Foundation pit engineering steel truss support and concrete support combined system servo system

Abstract

The utility model discloses a foundation pit engineering steel truss support and concrete support combined system servo system, which relates to the technical field of deep foundation pit engineering, and comprises an enclosure structure, the enclosure structure is embedded around a foundation pit, the outer side surface of the enclosure structure is abutted against a soil body of the foundation pit, an initial support is arranged between the opposite surfaces of the top of the enclosure structure, and a concrete support is arranged on the initial support. The inner side faces of the enclosure structures abut against the foundation pit combined supporting system. The foundation pit combined supporting system comprises a steel truss supporting system and a concrete supporting system, the concrete supporting system is installed in the middle of a foundation pit, the two ends of the concrete supporting system are fixedly connected with the steel truss supporting system, and the steel truss supporting system abuts against the inner side face of the enclosure structure through steel enclosing purlins. And a prestress loading unit is arranged between the opposite surfaces of the steel truss supporting system and the steel enclosing purlin. The foundation pit engineering steel truss support and concrete support combined system servo system has the advantages of being convenient to construct, short in construction period, low in cost and the like.

Description

Technical Field

[0001] This utility model relates to the field of deep foundation pit engineering technology, and in particular to a servo system for a combination of steel truss support and concrete support system for foundation pit engineering. Background Technology

[0002] In deep foundation pit engineering in soft soil areas, plate-type support structures combined with horizontal internal bracing are often used to control the deformation of the retaining structure during the excavation stage, protecting the safety of the foundation pit and its surrounding environment. To improve the ability to actively control foundation pit deformation, steel support servo systems and concrete support servo systems have been increasingly used in foundation pit engineering in recent years. The main problems with existing support servo systems include:

[0003] 1. Steel support servo system: This type of support servo system uses a one-to-one jack loading device for each support, and is mostly used for bracing arrangements in narrow strip foundation pits. When used in large-area foundation pits, the steel support span is large, and the stability of the support will decrease rapidly, easily leading to instability and failure, thus endangering the safety of the foundation pit project. In addition, steel support servo systems are mostly used in support systems without walers or with only one steel waler, and the horizontal spacing of the steel supports is relatively close, affecting the earthwork excavation speed;

[0004] 2. Concrete Support Servo System: This system uses jacks between the concrete waler and the retaining piles / walls. The support arrangement is flexible and suitable for large-area foundation pit projects. However, because the concrete support is constructed using cast-in-place construction, the construction and curing time is long after the foundation pit excavation reaches the support bottom elevation. During this process, the horizontal deformation of the retaining piles continuously develops, thus reducing the concrete support servo system's ability to control the horizontal deformation of the retaining piles.

[0005] In summary, existing steel support servo systems and concrete support servo systems cannot simultaneously meet the requirements of large-area foundation pit engineering and rapid support construction.

[0006] Developing a servo system for a combination of steel truss support and concrete support in foundation pit engineering to reduce support construction time and save construction period, while being applicable to large-area foundation pit engineering, has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0007] The purpose of this invention is to provide a servo system for a combination of steel truss support and concrete support in foundation pit engineering, thereby solving the problems listed in the background art.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] This utility model discloses a servo system for a combination of steel truss support and concrete support for foundation pit engineering, including a retaining structure. The retaining structure is embedded around the foundation pit, and the outer side of the retaining structure abuts against the soil of the foundation pit. Initial supports are installed between the opposite top surfaces of the retaining structure, and the inner sides of the retaining structure abut against the foundation pit combined support system.

[0010] The foundation pit combined support system includes a steel truss support system and a concrete support system. The concrete support system is installed in the middle of the foundation pit. Both ends of the concrete support system are fixedly connected to the steel truss support system. The steel truss support system abuts against the inner side of the retaining structure through steel walers. A prestressed loading unit is installed between the opposite surfaces of the steel truss support system and the steel walers.

[0011] Preferably, the concrete support system includes a support column, the upper end of which is fixedly connected to the lower surface of the initial support, and the lower end of which is located in the soil of the foundation pit.

[0012] A supporting beam is fixedly installed on the side wall of the supporting column.

[0013] Preferably, the steel truss support system includes a steel truss, the steel truss includes a steel truss body, and the steel truss body is fixedly connected to the end of the support beam through a connecting node.

[0014] Preferably, the connection node includes a limiting steel section, which is horizontally fixed to the side wall of the steel truss body by high-strength bolts, and the limiting steel section abuts against the upper and lower surfaces of the supporting beam respectively.

[0015] It also includes a limiting steel plate, which is vertically fixed to the side wall of the steel truss body by the high-strength bolts, and the limiting steel plate abuts against the left and right surfaces of the supporting beam respectively.

[0016] The end of the supporting beam is equipped with a through-beam sleeve; the limiting steel plate is fixedly connected to the supporting beam by tie bolts passing through the through-beam sleeve.

