Active adjusting embedded steel supporting system and active adjusting method thereof

Abstract

The invention provides an active adjusting embedded steel supporting system and an active adjusting method thereof. The system comprises a driving assembly, an active supporting vertical rod piece and an active supporting single-side supporting rod. A mounting groove is formed in the foundation pit and located between a first reinforced concrete support of the foundation pit and the bottom of the foundation pit. The driving assembly is fixedly mounted on the first reinforced concrete support, and the driving end of the driving assembly is in transmission connection with one end of the driving support vertical rod piece, so that the driving support vertical rod piece is vertically inserted into the mounting groove in a lifting manner through the driving assembly; one ends of the active supporting single-side supporting rods are movably connected to the active supporting vertical rod piece, the other ends of the active supporting single-side supporting rods can abut against the enclosure ground wall, and the multiple active supporting single-side supporting rods are symmetrically arranged in pairs relative to the active supporting vertical rod piece. The invention relates to the technical field of building engineering construction, and can solve the technical problems in the prior art.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to an active adjustment pre-embedded steel support system and its active adjustment method. Background Technology

[0002] In recent years, my country's construction industry has flourished, with a large amount of underground space being developed and utilized. This has placed higher demands on the construction of deep foundation pits. Deep foundation pit projects not only relate to the safe construction of underground structures but also directly affect the safety and stability of surrounding buildings, roads, and underground facilities. For construction convenience and to ensure the construction period, foundation pit construction typically employs a system of retaining structures plus steel supports to meet the safety requirements of the foundation pit. However, during the excavation process, factors such as soil stress release, groundwater changes, and construction disturbances often lead to a series of problems, including localized soil collapse and surface settlement, which can even result in engineering accidents in severe cases. Therefore, effectively controlling the deformation and settlement of supports during deep foundation pit excavation to ensure project safety and the stability of the surrounding environment is a key aspect of the entire foundation pit construction safety system.

[0003] In existing technologies, to control soil deformation and maintain the stability of the foundation pit, the principle of "supporting before excavation" is followed. This requires the erection of steel supports layer by layer, from the surface soil down to the excavation surface. The steel supports primarily utilize preset pressure values, and the axial force on each support is dynamically adjusted by regulating the hydraulic pressure of jacks, thus achieving the most reasonable distribution of axial force. However, for foundation pits near subway lines or complex foundation pits, due to the large number of steel supports used, the internal forces of the retaining structure and the axial force of the erected internal supports continuously change with the increasing excavation depth. This may lead to complete loss of axial force in some supports or even tensile stress. This can cause increased deformation of the retaining structure or, in severe cases, instability and collapse of the supports. Therefore, relying solely on pre-calculated axial force is insufficient to meet the support requirements.

[0004] The existing foundation pit support systems and their adjustment methods have the following problems:

[0005] 1) Existing steel support construction procedures are complex. Each steel support requires the installation of embedded pressure components, and axial force is applied to the upper steel support during construction. Scaffolding must be erected for high-altitude operations, posing safety hazards and increasing costs and construction time.

[0006] 2) The existing steel support system consists of a single load-bearing member with weak connection points, making it difficult to apply prestress and prone to causing foundation pit collapse accidents.

[0007] 3) When adjusting the axial force of the steel support, there may be problems due to time constraints and excessive or insufficient jack loading force.

[0008] Therefore, there is a need to provide an active adjustment system for embedded steel supports and its active adjustment method, which can solve the above-mentioned technical problems. Summary of the Invention

[0009] The purpose of this invention is to provide an active adjustment system for embedded steel supports and its active adjustment method, which can solve the above-mentioned technical problems.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows:

[0011] An active adjustment pre-embedded steel support system includes: a drive assembly, active support vertical members, and active support single-sided struts; an installation groove is formed in the foundation pit, located between the first reinforced concrete support and the bottom of the foundation pit; the drive assembly is fixedly installed on the first reinforced concrete support, and the drive end of the drive assembly is connected to one end of the active support vertical member, allowing the active support vertical member to be vertically inserted into the installation groove via the drive assembly; one end of the active support single-sided strut is movably connected to the active support vertical member, and the other end of the active support single-sided strut can be supported on the retaining wall; several active support single-sided struts are arranged symmetrically in pairs about the active support vertical member.

