilling construction difficulty can be effectively reduced through the multiple backfilling mode, the backfilling construction quality is guaranteed, and the stability of the bearing platform foundation is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and more specifically to a cap foundation backfill structure and a construction method. Background Art

[0002] Backfilling of the foundation pit is a key part of the cast-in-place box girder support construction project. When performing the backfilling operation of the foundation pit, it is necessary to pay attention to the following: (1) The backfill material can only be used after passing the inspection; (2) The rolling equipment should be equipped with reasonable rolling machinery, and small motorized tamping tools should be used in places where rollers cannot reach; (3) When filling, the soil should be filled evenly from both sides of the structure to avoid putting pressure on the structure. In this way, the settlement difference caused by filling can be effectively avoided and the stability of the support during use can be guaranteed.

[0003] There are two main backfilling technologies for existing cap foundation construction: plain concrete backfilling technology and earthwork layered compaction technology. When constructing the garage cover area, due to the large backfilling construction area, the one-time backfilling construction is difficult and may affect the stability of the final cap foundation.

[0004] Therefore, in view of this, the existing structure is studied and improved, and a foundation backfill structure and construction method are provided, in order to achieve a more practical purpose. Summary of the invention

[0005] 1. Technical problems to be solved

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a pedestal foundation backfill structure and construction method, which can effectively reduce the working time of a single backfill. At the same time, multiple backfilling methods can effectively reduce the difficulty of backfill construction, ensure the quality of backfill construction, and ensure the stability of the pedestal foundation.

[0007] 2. Technical solution

[0008] To solve the above problems, the present invention adopts the following technical solutions.

[0009] A cap foundation backfill structure, comprising a base layer and a cap structure, wherein two pile foundations are fixedly arranged at the bottom end of the cap structure, and the bottoms of the two pile foundations are buried inside the base layer, a steel structure frame group is arranged above the base layer and at the pile foundations, a lower layer of backfill soil is filled above the steel structure frame group, and a fixed concrete layer is arranged inside the steel structure frame group;

[0010] An upper layer of backfill soil is arranged above the lower layer of backfill soil, the lower layer of backfill soil and the upper layer of backfill soil are tightly attached to the outer side surface of the pile foundation after being compacted, the upper end surface of the upper layer of backfill soil is tightly attached to the lower end surface of the cap structure after being compacted, and a surface concrete layer is backfilled on the cap structure;

[0011] The steel structure frame group includes a No. 1 inner frame, a No. 2 inner frame and two outer frames, wherein the No. 1 inner frame and the No. 2 inner frame are in contact and engaged with each other, wherein one of the outer frames is arranged on one side of the No. 1 inner frame, and a No. 1 ring opening is formed between the two, wherein two No. 1 splicing half rings are arranged inside the No. 1 ring opening, and the inner side surface of the No. 1 splicing half ring is in close contact with the outer side surface of the pile foundation;

[0012] The other outer frame is arranged on one side of the second inner frame, and a second ring opening is formed between the two. Two second splicing half rings are arranged inside the second ring opening, and the inner side surface of the second splicing half ring is tightly attached to the outer side surface of the pile foundation.

[0013] Furthermore, the soil materials selected for the base layer, the lower backfill soil, and the upper backfill soil include one or more of crushed stone soil, sandy soil, blasting slag, clay soil, silt, silty soil, and expansive soil;

[0014] Among them, the maximum particle size of crushed stone soil, sandy soil and blasting slag shall not exceed 2 / 3 of the thickness of each layer of paving;

[0015] The moisture content of clay soil is less than or equal to 20%, and the particle size is less than or equal to 50mm;

[0016] The organic matter content in silt, silty soil and expansive soil is less than or equal to 5%, and the water-soluble sulfate content is less than or equal to 5%.

[0017] Furthermore, the No. 1 inner frame, the No. 2 inner frame and the two outer frames all contain a plurality of square frame structures, and the square frame structures have the same specifications.

