CN216239904U - Existing building underpins and consolidates connection structure - Google Patents
Existing building underpins and consolidates connection structure Download PDFInfo
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- CN216239904U CN216239904U CN202122223682.0U CN202122223682U CN216239904U CN 216239904 U CN216239904 U CN 216239904U CN 202122223682 U CN202122223682 U CN 202122223682U CN 216239904 U CN216239904 U CN 216239904U
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Abstract
The utility model discloses an existing building underpinning and fastening connection structure which comprises an original foundation, an original column connected to the original foundation, a reinforcing bearing platform respectively connected with the original foundation and the original column, reinforcing bearing platform inner ribs arranged inside the reinforcing bearing platform and an underpinning pile connected to the bottom of the original foundation, wherein the reinforcing bearing platform inner ribs are arranged on the reinforcing bearing platform; the top of the underpinning pile is embedded into the bottom of the original foundation, and the pile end of the underpinning pile is positioned on the bearing layer of the soil body on the lower part. Or the length from the bottom of the newly-built foundation to the bottom end of the underpinning pile is changed into the effective design length of the underpinning pile. The utility model provides a connecting and load-bearing force transmission structure for the underpinning pile through the arrangement of the reinforcing bearing platform inner ribs and the reinforcing bearing platform; the underpinning pile is a structural form that a steel pipe pile is additionally arranged in a jet grouting pile, so that the underpinning pile design is favorably carried out on the underground added layer of the existing building; the original column and the upper structure can be effectively connected through the new column after underpinning, the new foundation and the new column reserved rib, and further the original column and the upper structure are connected into a stress whole.
Description
Technical Field
The utility model belongs to the technical field of underpinning and reinforcing of existing buildings, and particularly relates to a connecting structure for underpinning and reinforcing of an existing building.
Background
The quantity of the existing buildings in China reaches 400 hundred million square meters (2018), the existing buildings needing to be reinforced and modified for various reasons are large in quantity, and the market quantity of the existing building reinforcement and modification is huge. The underground space development under the existing building is an important mode for expanding the area of the existing building and improving the functions of the existing building, and various underground space development forms are adopted to realize huge underground expansion market demands and huge market capacity for the existing building.
The existing building underground space expansion and reinforcement transformation needs to solve a series of problems of load transmission or conversion of the existing building structure, deformation control of the existing building in the reinforcement transformation process, connection of new and old structures and the like, and ensures that the structure has good safety performance, service performance and durability. The common underpinning is temporarily carried by underpinning piles, and secondary construction is still needed for the layer adding of the pile foundation of the newly built underground structure at the lower part, so that the underpinning can not be combined and utilized; and the method also lacks an efficient underpinning pile scheme for how to correspond the unfavorable geology or the stratum containing the underground water in the narrow space of the basement conveniently.
SUMMERY OF THE UTILITY MODEL
The utility model provides an existing building underpinning and fastening connection structure, which is used for solving the technical problems of underpinning and fastening of existing foundations, design and convenient construction of underpinned piles, application of underpinning pile devices and the like of existing building reinforcement and reconstruction.
In order to achieve the purpose, the utility model adopts the following technical scheme:
an existing building underpinning and connecting structure comprises an original foundation, an original column connected to the original foundation, a reinforcing bearing platform connected with the original foundation and the original column respectively, reinforcing bearing platform inner ribs connected inside the reinforcing bearing platform and an underpinning pile connected to the bottom of the original foundation; the underpinning pile is embedded into the bottom of the original foundation, the pile end of the underpinning pile is positioned on a bearing layer of a lower soil body, and the length from the foundation bottom of the newly-built underground structure to the pile bottom is the designed length of the underpinning pile.
Furthermore, chiseling surfaces are arranged on the periphery of the original foundation and the original column, and foundation planting ribs are symmetrically arranged on the chiseling surfaces; the upper part of the original foundation column is a floor slab or a basement top slab, and the proposed building is positioned below the original foundation.
Furthermore, the original foundation comprises an original column and an original column steel bar, and the bottom of the original column is a chiseled part and is correspondingly connected with the new foundation column; the original foundation and the original column are of reinforced concrete structures, or the original foundation is a rib-free expansion foundation, an expansion foundation, a strip foundation under the column, a raft foundation or a box foundation.
Furthermore, a new cushion layer, a new foundation and a new column are sequentially arranged on the bottom surface of the proposed foundation, wherein the central axis of the new column corresponds to the central axis of the original column, and the underpinning piles are symmetrically arranged around the new column.
