Inclined strut structure of foundation pit with cable-beam and construction method

Abstract

The present invention relates to a prestressed cable beam inclined support structure for foundation pits and a construction method. The prestressed cable beam inclined support structure for foundation pits includes a prestressed cable beam, and also includes an inclined support and an inclined support node. The embedded steel tie rod on one side of the prestressed cable beam is buried into the position of the external corner, and the embedded steel tie rod on the other side is anchored into the first concrete collar beam on one side of the external corner. One end of the inclined support is obliquely inserted downward into the soil in the foundation pit, and the other end is aligned with the second concrete collar beam on the other side of the external corner and is in the same vertical plane as the second concrete collar beam. The upper end of the inclined support applies prestress to the first concrete collar beam through a jack. By using the inclined support that can apply prestress to support the external corner and utilizing the second concrete collar beam at the external corner, the axis of the inclined support corresponds to the line of the retaining pile of the second concrete collar beam at the external corner, forming an overall force transmission on the same line, thereby avoiding the construction of cross-bracing across the foundation pit, greatly reducing the construction difficulty and the amount of work, and being able to well reduce the deformation of the external corner.

Description

Technical Field

[0001] The present invention relates to a combined structure of a cable - strut beam steel support for a foundation pit, and particularly to a cable - strut beam inclined support structure for a foundation pit, belonging to the technical field of building construction. Background Art

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

[0003] In the prior art, for a large - yang - angle foundation pit with many corners in the shape of the foundation pit, it is usually necessary to set up cross - braces to support the yang - angle to avoid large deformation of the yang - angle. The cross - braces will cross the entire foundation pit, affecting the construction and consuming a large amount of materials and construction period. Summary of the Invention

[0004] The purpose of the present invention is to provide a cable - strut beam inclined support structure for a foundation pit. The cable - strut beam is arranged on the yang - angle side, and an inclined support capable of applying prestress is arranged at the yang - angle. The inclined support is embedded in the soil body in the pit, supports the yang - angle, and bears the force transmitted by the cable - strut beam. It avoids the use of cross - braces, and reduces the deformation of the yang - angle by applying prestress through the inclined support node.

[0005] The present invention adopts the following technical solutions:

[0006] A cable - strut beam inclined support structure for a foundation pit includes a cable - strut beam 4, and also includes an inclined support 3 and an inclined support fulcrum 2. The embedded steel tie - rod on one side of the cable - strut beam 4 is buried in the yang - angle position, and the embedded steel tie - rod on the other side is anchored at the first concrete collar 6 on one side of the yang - angle. One end of the inclined support 3 is obliquely inserted downward into the soil body in the pit, and the other end is aligned with the second concrete collar 6' on the other side of the yang - angle and is in the same vertical plane as the second concrete collar 6'. The upper end of the inclined support 3 applies prestress to the first concrete collar 6 through a jack 304.

[0007] Preferably, the diagonal brace 3 consists of a diagonal brace insertion section 302, a diagonal brace joint 301, a 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. The stepped head 301b is embedded in the concrete corbel at the lower part of the first concrete collar 6, and the outer surface is wrapped with the isolation material 301a and poured together with the concrete corbel. The isolation material 301a allows the diagonal brace and the concrete corbel to separate along the direction of the diagonal brace into the pit when prestress is applied subsequently. The stepped head 301b and the wing plate 301c play a role in limiting and protecting, so that the diagonal brace 3 can only move in the direction of the pit; the embedded groove 303 is tightly attached to the diagonal brace joint 301, and the position is pre-set before concrete pouring. The attached surface is provided with a round hole 303a, so that when the jack 304 jacks up, it passes through the round hole 303a and jacks against the diagonal brace joint 301 to apply prestress; 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 mechanical locking to avoid the influence of hydraulic failure on safety.

[0008] Further, a right-angle structure for placing the jack 304 is formed between the concrete corbel and the first concrete collar 6, and the right-angle structure is located below the embedded steel tie rod 401 of the beam string structure 4.

[0009] Furthermore, the wing plate 301c and the connecting end plate 301e are symmetrically arranged, and the stiffening plates 301d are respectively provided on the inner sides.

[0010] 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 head 301b, and is clamped outside the large end of the stepped head 301b through the U-shaped groove and abuts against the wing plate 301c.

