Reverse support construction method and device for deep and long foundation pit

Abstract

The invention relates to the field of foundation pit supporting, and discloses a reverse supporting construction method for a deep and long foundation pit, which comprises the following steps: S1, after the foundation pit is excavated to a preset depth, drilling operation is carried out on the wall of the foundation pit; s2, a supporting device is installed through hoisting equipment, baffles are installed along the two sides of the pit wall, anchor rods are inserted after the baffles are in place, and the ends of the anchor rods are fixed to the baffles; s3, hoisting equipment is used for hoisting the supporting piece to the position between the baffles on the two sides, supporting arms are arranged on the two sides of the supporting piece and connected with the baffles, and then a crawling ladder is installed on the supporting piece; and S4, after the first-layer foundation pit is excavated and the supporting device is installed, the lower layer is excavated, and the steps from S1 to S4 are repeated. The construction method is stable in supporting and simple in structure.

Description

Technical Field

[0001] The present invention relates to the field of foundation pit support, and particularly to a reverse construction support device and construction method for deep and long foundation pits. Background Art

[0002] In the field of foundation pit engineering, the support of long and narrow foundation pits is a key task. Among them, deep and long narrow foundation pits are a special type of foundation pit, which is characterized by a large length but a narrow width. The excavation and support work of such foundation pits is relatively complex and requires considering various factors, such as soil stability and groundwater level changes. In the prior art, the traditional pile-anchor support system is often used for long and narrow foundation pits. During the construction process, the hole-forming operation of cast-in-place piles needs to be carried out first. However, due to the narrow space of long and narrow foundation pits, the operation of large hole-forming equipment is restricted, the construction difficulty is large, resulting in low hole-forming efficiency, and the verticality of cast-in-place piles is difficult to guarantee under complex geological conditions, which in turn affects the stability of the overall support structure. The patent with the publication number CN221800859U discloses a support mechanism for heating pipelines. As a support structure, it is not strongly connected to the soil layer and cannot increase the soil layer stability, so the support effect is poor. Generally speaking, the existing anchor pile support method has problems of poor stability and low support installation efficiency in the support of long and narrow foundation pits. Summary of the Invention

[0003] The present invention aims to provide a reverse construction support device and construction method for deep and long foundation pits, so as to provide a reverse construction support construction method for deep and long foundation pits with a simple support structure and stable support.

[0004] To achieve the above object, the present invention adopts the following technical solutions: including the following steps: S1: After excavating the foundation pit to a predetermined depth, carry out drilling operations on the pit wall of the foundation pit; S2: Use a hoisting device to install the support device, install baffles along both sides of the pit wall, insert anchor rods after the baffles are in place and fix the ends of the anchor rods on the baffles; S3: Use a lifting device to lift the support member between the baffles on both sides. The support member is provided with support arms on both sides, the support arms are connected to the baffles, and then install a ladder on the support member; S4: After excavating and installing the support device for one layer of the foundation pit, then excavate the lower layer, and repeat the steps of S1 to S4.

[0005] The beneficial effects of this technical solution are as follows: When carrying out the support of a long and narrow foundation pit, the baffles are placed block by block along the pit wall of the long and narrow foundation pit, and the anchor rods are sequentially installed on the baffles. The anchor rods enter the soil layers on both sides of the foundation pit. By setting the anchor rods to penetrate deep into the soil layer, the displacement and deformation of the soil on both sides of the foundation pit are reduced. At the same time, the baffles are firmly fixed on the surface of the foundation pit, effectively inhibiting the loosening of the soil and preventing the loosening of the baffles. By having the anchor rods penetrate deep into the foundation pit, there is no need to use large equipment for cast-in-place piles, and it can be applied to various construction environments.

[0006] In this technical solution, each unit and part are independent and standardized, which is convenient for factory prefabrication and rapid assembly on-site with the cooperation of a crane. It can adapt to the limited construction space of narrow foundation pits. Through the combination of multiple support units, the support system can be flexibly adjusted according to the length and shape of the foundation pit to meet the requirements of different construction sites and improve construction efficiency.

[0007] Preferably, as an improvement, the support device includes a number of support units. Each support unit includes a connecting part and at least one set of baffle parts. Each baffle part includes at least one set of oppositely arranged baffles. A number of anchor rods passing through the baffles and having ends that can be fixed to the baffles are provided on the baffles. The connecting part includes a number of support members with adjustable lengths and a support plate part capable of connecting the support members. The two ends of the support members are respectively connected to the baffles of the baffle part.

