Closed loop prefabricated mold architecture for karst geology pile foundation construction and closed loop

Abstract

The utility model discloses a kind of closed loop prefabricated mould frame and closed loop for karst geology pile foundation construction, comprising: cylindrical barrel concrete closed loop main body, the cylindrical inner cavity of cylindrical barrel concrete closed loop main body forms the space of concrete pouring and lowering of pile foundation reinforcement cage;Steel reinforcement lifting hook, fixedly connected in the both ends of cylindrical barrel concrete closed loop main body along its axial direction;Concrete closed loop main body can be vertically extended lengthening based on steel reinforcement lifting hook arrangement.Solved the technical problem that permanent steel casing follows and fills in when pile foundation construction is carried out to the geological condition that karst cave is deeper and multiple karst caves are in string-bead type layered distribution in prior art.

Description

Technical Field

[0001] This utility model relates to the field of bridge pile foundation engineering technology, and more specifically, to a closed-loop prefabricated mold structure and closed loop for karst geological pile foundation construction. Background Technology

[0002] With the continuous and rapid development of the transportation industry, bridges, as a key component of transportation routes, are becoming increasingly important, and the construction technology of bridge pile foundations is gradually becoming more and more perfect and is being widely used.

[0003] Currently, when construction is carried out near existing operational railway lines, it is generally necessary to minimize disruption to the normal operation of the existing railway. Traditional impact drilling is strictly prohibited due to its strong impact and vibration characteristics, which can easily cause adverse effects on the existing railway subgrade and track structure. Rotary drilling, on the other hand, has become the preferred construction method in this situation due to its high efficiency and low disturbance.

[0004] Meanwhile, due to complex geological conditions, different regions encounter different geological situations, with karst caves having a particularly significant impact on pile foundation construction. When facing shallow karst caves, construction typically employs a method of backfilling with a mixture of rubble and loess before drilling. This method can, to some extent, fill the cave space and create relatively stable geological conditions for drilling operations. However, when karst caves are deeper than the ground level or when multiple caves are distributed in a beaded, layered manner, backfilling alone is insufficient to meet the filling requirements.

[0005] Conventional construction methods typically involve using permanent steel casings to follow up with the filling. However, this approach has revealed numerous problems in practice. For instance, the lowering and welding of the steel casings is time-consuming, severely hindering construction efficiency; welding is inefficient and of questionable quality, affecting not only the connection strength of the steel casings but also posing a potential threat to the overall stability of the pile foundation; furthermore, precise verticality control during the extension of the steel casings further impacts the load-bearing capacity of the pile foundation; additionally, the use of steel casings in conventional geological sections between karst caves results in unnecessary material waste, significantly increasing construction costs and negatively impacting construction efficiency and economic benefits. Therefore, there is an urgent need to design a closed-loop structure and its prefabricated mold specifically for pile foundation construction in karst cave geology. Utility Model Content

[0006] To address this, the present invention provides a closed-loop precast mold structure and a closed loop for karst geological pile foundation construction, thereby solving the aforementioned technical problems in the prior art where permanent steel casings are used for follow-up filling when constructing pile foundations in karst geological conditions where the caves are deep and multiple caves are distributed in a beaded, layered manner.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A prefabricated closed ring for karst geological pile foundation construction, comprising:

[0009] The main body of the concrete closed ring is set as a cylindrical structure, and the cylindrical inner cavity of the main body of the concrete closed ring forms the space for the lowering of the pile foundation steel cage and the concrete pouring.

[0010] The steel bar hooks are fixedly connected to both ends of the cylindrical concrete closed ring body along its axial direction.

[0011] The concrete closed ring body can be extended vertically based on the steel bar hook.

[0012] Based on the above technical solution, the present invention is further described as follows:

[0013] As a further embodiment of this utility model,

[0014] The steel bar hooks are provided in several sets, and the several sets of steel bar hooks are respectively fixedly assembled at both ends of the cylindrical concrete closed ring body along its cylindrical axis.