[0018] Furthermore, the fixed concrete layer is formed by pouring concrete inside the square frame structure, and the concrete used to form the fixed concrete layer is C15.

[0019] Furthermore, fork-shaped docking ports are fixed at the edges of the No. 1 inner frame and the No. 2 inner frame that are close to each other;

[0020] The fork-shaped docking interface on the No. 1 inner frame is snap-fitted with the edge of the No. 2 inner frame;

[0021] The fork-shaped docking interface on the No. 2 inner frame is snap-fitted with the edge of the No. 1 inner frame.

[0022] Furthermore, a clamping strip is fixed on the side of the outer frame;

[0023] One of the outer frames is clamped with the first inner frame through a clamping strip, and the other outer frame is clamped with the second inner frame through a clamping strip.

[0024] Furthermore, the upper backfill soil layer includes three stacked plain soil backfill layers, and concrete is injected into the three plain soil backfill layers during backfilling, and the three plain soil backfill layers are bonded to each other through the concrete.

[0025] Furthermore, the thickness of the surface concrete layer ranges from 0.8 to 1.2 times the thickness of the plain soil backfill layer.

[0026] A construction method for a cap foundation backfill structure, the specific implementation steps of the construction method are as follows:

[0027] Step 1: Check the relevant facilities of the foundation pit where the foundation structure is located and complete the cleaning;

[0028] Step 2: splice the steel structure frame group on the side of the pile foundation, and then pour concrete inside the square frame structure of the steel structure frame group until the concrete solidifies to form a fixed concrete layer;

[0029] Step 3: backfill the lower layer of backfill soil. The paving thickness of the lower layer of backfill soil is 1 / 2 of the total paving thickness. Then, harrow and level it, and then tamp it three times.

[0030] Step 4: Backfill the upper layer of backfill soil in three times, and harrow and tamp three times after each backfill;

[0031] Step 5: Pour the surface concrete layer and complete backfill.

[0032] Furthermore, in the step 2, when splicing the steel structure frame group, firstly splice the No. 1 inner frame and the No. 2 inner frame, and then splice the two outer frames.

[0033] 3. Beneficial effects

[0034] Compared with the prior art, the advantages of the present invention are:

[0035] In this scheme, when backfilling the pedestal foundation, the backfill area is divided into a steel structure frame group, a lower backfill soil, an upper backfill soil and a surface concrete layer. Among them, the steel structure frame group cooperates with the fixed concrete layer to effectively improve the stability of the foundation after backfilling. Then, multiple backfillings are carried out using the lower backfill soil and the upper backfill soil, which effectively reduces the working time of a single backfill. At the same time, the multiple backfilling method can effectively reduce the difficulty of backfilling construction, ensure the quality of backfilling construction, and ensure the stability of the pedestal foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a three-dimensional structural schematic diagram of the backfill structure in the present invention;

[0037] Figure 2 It is a schematic diagram of the structure of the backfill structure in the present invention after being split;

[0038] Figure 3 It is a three-dimensional structural schematic diagram of the steel structure frame group in the present invention;

[0039] Figure 4 It is a schematic diagram of the structure of the steel structure frame group after being disassembled in the present invention;

[0040] Figure 5 It is a schematic diagram of the process of the construction method in the present invention.

[0041] Description of the numbers in the figure:

[0042] 1. Base layer; 2. Capping structure; 3. Pile foundation; 4. Steel structure frame group; 401. No. 1 inner frame; 4011. Square frame structure; 4012. Fork-shaped docking port; 402. No. 2 inner frame; 403. External frame; 4031. Clip; 404. No. 1 ring; 405. No. 1 splicing half ring; 406. No. 2 ring; 407. No. 2 splicing half ring; 5. Lower backfill; 6. Fixed concrete layer; 7. Upper backfill; 8. Surface concrete layer. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0044] Embodiment 1:

[0045] See also Figure 1 - Figure 4 A cap foundation backfill structure, comprising a base layer 1 and a cap structure 2, two pile foundations 3 are fixedly arranged at the bottom end of the cap structure 2, and the bottoms of the two pile foundations 3 are buried in the base layer 1, a steel structure frame group 4 is arranged above the base layer 1 and located at the pile foundation 3, a lower backfill soil 5 is filled above the steel structure frame group 4, and a fixed concrete layer 6 is arranged inside the steel structure frame group 4;

[0046] An upper layer of backfill soil 7 is arranged above the lower layer of backfill soil 5. The lower layer of backfill soil 5 and the upper layer of backfill soil 7 are tightly attached to the outer side surface of the pile foundation 3 after being compacted. The upper end surface of the upper layer of backfill soil 7 is tightly attached to the lower end surface of the cap structure 2 after being compacted. A surface concrete layer 8 is backfilled on the cap structure 2.

[0047] The steel structure frame group 4 includes a No. 1 inner frame 401, a No. 2 inner frame 402 and two outer frames 403. The No. 1 inner frame 401 and the No. 2 inner frame 402 are in contact and engaged with each other. One of the outer frames 403 is arranged on one side of the No. 1 inner frame 401, and a No. 1 ring opening 404 is formed between the two. Two No. 1 splicing half rings 405 are arranged inside the No. 1 ring opening 404. The inner side surface of the No. 1 splicing half ring 405 is in close contact with the outer side surface of the pile foundation 3.

[0048] Another outer frame 403 is arranged on one side of the second inner frame 402 , and a second ring opening 406 is formed therebetween. Two second splicing half rings 407 are arranged inside the second ring opening 406 , and the inner side surface of the second splicing half ring 407 is in close contact with the outer side surface of the pile foundation 3 .

[0049] See also Figure 1 and Figure 2 Specifically, the soil materials selected for the base layer 1, the lower backfill soil 5, and the upper backfill soil 7 include one or more of crushed stone soil, sandy soil, blasting slag, clay soil, silt, silty soil, and expansive soil;

[0050] Among them, the maximum particle size of crushed stone soil, sandy soil and blasting slag shall not exceed 2 / 3 of the thickness of each layer of paving;

[0051] The moisture content of clay soil is less than or equal to 20%, and the particle size is less than or equal to 50mm;

[0052] The organic matter content in silt, silty soil and expansive soil is less than or equal to 5%, and the water-soluble sulfate content is less than or equal to 5%.

[0053] The type of backfill soil can be determined based on the type of earthwork during excavation, the type of earthwork near the excavation, and project requirements. When backfilling, controlling the quality of the soil can ensure the backfill effect.

[0054] See also Figure 2 , Figure 3 and Figure 4 Specifically, the first inner frame 401, the second inner frame 402 and the two outer frames 403 all contain a plurality of square frame structures 4011, and the square frame structures 4011 have the same specifications.

[0055] The square frame structure 4011 can be easily filled with concrete to form a steel-concrete structure of concrete and steel structure.

[0056] Specifically, the fixed concrete layer 6 is formed by pouring concrete inside the square frame structure 4011, and the concrete used to form the fixed concrete layer 6 is C15.

[0057] The use of C15 concrete can ensure the quality of backfill and save the cost of backfill.

[0058] Specifically, fork-shaped docking ports 4012 are fixed at the edges of the No. 1 inner frame 401 and the No. 2 inner frame 402 that are close to each other;

[0059] The fork-shaped docking port 4012 on the first inner frame 401 is snap-fitted with the edge of the second inner frame 402;

[0060] The fork-shaped docking port 4012 on the second inner frame 402 is snap-fitted with the edge of the first inner frame 401 .

[0061] The snap-on method can avoid misalignment and offset during splicing.

[0062] Specifically, a clamping strip 4031 is fixed to the side of the outer frame 403;

[0063] One of the outer frames 403 is clamped with the first inner frame 401 through a clamping strip 4031 , and the other outer frame 403 is clamped with the second inner frame 402 through a clamping strip 4031 .