[0012] The drive assembly includes a drive motor and a reaction frame; the reaction frame is fixedly installed on the first reinforced concrete support, the drive motor is fixedly installed inside the reaction frame, and the output end of the drive motor is connected to one end of the active support vertical rod as the drive end of the drive assembly.

[0013] The drive assembly also includes a pressure sensor; the pressure sensor is installed between the top of one end of the active support vertical rod and the top of the reaction frame.

[0014] One end of the active support single-sided strut is rotatably connected to the active support vertical rod via a one-way ratchet.

[0015] The other end of the active support single-sided strut is provided with a one-way rotating support foot, which can abut against the inner wall of the retaining wall, so that the active support single-sided strut is obliquely supported between the active support vertical member and the retaining wall.

[0016] An active adjustment method for an embedded steel support system includes the following steps:

[0017] Step 1: Before the foundation pit construction, construct the retaining wall, the capping beam of the wall, and the first reinforced concrete support;

[0018] Step 2: After the retaining wall, the capping beam of the wall and the first reinforced concrete support have reached the design strength and meet the specifications, trenching is carried out at the installation position of the actively adjustable embedded steel support system to form the installation trench.

[0019] Step 3: Install several active support single-sided struts in pairs symmetrically on both sides of the active support vertical member, and then lower the active support vertical member and several active support single-sided struts into the installation groove;

[0020] Step 4: Drive the vertical rod of the active support downward by the drive motor of the drive component, so that the unidirectional rotating support foot on the one-sided support rod of the active support is tightly attached to the retaining wall, thereby giving the retaining wall the initial internal support force;

[0021] Step 5: Carry out the foundation pit construction. During the earthwork excavation and underground structure construction of the foundation pit, the height and position of the active support vertical members are dynamically adjusted by the drive motor of the drive component, so that the retaining wall always receives internal support force to control the lateral deformation of the retaining wall.

[0022] Step 6: After the underground structure's basement roof slab is backfilled, remove the active adjustment embedded steel support system and seal the reserved openings in the underground floor slab.

[0023] In step 3, the trench depth and the placement positions of the active support vertical members and several active support unilateral struts are all above the excavation elevation of the foundation pit, and a certain unilateral horizontal adjustable range is reserved between the unidirectional rotating support foot on the active support unilateral strut and the retaining wall.

[0024] In step 5, during the construction of the underground structure, an opening is reserved in the underground floor slab at the installation position of the active adjustment embedded steel support system, so that the active adjustment embedded steel support system can penetrate the underground floor slab.

[0025] In step 7, under the working state of the actively adjusted pre-embedded steel support system, the angle between the active support single-side strut and the horizontal direction is θ, the length of the active support single-side strut is La, the horizontal projection length of the active support single-side strut is Lh, the tension force on the active support vertical member by the drive motor of the drive component is Fv, and the internal support force obtained by the retaining wall is Fh, then: , .

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This invention uses a trenching machine to trench the location of the active support and then sinks the active adjustment pre-embedded steel support system. The drive motor controls the vertical members of the active support to pre-stress the retaining wall via the single-sided strut of the active support. A small force can be applied to the drive motor during earthwork excavation, while the single-sided strut generates a large variation in the axial force of the steel support. This eliminates the need to install steel supports before each excavation stage; all subsequent construction can proceed after the first concrete support is completed. This significantly saves loading and construction time. Furthermore, the structure is simple, easy to install and construct, and easy to disassemble, which helps control construction costs and schedule. It is particularly suitable for underground foundation pit projects with tight schedules and those near subway lines. This invention solves the problems in existing technologies where adjusting the axial force of the steel support may be limited by time constraints and may result in excessive or insufficient jack loading force.

