Reinforcing and supporting device for deep foundation pit and construction technology

Abstract

The invention discloses a reinforcing and supporting device for a deep foundation pit and a construction technology, and relates to the technical field of deep foundation pit construction, the reinforcing and supporting device comprises the foundation pit, a plurality of supporting columns are vertically inserted in the foundation pit at equal intervals, and a supporting bracket is horizontally arranged between the tops of the supporting columns; the supporting column is formed by coaxially connecting a plurality of supporting rods, one end of each supporting rod is provided with a threaded connector, and the other end of each supporting rod is internally provided with an internal thread corresponding to the threaded connector; two through holes are horizontally formed in the middle of the supporting rod in a penetrating mode, and the two through holes are symmetrically distributed relative to the supporting rod. According to the reinforcing and supporting device for the deep foundation pit, the construction process and the optimized and improved construction process and method, the reinforcing, supporting and water stopping effects of the foundation pit are achieved, meanwhile, the construction quality can be effectively controlled, the construction period is shortened, the corresponding engineering cost and cost loss are reduced, the water stopping requirement of the foundation pit is met, the construction period is shortened, loss is reduced, and cost is saved; a deep foundation pit high-water-level poor soil reinforcing and supporting construction method is researched.

Description

Technical Field

[0001] The invention relates to the technical field of deep foundation pit construction, and in particular to a reinforcement support device for a deep foundation pit and a construction process. Background Art

[0002] There are two concepts of deep foundation pit. One is that the depth of the foundation pit excavation has exceeded 5 meters, and it also includes 5 meters. In this case, it is a deep foundation pit. The other is that if the depth does not exceed 5 meters, but the surrounding environment and geological conditions are relatively complex, it can also be called a deep foundation pit.

[0003] When carrying out foundation pit construction, it is also necessary to protect the safety of surrounding buildings and some facilities. During the construction process, it is necessary to strengthen monitoring. If the earth excavation is unreasonable, it is very likely to affect the displacement of the foundation pit pile driver.

[0004] The protective structure during deep foundation pit construction is mainly composed of retaining structure. The construction methods and construction techniques adopted are different. The final maintenance structure can only be determined after comprehensive consideration of the depth of the foundation pit and geological conditions. At the same time, this structure is also a temporary retaining wall structure that can stabilize the foundation pit. Another support method is the I-beam pile retaining structure.

[0005] The quality of foundation pit support construction directly affects the stability of buildings and the surrounding buildings and environmental protection. Therefore, during the construction of deep foundation pit support, it is necessary not only to ensure the safety of the support structure construction, but also to control the deformation of the surrounding soil to ensure the safety of adjacent buildings and underground facilities.

[0006] At present, when the water level at the project location is high, the original foundation pit water-stopping curtain cannot meet the foundation pit water-stopping requirements. The backfill counter-pressure soil of the original supporting structure is asphalt road milling material, sand and gravel, etc. with large porosity. High water level immersion causes poor adhesion of the backfill counter-pressure soil and serious hole collapse. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a reinforcement support device and a construction process for a deep foundation pit, which solves the problems raised in the above-mentioned background technology.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: A reinforcement support device and construction process for a deep foundation pit, comprising a foundation pit, wherein a plurality of pillars are vertically inserted at equal intervals inside the foundation pit, and support brackets are horizontally arranged between the tops of the pillars;

[0009] The support column is composed of a plurality of support rods connected coaxially, one end of the support rod is provided with a threaded joint, and the other end of the support rod is internally provided with an internal thread corresponding to the threaded joint;

[0010] Two through holes are horizontally penetrated through the middle of the support rod, and the two through holes are symmetrically distributed with respect to the support rod.

[0011] Optionally, the plurality of support rods are connected to each other through the cooperation between the threaded joint and the internal thread.

[0012] Optionally, a plurality of convex strips are vertically arranged on the outer surface of the support rod, and the plurality of convex strips are distributed in parallel.

[0013] Optionally, the pillar further includes an end head, which is installed at the lower end of the pillar through a threaded connection.

[0014] Optionally, the supporting bracket is composed of two cross beams, a plurality of positioning beams and a plurality of fixing bolts, the two cross beams are distributed in parallel, and the positioning beams are installed equidistantly above the cross beams.

[0015] Optionally, both ends of each positioning beam are connected to the cross beam via a plurality of fixing bolts.

