Foundation pit beam string structure inclined strut structure and construction method

Abstract

The invention relates to a foundation pit string beam diagonal bracing structure and a construction method, the foundation pit string beam diagonal bracing structure comprises a string beam, a diagonal bracing and a diagonal bracing node; the pre-embedded steel pull rod on one side of the beam string structure is embedded into the external corner, and the pre-embedded steel pull rod on the other side of the beam string structure is anchored into the first concrete enclosing purlin on one side of the external corner; one end of the inclined strut is obliquely and downwards inserted into a soil body in the pit, and the other end of the inclined strut is aligned to the second concrete enclosing purlin on the other side of the external corner and is in the same vertical plane with the second concrete enclosing purlin; the upper ends of the inclined struts apply prestress to the first concrete enclosing purlins through the jacks. The diagonal bracings capable of applying prestress abut against the external corners, the second concrete enclosing purlins at the external corners are utilized, the axes of the diagonal bracings correspond to the lines of the fender posts of the second concrete enclosing purlins at the external corners, overall force transmission is formed on the same line, and therefore diagonal bracings for construction of the crossing foundation pit are avoided, the construction difficulty and the project amount are greatly reduced, and the construction efficiency is improved. And the deformation of the external corner can be well reduced.

Description

Technical Field

[0001] The invention relates to a foundation pit beam string steel support combined structure, in particular to a foundation pit beam string diagonal bracing structure, and belongs to the technical field of building construction. Background Art

[0002] In order to ensure the safety of underground structure construction and the surrounding environment of the foundation pit, it is necessary to adopt support, reinforcement and protection measures for the side walls of the foundation pit and the surrounding environment. In order to increase the excavation space and improve construction efficiency, the beam string system is widely used.

[0003] In the prior art, for large external angle foundation pits with many angles, it is usually necessary to set up braces to support the external angles to avoid large deformation of the external angles. The braces will cross the entire foundation pit, affecting the construction and consuming a large amount of materials and construction time. Summary of the invention

[0004] The purpose of the present invention is to provide a foundation pit beam string diagonal brace structure, in which the beam string is arranged on the edge of the external corner, and a diagonal brace capable of applying prestress is arranged at the external corner, the diagonal brace is embedded in the soil in the pit, the external corner is supported by the diagonal brace, and the force transmitted by the beam string is borne. The use of opposite braces is avoided, and the deformation of the external corner is reduced by applying prestress at the diagonal brace node.

[0005] The present invention adopts the following technical solutions: A foundation pit tension beam diagonal brace structure includes a tension beam 4, a diagonal brace 3, and a diagonal brace fulcrum 2; the embedded steel tie rod on one side of the tension beam 4 is embedded in the positive corner position, and the embedded steel tie rod on the other side is anchored in the first concrete purlin 6 on one side of the positive corner; one end of the diagonal brace 3 is inserted obliquely downward into the soil in the pit, and the other end is aligned with the second concrete purlin 6' on the other side of the positive corner, and is in the same vertical plane as the second concrete purlin 6'; the upper end of the diagonal brace 3 applies prestress to the first concrete purlin 6 through a jack 304.

[0006] Preferably, the diagonal brace 3 is composed of a diagonal brace insertion section 302, a diagonal brace joint 301, an embedded groove 303, and a jack 304 from bottom to top; the diagonal brace joint 301 includes a connecting end plate 301e, a stiffening plate 301d, a wing plate 301c, a stepped head 301b, and an isolation material 301a, and is connected to the diagonal brace insertion section 302 through the connecting end plate 301e, and the stepped head 301b is embedded in the concrete corbel at the lower part of the first concrete purlin 6, and the isolation material 301a is wrapped on the outside and cast together with the concrete corbel, so that the isolation material 301a can be applied to the subsequent prestressing When force is applied, the diagonal brace and the concrete corbel separate along the direction of the diagonal brace into the pit, and the stepped head 301b and the wing plate 301c play a role of limiting protection, so that the diagonal brace 3 can only move along the direction into the pit; the embedded groove 303 is close to the diagonal brace joint 301, and the position is set in advance before concrete pouring. A round hole 303a is opened on the close surface, so that the jack 304 can pass through the round hole 303a to push the diagonal brace joint 301 to apply prestress when lifting; after the prestress is applied, the diagonal brace joint 301 is separated from the concrete corbel, and a filling plate 9 is placed in the gap between the wing plate 301c and the concrete corbel as a mechanical lock to avoid hydraulic failure affecting safety.