[0064] By using the clamping method, misalignment and deviation can be avoided during splicing.

[0065] See also Figure 1 and Figure 2 Specifically, the upper backfill soil 7 includes three stacked plain soil backfill layers, and the three plain soil backfill layers are injected with concrete during backfilling, and the three plain soil backfill layers are bonded to each other through the concrete. The concrete is used together to improve the compaction degree of the backfill soil.

[0066] Specifically, the thickness of the surface concrete layer 8 is in the range of 0.8 to 1.2 times the thickness of the plain soil backfill layer.

[0067] Working principle:

[0068] In the backfill structure, the backfill area is divided into a steel structure frame group 4, a lower backfill soil 5, an upper backfill soil 7 and a surface concrete layer 8.

[0069] Among them, concrete is poured into the square frame structure 4011 of the steel structure frame group 4 to form a fixed concrete layer 6, which greatly improves the stability of the foundation after backfilling;

[0070] The lower backfill soil 5 can utilize its gravity to further increase the stability of the pile foundation 3 after backfilling;

[0071] The multiple backfilling construction of the upper backfill soil 7 effectively reduces the working time of a single backfilling. At the same time, each backfilling requires multiple tamping. The multiple backfilling method can effectively reduce the difficulty of backfilling construction, ensure the quality of backfilling construction, and ensure the stability of the base structure 2.

[0072] Embodiment 2:

[0073] Based on the above embodiment 1, further description is given.

[0074] See also Figure 5 , a construction method for a cap foundation backfill structure, the specific implementation steps of the construction method are as follows:

[0075] Step 1: Check the relevant facilities of the foundation pit where the cap structure 2 is located and complete the cleaning;

[0076] Step 2: splice the steel structure frame group 4 on the side of the pile foundation 3, and then pour concrete inside the square frame structure 4011 of the steel structure frame group 4 until the concrete solidifies to form a fixed concrete layer 6;

[0077] Specifically, when splicing the steel structure frame group 4, firstly, the first inner splicing frame 401 and the second inner splicing frame 402 are spliced, and then the two outer splicing frames 403 are spliced.

[0078] Step 3: backfill the lower layer of backfill soil 5, the paving thickness of the lower layer of backfill soil 5 is 1 / 2 of the total paving thickness, then harrow and tamp three times;

[0079] Step 4: backfill the upper layer of backfill soil 7 in three times, and harrow and tamp three times after each backfill;

[0080] Step 5: pour the surface concrete layer 8 and complete the backfill.

[0081] The above is only a preferred specific implementation of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and its improved conception within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A cap foundation backfill structure, comprising a base layer (1) and a cap structure (2), wherein two pile foundations (3) are fixedly arranged at the bottom end of the cap structure (2), and the bottoms of the two pile foundations (3) are both buried inside the base layer (1), characterized in that: A steel structure frame group (4) is provided above the base layer (1) and located on the pile foundation (3); a lower layer of backfill soil (5) is filled above the steel structure frame group (4); and a fixed concrete layer (6) is provided inside the steel structure frame group (4); An upper layer of backfill soil (7) is arranged above the lower layer of backfill soil (5); the lower layer of backfill soil (5) and the upper layer of backfill soil (7) are compacted and closely attached to the outer side surface of the pile foundation (3); the upper end surface of the upper layer of backfill soil (7) is compacted and closely attached to the lower end surface of the cap structure (2); and a surface concrete layer (8) is backfilled on the cap structure (2); The steel structure frame group (4) comprises a No. 1 inner frame (401), a No. 2 inner frame (402) and two outer frames (403), wherein the No. 1 inner frame (401) and the No. 2 inner frame (402) are in contact with and engage with each other, wherein one of the outer frames (403) is arranged on one side of the No. 1 inner frame (401), and a No. 1 ring opening (404) is formed between the two, and two No. 1 splicing half rings (405) are arranged inside the No. 1 ring opening (404), and the inner side surface of the No. 1 splicing half ring (405) is in close contact with the outer side surface of the pile foundation (3); The other outer frame (403) is arranged on one side of the second inner frame (402), and a second ring opening (406) is formed between the two. Two second splicing half rings (407) are arranged inside the second ring opening (406), and the inner side surfaces of the second splicing half rings (407) are closely attached to the outer side surfaces of the pile foundation (3).

