Pile foundation reinforcing structure based on karst cave landform

Abstract

The utility model belongs to the technical field of pile foundation construction, and particularly relates to a pile foundation reinforcing structure based on karst cave landform, which comprises a pile foundation body, a plurality of vertically arranged drill holes are arranged in the pile foundation body, steel pipe piles are arranged in the drill holes, and part or all of the steel pipe piles penetrate through an underground karst cave. The top ends of the steel pipe piles are flush with the top end of the pile foundation body or extend out of the top end of the pile foundation body, the bottom ends of the steel pipe piles are embedded into a bearing stratum below the underground karst cave, and grouting holes are formed in the side walls, penetrating through the underground karst cave, of the steel pipe piles. According to the utility model, the underground karst cave and the steel pipe piles are filled, and the steel pipe piles are utilized to share the load applied to the pile foundation body by the bearing platform, so that the integral bearing capacity of the pile foundation is increased, the pile foundation reinforcing quality is guaranteed, and the pile foundation is simple to construct and short in construction period.

Description

Technical Field

[0001] The utility model belongs to the technical field of pile foundation construction, and in particular relates to a pile foundation reinforcement structure based on karst cave landform. Background Art

[0002] At present, in geological survey, the diameter of geological exploration holes is usually 127mm and the cross-sectional area is 0.126m 2 The diameter of the on-site pile foundation is usually 1500mm and the cross-sectional area is 1.766m 2 In this way, the geological survey section accounts for 0.71% of the pile foundation section. Therefore, the geological survey work is to explore the karst development characteristics of the site in a point-to-point manner, which cannot fully represent all the geological conditions in the cross-sectional area of ​​the pile end. Moreover, complex geology such as karst often encounters strong karst development. When the number of pile foundation construction is large, after the pile foundation core sampling, there is a certain probability that a karst cave will be encountered within 5m below the pile bottom. This is a poor engineering geology and the pile foundation needs to be reinforced.

[0003] The traditional treatment method uses high-pressure grouting to jet, cut and clean the karst caves under the bearing layer at the pile end, and then use high-pressure grouting to reinforce the karst caves after the water returns. However, since the development of the karst caves at the bottom cannot be explored, it is difficult to guarantee the amount of cement slurry materials and the quality of pile foundation reinforcement. Therefore, it is necessary to design a reinforcement structure suitable for the constructed pile foundation. Utility Model Content

[0004] The utility model aims to provide a pile foundation reinforcement structure based on karst cave landform, so as to solve the problem that the traditional grouting consolidation method is difficult to ensure the quality of pile foundation reinforcement.

[0005] In order to achieve the above-mentioned purpose, the scheme of the utility model is: a pile foundation reinforcement structure based on karst cave landform, including a pile basic body, a plurality of vertically arranged boreholes are opened in the pile basic body, steel pipe piles are arranged in the boreholes, some or all of the steel pipe piles pass through the underground karst cave, and the top of the steel pipe pile is flush with the top of the pile basic body or protrudes from the top of the pile basic body, the bottom of the steel pipe pile is embedded in the bearing layer below the underground karst cave, and grouting holes are opened on the side walls of the steel pipe pile passing through the underground karst cave.

[0006] The working principle and beneficial effects of this scheme are as follows: in this scheme, after the steel pipe pile passes through the underground cave, it is embedded in the bearing layer below the underground cave, and then grouting is injected into the steel pipe pile passing through the underground cave, thereby filling the underground cave and the steel pipe pile, realizing the reinforcement of the pile bottom foundation, and using the steel pipe pile to share the load imposed by the cap on the pile basic body, thereby increasing the overall bearing capacity of the pile foundation. Therefore, compared with the traditional grouting consolidation method, this scheme can ensure the quality of pile foundation reinforcement. In addition, this scheme is simple to construct, has a short construction period, and high construction efficiency.

[0007] Optionally, the top end of the steel pipe pile protrudes from the top end of the pile basic body, and connecting steel bars are provided between adjacent two steel pipe piles, and both ends of the connecting steel bars are fixedly connected to the corresponding steel pipe piles.

[0008] In this solution, the top end of the steel pipe pile protrudes from the top end of the pile basic body. In this way, during the construction of the bearing platform, the top end of the steel pipe pile can be embedded into the bearing platform, so as to ensure that the steel pipe pile supports the bearing platform. And, since adjacent two steel pipe piles are connected by connecting steel bars, the integrity of the steel pipe piles is increased, and the support stability of the steel pipe piles to the bearing platform is improved.