[0028] 2. This invention can actively adjust the internal support force on the retaining wall to control the lateral deformation of the retaining wall, which can save time and effort. This invention not only has higher bending stiffness, but also can fully stimulate the passive earth pressure of the soil outside the pit through the application of prestress, thereby better controlling the horizontal displacement of the foundation pit, improving the stress condition of the entire foundation pit support structure, avoiding the occurrence of foundation pit collapse accidents, and reducing the difficulty and danger of high-altitude operations requiring the erection of scaffolding for additional loads, as well as labor costs, shortening construction time, and increasing construction safety. It has obvious advantages in terms of construction safety, economy and environmental protection. Attached Figure Description

[0029] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0030] Figure 1 This is an installation schematic diagram of the active adjustment pre-embedded steel support system of the present invention;

[0031] Figure 2 This is a schematic diagram of the working state of the active adjustment pre-embedded steel support system of the present invention.

[0032] In the diagram, 1 is the first reinforced concrete support, 2 is the ground wall capping beam, 3 is the retaining ground wall, 4 is the pressure sensor, 5 is the drive motor, 6 is the reaction frame, 7 is the active support vertical member, 8 is the active support single-sided strut, 9 is the unidirectional rotating support foot, and 10 is the mounting groove. Detailed Implementation

[0033] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the active adjustment system for embedded steel supports and its active adjustment method proposed in this invention. The advantages and features of this invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0034] Please see the appendix Figure 1 and attached Figure 2 An active adjustment pre-embedded steel support system includes a drive assembly, an active support vertical member 7, and an active support single-sided strut 8. An installation groove 10 is formed in the foundation pit, located between the first reinforced concrete support 1 and the bottom of the foundation pit. The drive assembly is fixedly installed on the first reinforced concrete support 1, and the drive end of the drive assembly is connected to one end of the active support vertical member 7, so that the active support vertical member 7 can be vertically inserted into the installation groove 10 through the drive assembly. One end of the active support single-sided strut 8 is movably connected to the active support vertical member 7, and the other end of the active support single-sided strut 8 can be supported on the retaining wall 3. Several active support single-sided struts 8 are arranged symmetrically in pairs about the active support vertical member 7.

[0035] The number of actively adjustable embedded steel support systems can be adaptively adjusted according to actual support needs. In each set of actively adjustable embedded steel support systems, the number of active support single-sided struts 8 can be determined according to the design number of steel supports, so that when a pair of active support single-sided struts 8 are supported on the retaining walls 3 on both sides, they can replace the existing steel supports. Therefore, it is not necessary to install steel supports before each earthwork excavation, which can greatly save the loading and construction time of steel supports, and has high bending stiffness, ensuring that effective internal support force is provided to the retaining wall 3 (internal support force refers to the internal support force of the retaining wall converted under the action of horizontal axial force, which is passive force).

[0036] The drive assembly is used to adjust the height of the active support vertical rod 7, thereby adjusting the angle of the active support single-sided strut 8 relative to the horizontal plane, that is, the support angle of the active support single-sided strut 8 on the retaining wall 3, so as to realize the adjustment of the axial force of the retaining wall 3, and thus provide appropriate internal support force at different construction stages, effectively avoiding lateral deformation of the retaining wall 3 and foundation pit collapse accidents. Compared with the existing steel support prestressing adjustment, it has higher safety and controllability, and is not limited by time and equipment such as jacks.

[0037] By symmetrically setting the active support single-sided strut 8 about the active support vertical member 7 and arranging multiple pairs of spaced-apart struts along the axial direction of the active support vertical member 7, internal support force can be provided to the retaining wall 3 at different heights. Compared with the single-member force-bearing structure of the prior art, the connection node is stable and safe, and it is easy to apply prestress through the drive component via the active support vertical member 7 and the active support single-sided strut 8, making the operation simpler and more convenient.