Furthermore, the reinforcing bearing platform inner rib is determined according to design calculation, and the horizontal rib is connected with the original foundation column within the height range.
Furthermore, the underpinning pile is an underpinning pile, and comprises an underpinning pile body, an underpinning pile rib connected inside the underpinning pile body and a reserved anchoring rib of the underpinning pile at the top of the underpinning pile body.
Furthermore, the underpinning pile body is composed of a core pile arranged in the jet grouting pile, underpinning pile ribs and underpinning pile reserved anchoring ribs are steel reinforcement cages, the underpinning pile ribs are positioned on the inner side of the steel pipe pile, and underpinning supporting piles are reserved anchoring ribs and anchored into a reinforcing bearing platform; the core pile is a steel pipe pile, or a precast concrete pile, an H-shaped steel or an I-shaped steel pile.
Furthermore, the effective pile diameter of the jet grouting pile is determined according to design calculation, generally 400-1000mm, the slurry is cement paste, the cement consumption is determined according to the design parameters (pile diameter, strength and the like) of the underpinning pile, and the water-cement ratio is preferably 0.7-1.2.
Furthermore, each section of the steel pipe pile is determined according to net height, generally 1-3m, and the steel pipe pile joint adopts a mode of butt welding plus segment welding or mantle fiber connection or groove welding and the like; the elevation of the pile top of the steel pipe is not lower than the elevation of the designed pile top, and cement slurry in the steel pipe is poured to be not less than 200mm above the elevation of the designed pile top.
Furthermore, a steel reinforcement cage is further arranged inside the steel pipe pile, the steel reinforcement cage is anchored and reinforced on the bearing platform, and the anchoring length is determined according to calculation.
The utility model has the beneficial effects that:
1) the utility model provides a connecting, bearing and load transferring structure for underpinning piles by the arrangement of the reinforcing bearing platform inner ribs and the reinforcing bearing platform;
2) according to the utility model, the underpinning pile is a structural form of additionally arranging the steel pipe pile in the jet grouting pile, so that the underpinning pile design on the underground added layer of the existing building is facilitated on one hand, and the rotary grouting steel pipe pile replacement is designed to be the arrangement of the pile foundation at the lower part of the underground added layer, so that the rotary grouting steel pipe pile replacement can be further utilized, the dual purposes of one pile are realized, and the construction process and the cost are saved;
3) the new column, the new foundation and the new foundation reserved rib can effectively connect the original foundation and the upper structure and are further connected into a stress whole;
the utility model is easy to implement, is convenient for underground layer increasing and reinforcing under the special working condition of the existing building, and can be greatly suitable for the conditions of underground soil layers and different basic working conditions; additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model; the primary objects and other advantages of the utility model may be realized and attained by the instrumentalities particularly pointed out in the specification.
Drawings
FIG. 1 is a schematic view of the installation and positioning of an underpinning pile on an original foundation;
FIG. 2 is a schematic view of the installation of the underpinning pile in position on the original foundation;
FIG. 3 is a layout view of construction underpinning piles;
FIG. 4 is a layout view of a reinforcing cap on a construction underpinning pile;
FIG. 5 is an excavation layout of a construction underpinning pile;
FIG. 6 is a schematic view of a new foundation for construction;
FIG. 7 is a schematic illustration of the removal of a reinforced foundation and partial underpinning of the pile;
FIG. 8 is a schematic view of the new column and its connection structure;
FIG. 9 is a top view of the primary column after underpinning is complete;
fig. 10 is a top plan view of a construction arrangement for constructing underpinning piles.
Reference numerals: 1-original foundation, 2-original column, 21-original column body, 22-original column steel bar, 3-foundation steel bar planting, 4-column steel bar planting, 5-reinforced bearing platform inner steel bar, 6-reinforced bearing platform, 7-underpinned pile, 71-underpinned pile body, 72-underpinned pile steel bar, 73-underpinned pile reserved anchoring steel bar, 8-original cushion layer, 9-soil body, 10-foundation ground, 11-new column, 12-new foundation, 13-new cushion layer, 14-new column reserved steel bar, 15-chiseling part and 16-slope protection pile.