[0007] Furthermore, a right-angle structure for placing a jack 304 is formed between the concrete corbel and the first concrete purlin 6 , and the right-angle structure is located below the embedded steel tie rod 401 of the tensioned beam 4 .

[0008] Furthermore, the wing plate 301c and the connecting end plate 301e are symmetrically arranged, and each is provided with the stiffening plate 301d on the inner side.

[0009] Furthermore, the filling plate 9 has a U-shaped groove with a width substantially equal to the outer diameter of the large end of the stepped profile 301b, and is clamped on the outside of the large end of the stepped profile 301b through the U-shaped groove and abuts against the wing plate 301c.

[0010] A construction method of a foundation pit beam string brace structure as described in any one of the above, comprising the following steps: S1. Excavation to the working surface; S2, positioning the diagonal support insertion section 302 and inserting it into the soil through the equipment; S3, install the diagonal brace joint 301 and the diagonal brace insertion section 302, wrap the diagonal brace joint 301 with the isolation material 301a, and place the opening surface of the embedded groove 303 close to the diagonal brace joint 301 in the designated position; S4, embedding the pre-buried steel tie rod 401 into the first concrete purlin 6 above the designated position; S5, pouring the first concrete purlin 6 and concrete corbel; S6, installing the beam string 4; S7, put the jack 304 into the embedded groove 303, lift the jack 304, apply the prestress to the specified value, lock the jack 304, and put the filling plate 9 into the gap between the wing plate 301c and the concrete corbel; S8, the beam string 4 applies prestress to itself; S9. Excavation.

[0011] The beneficial effects of the present invention are: 1) The external corner is supported by a prestressed diagonal brace, and the second concrete purlin at the external corner is used. The axis of the diagonal brace corresponds to the line of the retaining pile of the second concrete purlin at the external corner (located in the same plane), forming an overall force transmission on the same line, thereby avoiding the construction of a brace across the foundation pit, greatly reducing the construction difficulty and engineering workload, and can well reduce the deformation of the external corner; 2) The embedded groove can conveniently and accurately reserve the hole for applying prestress and reinforce the hole; 3) The diagonal brace joint is designed with a stepped embedded head. When prestress is applied, the node can only slide in one direction diagonally downward to ensure safe force transmission. In addition, the outside of the stepped embedded head is covered with isolation material, which makes it more stable to apply prestress after pouring. When displacement occurs, the diagonal brace can be separated from the concrete corbel more smoothly without causing damage to the surrounding concrete. 4) The jack is equipped with a mechanical lock, and the diagonal brace joint can be inserted with a filler plate as multiple protection to ensure the force transmission of the node. The filler plate is designed with a U-shaped groove structure, which can be directly inserted and stuck on the outside of the diagonal brace joint, which is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the foundation pit plan with a large sun angle.

[0013] Figure 2 It is a plan view of the foundation pit beam string diagonal bracing structure of the present invention.

[0014] Figure 3 yes Figure 2 AA section view in.

[0015] Figure 4 is a schematic diagram of the diagonal brace support, where (a) is a top view and (b) is a side view.

[0016] Figure 5 It is a plan view of the filling plate.

[0017] Figure 6 This is a schematic diagram of the embedded groove.

[0018] Figure 7 It is a schematic diagram of the diagonal brace joint.

[0019] In the figure, 1. first horizontal support, 2. diagonal brace support, 3. diagonal brace, 4. tension beam, 5. second horizontal support, 6. first concrete purlin, 6'. second concrete purlin, 7. enclosure structure, 8. concrete corbel, 9. filling plate, 301. diagonal brace joint, 302. diagonal brace insertion section, 303. embedded groove, 304. jack, 301a. isolation material, 301b. stepped head, 301c. wing plate, 301d. stiffening plate, 301e. connecting end plate, 401. embedded steel tie rod, 303a. round hole. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] See also Figure 1 , Figure 1 A plan view of a foundation pit with a large sun angle is shown as the implementation environment of this embodiment.

[0022] See also Figure 2-Figure 3 A foundation pit tension beam diagonal bracing structure includes a tension beam 4, a diagonal brace 3, and a diagonal brace fulcrum 2; the embedded steel tie rod on one side of the tension beam 4 is embedded in the positive corner position, and the embedded steel tie rod on the other side is anchored in the first concrete purlin 6 on one side of the positive corner; one end of the diagonal brace 3 is inserted obliquely downward into the soil in the pit, and the other end is aligned with the second concrete purlin 6' on the other side of the positive corner, and is in the same vertical plane as the second concrete purlin 6'; the upper end of the diagonal brace 3 applies prestress to the first concrete purlin 6 through a jack 304.