[0038] The drive assembly includes a drive motor 5 and a reaction frame 6; the reaction frame 6 is fixedly installed on the first reinforced concrete support 1, the drive motor 5 is fixedly installed inside the reaction frame 6, and the output end of the drive motor 5 is connected to one end of the active support vertical rod 7 as the drive end of the drive assembly.

[0039] The reaction frame 6 can be made of steel and reliably connected to the first reinforced concrete support 1 through bolting, embedded parts or other means.

[0040] The output end of the drive motor 5 and one end of the active support vertical rod 7 can be connected by a sawtooth rotation, such as existing transmission methods like worm gear and worm, bevel gear and screw, to ensure reliable transmission. The connection and transmission method between the drive motor 5 and the active support vertical rod 7 is not limited here. Driving the rod to rotate and raise / lower via a motor is a conventional technique in this field, and its specific structure, working process, and working principle will not be elaborated here.

[0041] The drive assembly also includes a pressure sensor 4; the pressure sensor 4 is installed between the top of one end of the active support vertical rod 7 and the top of the reaction frame 6.

[0042] Pressure sensor 4 is used to monitor the pressure value of the active support vertical member 7 in real time while the drive motor 5 is running. Based on this pressure value, the tension force on the active support vertical member 7 (i.e., the force given by the load applied to the active support vertical member 7 by the drive motor 5) can be adjusted. The specifications and model of pressure sensor 4 can be adapted to the actual application requirements.

[0043] One end of the active support single-sided strut 8 is rotatably connected to the active support vertical rod 7 via a one-way ratchet.

[0044] By rotating the one-way ratchet, the active support single-side strut 8 can be restricted to rotating only in one direction relative to the active support vertical rod 7. That is, under the driving force of the drive motor 5, the other end of the active support single-side strut 8 can rotate towards the retaining wall 3 and press against the retaining wall 3. When the retaining wall 3 is subjected to horizontal pressure and transmitted to the active support single-side strut 8, it can be ensured that the active support single-side strut 8 will not rotate in the opposite direction, thereby ensuring the support effectiveness of the active support single-side strut 8.

[0045] The other end of the active support single-sided strut 8 is provided with a one-way rotating support foot 9, which can abut against the inner wall of the retaining wall 3, so that the active support single-sided strut 8 is obliquely supported between the active support vertical member 7 and the retaining wall 3.

[0046] One end of the unidirectional rotating support leg 9 is rotatably connected to the other end of the active support unilateral support rod 8 via a unidirectional rotating shaft. The other end of the unidirectional rotating support leg 9 is a planar structure used to fit against the wall surface of the retaining wall 3, thereby ensuring the stability of the active support unilateral support rod 8 when it is supported on the retaining wall 3 and the effective transfer of load.

[0047] Please see the appendix Figure 1 and attached Figure 2 An active adjustment method for an embedded steel support system includes the following steps:

[0048] Step 1: Before the foundation pit construction, construct the retaining wall 3, the capping beam 2, and the first reinforced concrete support 1.

[0049] The ground wall capping beam 2 is constructed on top of the retaining ground wall 3, and the first reinforced concrete support 1 is supported between the two oppositely arranged ground wall capping beams 2, forming the first support structure in the foundation pit.

[0050] The retaining wall 3, the capping beam 2, and the first reinforced concrete support 1 can be constructed using conventional techniques, and their construction process will not be described in detail here.

[0051] Step 2: After the retaining wall 3, the wall capping beam 2 and the first reinforced concrete support 1 reach the design strength and meet the specifications, the trenching machine is used to perform trenching construction at the installation position of the actively adjustable pre-embedded steel support system to form the installation trench 10.

[0052] The number and location of the installation slots 10 are determined based on the number and installation location of the active adjustment pre-embedded steel support system.

[0053] The trenching construction using a trenching machine is a conventional construction method for underground structures in this field. The construction process will not be described in detail here. The installation trench 10 of the corresponding size can be formed according to the installation requirements of the actively adjustable pre-embedded steel support system.

