Bridge pile pre-protection structure excavated close to foundation pit

Abstract

The utility model discloses a bridge pile pre-protection structure for near foundation pit excavation, which comprises a first protection mechanism, a second protection mechanism and a third protection mechanism, the first protection mechanism comprises a plurality of sections of first steel casings, the first steel casings are in butt joint in sequence, and the adjacent first steel casings are fixedly connected through connecting pieces; the second protection mechanism comprises a second steel casing, and the second steel casing is coaxially arranged on the outer wall of the first steel casing in a sleeving mode; wherein a plurality of groups of first protection mechanisms and second protection mechanisms are arranged at equal intervals; square steel pipes are arranged between the second steel casings of the adjacent second protection mechanisms, the square steel pipes are fixedly connected with the top ends of the second steel casings, and the adjacent second steel casings are perpendicular to the square steel pipes. The two adjacent second square steel pipes are connected through the square steel pipes, so that the core protection structures between the two bridge piles are connected in series to achieve joint stress between the two second steel casings, and the respective deformation resisting effect is fully played.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge construction, in particular to a bridge pile pre-protection structure close to foundation pit excavation. Background Art

[0002] With the rapid development of urban infrastructure, infrastructure is becoming more and more dense, and the problems of crowded building space and complicated traffic are becoming increasingly prominent. In actual projects, there are more and more cases where tunnels and pipe galleries are close to viaduct piles. Due to the complex geological and hydrological conditions of underground engineering, if the design and construction plan are unreasonable, it is very easy to cause risks such as lateral displacement of bridge piles and collapse of bridge superstructures due to foundation pit excavation.

[0003] The control measures for the surrounding bridge substructures during foundation pit excavation mainly focus on controlling the deformation of the foundation pit itself, controlling the deformation during the transmission process, and directly taking reinforcement measures on the bridge piles. For the bridge substructure itself, the first two are to indirectly reduce its deformation. When the bridge substructure has a very low ability to resist deformation and indirect measures may not meet the deformation control requirements, it is necessary to take reinforcement measures on the bridge piles, such as replacing the pile foundation with a stronger pile foundation, or adding reinforcement piles, etc., to directly reduce the deformation and stress of the bridge substructure.

[0004] However, with the intelligentization of urban traffic planning, it is obvious that there will be a problem of proximity impact between the foundation pit of the planned tunnel or building and the piles of the bridge under construction. However, there is currently a lack of control measures for pre-protection of bridge piles.

[0005] Based on the above reasons, the utility model provides a bridge pile pre-protection structure close to foundation pit excavation. Utility Model Content

[0006] The utility model aims to provide a bridge pile pre-protection structure close to foundation pit excavation to solve the problems existing in the prior art.

[0007] To achieve the above purpose, the utility model provides the following solution: The utility model provides a bridge pile pre-protection structure close to the foundation pit excavation, including:

[0008] A first protection mechanism, the first protection mechanism comprising a plurality of first steel casings, the plurality of first steel casings are connected in sequence, and adjacent first steel casings are fixedly connected by a connecting piece;

[0009] A second protection mechanism, the second protection mechanism comprising a second steel casing, the second steel casing being coaxially sleeved on the outer wall of the first steel casing;

[0010] Among them, the first protective mechanism and the second protective mechanism are arranged in several groups at equal intervals; a square steel pipe is arranged between the second steel casings of adjacent second protective mechanisms, the square steel pipe is fixedly connected to the top of the second steel casing, and the adjacent second steel casings are vertically arranged to the square steel pipe.

[0011] According to the bridge pile pre-protection structure close to foundation pit excavation provided by the utility model, the top end of the first steel casing extends out of the second steel casing, and the distance between the top end of the first steel casing and the top end of the second steel casing is 30cm-40cm.

[0012] According to the bridge pile pre-protection structure close to foundation pit excavation provided by the utility model, the cross-sectional shape of the first steel casing is an annular structure, the wall thickness of the first steel casing is 12 mm, and the depth is 20 m.

[0013] According to the bridge pile pre-protection structure close to foundation pit excavation provided by the utility model, the cross-sectional shape of the second steel casing is adapted to the cross-sectional shape of the first steel casing, the wall thickness of the second steel casing is 20 mm, and the depth is 12 m.

[0014] According to the bridge pile pre-protection structure close to foundation pit excavation provided by the utility model, the diameter of the square steel pipe is 500 mm, and the square steel pipe is fixed to the second steel casing by welding.

[0015] According to the bridge pile pre-protection structure close to foundation pit excavation provided by the utility model, the diameter of the first steel casing is 0.1-0.2 times the diameter of the bridge pile, and the diameter of the second steel casing is 1.5-2 times the diameter of the bridge pile.

[0016] According to the bridge pile pre-protection structure close to foundation pit excavation provided by the utility model, the connecting member includes a connecting pin, and several sections of the first steel casing are fixedly connected by the connecting pin, and the diameter of the pin is 20 mm.