Detailed Description
Taking a proposed atrium project as an example, the proposed atrium project is located in a Hui-shaped building in Beijing City, A, B, C, D, E, F commercial buildings at the periphery all have 1-3 floors of basements, and the atrium part originally has no basements. And (3) newly adding 1 layer of sinking plazas in the middle court position, expanding the underground space and communicating with the peripheral building functions. The proposed project is commercial, the underground is 1 layer, the frame structure is a raft foundation, the plane dimension is 148m in length, 36m in width and 6.0m in foundation burial depth. The long side direction of the north side is close to the commercial buildings A, a newly-added atrium sinking square is communicated with an underground chamber part, the burial depth of the foundation of the commercial buildings A is 6.0m, the middle part of the foundation is communicated with the door head of the atrium, the burial depth of the foundation is 2m, and the design and construction of underpinning and reinforcement are needed.
As shown in fig. 10, the range of the present underpinning is four independent column foundations at the door head, the burial depth of the original foundation 1 is about 2m, the clearance is about 3.5m, the maximum load of a single column is about 170t, and a slope protection pile is arranged on one side. The project reinforcement construction period is urgent, the control requirements on noise and environmental pollution are high, normal business of the overground part cannot be influenced, and in addition, due to the limitation of the plane space and the construction net height of a construction site, the geological conditions are complex and the targeted design needs to be made.
When the engineering is designed and constructed, the following points need to be considered simultaneously: firstly, the existing foundation plate is not large in size and should not damage the original main reinforcement as much as possible, so that the diameter of the hole formed in the foundation plate is required to be as small as possible, but the diameter after pile forming needs to be as large as possible so as to obtain higher single pile bearing capacity; secondly, the lower part of the foundation is filled with miscellaneous filling soil and the original A-F seats have horizontal supporting structures such as unknown soil nails or anchor rods of the foundation pit, the pile position basically has no space for adjustment, and a drilling machine is required to have strong adaptability to the stratum, so that the pile can be formed at one time; thirdly, the space of the site is limited, and the equipment is required to be as small as possible, so that the requirements of low headroom and limited space operation are met; comprehensively considering the above requirements, the underpinning pile 7 is adopted for underpinning and reinforcing.
For underpinning reinforcement design, an existing building underpinning reinforcement connection structure is applied, and a reinforced existing building comprises an original foundation 1, an original cushion layer 8 and an original column 2; the top of the original foundation is connected with a floor slab or a basement top slab, and the proposed building is positioned below the original foundation 1. The original foundation 1 and the original column 2 are of reinforced concrete structures, or the original foundation 1 is a rib-free expansion foundation, an expansion foundation, a strip foundation under the column, a raft foundation or a box foundation.
With reference to fig. 1 to 10, a further description is given of an existing building underpinning and fastening structure, which includes the following specific steps:
firstly, combining an in-situ survey report and a supplementary survey report, and determining main physical and mechanical indexes, pile side friction resistance and pile end resistance of each soil layer in a pile body design range, thereby determining the designed pile length of the underpinned pile 77; the groundwater level and groundwater type are further ascertained during the replenishment survey.
Combining the original geological survey and the supplementary survey report, and passing through the main physical and mechanical indexes of each soil layer, the pile side friction resistance and the pile end resistance in the design range of the typical geological pile body. The depth of the filling soil in the fertilizer groove is 11.10 m. Through on-site excavation, excavation of peripheral deep foundation pits and the like, the lower part of the door head foundation is provided with miscellaneous filling soil and the original A-F seats are provided with horizontal supporting structures such as unknown soil nails or anchor rods of the foundation pits. And 1 layer of stable underground water is detected in the depth range of 25.0m under the current ground during the supplementary exploration. The stable water level burial depth is 9.50-9.60 m, and the underground water type is interlayer water.
And step two, carrying out tee joint leveling on the site to be built, slotting corresponding to the construction working face, symmetrically designing lower underpinning piles 7 on the original foundation 1 around two sides or the periphery of the original foundation 1, measuring and setting out, adopting static force to open holes, and marking the foundation steel bars 3 and the original column steel bars 4 in advance.
Step three, before formal construction, in order to debug equipment and obtain site construction parameters, a pile test is carried out; the pile hole of the underpinning pile 7 is correspondingly constructed by adopting a rotary spraying and static pressure device, a triple-pipe high-pressure rotary spraying cement paste, water and air are adopted for a screw-in hole to form a rotary spraying pile, and then the static pressure of the steel pipe pile is carried out; the construction of the jet grouting pile and the steel pipe pile can be divided into two independent steps or alternatively performed in sections.