[0017] Preferably, the prestressed loading unit includes a steel waler and a steel bracket, the steel bracket being fixedly installed on the side wall of the enclosure structure, and the lower surface of the steel waler abutting against the upper surface of the steel bracket.

[0018] Preferably, the free end of the steel truss body overlaps the steel bracket.

[0019] Preferably, it also includes a jack, one end of which abuts against the side wall of the steel waler, and the other end of which abuts against the side wall of the steel truss body.

[0020] Preferably, after the jacking operation is completed, a retaining box is installed between the steel waler and the side wall of the steel truss body.

[0021] Preferably, it also includes a suspension rod, the upper end of which is connected to the side wall of the enclosure structure, and the other end of which is fixedly connected to the steel truss body.

[0022] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0023] This utility model discloses a servo system for a combined steel truss support and concrete support system for foundation pit engineering. By adopting a basin-type excavation method for foundation pit engineering, the system first forms concrete support in the middle section, then excavates the soil around the foundation pit and quickly installs the steel truss support and steel walers. Prestress is applied to the retaining structure using jacks, which can effectively reduce the horizontal deformation of the retaining structure during the excavation stage of foundation pits in environmentally sensitive areas with soft soil, thus protecting the safety of the surrounding environment. Because the rigidity of the steel truss support system around the foundation pit is greatly improved compared to conventional walers, the spacing between concrete support columns in the middle area of ​​the foundation pit can be further increased, resulting in a more flexible layout and a larger construction space. This utility model also has the advantages of convenient construction, fast construction period, and low cost, and has the prospect of widespread application. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 This is a top view schematic diagram of a servo system for a combination of steel truss support and concrete support in foundation pit engineering according to this utility model.

[0026] Figure 2 This is a side view of the connection node between the steel truss support and the cast-in-place concrete support of this utility model.

[0027] Figure 3 This is a top view of the connection node between the steel truss support and the cast-in-place concrete support of this utility model.

[0028] Figure 4 This is a schematic diagram of the initial support construction of this utility model;

[0029] Figure 5 This is a schematic diagram of the basin-type excavation and concrete support construction in the middle part of the foundation pit in this utility model.

[0030] Figure 6 This is a schematic diagram of the excavation and steel truss support construction of the soil retention area around the foundation pit and the prestressing of the prestressing loading unit in this utility model.

[0031] Explanation of reference numerals in the attached drawings: 1. Enclosure structure; 2. Steel waler; 3. Steel truss; 31. Limiting steel section; 32. Steel truss body; 33. High-strength bolt; 34. Limiting steel plate; 35. Through-beam sleeve; 36. Tie bolt; 4. Support beam; 5. Jack; 6. Force holding box; 7. Initial support; 8. Support column; 9. Steel bracket; 10. Hanging rod. Detailed Implementation

[0032] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0033] like Figure 1-6 As shown, a servo system for a combination of steel truss support and concrete support for foundation pit engineering includes a retaining structure 1, which is buried around the foundation pit. The outer side of the retaining structure 1 abuts against the soil of the foundation pit. An initial support 7 is installed between the opposite top surfaces of the retaining structure 1, and the inner side of the retaining structure 1 abuts against the foundation pit combined support system.

[0034] The foundation pit combined support system includes a steel truss support system and a concrete support system. The concrete support system is installed in the middle of the foundation pit. Both ends of the concrete support system are fixedly connected to the steel truss support system. The steel truss support system abuts against the inner side of the retaining structure 1 through steel walers 2. A prestressed loading unit is installed between the opposite surfaces of the steel truss support system and the steel walers 2.

[0035] By setting up a concrete support system in the middle of the foundation pit and a steel truss support system around the foundation pit, and setting up a prestressed loading unit between the steel truss support system and the steel waler, combined with the basin-type excavation construction method, the concrete support system is first installed in the middle area of ​​the foundation pit, and then the steel truss support system is formed around the foundation pit. Based on the principle of the spatiotemporal effect of foundation pits in soft soil areas, the support formation speed is accelerated. In addition, by applying prestress to the steel truss support system, the horizontal deformation of the retaining structure during the foundation pit excavation stage is reduced, thus protecting the safety of the surrounding environment.

[0036] Furthermore, the steel truss support system is constructed by splicing together steel profiles, with high-strength bolts connecting the steel profiles.

[0037] The concrete support system can be a cast-in-place structure or a precast structure, and the connection between the concrete support system and the steel truss support system adopts a steel structure prefabricated connection.

[0038] Simultaneously, basin-style excavation and zoned construction are adopted. The concrete support system or structural beam and slab units in the middle area are constructed first. After reaching the corresponding strength and age, the surrounding sections are constructed symmetrically to quickly form a steel truss support system and apply prestress. This can effectively control the deformation of the retaining structure and the protected environment buildings, and make full use of the rigidity and reliability of the concrete support system.

