A vertical support system for deep foundation pits based on limited space

Abstract

The utility model relates to the technical field of foundation pit support, and discloses a vertical support system for deep foundation pits based on limited space, including at least two rows of support units vertically arranged along the deep foundation pit, each row of support units including a plurality of equally spaced flower pipe piles, two adjacent rows of flower pipe piles staggered, the lower ends of the flower pipe piles extending into the rock layer below the base, the flower pipe piles including steel flower pipes and a concrete layer located inside and outside the steel flower pipes, and a plurality of overflow holes evenly opened on the pipe body of the steel flower pipes; the center spacing between two adjacent flower pipe piles in each row of support units is 400-600mm, and the row spacing between two adjacent rows of support units is 600-800mm. In actual application, the utility model uses small mechanical equipment to complete the construction of the support system, and realizes the purpose of deep foundation pit support operation in built buildings or in limited space places where large machines cannot enter, greatly reducing the construction difficulty and construction cost, and ensuring the life safety of operators.

Description

Technical Field

[0001] The utility model relates to the technical field of foundation pit support, in particular to a deep foundation pit vertical support system based on limited space. Background Art

[0002] Old industrial bases across the country have begun to undergo adjustments, renovations, and industrial transformation and upgrading.

[0003] During the renovation and upgrading of old industrial bases, some old factories only carried out technical transformation of their production lines without changing the factory buildings. As a result, three objective factors appeared at the same time when the deep indoor foundation pit was actually excavated: limited indoor site area, limited indoor net height, and there were many buildings around. Therefore, how to support the deep foundation pit became a major problem.

[0004] At present, conventional support measures include: mechanical bored pile sheet wall, underground continuous wall, steel sheet pile, anchor wall or soil nail wall, etc. However, in existing buildings or places with limited net height, the above conventional support methods cannot achieve foundation pit support for the following reasons:

[0005] 1. Limited indoor site area: First, since the foundation pit to be excavated is located indoors and the indoor site is small, it is impossible to perform slope treatment around the foundation pit; secondly, when supporting the foundation pit with mechanically excavated pile-sheet wall, underground continuous wall and steel sheet pile, it is necessary to excavate pile holes or underground continuous wall trenches. The size of such hole-forming and trenching equipment is huge, and the indoor site area is limited, so it is impossible to perform trench excavation;

[0006] 2. Limited indoor net height: Due to the limited indoor net height, large construction machinery cannot enter, and mechanical bored pile sheet wall, underground continuous wall, and steel sheet pile support methods all require large construction machinery for drilling, hoisting, hammering, etc. for normal construction. For example, for steel sheet pile support, in order to ensure the support strength, the steel plate along the height of the foundation pit is an integral steel plate, so the height of the steel plate is relatively high, so a higher space is required for hoisting the steel plate. In addition, in order to ensure that the steel plate penetrates deep into the surface to play a supporting role, large hammering equipment is required to hammer on the top of the already high steel plate. Therefore, steel sheet pile support cannot be used in places with limited indoor net height;

[0007] 3. There are many buildings around: To support the foundation pit with anchor walls and soil nail walls, anchors or soil nails need to be inserted around the foundation pit, and the anchors or soil nails need to penetrate into the rock layer. Since there are many buildings around the foundation pit, anchors or soil nails are likely to damage the underground structures or pipelines of surrounding buildings during anchoring, affecting the foundation stability and structural safety of the building. Therefore, anchor fixing support is not suitable for confined space environments.

[0008] Since the above-mentioned conventional support methods are unable to support deep foundation pits in existing buildings or in confined spaces that cannot be entered by large machinery and equipment, the last available support method is for workers to dig holes for pile-sheet walls. However, manual hole digging operations have great safety risks, long construction periods, low work efficiency, and high costs. At the same time, they are difficult to implement when the groundwater level is high or when encountering adverse geological conditions such as quicksand. This often leads to risky and reckless operations in deep foundation pits without foundation pit support, causing major safety risks and seriously affecting the life and property safety of operators and enterprises.

[0009] In order to solve the above problems, the utility model provides a vertical support system for deep foundation pits based on limited space. Utility Model Content

[0010] The utility model aims to provide a vertical support system for deep foundation pits based on limited space, so as to achieve the purpose of performing deep foundation pit support operations in existing buildings or in limited spaces where large machinery and equipment cannot enter, greatly reducing construction difficulty and construction costs, and ensuring the life safety of operators.