[0008] The beneficial effects are as follows: In this technical solution, by setting a number of support units, each support unit includes a connecting part and a baffle. When carrying out the support of a narrow foundation pit, the baffles are placed one by one along the pit wall of the narrow foundation pit, and the anchor rods are installed on the baffles in sequence. The ends of the anchor rods away from the baffles enter the soil layers on both sides of the foundation pit. By setting the anchor rods to penetrate into the soil layer, the displacement and deformation of the soil on both sides of the foundation pit are reduced. At the same time, the baffles are firmly fixed on the surface of the foundation pit, effectively inhibiting the loosening of the soil and preventing the loosening of the baffles. By the anchor rods penetrating into the foundation pit, a support member for support is also provided between the oppositely arranged baffles. The support member can support the baffles to prevent the baffles from collapsing under the action of the soil layer, ensuring that a stable relative distance can be maintained between the opposite baffles for construction, improving the stability of the support structure and being suitable for complex geological conditions. And there is also a support plate part for connecting the support members, which can improve the structural stability of the support unit. At the same time, the operator can stand on the support plate part to operate, improving the convenience of use.

[0009] Preferably, as an improvement, the baffle part includes at least two sets of baffles. Each set of baffles includes two oppositely arranged baffles, and one set of baffles is placed above the other set of baffles.

[0010] The beneficial effects are as follows: By placing one set of baffles above the other set of baffles, the height of the support structure can be flexibly adjusted according to the excavation depth of the foundation pit to adapt to the construction requirements of foundation pits with different depths. There is no need to produce larger-sized baffles anymore, and they can be assembled according to the on-site situation. Compared with using larger baffles, setting two layers of baffles can carry out layered support on the foundation pit wall, disperse the soil pressure, improve the support stability, and save materials and processing time.

[0011] Preferably, as an improvement, the support member includes a support rod. At least one support arm is fixedly provided at both ends of the support rod. A support seat for connecting the end of the support arm is arrayed on the baffle.

[0012] The beneficial effects are as follows: By arranging supports on the baffle plate, the ends of the support arms can be quickly docked and fixed, simplifying the installation operation and improving the construction efficiency. By connecting the support arms and the supports, the support unit forms a rigid framework, enhancing the structural stability of the support unit.

[0013] Preferably, as an improvement, two support arms are provided at both ends of the support rod. The short support arm is connected to the upper part of the baffle plate, and the long support arm is connected to the lower part of the baffle plate.

[0014] The beneficial effects are as follows: The support rod is connected to the baffle plate through two support arms at both ends, transmitting the support force to multiple support points of the baffle plate, effectively dispersing the soil pressure and avoiding local instability caused by concentrated stress. At the same time, two support arms are provided at both ends of the support rod, enabling a single rod to support multiple positions of the baffle plate. Moreover, the included angle between the support arm and the support rod is an obtuse angle, making the cross-section of the support member in an inverted U shape, avoiding the occlusion of the traditional horizontal support to the bottom of the foundation pit, leaving a walking passage in the middle without obstruction, facilitating construction workers to pass along the bottom of the foundation pit to operate other construction links in the foundation pit, as well as the daily inspection and maintenance of the support system. At the same time, the support arm with an obtuse angle setting can form a stable support for the baffle plate.

[0015] Preferably, as an improvement, the support plate part includes a support plate, a locking pin, and multiple ear plates provided at the bottom of the support plate. Locking holes for the locking pin to pass through are provided on both the ear plates and the support member. The support plate is fixed on the support member by inserting the locking pin.

[0016] The beneficial effects are as follows: The insertion of the locking pin forms a vertical and horizontal structure, preventing the dislocation and displacement between the support members, enhancing the overall rigidity and durability of the support unit. When subjected to external loads or foundation pit deformation, the structure can remain stable; the locking pin fixing method can provide a high-strength connection, ensuring a tight combination between the support plate and the support member and not being easily loosened.

[0017] Preferably, as an improvement, it further includes a ladder. A collar is fixed at the end of the ladder, and a sliding hole for the locking pin to slide and insert is provided on the collar.