[0015] A prefabrication mold architecture for fabricating the aforementioned closed ring, the prefabrication mold architecture comprising:

[0016] The inner mold is a circular steel tube, which serves as the inner mold for forming the pre-made closed ring;

[0017] The bottom support steel plate platform can be directionally slidably fitted onto the inner mold circular steel tube, and the outer edge of the bottom support steel plate platform is higher than its inner edge relative to the outer edge of the inner mold circular steel tube.

[0018] A sheet metal outer ring template is correspondingly set on the outer side of the inner mold round steel tube body, and one end of the sheet metal outer ring template is detachably and correspondingly limited to the inner side of the outer edge of the bottom support steel plate platform. The other end of the sheet metal outer ring template is flush with the end of the inner mold round steel tube body away from the bottom support steel plate platform, so as to serve as the forming outer mold of the prefabricated closed ring.

[0019] The U-shaped limiting buckle is positioned at both ends of the inner mold round steel tube away from the bottom support steel plate platform and at the other end of the outer iron ring template.

[0020] As a further aspect of this utility model, it also includes:

[0021] Several sets of pre-embedded reinforcing bars are provided. The pre-embedded reinforcing bars are inserted through the bottom support steel plate platform, and the two ends of the pre-embedded reinforcing bars extend one-to-one to the outer side of the inner mold circular steel pipe body away from the bottom support steel plate platform and the outer side of the bottom support steel plate platform.

[0022] As a further embodiment of this utility model,

[0023] The inner mold circular steel pipe is set as a circular steel pipe with an inner diameter not less than the outer diameter of the karst pile foundation reinforcement cage.

[0024] The bottom support steel plate platform is configured as an annular platform fitted onto the outer side of the inner mold circular steel tube;

[0025] The longitudinal section of the annular bottom support steel plate platform is L-shaped at any position.

[0026] As a further embodiment of this utility model,

[0027] The bottom support steel plate platform is evenly provided with at least four sets of longitudinally extending reinforcing bar reserved holes along its circumference; at least four sets of pre-embedded reinforcing bars are provided, and one end of each of the at least four sets of pre-embedded reinforcing bars extends through the at least four sets of pre-embedded reinforcing bar reserved holes, and the other end of each of the at least four sets of pre-embedded reinforcing bars extends beyond the end of the inner mold circular steel tube body away from the bottom support steel plate platform.

[0028] As a further aspect of this utility model, it also includes:

[0029] A flexible steel mesh is wrapped around the outer side of at least four sets of pre-embedded steel bars, and the flexible steel mesh is fixedly tied to the at least four sets of pre-embedded steel bars by binding wire.

[0030] As a further embodiment of this utility model,

[0031] Several sets of pads are provided between the inner side of the outer ring template of the sheet metal and the flexible steel mesh.

[0032] As a further embodiment of this utility model,

[0033] The U-shaped limiting buckle is provided in at least four sets, and the at least four sets of the U-shaped limiting buckle are evenly positioned between the inner mold round steel tube and the outer iron ring template.

[0034] As a further embodiment of this utility model,

[0035] The outer side of the inner mold round steel tube, the inner end face of the bottom support steel plate platform, the inner side of the sheet metal outer ring template, and the inner end face of the U-shaped limiting buckle are all coated with a release agent layer and / or an oil layer.

[0036] This utility model has the following beneficial effects:

[0037] This architecture replaces permanent steel casings with prefabricated closed rings, which can effectively combine the specific development parameters of the karst caves to perform targeted alignment, extension and sealing of the caves, effectively reducing material waste in non-karst cave sections. At the same time, the use of prefabricated mold architecture allows the prefabrication process of the prefabricated closed rings to not occupy the construction period, and the closed rings can be prefabricated independently and flexibly according to the specific conditions of different pile foundations, which significantly improves the functional adaptability of the architecture. Attached Figure Description

[0038] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The structures, proportions, sizes, etc., drawn in this specification are only used to complement the content disclosed in the specification, so that those skilled in the art can understand and read them. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0039] Figure 1 A schematic diagram of the overall structure of a prefabricated closed ring for karst geological pile foundation provided in an embodiment of this utility model.