[0016] Optionally, the pillars are arranged in a square shape and are equidistantly arranged in the middle of the support bracket.

[0017] Optionally, a sensor unit is installed at the top of each of the pillars, and the sensor unit is configured to be one or more of a displacement sensor, a distance sensor, and an inclination monitoring sensor.

[0018] A construction process for a reinforcement support device for a deep foundation pit as claimed in any one of the above claims, comprising the following specific steps:

[0019] Step 1: Construction preparation, clear or relocate underground obstacles and pipelines in the enclosure construction area; lay out the enclosure centerline according to the design drawings and coordinate reference points, and review the coordinate data;

[0020] Step 2: On-site treatment, conduct on-site preparation work near the pile site, including cleaning and leveling the construction area, and surface soil treatment; check the engineering geological report, foundation depth and surrounding construction environment, determine the support form, place positioning steel, and place the pile according to the design drawings and measurement control points to ensure that the pile plane deviation is within the allowable range;

[0021] Step 3: Use a drilling machine to perform vertical drilling operations according to the pile position, then move the pile mixing machine to the working position, adjust the verticality of the pile frame, and use the theodolite to calibrate the verticality of the drill rod. The inclination rate must be less than 1%;

[0022] Step 4: Steel casing is buried. The casing is made of 8mm thick steel plate, with an inner diameter 10-20cm larger than the pile diameter. One or two overflow holes are opened on the top. When burying the casing, the casing hole is 40-50cm larger than the casing. The surrounding and bottom are backfilled and compacted with clay to prevent penetration. The casing is buried 1.5-2.0m deep. If the upper soil layer is thicker, it should pass through the loose soil layer to protect the hole opening and prevent hole collapse.

[0023] Step 5: Assemble the foundation piles. According to the required foundation pile length, select the corresponding number of support rods, connect and fix them through threaded joints and internal threads, install the end cap at the lower end of the lowest support rod, and fix the installed foundation pile on the pile driver;

[0024] Step 6: Support piling, carry out piling construction according to design requirements;

[0025] Step 7: Grouting. The grouting material is prepared according to the ratio of cement to fly ash = 1:7, and after being fully stirred, it is pressurized and injected into the pile hole by a grouting machine; the grouting pressure is 0.3-0.5Mpa;

[0026] Step 8: After the pile is constructed, the mud in the cast-in-place grass is removed and the ring beam is constructed according to the design. The ring beam construction must first break the cast-in-place pile head to expose the steel bar for a sufficient anchoring length, then pour the cushion layer, tie the ring beam steel bar, and set up the formwork; pour the ring beam concrete;

[0027] Step 9: Ring beam construction: install the measuring beam and positioning beam in sequence, and connect them with fixing bolts. After the ring beam is constructed, backfill the soil; after the concrete strength reaches the specified value, excavation is carried out, and drainage equipment is configured to prevent water gushing or accumulation in the foundation pit from affecting the construction;

[0028] Step 10: Quality inspection and acceptance. During the construction process, each process is quality inspected according to relevant standards and design requirements. The installation of the overall support device is judged by the sensor at the top of the pillar, and the pillar is adjusted for the second time according to the offset value of the sensor. After the foundation pit support construction is completed, a completion acceptance is carried out.

[0029] The present invention provides a reinforcement support device and construction process for a deep foundation pit, which has the following beneficial effects:

[0030] The reinforcement support device and construction technology for deep foundation pits are studied in depth in combination with the construction itself. While solving the reinforcement support construction problem of high water level and poor soil quality in deep foundation pits, it also meets the water stopping requirements of foundation pits, shortens the construction period, reduces losses and saves costs.

[0031] The cylindrical cement-soil consolidation body formed by high-pressure rotary jet piles has low strength, while the micro steel pipe pile drilling speed is fast, saving construction period; and the pile holes have sufficient supporting strength and are not prone to hole collapse. Pressure grouting can be carried out uniformly after batch drilling, which is conducive to quality control of the cement slurry specific gravity while reducing cement slurry loss and waste; for the depth of support structure embedded in the rock, the cost of down-the-hole hammer drilling is lower than that of rotary drilling drilling, which can save construction costs to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the foundation pit in the invention;

[0033] Figure 2 It is a schematic diagram of the pillar in the invention;

[0034] Figure 3 It is an enlarged schematic diagram of the support rod in the invention;

[0035] Figure 4 It is a full-section enlarged schematic diagram of the threaded joint in the invention;

[0036] Figure 5 It is a bottom view schematic diagram of the support rod in the invention.