[0018] The beneficial effects are as follows: In the construction environment of a narrow foundation pit, by arranging or adjusting the position of the ladder, after the locking pin slides and inserts, the collar is fixed on the foundation pit support device, effectively preventing the ladder from loosening or falling off; providing a safe and stable climbing passage for construction workers, reducing the risk of construction accidents, especially suitable for the complex construction conditions in a narrow foundation pit, adapting to the requirements of foundation pits with different depths and widths, and enhancing the flexibility and convenience of construction operations.

[0019] Preferably, as an improvement, it further includes a connecting piece. The ends of the support arms away from the support rod are all limitedly connected to the supports through the connecting piece.

[0020] The beneficial effects are as follows: By using a connecting member to limit and fix the end of the support arm to the support base, it effectively avoids the situation of the support arm shifting due to soil pressure or construction disturbance, ensures the stability of the support structure, and improves the overall support effect.

[0021] Preferably, as an improvement, anchor members that can be clamped with the baffle are provided at the ends of the anchor rods, and the ends of the anchor rods are fixed to the anchor members.

[0022] Preferably, as an improvement, after the support member is stably installed, the support plate is placed at the corresponding position on the support member, and the installation lock pin is inserted through the lock hole on the ear plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a side view of the support device according to an embodiment of the present invention; Figure 2 It is a structural schematic diagram of the support device according to an embodiment of the present invention; Figure 3 It is a structural schematic diagram of the support plate of the support device according to an embodiment of the present invention; Figure 4 It is a structural schematic diagram of the ladder of the support device according to an embodiment of the present invention; Figure 5 It is a structural schematic diagram of another embodiment of the support device of the present invention.

[0024] The reference numerals in the accompanying drawings of the specification include: baffle 1, anchor rod 2, hydraulic telescopic mechanism 3, support rod 4, support arm 5, support base 6, circular rotating shaft 7, anchor member 8, support plate 9, ear plate 10, lock pin 11, ladder 12, sliding groove 13, sliding pin 14, limiting plate 15, support pile 16. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following is a further detailed description through specific embodiments and examples: Construction method for inverse construction support of deep foundation pits: It includes the following steps: S1: Excavate the foundation pit to the predetermined depth; according to the pre-planned spacing and position, use a suitable drilling machine to drill holes along the pit wall of the foundation pit. The drilling depth is matched with the length of the anchor rod 2 to ensure no gap after installation. The diameter of the drilled hole is slightly smaller than the diameter of the anchor rod 2, and at the same time, the drilled hole should be kept straight.

[0026] S2: Install the support device using a hoisting equipment. Lift the prefabricated baffle 1 to the side of the foundation pit. The baffle 1 is made of a suitable material and has a suitable specification according to the design, with sufficient strength and anti-deformation ability. When hoisting, use equipment such as a crane or a lifting device to accurately position the baffle 1 against the foundation pit wall. The installation personnel install the upper baffle part along the foundation pit wall one by one, ensuring that the adjacent baffles 1 of the baffle part are spliced tightly and the gaps are uniform. After the baffle 1 is in place, screw in the anchor rod 2 and fix the end of the anchor rod 2 on the baffle 1. The anchor rod 2 is inserted into the reserved hole without gaps. Then, fix and connect the anchor rod 2 and the baffle 1 through the anchor fitting 8 to make the baffle 1 firmly fit against the foundation pit wall.

[0027] S3: Use a lifting device to lift the support member to the designated position, and stably connect the end of the support arm 5 far from the support rod 4 to the support 6 through the installation circular rotating shaft 7. After installing several adjacent support members, adjust the telescopic amount of the hydraulic telescopic mechanism 3 to adjust the length of the support member according to the width of the foundation pit to form a stable support.

[0028] S4: After the support member is installed stably, place the support plate 9 at the corresponding position on the support member. Insert the installation lock pin 11 through the lock hole on the ear plate 10. After inserting the lock pin 11 partially, install the ladder 12 and align the sliding hole of the ladder 12 with the lock pin 11, and then continue to push the lock pin 11 in for fixation.

[0029] S5: After the excavation and installation of the support structure for the first layer of the foundation pit are completed, then excavate the lower layer, and repeat the steps of S1 to S4.