[0009] Optionally, the pile foundation reinforcement structure further includes a jacking component. The jacking component includes a vertical steel bar, a radial cylinder, an elastic member, and a plug rod that can be in clearance fit with the grouting hole. The radial cylinder is fixedly connected to the vertical steel bar. One end of the radial cylinder is closed. The plug rod and the elastic member are both arranged inside the radial cylinder. One end of the elastic member is fixedly connected to the plug rod, and the other end of the elastic member is fixedly connected to the closed end of the radial cylinder. When the elastic member is in a natural state, the end of the plug rod close to the elastic member is located inside the radial cylinder.

[0010] In this solution, after the grouting is completed, the vertical steel bar is lowered, and the vertical steel bar moves downward along the axis of the steel pipe pile. After the radial cylinder moves downward to be coaxial with the grouting hole, the plug rod pops out under the action of the elastic member and penetrates through the grouting hole. In this way, the following effects can be achieved: 1) When the clearance between the plug rod and the grouting hole is zero, the outer peripheral wall of the plug rod fits with the inner peripheral wall of the grouting hole, improving the bearing capacity of the steel pipe pile;

[0011] 2) The plug rod is embedded in the cement slurry in the underground karst cave, increasing the connection between the steel pipe pile and the filling material of the underground karst cave, and improving the bearing capacity of the steel pipe pile.

[0012] Optionally, limiting pieces are arranged on the inner wall of the steel pipe pile. The limiting pieces are arranged along the axis of the steel pipe pile. An axial limiting groove for the radial cylinder to be clamped into is formed between the two limiting pieces. During the process of the radial cylinder sliding along the axial limiting groove, the axis of the grouting hole and the axis of the plug rod coincide in the projection on the radial plane of the steel pipe pile.

[0013] In this solution, the axial limiting groove restricts the vertical sliding path of the radial cylinder to ensure that the radial cylinder is coaxial with the grouting hole after sliding downward.

[0014] Optionally, the number of the axial limiting grooves is two, and the two axial limiting grooves are arranged symmetrically about the center axis of the steel pipe pile.

[0015] In this solution, when the number of the axial limiting grooves is two, the two ends of the radial cylinder can be limited, and the limiting effect is better.

[0016] Optionally, the outer diameter of the steel pipe pile is 108 mm, and the wall thickness of the steel pipe pile is 12 mm.

[0017] In this solution, the specifications of the steel pipe piles are clarified.

[0018] Optionally, the bottom end of the steel pipe pile is embedded into the bearing stratum below the underground karst cave by at least 1 m.

[0019] In this solution, the depth of the bottom end of the steel pipe pile embedded into the bearing stratum below the underground karst cave is specified to ensure the bearing capacity of the steel pipe pile. Description of the Drawings

[0020] Figure 1 It is the axial sectional view of the pile foundation reinforcement structure based on the karst landform in the first embodiment of the present utility model;

[0021] Figure 2 It is the top view of the pile foundation reinforcement structure based on the karst landform in the first embodiment of the present utility model;

[0022] Figure 3 It is Figure 1 the enlarged schematic view of A in

[0023] Figure 4 It is the radial sectional view of the steel pipe pile in the first embodiment of the present utility model;

[0024] Figure 5 It is the axial sectional view of the pile foundation reinforcement structure based on the karst landform in the second embodiment of the present utility model;

[0025] Figure 6 It is the top view of the pile foundation reinforcement structure based on the karst landform in the second embodiment of the present utility model;

[0026] Figure 7 It is in accordance with Figure 1 the enlarged schematic view of part A in

[0027] Figure 8 It is the radial sectional view of the steel pipe pile and the socket assembly in the third embodiment of the present utility model;

[0028] Figure 9 It is the radial sectional view when the inserting rod penetrates the grouting hole in the third embodiment of the present utility model. Detailed Description of the Invention

[0029] The following is a further detailed description through specific embodiments:

[0030] The reference signs in the drawings of the specification include: pile foundation body 1, steel pipe pile 2, grouting hole 201, underground karst cave 3, bearing stratum 4, connecting steel bars 5, vertical steel bars 6, radial cylinder 7, elastic member 8, inserting rod 9, limiting piece 10.