[0023] The external corner is supported by a prestressed diagonal brace, and the second concrete purlin 6' at the external corner is used. The axis of the diagonal brace corresponds to the line of the retaining piles of the second concrete purlin 6' at the external corner (located in the same plane), forming an overall force transmission on the same line, thereby avoiding the construction of a brace across the foundation pit, greatly reducing the construction difficulty and engineering workload, and can effectively reduce the deformation of the external corner.

[0024] In this embodiment, the diagonal brace 3 is composed of a diagonal brace insertion section 302, a diagonal brace joint 301, an embedded groove 303, and a jack 304 from bottom to top. Figure 4 shown.

[0025] The diagonal brace joint 301 includes a connecting end plate 301e, a stiffening plate 301d, a wing plate 301c, a stepped head 301b, and an isolation material 301a, and is connected to the diagonal brace insertion section 302 through the connecting end plate 301e. Figure 7 shown.

[0026] Combination Figure 4 and Figure 7The stepped head 301b is embedded in the concrete corbel at the lower part of the first concrete purlin 6, and the isolation material 301a is wrapped on the outside and cast together with the concrete corbel. The isolation material 301a can allow the diagonal brace and the concrete corbel to be separated along the direction of the diagonal brace into the pit when prestressing is applied later. The stepped head 301b and the wing plate 301c play a role of limiting protection, so that the diagonal brace 3 can only move along the direction in the pit; the embedded groove 303 is close to the diagonal brace joint 301, and the position is put in advance before concrete pouring. The close surface is provided with a circular hole 303a, so that the jack 304 can pass through the circular hole 303a to push the diagonal brace joint 301 to apply prestressing when lifting; after the prestressing is applied, the diagonal brace joint 301 is separated from the concrete corbel, and a filling plate 9 is placed in the gap between the wing plate 301c and the concrete corbel as a mechanical lock to avoid hydraulic failure affecting safety.

[0027] See also Figure 4 (b) A right-angle structure for placing a jack 304 is formed between the concrete corbel and the first concrete purlin 6 , and the right-angle structure is located below the embedded steel tie rod 401 of the tension beam 4 .

[0028] In this embodiment, see Figure 7 The wing plate 301c and the connecting end plate 301e are symmetrically arranged, and each is provided with the stiffening plate 301d on the inner side.

[0029] In this embodiment, combined with Figure 4 and Figure 7 The filling plate 9 has a U-shaped groove with a width substantially equal to the outer diameter of the large end of the stepped profile head 301b. The filling plate 9 is clamped on the outside of the large end of the stepped profile head 301b and abuts against the wing plate 301c through the groove.

[0030] The construction method of the foundation pit beam string brace structure comprises the following steps: S1. Excavation to the working surface; S2, positioning the diagonal support insertion section 302 and inserting it into the soil through the equipment; S3, install the diagonal brace joint 301 and the diagonal brace insertion section 302, wrap the diagonal brace joint 301 with the isolation material 301a, and place the opening surface of the embedded groove 303 close to the diagonal brace joint 301 in the designated position; S4, embedding the pre-buried steel tie rod 401 into the first concrete purlin 6 above the designated position; S5, pouring the first concrete purlin 6 and concrete corbel; S6, installing the beam string 4; S7, put the jack 304 into the embedded groove 303, lift the jack 304, apply the prestress to the specified value, lock the jack 304, and put the filling plate 9 into the gap between the wing plate 301c and the concrete corbel; S8, the beam string 4 applies prestress to itself; S9. Excavation.

[0031] The present invention supports the external angle by using a diagonal brace that can apply prestress, and uses the second concrete purlin at the external angle. The axis of the diagonal brace corresponds to the line of the guard pile of the second concrete purlin at the external angle (located in the same plane), and forms an overall force transmission on the same line, thereby avoiding the construction of a cross-bracing across the foundation pit, greatly reducing the construction difficulty and engineering volume, and can well reduce the deformation of the external angle; the embedded groove can conveniently and accurately reserve a hole for applying prestress, and play a reinforcing role at the hole; the diagonal brace joint is designed with a stepped embedded head, so that when prestress is applied, the node can only slide unidirectionally downward to ensure the safety of force transmission. In addition, the outer coating of the stepped embedded head is an isolation material, so that the prestress is applied more smoothly after pouring, and the diagonal brace can be separated from the concrete corbel more smoothly when displacement occurs and does not cause damage to the surrounding concrete; the jack has a mechanical lock, and the diagonal brace joint can be inserted with a filling plate as multiple protection to ensure the node force transmission, and the filling plate is designed as a structure with a U-shaped groove, which can be directly inserted and stuck on the outer side of the diagonal brace joint, and is easy to implement.