[0039] Furthermore, the stress on the steel waler is transformed into a steel truss + steel waler + concrete support system, which has greater stiffness, more reliable deformation control, and a clearer force transmission system. The spacing of the concrete supports and the number of bracing frames can be flexibly adjusted according to the stress per meter of the steel waler and the support size. The supports can avoid the underground structure that is constructed first, or form large open areas without supports, which is conducive to construction organization and flexible adjustment of the construction plan, and accelerates the overall construction progress of the project.

[0040] It can also make full use of the strength and rigidity of concrete supports, greatly improve the utilization rate of column piles and engineering piles, and reduce the cost of supports, columns and column piles.

[0041] Specifically, the concrete support system includes a support column 8, the upper end of which is fixedly connected to the lower surface of the initial support 7, and the lower end of which is located in the soil of the foundation pit.

[0042] The supporting column 8 is fixedly installed with a supporting beam 4 on its side wall. By adopting a basin-type excavation method, the precast / cast-in-place concrete support in the middle part is first formed, the soil is left around the excavated foundation pit, and finally the steel truss support system and steel waler are quickly installed. This can speed up the formation of foundation pit support and effectively reduce the horizontal deformation of the retaining structure during the foundation pit excavation stage.

[0043] Specifically, the steel truss support system includes a steel truss 3, the steel truss 3 includes a steel truss body 32, and the steel truss body 32 is fixedly connected to the end of the support beam 4 through a connection node;

[0044] By adjusting parameters such as the steel section and spacing of the steel truss support system, the bending resistance of the system can be adjusted to meet different foundation pit requirements. Because the stiffness of the steel truss support system around the foundation pit is significantly higher than that of conventional walers, the spacing of the concrete support members in the central area of ​​the pit can be further increased, allowing for more flexible arrangement, greater construction space, and facilitating foundation pit excavation and ensuring that the support members avoid obstructing vertical walls and columns of the basement.

[0045] Specifically, the connection node includes a limiting steel section 31, which is horizontally fixed on the side wall of the steel truss body 32 by high-strength bolts 33, and the limiting steel section 31 abuts against the upper and lower surfaces of the supporting beam 4 respectively.

[0046] It also includes a limiting steel plate 34, which is vertically fixed on the side wall of the steel truss body 32 by the high-strength bolts 33, and the limiting steel plate 34 abuts against the left and right surfaces of the supporting beam 4 respectively.

[0047] The end of the supporting beam 4 is equipped with a through-beam sleeve 35; the limiting steel plate 34 is fixedly connected to the supporting beam 4 by tie bolts 36 passing through the through-beam sleeve 35.

[0048] Limiting steel plates 34 are installed on the upper and lower surfaces of the supporting beam 4 on the side of the steel truss body 32 at the connection interface, limiting steel plates 34 are installed on the left and right sides of the supporting beam 4, and horizontal beam sleeves 35 are installed inside the supporting beam 4. The limiting steel plates 34 on the left and right sides are tightly connected to the supporting beam 4 by tie bolts 36 installed in the beam sleeves 35. The limiting steel plates, limiting steel sections and other steel components at the connection nodes are all connected together by high-strength bolts 33.

[0049] The limiting steel 31 located on the upper and lower surfaces of the supporting beam 4 can be in the form of ribbed steel plates, steel walkway plates, channel steel, etc.

[0050] Specifically, the prestressed loading unit includes a steel waler 2 and a steel bracket 9. The steel bracket 9 is fixedly installed on the side wall of the enclosure structure 1, and the lower surface of the steel waler 2 abuts against the upper surface of the steel bracket 9.

[0051] Specifically, the free end of the steel truss body 32 is attached to the steel bracket 9.

[0052] Specifically, it also includes a jack 5, one end of which abuts against the side wall of the steel waler 2, and the other end of which abuts against the side wall of the steel truss body 32. By applying prestress to the steel waler through the jack, the horizontal deformation of the retaining structure during the foundation pit excavation stage can be effectively reduced.

[0053] Specifically, after the lifting operation of the jack 5 is completed, a force-holding box 6 is installed between the steel waler 2 and the side wall of the steel truss body 32. The jack pushes the steel truss body 32 away from the steel waler 2 along the upper surface of the steel bracket, so that prestress is applied between the steel truss body 32 and the steel waler 2. After the prestress is applied and the force-holding box is installed, the jack can be removed and used for the construction of the next steel truss support system, thereby improving the efficiency of jack use and reducing the number of jacks required.

[0054] Specifically, it also includes a suspension rod 10, the upper end of which is connected to the side wall of the enclosure structure 1, and the other end of which is fixedly connected to the steel truss body 32.