[0031] Embodiment 1

[0032] This embodiment is basically as Figure 1 andFigure 2 As shown: A pile foundation reinforcement structure based on karst landform, including a pile foundation body 1. A number of vertically arranged drill holes are opened in the pile foundation body 1, and steel pipe piles 2 are arranged in the drill holes. Some or all of the steel pipe piles 2 pass through the underground karst cave 3. Specifically, the number of steel pipe piles 2 passing through the underground karst cave 3 depends on the position of the underground karst cave 3 below the pile foundation body 1. For example, when the underground karst cave 3 is directly below the pile foundation body 1 and the cross-sectional area of the underground karst cave 3 is larger than the cross-sectional area of the pile foundation body 1, all the steel pipe piles 2 pass through the underground karst cave 3; when a part of the underground karst cave 3 is directly below the pile foundation body 1 and the cross-sectional area of this part is smaller than the cross-sectional area of the pile foundation body 1, some of the steel pipe piles 2 pass through the underground karst cave 3. Combined with Figure 3 As shown, in this embodiment, taking some of the steel pipe piles 2 passing through the underground karst cave 3 as an example, the number of steel pipe piles 2 is thirteen, and the thirteen steel pipe piles 2 are evenly distributed on the pile foundation body 1. Combined with Figure 4 As shown, grouting holes 201 are opened on the side walls of the steel pipe piles 2 passing through the underground karst cave 3.

[0033] The top end of the steel pipe pile 2 is flush with the top end of the pile foundation body 1 or protrudes from the top end of the pile foundation body 1, and the bottom end of the steel pipe pile 2 is embedded into the bearing stratum 4 below the underground karst cave 3 by at least 1 m; in this embodiment, the top end of the steel pipe pile 2 is flush with the top end of the pile foundation body 1, the bottom end of the steel pipe pile 2 is embedded into the bearing stratum 4 3 m below the underground karst cave 3, and the steel pipe pile 2 is made of seamless steel pipe with an outer diameter of 108 mm and a wall thickness of 12 mm.

[0034] In this embodiment, some of the steel pipe piles 2 pass through the pile foundation body 1 and then through the underground karst cave 3, and then are embedded into the bearing stratum 4 three meters below the underground karst cave 3. The other part of the steel pipe piles 2 pass through the pile foundation body 1 and are directly embedded into the bearing stratum 4 below the pile foundation body 1, and ensure that their bottom ends are flush with the bottom ends of the steel pipe piles 2 passing through the underground karst cave 3. Grout is injected into the underground karst cave 3 through the grouting holes 201 on the steel pipe piles 2, so as to fill the underground karst cave 3 (it is also possible to inject grout into the underground karst cave 3 before lowering the steel pipe piles 2 and then lower the steel pipe piles 2), and continue to inject grout into the steel pipe piles 2 to fill the steel pipe piles 2. In this way, on the one hand, the geological structure below the pile foundation body 1 is reinforced by filling the underground karst cave 3, and on the other hand, the steel pipe piles 2 are used to share the load exerted by the bearing platform on the pile foundation body 1, thereby increasing the overall bearing capacity of the pile foundation. Compared with the traditional grouting consolidation method, this embodiment can ensure the quality of pile foundation reinforcement, and the construction process of this embodiment is simple, the construction period is short, and the construction efficiency is high.

[0035] Embodiment 2

[0036] The difference between this embodiment and Embodiment 1 is that: As Figure 5 and Figure 6As shown in the figure, in this embodiment, the top end of the steel pipe pile 2 protrudes from the top end of the pile basic body 1. Connecting steel bars 5 are provided between two adjacent steel pipe piles 2, and both ends of the connecting steel bars 5 are welded to the corresponding steel pipe piles 2.

[0037] In this embodiment, the connecting steel bars 5 are used to connect two adjacent steel pipe piles 2, thereby increasing the integrity of the steel pipe piles 2 and improving the support stability of the steel pipe piles 2 for the bearing platform. Moreover, the top end of the steel pipe pile 2 protrudes from the top end of the pile basic body 1. Therefore, the top end of the steel pipe pile 2 and the connecting steel bars 5 can both be embedded in the bearing platform, ensuring that the steel pipe piles 2 exert a supporting force on the bearing platform.

[0038] Embodiment Three

[0039] The difference between this embodiment and Embodiment One or Embodiment Two is that: as Figure 7 and Figure 8 shown, the pile foundation reinforcement structure in this embodiment further includes a jacking component. The jacking component includes a vertical steel bar 6, a radial cylinder 7, an elastic member 8, and a plug rod 9 that can be in clearance fit with the grouting hole 201. In this embodiment, the clearance between the plug rod 9 and the grouting hole 201 is zero. The radial cylinder 7 is welded to the vertical steel bar 6. One end of the radial cylinder 7 is closed. The plug rod 9 and the elastic member 8 are arranged inside the radial cylinder 7. One end of the elastic member 8 is welded to the plug rod 9, and the other end of the elastic member 8 is welded to the closed end of the radial cylinder 7. When the elastic member 8 is in a natural state, the end of the plug rod 9 close to the elastic member 8 is located inside the radial cylinder 7, and the plug rod 9 slides along the axial direction of the radial cylinder 7. In this embodiment, the elastic member 8 is a spring. A limiting piece 10 is integrally formed on the inner wall of the steel pipe pile 2. The limiting piece 10 is arranged along the axial direction of the steel pipe pile 2. An axial limiting groove for the radial cylinder 7 to be inserted into is formed between the two limiting pieces 10. The number of axial limiting grooves is two, and the two axial limiting grooves are symmetrically arranged about the central axis of the steel pipe pile 2. During the process of the radial cylinder 7 sliding along the axial limiting groove, the projection of the axis of the grouting hole 201 and the axis of the plug rod 9 on the radial plane of the steel pipe pile 2 coincides.

