A pit support structure for underground engineering and construction method thereof

Abstract

The present invention relates to a pit support structure for underground engineering, comprising a pit, a horizontal plate support is arranged in advance on the bottom surface of the pit, a plurality of vertical support piles are arranged on the inner circumference of the pit, and the tops of the plurality of support piles are connected to form an integral support structure through surrounding purlins. The pit support structure for the underground engineering is simple in structure and safe and stable in structure. It not only overcomes the shortcomings of the traditional foundation pit support structure, such as the long length of the support piles, the need to penetrate the soft soil layer, the large deformation, the long construction period, and the multiple cross-processes, but also realizes a stereotyped tool-type support structure with a fast construction speed and can be used repeatedly. It is suitable for supporting small-area pit excavations such as basement pits, basement elevator shafts, tower crane foundations, pump rooms, septic tanks, underground pipelines, etc., and can achieve safe, economical, fast, and effective foundation pit support.

Description

Technical Field

[0001] The invention relates to a pit support structure for underground engineering and a construction method thereof. Background Art

[0002] With the continuous development of urbanization, land resources are decreasing day by day, and the demand for the development and utilization of urban underground space is becoming more and more urgent. There are more and more underground civil and public facilities such as subways, underground stations, underground parking garages, underground shopping malls, underground pump rooms, underground sewage treatment plants, underground pipelines, and underground civil defense works. The development of underground engineering has led to the inevitable construction of foundation pits under various complex hydrological, geological, and environmental conditions. The excavation of foundation pit engineering often causes damage to the surrounding environment, damage to the engineering piles in the pit, and damage to the underground structure.

[0003] Therefore, designing a safe, economical, fast and effective foundation pit support structure is an important issue in current underground engineering. Summary of the invention

[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a pit support structure for underground engineering and a construction method thereof.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: a pit support structure for underground engineering, including a pit, a horizontal plate support is arranged in advance on the bottom surface of the pit, a plurality of vertical support piles are arranged on the inner circumference of the pit, and the tops of the plurality of support piles are connected by surrounding purlins to form an integral supporting structure.

[0006] Preferably, the advance-set horizontal plate-like support is a concrete horizontal plate-like support or a mortar horizontal plate-like support.

[0007] Preferably, the supporting piles are tool-type supporting piles or precast concrete supporting piles.

[0008] Preferably, the supporting structure also includes a positioning frame located on each side of the pit, the positioning frame is screwed and fixedly connected to the purlin on the same side via a screw and nuts locked at both ends of the screw, and a plurality of support piles on the same side are positioned and fastened between the positioning frame and the purlin.

[0009] Preferably, the bottoms of several supporting piles are inserted into the bottom of the pit.

[0010] Preferably, straight welds are used to connect the straight sections of the purlins, oblique welds are used to connect the corners of the purlins, and a reinforcing plate is welded between the corners of the two purlins.

[0011] A construction method for a pit support structure of an underground project is carried out according to the following steps: during the specific implementation of the support structure, (1) firstly, the horizontal plate support is constructed. According to the layout position, a spiral drill bit modified from an excavator is used to drill to about 500 mm below the pit bottom, and then the measured concrete or mortar is poured into the center tube of the drill bit. The drill bit is lifted and rotated to the pit bottom position. The drill bit is reversed and lifted to the ground, and then moved to the next adjacent hole position for construction until all the horizontal plate support construction is completed; (2) the spiral drill bit is removed and replaced with a hydraulic vibrating hammer, and support piles and purlins are laid. The support piles are pressed into place one by one according to the designed pile positions, and the support piles and purlins are reliably connected to complete the construction of the entire pit support structure.

[0012] Preferably, in order to prevent the adjacent piles from being too strong and making it difficult to drill and insert the supporting piles, a certain proportion of retarder should be added to the concrete or mortar.

[0013] Preferably, in order to facilitate the extraction of the supporting piles, a certain thickness of friction reducer should be applied on the surface of the supporting piles. In order to ensure that the horizontal plate support has sufficient strength, sufficient curing time should be allowed after the construction of the supporting structure is completed.

[0014] Preferably, in order to facilitate the construction of the underground structure and speed up the construction, non-recyclable precast concrete support piles may also be used.

[0015] Compared with the prior art, the present invention has the following beneficial effects: the structure of the pit support structure of the underground project is simple, the structure is safe and stable, and it not only overcomes the shortcomings of the traditional foundation pit support structure, such as long support pile length, need to penetrate soft soil layer, large deformation, long construction period, multiple cross-processes, etc., but also realizes a stereotyped tool-type support structure, fast construction speed, and can be used repeatedly. It is suitable for the support of small-area pit excavation such as basement pit, basement elevator shaft, tower crane foundation, pump room, septic tank, underground pipeline, etc., and can achieve safe, economical, fast and effective foundation pit support.

[0016] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a side view of an embodiment of the present invention.

[0018] Figure 2 It is the top view of the connection node of tool support piles.

[0019] Figure 3 for Figure 2 AA section view.

[0020] Figure 4 This is a top view of the connection node of precast concrete support piles.

[0021] Figure 5 for Figure 4 BB cross-sectional view.

[0022] Figure 6 This is a schematic diagram of the connection between the straight sections of the purlin.

[0023] Figure 7 This is a schematic diagram of the corner connection of the purlin.

[0024] Figure 8 The principle of pressure filling for spiral drill bit Figure 1 .

[0025] Fig. 9 The principle of pressure filling for spiral drill bit Figure 2 .

[0026] Fig.10 The following is a construction flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description.

[0028] like Figures 1 to 10 As shown, a pit support structure for underground engineering includes a pit 1, a horizontal plate support 2 is arranged in advance on the bottom surface of the pit, a plurality of vertical support piles 3 are arranged on the inner circumference of the pit, and the tops of the plurality of support piles are connected by surrounding purlins 4 to form an integral supporting structure.