[0017] The utility model discloses the following technical effects:

[0018] 1) The utility model realizes the connection between two adjacent second square steel tubes through square steel tubes, so that the core protection structure between two bridge piles is connected in series to realize the common force between the two second steel casings, and give full play to their respective deformation resistance functions.

[0019] 2) The first steel casing is constructed together with the drilling of the bridge piles, and is pulled out after the first steel casing and the pouring of concrete for the bridge piles are completed. This not only ensures the quality of the bridge pile construction, but also avoids the risk of collapse of the bridge pile hole wall caused by the construction of the first steel casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a side view of the bridge pile pre-protection structure of the utility model close to the foundation pit excavation;

[0022] Figure 2 It is a top view of the bridge pile pre-protection structure close to the foundation pit excavation of the utility model;

[0023] Figure 3 It is a schematic diagram of the butt joint structure of the steel casing of the utility model.

[0024] Among them, 1. Bridge piles; 2. Second steel casing; 3. Sleeve valve pipe grouting body; 4. MJS method piles; 5. Square steel pipes; 6. Foundation pit support piles; 7. Crown beams; 8. Water-stop curtains; 9. Pier caps; 10. First steel casing; 11. Connecting pins. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0027] Reference Figure 1-3 The utility model provides a bridge pile pre-protection structure close to foundation pit excavation, comprising:

[0028] A first protection mechanism, the first protection mechanism comprises a plurality of first steel casings 10, the plurality of first steel casings 10 are connected in sequence, and adjacent first steel casings 10 are fixedly connected by connecting pieces;

[0029] A second protection mechanism, the second protection mechanism comprises a second steel casing 2, and the second steel casing 2 is coaxially sleeved on the outer wall of the first steel casing 10;

[0030] Among them, several groups of first protective mechanisms and second protective mechanisms are arranged at equal intervals; square steel pipes 5 are arranged between the second steel casings 2 of adjacent second protective mechanisms, the square steel pipes 5 are fixedly connected to the top ends of the second steel casings 2, and the adjacent second steel casings 2 and the square steel pipes 5 are vertically arranged.

[0031] The utility model realizes the connection between two adjacent second square steel tubes 5 through square steel tubes 5, so that the core protection structure between the two bridge piles 1 is connected in series to realize the common force between the two second steel casings 2, and gives full play to the role of each in resisting deformation. The first steel casing 10 is constructed together with the drilling of the bridge pile 1, and is pulled out after the first steel casing 10 and the pouring of concrete for the bridge pile 1 are completed, which not only ensures the construction quality of the bridge pile 1, but also avoids the risk of the first steel casing 10 causing the collapse of the hole wall of the bridge pile 1.

[0032] According to a further optimization scheme, the top end of the first steel casing 10 extends out of the second steel casing 2, and the distance between the top end of the first steel casing 10 and the top end of the second steel casing 2 is 30 cm-40 cm.

[0033] According to a further optimization scheme, the cross-sectional shape of the first steel casing 10 is a ring structure, the wall thickness of the first steel casing 10 is 12 mm, and the depth is 20 m.

[0034] According to a further optimization scheme, the cross-sectional shape of the second steel casing 2 is matched with the cross-sectional shape of the first steel casing 10, and the wall thickness of the second steel casing 2 is 20 mm and the depth is 12 m.

[0035] According to a further optimized solution, the diameter of the square steel pipe 5 is 500 mm, and the square steel pipe 5 is fixed to the second steel casing 2 by welding.

[0036] According to a further optimized solution, the diameter of the first steel casing 10 is 0.1-0.2 times the diameter of the bridge pile 1 , and the diameter of the second steel casing 2 is 1.5-2 times the diameter of the bridge pile 1 .

[0037] According to a further optimized solution, the connecting piece includes a connecting pin 11, and several sections of the first steel casing 10 are fixedly connected by the connecting pin 11, and the diameter of the pin is 20 mm.

[0038] Specific construction process:

[0039] Step 1: Use a total station to determine the center position of bridge pile 1 and mark it.

[0040] Step 2: Use a rotary drilling machine to drill a hole at the center of the pile position to a depth of about 1m, and then use a crawler crane to place the first steel casing 10 in the drilled hole to ensure that its center line coincides with the center of the pile. After the first steel casing 10 is fixed in the correct position, it is backfilled and compacted with clay to ensure its verticality.

[0041] Step 3: Press down the first steel casing 10 while rotary excavating to take soil. When the first steel casing 10 is not long enough, use the connecting pin 11 to connect it. Rotate until the designed excavation depth is reached and stop the construction. Cut the surface of the excess first steel casing 10, leaving only a 30cm part exposed above the ground.

[0042] Step 4: Clean the hole. After drilling is completed, use a hole cleaning drill to perform preliminary hole cleaning. After the steel cage and conduit are installed, perform a secondary hole cleaning to ensure that the thickness of the sediment at the bottom of the pile is no more than 50mm.