[0040] Figure 2 A side sectional view of the closed-loop prefabricated mold structure for karst pile foundation construction provided in this embodiment of the present invention.

[0041] Figure 3 The closed-loop precast mold structure for karst geological pile foundation construction provided in this embodiment of the utility model corresponds to Figure 2 A schematic diagram of the isometric structure in the state.

[0042] Figure 4 This is one of the side sectional structural schematic diagrams of the closed-loop prefabricated mold structure for karst geological pile foundation construction provided in the embodiments of this utility model, corresponding to its assembly process state.

[0043] Figure 5 The closed-loop precast mold structure for karst geological pile foundation construction provided in this embodiment of the utility model corresponds to Figure 4 A schematic diagram of the isometric structure in the state.

[0044] Figure 6 The second side sectional view of the closed-loop prefabricated mold structure for karst pile foundation construction provided in this embodiment of the present invention, corresponding to its assembly process state.

[0045] Figure 7The closed-loop precast mold structure for karst geological pile foundation construction provided in this embodiment of the utility model corresponds to Figure 6 A schematic diagram of the isometric structure in the state.

[0046] Figure 8 The third side sectional view of the closed-loop prefabricated mold structure for karst pile foundation construction provided in this embodiment of the present invention, corresponding to its assembly process state.

[0047] Figure 9 The closed-loop precast mold structure for karst geological pile foundation construction provided in this embodiment of the utility model corresponds to Figure 8 A schematic diagram of the isometric structure in the state.

[0048] Figure 10 This is a schematic side sectional view of the closed-loop prefabricated mold structure for karst pile foundation construction provided in this embodiment of the present invention, corresponding to its assembly process state.

[0049] Figure 11 The closed-loop precast mold structure for karst geological pile foundation construction provided in this embodiment of the utility model corresponds to Figure 10 A schematic diagram of the overall isometric structure of the state.

[0050] The attached diagram lists the components represented by each number as follows:

[0051] 1. Inner mold round steel pipe body; 2. Bottom support steel plate platform; 21. Through-reinforcement reserved hole; 3. Embedded steel bar; 4. Flexible steel mesh; 5. Binding steel wire; 6. Sheet metal outer ring template; 7. U-shaped limit buckle;

[0052] 8. Concrete closed ring body; 9. Rebar hook. Detailed Implementation

[0053] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0054] The terms "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation of this utility model. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of implementation of this utility model.

[0055] like Figures 1 to 11As shown, this utility model embodiment provides a prefabricated closed ring and its prefabricated mold structure for karst geological pile foundation construction. The prefabricated closed ring includes a concrete closed ring body 8, and the prefabricated mold structure includes an inner mold circular steel pipe body 1, a bottom support steel plate platform 2, embedded reinforcing bars 3, a flexible steel mesh 4, binding steel wires 5, a sheet metal outer ring template 6, and a U-shaped limiting buckle 7. This prefabricated closed ring replaces the permanent steel casing, effectively combining specific karst cave development parameters to perform targeted alignment, extension, and sealing of karst caves, effectively reducing material waste in non-karst cave sections. Simultaneously, the prefabricated mold structure allows the prefabrication process of the closed ring to not occupy the construction period, enabling independent and flexible prefabrication of the closed ring according to the specific conditions of different pile foundations, significantly improving the functional adaptability of the structure. Specific settings are as follows:

[0056] Please refer to Figure 1 The prefabricated closed ring includes a concrete closed ring body 8, which is configured as a cylindrical structure. Several sets of steel bar hooks 9 are fixedly assembled at both ends of the cylindrical concrete closed ring body 8 along its axial direction. These hooks are used to effectively serve as a space for lowering the pile foundation steel cage and pouring concrete through the cylindrical inner cavity of the concrete closed ring body 8. At the same time, the steel bar hooks 9 are used to effectively extend the concrete closed ring body 8 vertically to accurately seal multiple or deep karst caves.

[0057] Please refer to Figures 2 to 5 The inner mold circular steel pipe 1 is set as a circular steel pipe with an inner diameter not less than the outer diameter of the karst pile foundation reinforcement cage, and is used as the forming inner mold of the prefabricated closed ring through the inner mold circular steel pipe 1.