[0030] The support device is basically as shown in the appendix Figures 1-4 shown, such as Figure 1 and Figure 2 shown in the support device, which includes a number of support units. Each support unit includes a connecting part and at least one set of baffle parts. Each baffle part includes at least one set of oppositely arranged baffles 1. A number of anchor rods 2 that pass through the baffle 1 and whose ends can be fixed to the baffle 1 are provided on the baffle 1. The connecting part includes a number of support members with adjustable lengths and a support plate part that can connect the support members. The two ends of the support member are respectively connected to the baffle 1 of the baffle part. To make the structure simple, reliable and easy to assemble, the preferred implementation adopted by the present invention is that the baffle part includes at least two sets of baffles 1. Each set of baffles 1 includes two oppositely arranged baffles 1, and one set of baffles 1 is placed above the other set of baffles 1.

[0031] In this technical solution, several support units are provided. Each support unit includes a connecting part and a baffle 1. When supporting a long and narrow foundation pit, the baffles 1 are placed one by one along the pit wall of the long and narrow foundation pit. Anchor rods 2 are sequentially installed on the baffles 1. The ends of the anchor rods 2 away from the baffles 1 enter the soil layers on both sides of the foundation pit. By setting the anchor rods 2 to penetrate deep into the soil layer, the displacement and deformation of the soil on both sides of the foundation pit are reduced. At the same time, the baffles 1 are firmly fixed on the surface of the foundation pit, effectively inhibiting the loosening of the soil and preventing the loosening of the baffles 1. By having the anchor rods 2 penetrate into the foundation pit, there is no need to use large equipment for cast-in-place piles, and it can be applied to various construction environments. In addition, a support member for supporting is provided between the oppositely arranged baffles 1. The support member can support the baffles 1 to prevent the baffles 1 from collapsing under the action of the soil layer, ensuring that a stable relative distance can be maintained between the opposite baffles 1 for construction, improving the stability of the support structure, and being suitable for complex geological conditions. And there is also a support plate part for connecting the support member, which can improve the structural stability of the support unit. At the same time, operators can stand on the support plate part to operate, improving the convenience of use. By placing a group of baffles 1 above another group of baffles 1, the height of the support structure can be flexibly adjusted according to the excavation depth of the foundation pit to meet the construction requirements of foundation pits with different depths. There is no need to produce larger-sized baffles 1 anymore, and they can be assembled according to the site conditions. Compared with using larger baffles 1, setting two layers of baffles 1 can carry out layered support on the foundation pit wall, disperse the soil pressure, improve the support stability, and save materials and processing time.

[0032] To make the structure simple, reliable and easy to assemble, the preferred embodiment adopted in the present invention is that the support member includes a support rod 4, and at least one support arm 5 is fixedly provided at both ends of the support rod 4. A support 6 for connecting with the end of the support arm 5 is arranged in an array on the baffle 1. By arranging the support 6 on the baffle 1, the end of the support arm 5 can be quickly butted and fixed, simplifying the installation operation and improving the construction efficiency. By arranging the support arm 5 and the support 6 to be connected, a rigid framework is formed for the support unit, improving the structural stability of the support unit. It also includes a hydraulic telescopic mechanism 3. The support rod 4 is divided into two sections, and the two support rods 4 at both ends are connected by the hydraulic telescopic mechanism 3 to improve the applicability of the support device. Especially in the construction of narrow foundation pits with different widths, the length of the support rod 4 can be adjusted quickly by adjusting the length of the support rod 4 without replacing components, effectively dispersing the soil pressure on the baffle 1 and preventing the structure from deforming or losing stability due to concentrated force. The hydraulic telescopic mechanism 3 can accurately adjust the length of the support rod 4 and flexibly adapt to the changes in the width and shape of the foundation pit; To make the structure simple, reliable and easy to assemble, the preferred embodiment adopted in the present invention is that two support arms 5 are provided at both ends of the support rod 4. The short support arm 5 is connected to the upper part of the baffle 1, and the long support arm 5 is connected to the lower part of the connected baffle 1. And an obtuse angle is formed between the support arm 5 and the support rod 4, making the overall cross-section of the support member in an inverted U shape. The support rod 4 is connected to the baffle 1 through the two support arms 5 at both ends, avoiding the occlusion of the traditional horizontal support to the bottom of the foundation pit, leaving a walking passage without middle obstruction, facilitating the construction personnel to pass along the bottom of the foundation pit to operate other construction links in the foundation pit, as well as the daily inspection and maintenance of the support system. At the same time, the support arm 5 with an obtuse angle setting can form a stable support for the baffle 1.