In this embodiment, before formal construction, 1 set of test pile tests is performed in order to debug equipment and obtain site construction parameters. The pile-test ending pile-pressing force is 2025 kN. When the load reaches the design value, the pile body settlement is about 3mm, and the bearing capacity design requirement and the settlement control requirement after the underpinning of the door head column are met. In this embodiment, the rotary-jet steel pipe pile replacement is arranged in each independent foundation, and in order to bear the upper structural load through the newly-added underpinning pile-bearing platform structure, from the perspective of load transfer, the closer the newly-added underpinning pile is to the original structural column, the better, but the construction space of the underpinning pile 7 and the distance between the underpinning pile and the original structural column 2 are also considered in the pile position arrangement. Meanwhile, the position centroid of the pile is close to the position of the load gravity center as much as possible; in addition, the hole of the original foundation 1 needs to be as small as possible, and the combination of the consideration that the outer diameter of the lower steel pipe is 245mm and the diameter of the static force hole is 400 mm.
In the embodiment, the applied device comprises a grooving machine for opening the hole of the original foundation 1 and a mounting rotary spraying and static pressure device for the underpinning pile 7; the grooving machine is used for grooving corresponding to the construction working face; a jet grouting and static pressure device is installed for constructing the underpinning pile 7.
In this embodiment, the underpinning pile 7 includes an underpinning pile body 71, underpinning pile ribs 72 connected to the inside of the underpinning pile body 71, and underpinning pile reserved anchoring ribs 73 on the top of the underpinning pile body 71. Wherein, underpinning pile body 71 is set up the core pile by the jet grouting pile and is constituteed, underpins stake muscle 72 and underpins stake reservation anchor muscle 73 and be the steel reinforcement cage, and underpins stake muscle 72 and is located the steel-pipe pile inboard, underpins stake reservation anchor muscle 73 and consolidates cushion cap 6. The core pile is a steel pipe pile, or a precast concrete pile, an H-shaped steel or an I-shaped steel pile.
In the embodiment, when the jet grouting pile is constructed, the weight of water and cement is measured according to the designed water cement ratio, and after the water and the cement are uniformly stirred in a slurry stirring barrel, the mixture is filtered by a 20-mesh sieve and is placed in a slurry storage barrel; the slurry storage barrel is used for continuously stirring the cement slurry to prevent the cement slurry from precipitating; the pump head of the grouting pump is covered by a fine mesh screen to prevent coarse particles from being sucked to block a drill nozzle. Drilling operation and water treatment: after the drilling machine is in place, the power head is started to rotate the drill rod, high-pressure air is provided for a drill bit at the bottom of the drill rod, soil is cut while sinking and drilling are carried out through double high-pressure jet flows in the horizontal direction of the drill bit and the bottom direction of the drill bit, and the designed pile bottom elevation is drilled; spraying high-pressure cement slurry for one time: after the designed pile bottom elevation is drilled, the power head is started to rotate the drill rod, the high-pressure grouting pump is started, high-pressure air and slurry are provided for the drill bit at the bottom of the drill rod, and the slurry is sprayed while soil is cut and the drill bit sinks through the double high-pressure jet flows in the horizontal direction and the bottom direction of the drill bit. And controlling the pressure of the high-pressure grouting pump, and spraying to the elevation of the designed pile top of the rotary spraying.
Fourthly, the steel pipe pile must be kept vertical in position, the axis of the steel pipe pile is concentric and coaxial with the jet grouting pile, the same vertical line is kept, bias pressure is not needed, and a steel pile cap is sleeved during pile pressing and then the pile pressing is carried out; meanwhile, the height of the pile top of the last section of steel pipe is controlled by a feeder.
In the fourth step, the top of the rotary spraying steel pipe pile is embedded into the original foundation 1, wherein the effective pile diameter of the rotary spraying pile is not less than 600mm, the slurry adopts cement paste, the cement consumption is not less than 140kg/m, and the water-cement ratio is 0.7; designing parameters of the jet grouting pile, wherein the water spraying pressure is less than or equal to 3 MPa; the guniting pressure is more than or equal to 10 MPa; the airflow pressure is more than or equal to 0.7 MPa; the lifting speed is less than or equal to 300 mm/min; the lifting rotating speed is 18-20 r/min; the steel pipe pile is pressed into each section by sections with the length of 2.5m, and the joint of the steel pipe pile adopts butt welding and segment welding.
In the fourth step, the elevation of the pile top of the steel pipe is not lower than the elevation of the designed pile top, and cement slurry in the steel pipe is poured to be not less than 200mm above the elevation of the designed pile top; after the cement paste is hardened, pile head cutting construction is carried out, and the pile head of the steel pipe pile is cut to the designed pile top elevation; the steel-pipe pile outside still is provided with steel reinforcement cage or vertical reinforcement, and reinforcement cushion cap 6 is gone into to steel reinforcement cage and vertical reinforcement top anchor, or is connected with reinforcement 5 in the 6 cushion caps of reinforcement respectively.