[0058] The bottom support steel plate platform 2 is configured as an annular platform fitted around the outer side of the inner mold circular steel tube 1. The longitudinal section of the annular bottom support steel plate platform 2 is L-shaped at any position, that is, the height of the outer edge of the annular bottom support steel plate platform 2 is greater than that of its inner edge, thereby forming a bottom support limiting platform.

[0059] The bottom support steel plate platform 2 is evenly provided with at least four sets of longitudinally extending reinforcing bar reserved holes 21 along its circumference; at least four sets of pre-embedded reinforcing bars 3 are provided, one end of each of the at least four sets of pre-embedded reinforcing bars 3 extends through the at least four sets of pre-embedded reinforcing bar reserved holes 21, and the other end of each of the at least four sets of pre-embedded reinforcing bars 3 extends beyond the end of the inner mold circular steel tube 1 away from the bottom support steel plate platform 2, so as to form the reinforcing bar hook 9 of the subsequent concrete closed ring body 8 by bending the pre-embedded reinforcing bars 3.

[0060] Please refer to Figures 6 to 11The flexible steel mesh 4 is wrapped around the outer side of at least four sets of pre-embedded steel bars 3, and the flexible steel mesh 4 is tied and fixed to the at least four sets of pre-embedded steel bars 3 by the binding steel wire 5, so as to significantly improve the anchoring performance for subsequent concrete pouring.

[0061] The outer ring template 6 is configured as an annular cylindrical structure, and one end of the outer ring template 6 is separable and limited to the inner side of the annular bottom support steel plate platform 2. The other end of the outer ring template 6 is flush with the end of the inner mold circular steel tube 1 away from the bottom support steel plate platform 2. At least four sets of U-shaped limiting buckles 7 are provided, and at least four sets of U-shaped limiting buckles 7 are evenly limited and locked between the end of the inner mold circular steel tube 1 away from the bottom support steel plate platform 2 and the other end of the outer ring template 6, so as to form an end limiting effect through the U-shaped limiting buckles 7, effectively preventing the outer ring template 6 from expanding and running out of the formwork due to subsequent concrete pouring.

[0062] As a preferred embodiment, the outer side of the inner mold round steel tube 1, the inner end face of the bottom support steel plate platform 2, the inner side of the sheet metal outer ring template 6, and the inner end face of the U-shaped limiting buckle 7 are all coated with a release agent layer and / or an oil layer to facilitate the demolding of the closed ring.

[0063] As another preferred embodiment, a number of pads are provided between the inner side of the outer ring template 6 and the flexible steel mesh 4 to further improve the positional stability of the outer ring template 6.

[0064] As another preferred embodiment, the inner mold circular steel tube 1 and the bottom support steel plate platform 2 are slidably assembled together, and the other end of the outer iron ring template 6 is always flush with the end position of the inner mold circular steel tube 1, so as to adapt to the preparation of prefabricated closed rings of different lengths.

[0065] Please continue to refer to this. Figures 4 to 11 The process of using the aforementioned closed-loop precast mold structure for karst geological pile foundation construction specifically includes the following steps:

[0066] S101: Based on the sliding adjustment of the position of the bottom support steel plate platform 2 of the inner mold circular steel tube 1, the inner mold length of the inner mold circular steel tube 1 is determined to meet the length requirements of the prefabricated closed ring.

[0067] Based on the bottom support steel plate platform 2 on the outer side of the inner mold circular steel pipe 1, pre-embedded steel bars 3 are inserted through the corresponding pre-reserved holes 21, and the pre-embedded steel bars 3 serve as the subsequent connecting components of the closed ring.

[0068] After the pre-embedded steel bar 3 is inserted, the side gap of the pre-reserved hole 21 for inserting the steel bar is sealed with expanding foam.

[0069] S102: Wrap the flexible steel mesh 4 around the outer side of the embedded steel bar 3, and further use the binding wire 5 to bind and fix the embedded steel bar 3 and the flexible steel mesh 4.