[0040] In this embodiment, the axial limiting groove restricts the vertical sliding path of the radial cylinder 7 to ensure that the radial cylinder 7 is coaxial with the grouting hole 201 after sliding down. After the steel pipe pile 2 passes through the underground karst cave 3 and is embedded in the bearing stratum 4 below the underground karst cave 3, the jacking component is placed into the corresponding steel pipe pile 2 with the grouting hole 201. The radial cylinder 7 slides down along the axial limiting groove, so that the radial cylinder 7 is located above the corresponding grouting hole 201, and the top end of the vertical steel bar 6 protrudes from the steel pipe pile 2. After the grouting is completed and the concrete is in the initial setting state, the vertical steel bar 6 is lowered, and the radial cylinder 7 continues to slide down. When the plug rod 9 is coaxial with the grouting hole 201, the plug rod 9 pops out under the action of the elastic member 8, and the plug rod 9 penetrates through the grouting hole 201, as Figure 9As shown, the end of the insertion rod 9 away from the elastic member 8 is embedded in the cement slurry of the underground karst cave 3. In this way, the insertion rod 9 not only seals the grouting hole 201 after the grouting is completed, improving the bearing capacity of the steel pipe pile 2, but also increases the connection between the steel pipe pile 2 and the filling material of the underground karst cave 3, further improving the bearing capacity of the steel pipe pile 2.

[0041] The above are only embodiments of the present invention, and common knowledge such as specific structures and characteristics known in the art are not described in detail herein. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the present invention. The specific implementation manners and the like in the specification can be used to explain the content of the claims.

Claims

1. A pile foundation reinforcement structure based on karst cave landform, comprising a pile base body, a plurality of vertically arranged boreholes are opened in the pile base body, and steel pipe piles are arranged in the boreholes, characterized in that: Part or all of the steel pipe piles pass through the underground cave, and the top of the steel pipe pile is flush with the top of the pile basic body or protrudes from the top of the pile basic body, the bottom of the steel pipe pile is embedded in the bearing layer below the underground cave, and grouting holes are opened on the side wall of the steel pipe pile passing through the underground cave.

2. The pile foundation reinforcement structure based on karst cave landform according to claim 1 is characterized in that: The top of the steel pipe pile protrudes from the top of the pile basic body, and connecting steel bars are arranged between two adjacent steel pipe piles, and both ends of the connecting steel bars are fixedly connected to the corresponding steel pipe piles.

3. The pile foundation reinforcement structure based on cave landform according to claim 1 or 2, characterized in that: The pile foundation reinforcement structure also includes a socket assembly, which includes vertical steel bars, a radial tube, an elastic member and an insertion rod that can match the gap of the grouting hole. The radial tube is fixedly connected to the vertical steel bars, one end of the radial tube is closed, the insertion rod and the elastic member are both arranged in the radial tube, one end of the elastic member is fixedly connected to the insertion rod, and the other end of the elastic member is fixedly connected to the closed end of the radial tube. When the elastic member is in a natural state, the end of the insertion rod close to the elastic member is located in the radial tube.

4. The pile foundation reinforcement structure based on karst landform according to claim 3 is characterized in that: A limit plate is provided on the inner wall of the steel pipe pile, and the limit plate is arranged along the axial direction of the steel pipe pile. An axial limit groove for the radial tube to be inserted is formed between the two limit plates. When the radial tube slides along the axial limit groove, the axis of the grouting hole coincides with the projection of the axis of the insertion rod on the radial surface of the steel pipe pile.

5. The pile foundation reinforcement structure based on karst cave landform according to claim 4 is characterized in that: The number of the axial limit grooves is two, and the two axial limit grooves are symmetrically arranged along the central axis of the steel pipe pile.

6. The pile foundation reinforcement structure based on karst cave landform according to claim 1 is characterized in that: The outer diameter of the steel pipe pile is 108 mm, and the wall thickness of the steel pipe pile is 12 mm.

7. The pile foundation reinforcement structure based on karst cave landform according to claim 1 is characterized in that: The bottom end of the steel pipe pile is embedded in the bearing layer below the underground cave for at least 1m.

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