[0043] Step 5: temporarily close the opening of the first steel casing 10 on the ground with a circular steel plate to prevent foreign matter from entering the borehole. Then construct the second steel casing 2, which is constructed using a vibrating hammer, with the bottom reaching the bedrock surface and the top flush with the ground.

[0044] Step 6: Use a crawler crane to vertically lift the steel cage into the hole, fix the steel cage, and then install the guide tube to prepare for pouring the bridge pile concrete.

[0045] Step 7: Pull out the first steel casing 10 while pouring the bridge pile concrete. During the pulling out process, a vibrating hammer is used to lift it, and the drop value of the concrete surface in the first steel casing 10 should be monitored at any time and recorded.

[0046] Step eight, construct the sleeve valve pipe grouting body 3, first measure and lay out to determine the drilling position, then use the casing wall water flushing method to drill the hole, then lower the sleeve valve pipe into the hole, clean the hole with high-pressure water, and use quick-setting cement mortar to seal the area from the ground around the hole mouth to 1m below the ground, and finally adopt segmented grouting. After each segment of grouting is completed, move the core pipe length up or down by one step. After the grouting is completed, cover the upper mouth of the grouting pipe with a cover to facilitate the re-injection construction.

[0047] Step 9: Manually dig a trench downward between the two second steel casings 2, then lift the square steel pipe 5 into the trench, and finally weld the two ends of the square steel pipe 5 to the surfaces of both sides of the second steel casing 2.

[0048] Step 10, construct MJS method pile 4, first lay out the line to determine the position, then use the drilling rig to lead the hole, lower the outer casing, pull out the outer casing, lower the drill rod, spray grouting to the bottom of the pulled-out casing, pull out the outer casing again, spray grouting to the bottom of the pulled-out casing again, pull out all the outer casing, and spray grouting to the designed elevation.

[0049] Step 11: construct the bridge pier cap 9, first break the bridge pile 1 head, then tie the steel bars, then install the formwork, and finally pour the bridge pier cap 9 concrete.

[0050] Step 12: The foundation pit support piles 6 are constructed in the form of bored cast-in-place piles, which are formed by drilling holes, cleaning holes, hoisting steel cages, installing guide tubes, and pouring concrete.

[0051] Step 13: Use a three-axis cement mixing pile driver to construct the water-stop curtain 8.

[0052] Step 14: construct the crown beam 7 , dig and clean the trenches manually along the arrangement direction of the foundation pit supporting piles 6 , remove the pile heads of the foundation pit supporting piles 6 , tie steel bars and pour concrete to form the crown beam 7 .

[0053] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0054] The embodiments described above are only descriptions of the preferred methods of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A bridge pile pre-protection structure close to foundation pit excavation, characterized in that: include: A first protection mechanism, the first protection mechanism comprising a plurality of first steel casings (10), the plurality of first steel casings (10) being connected in sequence, and adjacent first steel casings (10) being fixedly connected via a connecting piece; A second protection mechanism, the second protection mechanism comprising a second steel casing (2), the second steel casing (2) being coaxially sleeved on the outer wall of the first steel casing (10); Wherein, the first protection mechanism and the second protection mechanism are arranged in a plurality of groups at equal intervals; a square steel pipe (5) is arranged between the second steel casings (2) of adjacent second protection mechanisms, the square steel pipe (5) is fixedly connected to the top end of the second steel casing (2), and the adjacent second steel casings (2) and the square steel pipe (5) are vertically arranged.

2. The bridge pile pre-protection structure close to foundation pit excavation according to claim 1 is characterized by: The top end of the first steel casing (10) extends out of the second steel casing (2), and the distance between the top end of the first steel casing (10) and the top end of the second steel casing (2) is 30 cm-40 cm.

3. The bridge pile pre-protection structure close to foundation pit excavation according to claim 1 is characterized by: The cross-sectional shape of the first steel casing (10) is an annular structure, the wall thickness of the first steel casing (10) is 12 mm, and the depth is 20 m.

4. The bridge pile pre-protection structure close to foundation pit excavation according to claim 1 is characterized by: The cross-sectional shape of the second steel casing (2) matches the cross-sectional shape of the first steel casing (10), and the wall thickness of the second steel casing (2) is 20 mm and the depth is 12 m.

5. The bridge pile pre-protection structure close to foundation pit excavation according to claim 1 is characterized by: The diameter of the square steel pipe (5) is 500 mm, and the square steel pipe (5) is fixed to the second steel casing (2) by welding.

6. The bridge pile pre-protection structure close to foundation pit excavation according to claim 1 is characterized by: The diameter of the first steel casing (10) is 0.1-0.2 times the diameter of the bridge pile (1), and the diameter of the second steel casing (2) is 1.5-2 times the diameter of the bridge pile (1).

7. The bridge pile pre-protection structure close to foundation pit excavation according to claim 1 is characterized by: The connecting piece comprises a connecting pin (11), and a plurality of sections of the first steel casing (10) are fixedly connected by the connecting pin (11), and the diameter of the pin is 20 mm.

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