[0011] A construction method for the foundation pit beam string structure diagonal brace structure described in any one of the above, comprising the following steps:

[0012] S1. Excavate the soil to the working surface;

[0013] S2. Fix the position of the diagonal brace insertion section 302 and insert it into the soil through equipment;

[0014] S3. Install the diagonal brace joint 301 and the diagonal brace insertion section 302, wrap the isolation material 301a on the diagonal brace joint 301, and place the opening surface of the embedded groove 303 against the diagonal brace joint 301 at the designated position;

[0015] S4. Embed the embedded steel tie rod 401 into the first concrete collar 6 above the designated position;

[0016] S5. Pour the first concrete collar 6 and the concrete corbel;

[0017] S6. Install the beam string structure 4;

[0018] S7. Place the jack 304 into the embedded groove 303, lift the jack 304, apply the prestress to the specified value, lock the jack 304, and place the filler plate 9 into the gap between the wing plate 301c and the concrete corbel;

[0019] S8. Apply prestress to the beam string structure 4 itself;

[0020] S9. Excavate the soil.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1) By using the inclined strut that can apply prestress to support the external corner, and making use of the second concrete collar at the external corner, the axis of the inclined strut corresponds to the line of the retaining pile of the second concrete collar at the external corner (in the same plane), and an integral force transmission is formed on the same line, thereby avoiding the construction of the cross-bracing across the foundation pit, greatly reducing the construction difficulty and the engineering quantity, and well reducing the deformation of the external corner;

[0023] 2) The embedded groove can conveniently and accurately reserve the hole for applying prestress and play a role in strengthening the hole;

[0024] 3) Through the design of the stepped embedded head at the inclined strut joint, when applying prestress, the joint can only slide unidirectionally obliquely downward, ensuring the safety of force transmission. And the external of the stepped embedded head is coated with isolation material, making the application of prestress more stable after pouring, and when displacement occurs, the inclined strut can be disengaged from the concrete corbel more smoothly and without causing damage to the surrounding concrete;

[0025] 4) The jack is equipped with a mechanical lock, and the inclined strut joint can be inserted with a filler plate as multiple protection to ensure the force transmission at the joint. The filler plate is designed with a U-shaped groove structure and can be directly inserted and clamped on the outside of the inclined strut joint, which is convenient to implement. Description of the Drawings

[0026] Figure 1 is a schematic plan view of a foundation pit with a large external corner.

[0027] Figure 2 is a schematic plan view of the beam string inclined strut structure of the foundation pit of the present invention.

[0028] Figure 3 is Figure 2 the A-A sectional view in

[0029] Figure 4 is a schematic view of the inclined strut support point, where (a) is a top view and (b) is a side view.

[0030] Figure 5 It is a plan view of the filler plate.

[0031] Figure 6 It is a schematic diagram of the embedded channel.

[0032] Figure 7 It is a schematic diagram of the inclined strut joint.

[0033] In the figure, 1. First horizontal support, 2. Inclined strut fulcrum, 3. Inclined strut, 4. Tensegrity beam, 5. Second horizontal support, 6. First concrete collar, 6'. Second concrete collar, 7. Retaining structure, 8. Concrete corbel, 9. Filler plate, 301. Inclined strut joint, 302. Inclined strut insertion section, 303. Embedded channel, 304. Jack, 301a. Isolation material, 301b. Step-shaped head, 301c. Wing plate, 301d. Stiffening plate, 301e. Connecting end plate, 401. Embedded steel tie rod, 303a. Round hole. Specific implementation mode

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] See Figure 1 , Figure 1 which shows a plan view of the foundation pit with a large external corner as the implementation environment of this embodiment.

[0036] See Figures 2 - 3 , a tensegrity beam inclined strut structure for a foundation pit, including a tensegrity beam 4, and also including an inclined strut 3 and an inclined strut fulcrum 2; the embedded steel tie rods on one side of the tensegrity beam 4 are buried into the position of the external corner, and the embedded steel tie rods on the other side are anchored at the first concrete collar 6 on one side of the external corner; one end of the inclined strut 3 is obliquely inserted downward into the soil in the pit, and the other end is aligned with the second concrete collar 6' on the other side of the external corner and is in the same vertical plane as the second concrete collar 6'; the upper end of the inclined strut 3 applies prestress to the first concrete collar 6 through a jack 304.

[0037] By using the inclined strut that can apply prestress to support the external corner, and utilizing the second concrete collar 6' at the external corner, the axis of the inclined strut corresponds to the line of the retaining pile of the second concrete collar 6' at the external corner (in the same plane), and an overall force transmission is formed on the same line, thus avoiding the cross-bracing across the foundation pit, greatly reducing the construction difficulty and the engineering quantity, and being able to well reduce the deformation of the external corner.

[0038] In this embodiment, the inclined strut 3 is composed of an inclined strut insertion section 302, an inclined strut joint 301, an embedded channel 303, and a jack 304 from bottom to top, as shown in Figure 4 .

[0039] The diagonal brace joint 301 includes a connecting end plate 301e, a stiffening plate 301d, a flange 301c, a stepped head 301b, and a spacer material 301a, and is connected to the diagonal brace insertion section 302 through the connecting end plate 301e, as Figure 7 shown.