[0032] The above are preferred embodiments of the present invention. Those skilled in the art may also make respective changes or improvements thereon. Without departing from the general concept of the present invention, these changes or improvements shall fall within the scope of protection claimed by the present invention.

Claims

1. A foundation pit beam string bracing structure, comprising a beam string (4), characterized in that: It also includes a diagonal brace (3) and a diagonal brace support (2); a pre-buried steel tie rod on one side of the string beam (4) is buried in the position of the external corner, and a pre-buried steel tie rod on the other side is anchored in the first concrete purlin (6) on one side of the external corner; One end of the diagonal brace (3) is inserted obliquely downward into the soil in the pit, and the other end is aligned with the second concrete purlin (6') on the other side of the positive angle, and is in the same vertical plane as the second concrete purlin (6'); The upper end of the diagonal brace (3) applies prestress to the first concrete purlin (6) via a jack (304).

2. The foundation pit beam string bracing structure according to claim 1, characterized in that: The diagonal brace (3) is composed of a diagonal brace insertion section (302), a diagonal brace joint (301), an embedded groove (303), and a jack (304) from bottom to top; The diagonal brace joint (301) comprises a connecting end plate (301e), a stiffening plate (301d), a wing plate (301c), a stepped head (301b), and an isolation material (301a), and is connected to the diagonal brace insertion section (302) via the connecting end plate (301e); the stepped head (301b) is embedded in the concrete corbel at the lower part of the first concrete purlin (6); the isolation material (301a) is wrapped on the outer surface and cast together with the concrete corbel; the diagonal brace and the concrete corbel are separated along the direction of the diagonal brace into the pit; the stepped head (301b) and The wing plate (301c) plays a role of limiting protection, so that the diagonal brace (3) can only move along the direction inside the pit; the embedded groove (303) is close to the diagonal brace joint (301), and is placed in position before concrete pouring. A circular hole (303a) is opened on the close surface, so that the jack (304) can pass through the circular hole (303a) and push against the diagonal brace joint (301) to apply prestress when lifting; after the prestress is applied, the diagonal brace joint (301) is separated from the concrete bracket, and a filling plate (9) is placed in the gap between the wing plate (301c) and the concrete bracket as a mechanical lock to prevent hydraulic failure from affecting safety.

3. The foundation pit beam string bracing structure according to claim 2, characterized in that: A right-angle structure for placing a jack (304) is formed between the concrete corbel and the first concrete purlin (6), and the right-angle structure is located below the embedded steel tie rod (401) of the tension beam (4).

4. The foundation pit beam string bracing structure according to claim 3, characterized in that: The wing plate (301c) and the connecting end plate (301e) are symmetrically arranged, and each is provided with the stiffening plate (301d) on the inner side.

5. The foundation pit beam string bracing structure according to claim 3, characterized in that: The filling plate (9) has a U-shaped groove with a width matching the outer diameter of the large end of the stepped head (301b), and is clamped on the outside of the large end of the stepped head (301b) through the U-shaped groove and abuts against the wing plate (301c).

6. A construction method for a foundation pit beam string brace structure as claimed in any one of claims 3 to 5, characterized in that: The following steps are involved: S1. Excavation to the working surface; S2, positioning the diagonal support insertion section (302) and inserting it into the soil through the equipment; S3, installing the diagonal brace joint (301) and the diagonal brace insertion section (302), wrapping the diagonal brace joint (301) with the isolation material (301a), and placing the opening surface of the embedded groove (303) close to the diagonal brace joint (301) at a designated position; S4, embedding the pre-buried steel tie rod (401) in the first concrete purlin (6) above the designated position; S5, pouring the first concrete purlin (6) and corbels; S6, installing the beam string (4); S7, placing the jack (304) into the embedded groove (303), lifting the jack (304), applying a specified prestress value, locking the jack (304), and placing the filler plate (9) into the gap between the wing plate (301c) and the concrete corbel; S8, the beam string (4) applies prestress to itself; S9. Excavation.

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