[0033] It also includes a connecting piece. The ends of the support arms 5 far from the support rod 4 are both connected with the support 6 in a limit manner through the connecting piece. By using the connecting piece to limit and fix the ends of the support arms 5 to the support 6, the situation that the support arms 5 are displaced due to soil pressure or construction disturbance can be effectively avoided, ensuring the stability of the support structure and improving the overall support effect. The forms of the connecting piece are diverse, and plug-in type, snap-fastener type or bolt fixing and other forms can be adopted. For the convenience of quick installation and adjustment on site, the connecting piece in the present invention is a circular rotating shaft 7. The circular rotating shaft 7 passes through the support 6 and the end of the support arm 5 for connection. When the soil layer vibrates, the connection part can rotate slightly relative to the support 6 compared with the fixed connection of the support arm 5 and then reset under the elastic force of the support rod 4, avoiding the direct fracture of the end of the support arm 5 at the connection part when receiving a large lateral force and improving the stability of the structure.

[0034] An anchor fitting 8 capable of being clamped with the baffle 1 is provided at the end of each anchor rod 2. The end of the anchor rod 2 is fixed to the anchor fitting 8. The fixing form of the end of the anchor rod 2 to the anchor fitting 8 is diverse. In the present invention, the end of the anchor rod 2 is bolt-fastened to the anchor fitting 8. To ensure the dense connection with the soil layer, the anchor rod 2 in the present invention is a threaded anchor rod 2.

[0035] To make the structure stable, the preferred implementation adopted in the present invention is that at least three support members are provided on each support unit. The three support members are evenly distributed between the baffles 1, which can effectively disperse the earth pressure borne by the baffle 1, reduce the stress load on a single support member, and improve the compressive capacity of the system. To make the structure simple, reliable and easy to assemble, the preferred implementation adopted in the present invention is as follows Figure 1 and Figure 3 As shown, the support plate part includes a support plate 9, a locking pin 11 and a plurality of ear plates 10 arranged at the bottom of the support plate 9. Locking holes for the locking pin 11 to pass through are provided on both the ear plates 10 and the support members. By inserting the locking pin 11, the support plate 9 is fixed on the support member. The inserted locking pin 11 forms a vertical and horizontal structure, preventing the misalignment and displacement between the support members, enhancing the overall rigidity and durability of the support unit. When subjected to external loads or foundation pit deformation, the structure can remain stable. At the same time, the support plate 9 is provided to facilitate the construction personnel to stand on the support plate 9 for operation; the fixing method of the locking pin 11 can provide a high-strength connection, ensuring a tight combination between the support plate 9 and the support member and not easy to loosen.

[0036] To ensure the stability of the connection, the cross-section of the locking pin 11 is rectangular, and the locking pin 11 is an integral one. Compared with the circular locking pin 11, the wide side of the rectangular locking pin 11 provides a larger shear area, can withstand higher shear forces, and improves the anti-deformation ability of the support unit. As Figure 4 shown, it also includes a ladder 12. A collar is fixed at the end of the ladder 12, and a sliding hole for the locking pin 11 to slide and insert is opened on the collar. After the locking pin 11 slides and inserts, the collar is fixed on the foundation pit support device, effectively preventing the ladder 12 from loosening or falling off; since the locking pin 11 is rectangular, after the ladder 12 is installed, the ladder 12 will not shake, improving the safety of use, providing a safe and stable climbing passage for construction personnel, reducing the risk of construction accidents, especially suitable for complex construction conditions in long and narrow foundation pits, adapting to the requirements of foundation pits with different depths and widths, and enhancing the flexibility and convenience of construction operations.