[0011] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a vertical support system for deep foundation pits based on limited space, comprising at least two rows of support units vertically arranged along the deep foundation pit, each row of support units comprising a plurality of equally spaced flower pipe piles, the flower pipe piles of two adjacent rows are staggered, the lower ends of the flower pipe piles extend into the rock layer below the base, the flower pipe piles comprise steel flower pipes and a concrete layer located inside and outside the steel flower pipes, a plurality of overflow holes are evenly opened on the pipe body of the steel flower pipes; the center spacing between two adjacent flower pipe piles in each row of the support units is 400-600mm, and the row spacing between two adjacent rows of support units is 600-800mm.

[0012] The principle of this scheme is: when digging a deep foundation pit in an existing building or in a confined space where large machinery cannot enter, the existing conventional support method cannot be implemented due to limited site and inaccessibility of large equipment. In the utility model, a small excavator is used to drill multiple small-diameter pile holes around the foundation pit to be excavated, and then a small lifting equipment is used to install the steel pipe into the drilled hole, and then grouting is injected into the steel pipe to form a composite cement-soil reinforced wall structure between the steel pipe, soil and mortar, thereby realizing vertical support for the deep foundation pit.

[0013] Beneficial effects:

[0014] 1. The vertical support system of the utility model is to place steel flower pipes in the pile holes and perform grouting to form concrete flower pipe piles perpendicular to the deep foundation pit, and the lower end of the flower pipe piles extends into the rock layer below the base, so that the deep foundation pit is fully supported in the depth direction, and the overall structure is more stable; further, in this scheme, the flower pipe piles are staggered in rows, and the center spacing and row spacing between adjacent flower pipe piles are set to 400-600mm and 600-800mm respectively. According to construction experience, the radius of the grouting influence zone after grouting is 500mm. The staggered and close arrangement of the flower pipe piles makes the adjacent two rows of support units The grouting penetration influence zones after the initial grouting are interconnected, making the entire support structure connected into a whole, making the overall stability and resistance of the support structure stronger. Compared with conventional support methods, the structure is simpler and can effectively support deep foundation pits. The construction is simple and does not require the use of large-scale machinery and equipment. It greatly solves the problem that deep foundation pits in places with limited space cannot be supported by conventional support methods. It effectively avoids the risk of collapse and hydrogeological disasters caused by no support or improper support of deep foundation pits, ensuring the safety of surrounding buildings in the construction environment and the safety of life and property of workers.

[0015] 2. The utility model adopts a small-diameter steel pipe with overflow holes on the pipe body, which absorbs the advantages of steel sheet piles and sheet pile walls. While ensuring the stress-bearing performance of the steel pipe, the steel pipe can be used as a grouting pipe in the deep soil layer, so that the steel pipe after grouting, together with the mortar and soil layer, forms a composite cement-soil reinforced wall structure, strengthens the coordinated stress of the soil, and makes the overall support structure more capable of bearing and more stable.

[0016] Furthermore, each of the flower tube piles includes a plurality of steel flower tubes, each of the steel flower tubes is 3 to 6 meters long, and two adjacent steel flower tubes are directly connected and fixed by welding.

[0017] The above-mentioned arrangement makes the connection of the steel flower pipe stable and reliable. At the same time, the shorter steel flower pipe is extended to achieve segmented installation, which effectively reduces the net height of the space required for installation and realizes small-scale mechanization in the construction method, making the overall construction more economical and efficient.

[0018] Furthermore, the diameter of the steel flower tube is 100-300 mm, the diameter of the overflow hole is 10-15 mm, and the distance between adjacent overflow holes along the length direction of the steel flower tube is 100-200 mm.

[0019] The above arrangement not only ensures the stress and bending resistance of the steel flower pipe, but also plays the role of a deep grouting pipeline of the soil, effectively enhancing the coordinated stress between the steel flower pipe, mortar and soil after grouting.

[0020] Furthermore, the diameter of the pile hole of the flower pipe pile is 150-300 mm.