[0054] Step 3: Install several active support single-sided struts 8 in pairs symmetrically on both sides of the active support vertical member 7, and then sink the active support vertical member 7 and several active support single-sided struts 8 into the installation groove 10.

[0055] In step 3, the trenching depth of the installation groove 10 and the placement positions of the active support vertical rods 7 and several active support single-sided struts 8 are all above the excavation elevation of the foundation pit. Furthermore, a certain unilateral horizontal adjustable range δ is reserved between the unidirectional rotating support foot 9 on the active support single-sided strut 8 and the retaining wall 3.

[0056] By constructing the trench 10 and lowering the active support vertical members 7 and several active support single-sided struts 8, the construction of the trench 10 and the installation of the active support vertical members 7 and several active support single-sided struts 8 are carried out, thus avoiding the need for scaffolding to be erected for high-altitude operations in the existing technology. This is conducive to improving construction safety, reducing construction costs, and shortening the construction period.

[0057] Step 4: Drive the active support vertical rod 7 downward by the drive motor 5 of the drive component, so that the unidirectional rotating support foot 9 on the active support single-side support rod 8 is tightly attached to the retaining wall 3, thereby enabling the retaining wall 3 to obtain the initial internal support force.

[0058] At this point, the actively adjustable embedded steel support system begins to operate, as shown in the attached diagram. Figure 2 As shown, the retaining wall 3 is provided with appropriate internal support force by actively supporting the single-sided strut 8 to control the lateral deformation of the retaining wall 3.

[0059] Step 5: Carry out the foundation pit construction. During the earthwork excavation and underground structure construction of the foundation pit, the height position of the active support vertical rod 7 is dynamically adjusted by the drive motor 5 of the drive component, so that the retaining wall 3 always obtains internal support force to control the lateral deformation of the retaining wall 3.

[0060] In step 5, during the construction of the underground structure, an opening is reserved in the underground floor slab at the installation position of the active adjustment embedded steel support system, so that the active adjustment embedded steel support system can penetrate the underground floor slab, ensuring the normal construction of the underground structure and avoiding interference with the active adjustment embedded steel support system.

[0061] In step 5, under the working state of the actively adjusted pre-embedded steel support system, the angle between the active support single-side strut 8 and the horizontal direction is θ, the length of the active support single-side strut 8 is La, and the horizontal projection length of the active support single-side strut 8 is Lh. The tension force on the active support vertical member 7 by the drive motor 5 is Fv (when the active support vertical member 7 is at different heights, the pressure sensor 4 detects that the pressure between it and the reaction frame 6 is different, i.e., the tension force is different, and this tension force can be measured by the pressure sensor 4). The retaining wall 3 obtains an internal support force of Fh. Then, according to a simple mechanical conversion relationship, it can be known that... , Based on this formula, the tension of the active support vertical rod 7 can be adjusted by driving motor 5. The adjusted tension is the prestress of the support system, so that the retaining wall 3 can obtain a suitable internal support force, thereby controlling the lateral deformation of the retaining wall 3, and the application of prestress is more convenient.

[0062] Step 6: After the underground structure's basement roof slab is backfilled, remove the active adjustment embedded steel support system and seal the reserved openings in the underground floor slab.

[0063] Based on the installation process of the actively adjustable embedded steel support system, it can be removed by reversing the operation; the specific removal process will not be described in detail here.

[0064] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. An actively adjustable pre-embedded steel support system, characterized in that, include: The structure includes a drive assembly, an active support vertical member (7), and an active support single-sided strut (8). An installation groove (10) is formed in the foundation pit, located between the first reinforced concrete support (1) and the bottom of the foundation pit. The drive assembly is fixedly installed on the first reinforced concrete support (1), and the drive end of the drive assembly is connected to one end of the active support vertical member (7) so that the active support vertical member (7) can be vertically inserted into the installation groove (10) through the drive assembly. One end of the active support single-sided strut (8) is movably connected to the active support vertical member (7), and the other end of the active support single-sided strut (8) can be supported on the retaining wall (3). Several active support single-sided struts (8) are arranged symmetrically in pairs about the active support vertical member (7).