[0070] S103: Install a sheet metal outer ring template 6 of a specific length on the outer side of the flexible steel mesh 4, so that the other end of the sheet metal outer ring template 6 is flush with the end of the inner mold round steel pipe 1, and place a support pad to improve positional stability between the sheet metal outer ring template 6 and the flexible steel mesh 4.

[0071] S104: Continue to configure a number of U-shaped limiting buckles 7 with a specific spacing between the outer ring template 6 and the inner round steel tube 1 to fix the outer ring template 6 and the inner round steel tube 1 in place.

[0072] S105: Concrete is poured between the outer iron ring template 6 and the inner round steel pipe 1. After the strength reaches 70%, the U-shaped limiting buckle 7 and the outer iron ring template 6 are removed to form a prefabricated closed ring with embedded steel bars 3. The prefabricated closed rings are then stacked and cured for use in pile foundation construction.

[0073] The application process of the precast closed rings used in karst geological pile foundation construction includes the following steps:

[0074] S201: Accurately lay out the design pile foundation location to determine the design and construction pile positions;

[0075] S202: Corresponds to the drilling and detection hole positions for the designed and constructed pile locations;

[0076] The specific process is as follows: Based on the design and construction pile position, a tool steel casing position is pre-set coaxially with the pile center position, and vertical holes are drilled corresponding to the outer side and the pile center position of the design and construction pile position to form at least four sets of outer detection holes and one set of central detection holes. The diameter of the circle formed by connecting the at least four sets of outer detection holes is greater than the diameter of the pre-set tool steel casing position.

[0077] S203: Obtain the specific location and development depth parameters of the karst cave based on the detection borehole locations;

[0078] The specific process is as follows: use an in-hole imaging detector to probe each hole location, and determine the specific location and development depth parameters of the cave based on the displayed images and depth information;

[0079] S204: Steel casing for installation tools;

[0080] The specific process is as follows: Install tool steel casings at the preset locations, with the height of the tool steel casings protruding above the ground not less than 50cm. The tool steel casings serve as a protective guide foundation for subsequent drilling and construction.

[0081] S205: Rotary drilling operations are performed based on the designed construction pile locations to form construction pile holes;

[0082] S206: Based on the determined specific location and development depth parameters of the karst caves, the karst caves are sequentially aligned from bottom to top using the construction pile holes and tool steel casings, and prefabricated closed rings are lowered down.

[0083] The specific process is as follows: the first prefabricated closed ring is lowered into the construction pile hole, and the four sets of pre-embedded steel bars 3 of the first prefabricated closed ring are welded to the tool steel casing to establish temporary fixation;

[0084] Then, the next prefabricated closed ring is lifted, and the four sets of pre-embedded steel bars 3 of the next prefabricated closed ring and the four sets of pre-embedded steel bars 3 of the first prefabricated closed ring are bent into pre-embedded steel bars according to the determined specific location of the karst cave and its development depth parameters, so as to obtain steel bar hooks 9 of the specified length and connect them to the two prefabricated closed rings, thereby cutting off the temporary fixation between the first prefabricated closed ring and the tool steel casing.

[0085] Continue lowering the next precast closed ring section and the first precast closed ring section, and weld the four sets of pre-embedded steel bars of the next precast closed ring section to the tool steel casing. Then continue to lift the next precast closed ring section and connect the steel bars between the next precast closed ring section and the next precast closed ring section. Continue this process until all precast closed rings are lowered into place. Retain the temporary fixation between the last precast closed ring section and the tool steel casing to ensure that all precast closed rings are firmly connected to the tool steel casing, thus completing the targeted sealing of the distributed karst caves.

[0086] More specifically, based on the determined specific location and development depth parameters of the karst cave, a prefabricated sealing ring of a specific length that can completely seal the karst cave is pre-selected. When connecting the prefabricated sealing ring with a steel bar hook, the bending position of the steel bar hook is determined according to the standard that the prefabricated sealing ring can accurately align with the corresponding karst cave. And / or, at least one pre-set length of extension steel bar is added between the steel bar hooks of two adjacent prefabricated sealing rings to accurately seal all distributed karst caves with determined specific locations and development depths.