[0021] In the above arrangement, the flower pipe piles use small-diameter pile holes, so that during construction, no large-scale rotary drilling rig is required. A small excavator drill can be used, and the operation can be carried out within an operating space of less than 5m. The overall construction equipment is miniaturized and the cost is lower, which is safer, more convenient and economical.

[0022] According to construction experience, the radius of the grouting influence zone after grouting is 500mm. The above-mentioned two rows of drill holes are staggered so that the grouting penetration influence zones after grouting of the front and rear rows of pile holes are interconnected, making the entire support structure connected as a whole, making the overall stability of the support structure stronger and the resistance to impact stronger.

[0023] Furthermore, the flower tube piles also include a crown beam located at the top of the steel flower tube, and the crown beam connects all the flower tube piles into a whole.

[0024] The above arrangement connects the flower pipe piles in sequence into one whole through the crown beam, which does not need to occupy more construction space, can further increase the integrity of the support structure, further increase the overall strength of the support structure, enhance the deformation resistance, and make the structure more stable.

[0025] Furthermore, the width of the cap beam is greater than the width of the two rows of pile holes.

[0026] The above-mentioned setting connects all the flower pipe piles into one, improves the overall stability of the support system and improves the bending resistance; at the same time, it also constrains the top of the flower pipe pile, effectively limiting the horizontal displacement of the pile top into the pit caused by force, and reducing the risk of support structure damage caused by pile top movement.

[0027] Furthermore, a cushion layer is laid at the bottom of the crown beam, and the concrete strength of the crown beam is higher than the concrete strength of the cushion layer.

[0028] The above-mentioned setting transfers the load borne by the crown beam to the excavation surface of the foundation pit or the foundation more evenly through the cushion layer, reduces structural damage caused by local stress concentration, and can also effectively prevent groundwater, soil or other harmful media from directly contacting and corroding the concrete at the bottom of the crown beam, thereby extending the service life of the crown beam; at the same time, the concrete strength of the cushion layer and the crown beam is different, which not only ensures the overall stability and durability of the crown beam, but also optimizes the construction process and reduces construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of the first embodiment of the present utility model.

[0030] Figure 2 This is a schematic diagram of the connection of the steel flower pipe in the first embodiment of the utility model.

[0031] Figure 3 It is a partial cross-sectional schematic diagram of the vertical support system of the first embodiment of the utility model. DETAILED DESCRIPTION

[0032] The following is further described in detail through specific implementation methods:

[0033] The figure marks in the drawings of the specification include: support unit 1, flower pipe pile 2, steel flower pipe 3, overflow hole 31, direct joint 4, crown beam 5, crown beam base groove 51, cushion layer 52, and mold 53.

[0034] Example

[0035] A vertical support system for a deep foundation pit based on limited space includes at least two rows of support units 1 arranged along the deep foundation pit, such as Figure 1 , Figure 3 As shown, in this embodiment, the support system includes two rows of support units 1, each row of support units 1 includes a plurality of equidistantly distributed flower pipe piles 2, and the flower pipe piles 2 in two adjacent rows are staggered, and the lower ends of the flower pipe piles 2 extend into the stroke flower rock below the base, and the center distance between two adjacent flower pipe piles 2 in each row of support units 1 is 400-600mm, and the row distance between two adjacent rows of support units 1 is 600-800mm. According to construction experience, the radius of the grouting influence zone is 500mm. The staggered arrangement of the flower pipe piles 2 is conducive to the interconnection of the grouting penetration influence zones of the two adjacent rows of flower pipe piles 2 after grouting, so that the entire support structure is connected into a whole, so that the overall stability and resistance of the support structure are stronger; preferably, in this embodiment, the center distance between adjacent flower pipe piles 2 is 500mm, and the row distance is 700mm.