2. The cap foundation backfill structure according to claim 1, characterized in that: The soil materials selected for the base layer (1), the lower backfill soil (5) and the upper backfill soil (7) include one or more of crushed stone soil, sandy soil, blasting slag, clay soil, silt, silty soil and expansive soil; Among them, the maximum particle size of crushed stone soil, sandy soil and blasting slag shall not exceed 2 / 3 of the thickness of each layer of paving; The moisture content of clay soil is less than or equal to 20%, and the particle size is less than or equal to 50mm; The organic matter content in silt, silty soil and expansive soil is less than or equal to 5%, and the water-soluble sulfate content is less than or equal to 5%.

3. The cap foundation backfill structure according to claim 1, characterized in that: The first inner frame (401), the second inner frame (402) and the two outer frames (403) all contain a plurality of square frame structures (4011), and the square frame structures (4011) have the same specifications.

4. The cap foundation backfill structure according to claim 3, characterized in that: The fixed concrete layer (6) is formed by pouring concrete inside the square frame structure (4011), and the concrete used to form the fixed concrete layer (6) is C15.

5. The cap foundation backfill structure according to claim 1, characterized in that: A fork-shaped docking interface (4012) is fixed at the mutually adjacent edges of the No. 1 inner assembly frame (401) and the No. 2 inner assembly frame (402); The fork-shaped docking port (4012) on the first inner assembly frame (401) is snap-fitted with the edge of the second inner assembly frame (402); The fork-shaped docking port (4012) on the second inner frame (402) is snap-fitted with the edge of the first inner frame (401).

6. The cap foundation backfill structure according to claim 1, characterized in that: A clamping strip (4031) is fixed on the side of the outer frame (403); One of the outer frames (403) is clamped with the first inner frame (401) via a clamping strip (4031), and the other outer frame (403) is clamped with the second inner frame (402) via a clamping strip (4031).

7. The cap foundation backfill structure according to claim 1, characterized in that: The upper backfill soil (7) comprises three stacked plain soil backfill layers, and concrete is injected into the three plain soil backfill layers during backfilling, and the three plain soil backfill layers are bonded to each other through the concrete.

8. The cap foundation backfill structure according to claim 7, characterized in that: The thickness of the surface concrete layer (8) is in the range of 0.8 to 1.2 times the thickness of the plain soil backfill layer.

9. A construction method for a cap foundation backfill structure obtained according to any one or more of claims 1 to 9, characterized in that: The specific implementation steps of this construction method are as follows: Step 1: Check the relevant facilities of the foundation pit where the foundation structure (2) is located and complete the cleaning; Step 2: splice the steel structure frame group (4) on the side of the pile foundation (3), and then pour concrete inside the square frame structure (4011) of the steel structure frame group (4) until the concrete solidifies to form a fixed concrete layer (6); Step 3, backfilling the lower layer of backfill soil (5), the paving thickness of the lower layer of backfill soil (5) is 1 / 2 of the total paving thickness, and then raking and tamping three times; Step 4: backfill the upper layer of backfill soil (7) in three times, and harrow and tamp three times after each backfill; Step 5: pour the surface concrete layer (8) and complete the backfill.

10. The construction method of a cap foundation backfill structure according to claim 9, characterized in that: In the step 2, when assembling the steel structure frame group (4), firstly the first inner assembly frame (401) and the second inner assembly frame (402) are assembled, and then the two outer assembly frames (403) are assembled.

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