In this embodiment, the jet grouting pile adopts a hole leading of a spinning all-in-one machine, the precession hole adopts triple-pipe high-pressure jet grouting, the effective pile diameter of the jet grouting pile is not less than 600mm, and the steel pipe is implanted after the jet grouting. The outer diameter of the steel pipe is 245mm, the wall thickness of the steel pipe is 8mm, and the material quality of the steel pipe is Q345; the effective pile length is 21m, the support layer is formed by the fine sand of the sixth layer, and the characteristic value of the bearing capacity of a single pile is 375kN, and the total number of the piles is 24.
In the embodiment, before the initial setting of the steel pipe pile pore-forming grouting cement paste, a steel reinforcement cage is embedded in the pile head, the lower part of the steel reinforcement cage is inserted into the steel pipe pile by 1.5m, and the upper part of the steel reinforcement cage is anchored into the reinforcement bearing plate by not less than 1.1 m.
Fifthly, after the underpinned pile 77 is detected, pile sealing is carried out, then foundation planting ribs 3 are connected to the periphery and the vertical direction of the original foundation 11 at intervals, original column planting ribs 4 are connected to the periphery and the vertical direction of the original column 22, and a reinforcing bearing platform 66 and reinforcing bearing platform inner ribs 55 are designed corresponding to the original foundation 11; pouring to finish the reinforced bearing platform 66 and the reinforced bearing platform inner ribs 55, and excavating the soil 9 at the lower part of the original foundation 11 until the soil is excavated to the bottom surface 10 of the proposed foundation;
in the fifth step, when the reinforcing bearing platform 66 and the reinforcing bearing platform inner ribs 55 are constructed, the peripheries of the original foundation 11 and the original foundation 1 column 2 are chiseled, and the foundation embedded ribs 3 are symmetrically arranged; wherein, the reinforcing bearing platform inner rib 55 at least comprises a double-layer horizontal rib, and the height range of the horizontal rib is connected with the original foundation 1 column 2. The design of the reinforcing bearing platform 66 needs to meet the requirements of bending resistance, impact cutting resistance and shearing resistance; through calculation, the thickness of the reinforced bearing platform 66 is 1100-1300mm, the design strength of concrete is C30, the diameter of the double-layer bidirectional reinforcing steel bar is 12mm, the distance between the double-layer bidirectional reinforcing steel bar and the double-layer bidirectional reinforcing steel bar is 120mm, and the three-level steel can meet the design requirement.
In this embodiment, the connection between the original foundation 11 and the newly added reinforcing bearing plate is a key force transmission node for ensuring the function of the rotary-spraying steel pipe pile-changing 7. The mode of chemical bar planting is adopted in this engineering, realizes the transmission of shear force and the moment of flexure of former basis 11 and newly-increased reinforcement carrier plate. The method comprises the steps of roughening the surface layer of the existing foundation, drilling, cleaning holes, carrying out chemical bar planting, removing the surface layer of the foundation and coating an interface agent, and pouring the foundation and a steel pipe pile top reinforcement cage together after binding of the foundation reinforcement, wherein after the project is used for 1 year, the maximum settlement of the foundation is about 4mm, and the maximum inclination rate of the building is 0.7 per mill, and all the design requirements are met.
Constructing a new cushion 1315, a new foundation 1214 and a new column 1113 on the bottom surface 10 of the proposed foundation, wherein the central axis of the new column 1113 corresponds to the central axis of the original column 22, and the underpinning piles 77 are symmetrically arranged about the column 13 of the new foundation 12;
and seventhly, connecting the top of the new column 1113 to the bottom of the original foundation 11, transmitting the upper structural load into the new column 1113 through the original foundation 11, transferring the load from the underpinning pile 77 to the new column 11 after the new column 1113 is stably connected, and then cutting off the reinforcing bearing platform 66 and the underpinning pile 77.
As shown in fig. 8 and 9, the original foundation 11 comprises an original column 2121 and an original column reinforcement 2222, and the bottom of the original column 2121 is a chiseled portion 1517 to facilitate the connection of the new column 1113; the new post 1113 is also provided with new post pre-cut ribs 1416 to facilitate the joining of the superstructure to form a unitary structure.