[0036] like Figure 2 , Figure 3 As shown in combination, the flower pipe pile 2 includes a steel flower pipe 3 and a concrete layer located inside and outside the steel flower pipe 3, each flower pipe pile includes a plurality of steel flower pipes 3, and the plurality of steel flower pipes 3 are connected in pairs through direct joints 4 and welded and fixed, so that the segmented installation of the steel flower pipes 3 is realized without being restricted by the net height of the space; the pile hole diameter of the flower pipe pile 2 is 150-350mm, wherein the steel flower pipe 3 is made of seamless steel pipe, and the length of each steel flower pipe 3 is 3-6mm and the diameter is 100-300mm, so as to avoid drilling construction with large equipment; preferably, in this embodiment, the pile hole diameter of the flower pipe pile 2 is 200mm, and the diameter of the steel flower pipe 3 is 200mm. The length of the adjacent steel flower pipes 3 is 150mm, and the lengths of the two adjacent steel flower pipes 3 are 3m and 6m respectively, so as to ensure that the joints of the adjacent flower pipe piles 2 are staggered; a plurality of overflow holes 31 are spirally and evenly opened on the pipe body of each steel flower pipe 3, and the aperture of the overflow hole 31 is 10-15mm, and the distance between two adjacent overflow holes 31 along the length direction of the steel flower pipe 3 is 100-200mm, so that while ensuring the stress and bending performance of the steel flower pipe 3, it can also play the role of a deep grouting pipeline in the soil; preferably, in this embodiment, the aperture of the overflow hole 31 on the steel flower pipe 3 is 12mm, and the distance between adjacent overflow holes 31 along the length direction of the steel flower pipe 3 is 150mm.

[0037] like Figure 1 As shown, the flower pipe pile 2 also includes a crown beam 5 arranged on the top of the steel flower pipe 3. The width of the crown beam 5 is greater than the width of two rows of flower pipe piles 2. A crown beam base groove 51 is dug on the ground along the arrangement shape of the flower pipe piles 2. A cushion layer 52 is laid at the bottom of the crown beam base groove 51. The concrete strength of the cushion layer 52 is lower than the concrete strength of the crown beam 5. A mold 53 is built along the groove wall in the crown beam base groove 51. The mold 53 is located above the cushion layer 52. A steel cage that meets the design plan is placed in the middle of the mold 53. The top of the steel flower pipe 3 is completely located in the steel cage. Then concrete is poured to form the crown beam 5. All the flower pipe piles 2 are connected into a whole through the crown beam 5 to enhance the overall deformation resistance of the support system.

[0038] The above is only an embodiment of the utility model, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the utility model, several deformations and improvements can be made, which should also be regarded as the protection scope of the utility model, and these will not affect the effect of the implementation of the utility model and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A vertical support system for deep foundation pits based on limited space, characterized by: It comprises at least two rows of support units vertically arranged along the deep foundation pit, each row of support units comprises a plurality of equally spaced pattern pipe piles, the pattern pipe piles of two adjacent rows are staggered, the lower ends of the pattern pipe piles extend into the rock layer below the base, the pattern pipe piles comprise steel pattern pipes and a concrete layer inside and outside the steel pattern pipes, a plurality of overflow holes are evenly opened on the pipe body of the steel pattern pipes; the center spacing between two adjacent pattern pipe piles in each row of the support units is 400-600 mm, and the row spacing between two adjacent rows of support units is 600-800 mm.

2. A vertical support system for deep foundation pits based on limited space according to claim 1, characterized in that: Each of the flower pipe piles includes a plurality of steel flower pipes, each of which has a length of 3 to 6 meters, and two adjacent steel flower pipes are connected and fixed by direct joints.

3. A vertical support system for deep foundation pits based on limited space according to claim 2, characterized in that: The diameter of the steel flower tube is 100-300 mm, the diameter of the overflow hole is 10-15 mm, and the distance between adjacent overflow holes along the length direction of the steel flower tube is 100-200 mm.

4. A vertical support system for deep foundation pits based on limited space according to claim 3, characterized in that: The pile hole diameter of the flower pipe pile is 150-300 mm.

5. A vertical support system for deep foundation pits based on limited space according to claim 4, characterized in that: The flower pipe piles also include a crown beam located at the top of the steel flower pipe, and the crown beam connects all the flower pipe piles into a whole.

6. A vertical support system for deep foundation pits based on limited space according to claim 5, characterized in that: The width of the cap beam is greater than the width of the two rows of pile holes.

7. A vertical support system for deep foundation pits based on limited space according to claim 6, characterized in that: A cushion layer is laid at the bottom of the crown beam, and the concrete strength of the crown beam is higher than the concrete strength of the cushion layer.

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