[0029] In an embodiment of the present invention, the advanced horizontal plate-like support is a concrete horizontal plate-like support or a mortar horizontal plate-like support.

[0030] In the embodiment of the present invention, the supporting piles are tool-type supporting piles 5 or prefabricated concrete supporting piles 6 .

[0031] In an embodiment of the present invention, the supporting structure also includes a positioning frame 7 located on each side of the pit. The positioning frame is screwed and fixedly connected to the purlin on the same side through a screw 8 and nuts locked at both ends of the screw, and a plurality of supporting piles on the same side are positioned and fastened between the positioning frame and the purlin.

[0032] In the embodiment of the present invention, the bottoms of a plurality of supporting piles are inserted into the bottom of the pit.

[0033] In the embodiment of the present invention, the straight sections of the purlins are connected by straight welds 9, the corners of the purlins are connected by oblique welds 10, and a reinforcing plate 11 is welded between the corners of the two purlins.

[0034] A construction method for a pit support structure of an underground project is carried out according to the following steps: during the specific implementation of the support structure, (1) firstly carry out the construction of a horizontal plate support, according to the layout position, use a spiral drill bit modified from an excavator to drill to about 500 mm below the pit bottom, then pressurize the measured concrete or mortar into the center of the drill bit (at the valve), and rotate the drill bit while lifting it to the pit bottom position, reversely drill and lift the drill bit to the ground, and move to the next adjacent hole position for construction until all horizontal plate support construction is completed; (2) remove the spiral drill bit, replace it with a hydraulic vibrating hammer, lay support piles and purlins, and press the support piles one by one according to the designed pile position (the pile bottom is generally controlled to be 500 mm deeper than the horizontal sheet pile support bottom), and reliably connect the support piles and purlins to complete the construction of the entire pit support structure. It not only overcomes the shortcomings of the traditional foundation pit support structure, such as long support pile length, need to penetrate soft soil layer, large deformation, long construction period, and multiple cross-processes, but also realizes a stereotyped tool-type support structure, fast construction speed, and can be used repeatedly; the pit bottom uses spiral drilling tools to construct a full-floor horizontal plate concrete (or mortar) advance support, with high rigidity and small deformation; the miniaturized equipment is suitable for construction in the pit; it saves engineering costs and reduces engineering risks. It is a support suitable for small-area pit excavation such as basement pits, basement elevator shafts, tower crane foundations, pump rooms, septic tanks, underground pipelines, etc., and can achieve safe, economical, fast and effective foundation pit support. The length of the supporting piles passing through the soft soil layer is greatly shortened, and the standardized steel (or precast concrete) tool-type (recyclable) supporting structure is realized. The green construction is convenient, fast and cost-saving. The pit bottom is pre-supported by a spiral drill to fill the horizontal plate concrete (or mortar) in the pit. The structure is simple and reasonable, with high rigidity and small deformation. The construction equipment is miniaturized, easy to move in the pit, convenient and flexible, and has little impact on the engineering piles.

[0035] In the embodiment of the present invention, in order to prevent the adjacent piles from being too strong and making it difficult to drill and insert the supporting piles, a certain proportion of retarder is preferably added to the concrete or mortar.

[0036] In the embodiment of the present invention, in order to facilitate the extraction of the supporting piles, a certain thickness of friction reducer should be applied on the surface of the supporting piles. In order to ensure that the horizontal plate support has sufficient strength, sufficient maintenance time should be allowed after the construction of the supporting structure is completed.

[0037] In the embodiment of the present invention, in order to facilitate the construction of the underground structure and speed up the construction, non-recyclable prefabricated concrete support piles may also be used.

[0038] The present invention is not limited to the above-mentioned best implementation mode. Anyone can derive other various forms of underground engineering pit support structures and construction methods under the enlightenment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A pit support structure for underground engineering, characterized in that: The invention comprises a pit, wherein a horizontal plate-shaped support is arranged in advance on the bottom surface of the pit, and a plurality of vertical supporting piles are arranged on the inner peripheral side of the pit, and the tops of the plurality of supporting piles are connected to form an integral supporting structure through a surrounding purlin; the horizontal plate-shaped support arranged in advance is a concrete horizontal plate-shaped support or a mortar horizontal plate-shaped support; the supporting piles are tool-type supporting piles or prefabricated concrete supporting piles; the supporting structure also comprises a positioning frame located on each side of the pit, the positioning frame is screwed and fixedly connected to the surrounding purlin on the same side through a screw and a nut locked at both ends of the screw, and a plurality of supporting piles on the same side are positioned and fastened between the positioning frame and the surrounding purlin; the bottoms of the plurality of supporting piles are inserted into the bottom of the pit; the straight sections of the surrounding purlin are connected by straight welds, the corners of the surrounding purlin are connected by oblique welds, and the surrounding purlins are connected by oblique welds at both sides. A reinforcing plate is welded between the corners of the purlin. The construction method of the pit support structure of the underground project is carried out according to the following steps: During the specific implementation of the support structure, (1) the horizontal plate support is constructed first. According to the layout position, a spiral drill bit modified by an excavator is used to drill to 500 mm below the pit bottom, and then the measured concrete or mortar is poured into the center tube of the drill bit. The drill bit is lifted and rotated to the bottom of the pit. The drill bit is reversed and lifted to the ground, and then moved to the next adjacent hole position for construction until all horizontal plate support construction is completed; (2) The spiral drill bit is removed and replaced with a hydraulic vibrating hammer, and support piles and purlins are laid. The support piles are pressed into the designed pile positions one by one, and the support piles and purlins are reliably connected to complete the construction of the entire pit support structure.

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