[0087] S207: Continue to lower the reinforcing cage corresponding to the tool steel casing and the prefabricated closed ring connected in series;

[0088] S208: After the steel cage is lowered into place, a guide pipe extending to the bottom of the pile hole is installed to perform the pumping and cleaning operation. After the cleaning operation is completed, concrete is poured into the corresponding steel cage to complete the entire pile foundation construction process.

[0089] Although the present invention has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A closed ring for pile foundation construction in karst geology, characterized in that, include: The main body of the concrete closed ring is set as a cylindrical structure, and the cylindrical inner cavity of the main body of the concrete closed ring forms the space for the lowering of the pile foundation steel cage and the concrete pouring. The steel bar hooks are fixedly connected to both ends of the cylindrical concrete closed ring body along its axial direction. The concrete closed ring body can be extended vertically based on the steel bar hook.

2. The closed ring for karst geological pile foundation construction according to claim 1, characterized in that, The steel bar hooks are provided in several sets, and the several sets of steel bar hooks are respectively fixedly assembled at both ends of the cylindrical concrete closed ring body along its cylindrical axis.

3. A prefabricated mold structure for constructing closed-loop pile foundations in karst geological conditions, used to prepare the closed-loop as described in any one of claims 1-2, characterized in that, The closed-loop precast mold structure for karst geological pile foundation construction includes: The inner mold is a circular steel tube, which serves as the inner mold for forming the pre-made closed ring; The bottom support steel plate platform can be directionally slidably fitted onto the inner mold circular steel tube, and the outer edge of the bottom support steel plate platform is higher than its inner edge relative to the outer edge of the inner mold circular steel tube. A sheet metal outer ring template is correspondingly set on the outer side of the inner mold round steel tube body, and one end of the sheet metal outer ring template is detachably and correspondingly limited to the inner side of the outer edge of the bottom support steel plate platform. The other end of the sheet metal outer ring template is flush with the end of the inner mold round steel tube body away from the bottom support steel plate platform, so as to serve as the forming outer mold of the prefabricated closed ring. The U-shaped limiting buckle is positioned at both ends of the inner mold round steel tube away from the bottom support steel plate platform and at the other end of the outer iron ring template.

4. The closed-loop precast mold structure for karst pile foundation construction according to claim 3, characterized in that, Also includes: Several sets of pre-embedded reinforcing bars are provided. The pre-embedded reinforcing bars are inserted through the bottom support steel plate platform, and the two ends of the pre-embedded reinforcing bars extend one-to-one to the outer side of the inner mold circular steel pipe body away from the bottom support steel plate platform and the outer side of the bottom support steel plate platform.

5. The closed-loop precast mold structure for karst geological pile foundation construction according to claim 3, characterized in that, The inner mold circular steel pipe is set as a circular steel pipe with an inner diameter not less than the outer diameter of the karst pile foundation reinforcement cage. The bottom support steel plate platform is configured as an annular platform fitted onto the outer side of the inner mold circular steel tube; The longitudinal section of the annular bottom support steel plate platform is L-shaped at any position.

6. The closed-loop precast mold structure for karst pile foundation construction according to claim 4, characterized in that, The bottom support steel plate platform is evenly provided with at least four sets of longitudinally extending reinforcing bar reserved holes along its circumference; at least four sets of pre-embedded reinforcing bars are provided, and one end of each of the at least four sets of pre-embedded reinforcing bars extends through the at least four sets of pre-embedded reinforcing bar reserved holes, and the other end of each of the at least four sets of pre-embedded reinforcing bars extends beyond the end of the inner mold circular steel tube body away from the bottom support steel plate platform.

7. The closed-loop precast mold structure for karst geological pile foundation construction according to claim 6, characterized in that, Also includes: A flexible steel mesh is wrapped around the outer side of at least four sets of pre-embedded steel bars, and the flexible steel mesh is fixedly tied to the at least four sets of pre-embedded steel bars by binding wire.

Images