2. The active adjustment pre-embedded steel support system as described in claim 1, characterized in that, The drive assembly includes a drive motor (5) and a reaction frame (6); the reaction frame (6) is fixedly installed on the first reinforced concrete support (1), the drive motor (5) is fixedly installed inside the reaction frame (6), and the output end of the drive motor (5) is connected to one end of the active support vertical rod (7) as the drive end of the drive assembly.

3. The active adjustment pre-embedded steel support system as described in claim 2, characterized in that, The drive assembly also includes a pressure sensor (4); the pressure sensor (4) is installed between the top of one end of the active support vertical rod (7) and the top of the reaction frame (6).

4. The active adjustment pre-embedded steel support system as described in claim 1, characterized in that, One end of the active support single-sided strut (8) is rotatably connected to the active support vertical rod (7) via a one-way ratchet.

5. The active adjustment pre-embedded steel support system as described in claim 1 or 4, characterized in that, The other end of the active support single-sided strut (8) is provided with a one-way rotating support foot (9). The one-way rotating support foot (9) can abut against the inner wall of the retaining wall (3), so that the active support single-sided strut (8) is obliquely supported between the active support vertical member (7) and the retaining wall (3).

6. An active adjustment method for an active adjustment pre-embedded steel support system according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Before the foundation pit construction, construct the retaining wall (3), the capping beam (2) of the wall and the first reinforced concrete support (1); Step 2: After the retaining wall (3), the wall capping beam (2) and the first reinforced concrete support (1) reach the design strength and meet the specifications, trenching is carried out at the installation position of the active adjustment pre-embedded steel support system to form the installation trench (10). Step 3: Install several active support single-sided struts (8) in pairs symmetrically on both sides of the active support vertical member (7), and sink the active support vertical member (7) and several active support single-sided struts (8) into the installation groove (10); Step 4: Drive the active support vertical rod (7) downward by the drive motor (5) of the drive component, so that the unidirectional rotating support foot (9) on the active support single-side support rod (8) is tightly fixed to the retaining wall (3), thereby so that the retaining wall (3) obtains the initial internal support force; Step 5: Carry out the foundation pit construction. During the earthwork excavation and underground structure construction of the foundation pit, the height position of the active support vertical rod (7) is dynamically adjusted by the drive motor (5) of the drive component, so that the retaining wall (3) always obtains internal support force to control the lateral deformation of the retaining wall (3). Step 6: After the underground structure's basement roof slab is backfilled, remove the active adjustment embedded steel support system and seal the reserved openings in the underground floor slab.

7. The active adjustment method as described in claim 6, characterized in that, In step 3, the trenching depth of the installation groove (10) and the placement positions of the active support vertical rods (7) and several active support single-sided struts (8) are all above the excavation elevation of the foundation pit. Furthermore, a certain unilateral horizontal adjustable range is reserved between the unidirectional rotating support foot (9) on the active support single-sided strut (8) and the retaining wall (3).

8. The active adjustment method as described in claim 6, characterized in that, In step 5, during the construction of the underground structure, an opening is reserved in the underground floor slab at the installation position of the active adjustment embedded steel support system, so that the active adjustment embedded steel support system can penetrate the underground floor slab.

9. The active adjustment method as described in claim 6 or 8, characterized in that, In step 7, under the working state of actively adjusting the pre-embedded steel support system, the angle between the active support single-sided strut (8) and the horizontal direction is θ, the length of the active support single-sided strut (8) is La, the horizontal projection length of the active support single-sided strut (8) is Lh, the tension force on the active support vertical member (7) by the drive motor (5) of the drive assembly is Fv, and the internal support force obtained by the retaining wall (3) is Fh, then: , .

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