[0037] As Figure 5In another embodiment of the present invention shown, the baffle portion includes at least two groups of baffles 1. One group of baffles 1 can be arranged above the other group of baffles 1. A plurality of chute portions are provided at the connection of adjacent two groups of baffles 1. It further includes slide pins 14 that are the same in number as the chute portions and can be inserted into the chute portions in a matching manner. The chute portion includes a chute 13 and a limiting plate 15. Chutes 13 are opened at the connections of the upper and lower two groups of baffles 1, and the limiting plate 15 is arranged outside the chute 13 on the lower side. There is a gap between the limiting plate 15 and the bottom of the chute 13 that can allow the chute 13 to be snapped into. The cross-section of the slide pin 14 is L-shaped, and the height of the slide pin 14 is greater than the height of the chute 13. After sliding insertion, it is snapped with the limiting plate 15 to realize the snap-limiting connection of the upper and lower two groups of baffles 1. Through the above settings, the connectivity of the upper and lower two groups of baffles 1 can be increased, and the dislocation of the upper and lower two layers of baffles 1 can be prevented. To ensure the stability of the connection, in this embodiment, the slide pins 14 close to the support plate 9 are all fixedly connected or integrally formed with the support plate 9, which is convenient for the support plate 9 to support the slide pins 14 and ensure the stability of the connection between the baffles 1. To ensure the stability of the support, a support pile 16 is further provided on the lower side of the support plate 9. The cross-section of the support pile 16 is triangular, and one side surface can abut against the upper surface of the support arm 5. Through the above settings, the supportability of the support arm 5 for the support plate 9 and the slide pins 14 is improved.

[0038] The above are only embodiments of the present invention. Specific technical solutions and / or common knowledge such as characteristics well known in the art are not described in detail here. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can still be made, and these 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 patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. The reverse construction support construction method for deep foundation pits is characterized in that It includes the following steps: S1: After excavating the foundation pit to a predetermined depth, drilling operations are carried out on the pit wall of the foundation pit; S2: Use lifting equipment to install the support device, install the baffle plates (1) along both sides of the pit wall. After the baffle plates (1) are in place, insert the anchor rods (2) and fix the ends of the anchor rods (2) on the baffle plates (1); S3: Use lifting equipment to hoist the support member between the baffle plates (1) on both sides. Support arms (5) are provided on both sides of the support member, and the support arms (5) are connected to the baffle plates (1), and then install a ladder on the support member; S4: After the excavation and installation of the support device for one layer of the foundation pit are completed, then excavate the lower layer, and repeat the steps of S1 to S4.

2. The support device according to claim 1, characterized in that: The support device includes a number of support units. Each support unit includes a connecting part and at least one set of baffle parts. Each baffle part includes at least one set of oppositely arranged baffle plates (1). A number of anchor rods (2) that pass through the baffle plates (1) and whose ends can be fixed to the baffle plates (1) are provided on the baffle plates (1). The connecting part includes a number of support members with adjustable lengths and a support plate part that can connect the support members. Both ends of the support member are respectively connected to the baffle plates (1) of the baffle part.

3. The support device according to claim 2, characterized in that: The baffle part includes at least two sets of baffle plates (1). Each set of baffle plates (1) includes two oppositely arranged baffle plates (1), and one set of baffle plates (1) is placed above the other set of baffle plates (1).

4. The support device according to claim 2, characterized in that: The support member includes a support rod (4). At least one support arm (5) is fixedly provided at both ends of the support rod (4). Seats (6) for connecting to the ends of the support arms (5) are arranged in an array on the baffle plates (1).

5. The support device according to claim 4, characterized in that: Two support arms (5) are provided at both ends of the support rod (4). The short support arm (5) is connected to the upper part of the baffle plate (1), and the long support arm (5) is connected to the lower part of the baffle plate (1).

6. The support device according to claim 2, wherein: The support plate part includes a support plate (9), a locking pin (11), and a plurality of ear plates (10) provided at the bottom of the support plate (9). Locking holes for the locking pin (11) to pass through are provided on both the ear plates (10) and the support member. The support plate (9) is fixed to the support member by inserting the locking pin (11).

7. The support device according to claim 6, characterized in that: It also includes a ladder (12). A collar is fixed at the end of the ladder (12), and a sliding hole for the locking pin (11) to slide and insert is provided on the collar.

8. The support device according to claim 4, characterized in that: It also includes a connecting piece. The ends of the support arms (5) far from the support rod (4) are respectively connected to the seats (6) in a limited way through the connecting piece.

9. The support device according to claim 2, characterized in that: Anchor parts (8) that can be clamped with the baffle plates (1) are provided at the ends of the anchor rods (2), and the ends of the anchor rods (2) are fixed to the anchor parts (8).

10. The inverse construction method for a deep and long foundation pit according to claim 1, characterized in that: After the support member is stably installed, place the support plate (9) at the corresponding position on the support member, and insert and install the locking pin (11) from the locking hole on the ear plate (10).

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