Step eight, the construction process is gradually developed according to the subareas of the construction operation, and the construction operation surface of the underpinning pile 77 is symmetrical by considering the symmetry of the engineering structure and the load; only one pile can be constructed on the same foundation at a time, and the construction time interval between adjacent piles on the same foundation is not less than 1 day, so that underpinning is completed.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that may be made by those skilled in the art within the technical scope of the present invention will be covered by the scope of the present invention.
Claims (10)
1. An existing building underpinning and connecting structure is characterized by comprising an original foundation, an original column connected to the original foundation, a reinforcing bearing platform (6) respectively connected with the original foundation (1) and the original column (2), reinforcing bearing platform inner ribs (5) connected inside the reinforcing bearing platform (6) and an underpinning pile connected to the bottom of the original foundation; the top of the underpinning pile is embedded into the bottom of the original foundation, and the pile end of the underpinning pile is positioned on the bearing layer of the soil body on the lower part.
2. The underpinning and fastening structure of the existing building as claimed in claim 1, wherein the original foundation (1) and the original column (2) are provided with burrs around and symmetrically provided with foundation planting bars (3); the floor or the basement top plate is arranged above the original column (2), and the proposed building is positioned below the original foundation (1).
3. An existing building underpinning and fastening structure as claimed in claim 2, wherein said original foundation (1) comprises an original column (21) and an original column reinforcement (22), the bottom of the original column (21) is a chiseled part (15) and is correspondingly connected with the new column (11); the original foundation (1) and the original column (2) are of reinforced concrete structures, or the original foundation (1) is an expanded foundation, a strip foundation under the column, a raft foundation or a box foundation.
4. An existing building underpinning and fastening structure as claimed in claim 1, wherein the base (10) to be built is provided with a new bedding (13), a new foundation (12) and a new column (11) in sequence, wherein the central axis of the new column (11) corresponds to the central axis of the original column (2), and the underpinning piles are symmetrically arranged with respect to the new foundation (12).
5. An existing building underpinning and fastening structure as claimed in claim 1, wherein the reinforcement bearing platform inner ribs (5) are determined by design calculation, and are connected with the original foundation (1) column within the height range of the horizontal ribs.
6. An existing building underpinning and fastening structure as claimed in claim 1, wherein said underpinning pile is an underpinning pile (7), the underpinning pile (7) comprising an underpinning pile body (71), underpinning pile ribs (72) connected inside the underpinning pile body (71), and reserved anchoring ribs (73) on top of the underpinning pile body (71).
7. An existing building underpinning and fastening structure as claimed in claim 6, wherein the underpinning pile body (71) is composed of a core pile arranged in a jet grouting pile, underpinning pile ribs (72) and underpinning pile reserved anchoring ribs (73) are steel reinforcement cages, the underpinning pile ribs (72) are positioned at the inner side of the steel pipe pile, and the underpinning pile reserved anchoring ribs (73) are anchored into the reinforcing bearing platform (6);
the core pile is a steel pipe pile, or a precast concrete pile, an H-shaped steel or an I-shaped steel pile.
8. The existing building underpinning fastening structure as claimed in claim 7, wherein the underpinning pile is a composite pile, the effective diameter of the jet grouting pile is generally 400-1000mm, the slurry is cement paste, the cement consumption is determined according to the design requirements of the jet grouting pile diameter and strength, and the water cement ratio is preferably 0.7-1.2.
9. The existing building underpinning and fastening structure of claim 7, wherein the length of each section of the steel pipe pile is determined according to the net height and can be generally segmented according to 1-3m, and the steel pipe pile joint adopts a connection mode of butt welding and tube sheet welding, mantle fiber connection or groove welding; the elevation of the pile top of the steel pipe is not lower than the elevation of the designed pile top, and cement slurry in the steel pipe is poured to be not less than 200mm above the elevation of the designed pile top.
10. An existing building underpinning and fastening structure as claimed in claim 7, wherein a reinforcement cage is further arranged inside the steel pipe pile, and the reinforcement cage is anchored into the reinforcing bearing platform (6).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122223682.0U CN216239904U (en) | 2021-09-14 | 2021-09-14 | Existing building underpins and consolidates connection structure |
Applications Claiming Priority (1)
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| CN114892735A (en) * | 2022-05-27 | 2022-08-12 | 青海送变电工程有限公司 | In-situ processing method for quality defects of pile foundation of power transmission tower |
| CN114892735B (en) * | 2022-05-27 | 2024-02-13 | 青海送变电工程有限公司 | In-situ processing method for quality defect of pile foundation of power transmission tower |
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