[0040] Combined Figure 4 with Figure 7 , the stepped head 301b is embedded in the concrete corbel at the lower part of the first concrete collar 6, and the outer surface is wrapped with the spacer material 301a and poured together with the concrete corbel. The spacer material 301a allows the diagonal brace and the concrete corbel to separate along the direction of the diagonal brace into the pit when prestress is applied subsequently. The stepped head 301b and the flange 301c play a role in limiting and protecting, so that the diagonal brace 3 can only move along the direction into the pit; the embedded groove 303 is closely attached to the diagonal brace joint 301, and the position is pre-set before concrete pouring. The surface of the close attachment is provided with a round hole 303a, so that the jack 304 can pass through the round hole 303a to top against the diagonal brace joint 301 to apply prestress; after the prestress is applied, the diagonal brace joint 301 is separated from the concrete corbel, and a packing plate 9 is placed in the gap between the flange 301c and the concrete corbel as mechanical locking to avoid affecting safety due to hydraulic failure.

[0041] See Figure 4 Figure (b), a right-angle structure for placing the jack 304 is formed between the concrete corbel and the first concrete collar 6, and the right-angle structure is located below the embedded steel tie rod 401 of the beam string structure 4.

[0042] In this embodiment, see Figure 7 , the flange 301c and the connecting end plate 301e are symmetrically arranged, and the stiffening plates 301d are respectively provided towards the inside.

[0043] In this embodiment, combined Figure 4 with Figure 7 , the packing plate 9 has a U-shaped groove with a width substantially equal to the outer diameter of the large end of the stepped head 301b, and is stuck outside the large end of the stepped head 301b through the groove and abuts against the flange 301c.

[0044] The construction method of the above-mentioned beam string structure with diagonal braces in the foundation pit includes the following steps:

[0045] S1. Excavate the soil to the working surface;

[0046] S2. Fix the position of the diagonal brace insertion section 302 and insert it into the soil through equipment;

[0047] S3. Install the diagonal brace joint 301 and the diagonal brace insertion section 302, wrap the diagonal brace joint 301 with the spacer material 301a, and place the embedded groove 303 with the opening surface against the diagonal brace joint 301 at the designated position;

[0048] S4. Embed the embedded steel tie rod 401 into the first concrete collar beam 6 above the specified position;

[0049] S5. Pour the first concrete collar beam 6 and the concrete corbel;

[0050] S6. Install the beam string structure 4;

[0051] S7. Place the jack 304 into the embedded groove 303, lift the jack 304, apply the specified prestress value, lock the jack 304, and place the filler plate 9 into the gap between the wing plate 301c and the concrete corbel;

[0052] S8. Apply prestress to the beam string structure 4 itself;

[0053] S9. Excavate the soil.

[0054] In the present invention, the external corner is braced by the inclined strut that can apply prestress. By utilizing the second concrete collar beam at the external corner, the axis of the inclined strut corresponds to the line of the retaining pile of the second concrete collar beam at the external corner (lying in the same plane), and integral force transmission is formed on the same line, thereby avoiding the construction of cross-bracing across the foundation pit, greatly reducing the construction difficulty and the amount of work, and being able to well reduce the deformation of the external corner; the embedded groove can conveniently and accurately reserve the hole for applying prestress and play a role in strengthening the hole; through the design of the stepped embedded head for the inclined strut joint, when applying prestress, the joint can only slide unidirectionally downward obliquely, ensuring the safety of force transmission. Moreover, the external of the stepped embedded head is coated with isolation material, making the application of prestress more stable after pouring, and when displacement occurs, the inclined strut can be disengaged from the concrete corbel more smoothly without causing damage to the surrounding concrete; the jack is equipped with a mechanical lock, and the inclined strut joint can be inserted with a filler plate as multiple protection to ensure the force transmission at the joint. The filler plate is designed with a U-shaped groove structure and can be directly inserted and clamped on the outside of the inclined strut joint, which is convenient to implement.

[0055] The above are the preferred embodiments of the present invention. Those of ordinary skill in the art can also make various transformations or improvements based on this. Without departing from the general concept of the present invention, these transformations or improvements should all fall within the scope of protection required 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); no counter-bracing is used at the external corner; the pre-buried steel tie rod on one side of the string beam (4) is buried in the external corner position, and the pre-buried steel tie rod on the other side is anchored in the first concrete purlin (6) on one side of the external corner; The number of the diagonal brace (3) is one, one end of which is tilted downward and inserted 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); 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); The diagonal brace (3) is composed of a diagonal brace insertion section (302), a diagonal brace joint (301), a pre-buried 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). 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 outside 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) passes through the circular hole (303a) and pushes 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; 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).

2. The foundation pit beam string bracing structure according to claim 1, 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.

3. A construction method for a foundation pit beam string bracing structure as claimed in claim 1 or 2, characterized in that: The following steps are involved: S1. Excavation to the working face; S2, positioning the diagonal brace 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) in the 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 corbel; S6, installing the beam string (4); S7, the jack (304) is placed in the embedded groove (303), the jack (304) is lifted, and the prestress is applied to the specified value, the jack (304) is locked, and the filling plate (9) is placed in 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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