[0055] A construction process for a servo system of a combined steel truss support and concrete support system for foundation pit engineering includes the following steps:

[0056] Step 1: Drive in the retaining structure and supporting columns, excavate the first layer of soil, and construct the initial support;

[0057] Step 2: The foundation pit is excavated using a basin-style method. The soil in the middle part of the foundation pit is excavated to the elevation of the next support bottom, and the support beam in the middle part is constructed.

[0058] Step 3: Excavate the soil around the foundation pit to the next support bottom elevation, construct steel brackets on the side walls of the retaining structure, place steel walers and jacks on the steel brackets, and fix them with lifting rods;

[0059] Step 4: Fix and install the steel truss at the end of the supporting beam;

[0060] Step 5: The fixed end of the jack abuts against the steel waler, and the working end of the jack abuts against the steel truss. Prestress is applied between the steel waler and the steel truss through the jack to control the horizontal deformation of the enclosure structure.

[0061] Step 6: After the prestressing is applied, install the retaining box between the steel waler and the steel truss, and move the jacks to the next working face;

[0062] Step 7: Repeat steps 2 and 6 to construct the steel truss support system and the concrete support system sequentially downwards.

[0063] This technology is particularly suitable for the overall excavation of ultra-large area foundation pits. It can accelerate the construction progress, reduce the project cost, and reduce the number of partition and retaining structures. Furthermore, the prestressed steel truss support system reduces deformation and environmental impact. It is also suitable for foundation pits of various shapes, especially those with irregular shapes. The steel truss support system uses triangular trusses, which can be combined according to the shape of the foundation pit. Deformation is controlled by the axial force servo system perpendicular to the edge of the foundation pit, which makes the boundary shape of the inner concrete support system regular and facilitates the support layout.

[0064] Furthermore, this process can be combined with the central island process, which can not only speed up the construction period, but also effectively utilize the structural beams and slabs of the central island as a support system, thereby effectively reducing the project cost.

[0065] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0066] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A servo system for a combined steel truss support and concrete support system for foundation pit engineering, comprising a retaining structure (1), wherein the retaining structure (1) is embedded around the foundation pit, the outer surface of the retaining structure (1) abuts against the soil of the foundation pit, and initial supports (7) are installed between the opposite top surfaces of the retaining structure (1), characterized in that: The inner surface of the retaining structure (1) abuts against the foundation pit combined support system; The foundation pit combined support system includes a steel truss support system and a concrete support system. The concrete support system is installed in the middle of the foundation pit. Both ends of the concrete support system are fixedly connected to the steel truss support system. The steel truss support system abuts against the inner side of the retaining structure (1) through a steel waler (2). A prestressed loading unit is installed between the opposite surfaces of the steel truss support system and the steel waler (2).

2. The servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 1, characterized in that: The concrete support system includes a support column (8), the upper end of which is fixedly connected to the lower surface of the initial support (7), and the lower end of which is located in the soil of the foundation pit. A support beam (4) is fixedly installed on the side wall of the support column (8).

3. The servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 2, characterized in that: The steel truss support system includes a steel truss (3), the steel truss (3) includes a steel truss body (32), and the steel truss body (32) is fixedly connected to the end of the support beam (4) through a connection node.

4. The servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 3, characterized in that: The connection node includes a limiting steel section (31), which is horizontally fixed on the side wall of the steel truss body (32) by high-strength bolts (33), and the limiting steel section (31) abuts against the upper and lower surfaces of the supporting beam (4). It also includes a limiting steel plate (34), which is vertically fixed on the side wall of the steel truss body (32) by the high-strength bolts (33), and the limiting steel plate (34) abuts against the left and right surfaces of the supporting beam (4) respectively; The end of the supporting beam (4) is equipped with a beam-through sleeve (35); the limiting steel plate (34) is fixedly connected to the supporting beam (4) by passing through the beam-through sleeve (35) through the tie bolt (36).

5. The servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 4, characterized in that: The prestressed loading unit includes a steel waler (2) and a steel bracket (9). The steel bracket (9) is fixedly installed on the side wall of the enclosure structure (1). The lower surface of the steel waler (2) abuts against the upper surface of the steel bracket (9).

6. The servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 5, characterized in that: The free end of the steel truss body (32) overlaps the steel bracket (9).

7. A servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 6, characterized in that: It also includes a jack (5), one end of which abuts against the side wall of the steel waler (2), and the other end of which abuts against the side wall of the steel truss body (32).

8. The servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 7, characterized in that: After the jack (5) completes the lifting operation, a retaining box (6) is installed between the steel waler (2) and the side wall of the steel truss body (32).

9. A servo system for a combined steel truss support and concrete support system for foundation pit engineering according to claim 8, characterized in that: It also includes a suspension rod (10), the upper end of which is connected to the side wall of the enclosure structure (1), and the other end of which is fixedly connected to the steel truss body (32).

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