[0037] In the figure: 1, foundation pit; 2, pillar; 201, support rod; 202, threaded joint; 203, internal thread; 204, through hole; 205, convex strip; 206, end; 3, supporting bracket; 301, cross beam; 302, positioning beam; 303, fixing bolt. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] See also Figures 1 to 5 The present invention provides a technical solution: a reinforcement support device and construction process for a deep foundation pit, comprising a foundation pit 1, a plurality of pillars 2 are vertically inserted at equal intervals inside the foundation pit 1, and support brackets 3 are horizontally arranged between the tops of the pillars 2;

[0042] The support 2 is composed of a plurality of support rods 201 connected coaxially, one end of the support rod 201 is provided with a threaded joint 202, and the other end of the support rod 201 is provided with an internal thread 203 corresponding to the threaded joint 202;

[0043] Two through holes 204 are horizontally penetrated in the middle of the support rod 201 , and the two through holes 204 are symmetrically distributed with respect to the support rod 201 .

[0044] In this embodiment, Figure 2 and Figure 4 As shown, a plurality of support rods 201 are connected by the cooperation between the threaded joint 202 and the internal thread 203 .

[0045] In this embodiment, Figure 3 As shown, a plurality of convex strips 205 are vertically disposed on the outer surface of the support rod 201 , and the plurality of convex strips 205 are distributed in parallel.

[0046] In this embodiment, Figure 1 and Figure 2 As shown, the support 2 also includes an end cap 206, which is installed at the lower end of the support 2 by threaded connection.

[0047] In this embodiment, Figure 1 As shown, the support bracket 3 is composed of two cross beams 301 , a plurality of positioning beams 302 and a plurality of fixing bolts 303 . The two cross beams 301 are arranged in parallel, and the positioning beams 302 are installed above the cross beams 301 at equal distances.

[0048] In this embodiment, Figure 1 As shown, both ends of each positioning beam 302 are connected to the cross beam 301 through a plurality of fixing bolts 303 .

[0049] In this embodiment, Figure 1 As shown, the pillars 2 are arranged in a square shape and are equidistantly in the middle of the support frame 3.

[0050] In this embodiment, Figure 1 As shown, a sensor unit is installed at the top of each pillar 2, and the sensor unit is configured as one or more of a displacement sensor, a distance sensor, and an inclination monitoring sensor.

[0051] A construction process for a reinforcement support device for a deep foundation pit comprises the following specific steps:

[0052] Step 1: Construction preparation, clear or relocate underground obstacles and pipelines in the enclosure construction area; lay out the enclosure centerline according to the design drawings and coordinate reference points, and review the coordinate data;

[0053] Step 2: On-site treatment, conduct on-site preparation work near the pile site, including cleaning and leveling the construction area, and surface soil treatment; check the engineering geological report, foundation depth and surrounding construction environment, determine the support form, place positioning steel, and place the pile according to the design drawings and measurement control points to ensure that the pile plane deviation is within the allowable range;

[0054] Step 3: Use a drilling machine to perform vertical drilling operations according to the pile position, then move the pile mixing machine to the working position, adjust the verticality of the pile frame, and use the theodolite to calibrate the verticality of the drill rod. The inclination rate must be less than 1%;

[0055] Step 4: Steel casing is buried. The casing is made of 8mm thick steel plate, with an inner diameter 10-20cm larger than the pile diameter. One or two overflow holes are opened on the top. When burying the casing, the casing hole is 40-50cm larger than the casing. The surrounding and bottom are backfilled and compacted with clay to prevent penetration. The casing is buried 1.5-2.0m deep. If the upper soil layer is thicker, it should pass through the loose soil layer to protect the hole opening and prevent hole collapse.

[0056] Step 5: Assembling the foundation piles, according to the required foundation pile length, select the corresponding number of support rods 201, and connect and fix them through the threaded joints 202 and the internal threads 203, and install the end cap 206 at the lower end of the lowest support rod 201, and fix the installed foundation pile on the pile driver;

[0057] Step 6: Support piling, carry out piling construction according to design requirements;

[0058] Step 7: Grouting. The grouting material is prepared according to the ratio of cement to fly ash = 1:7, and after being fully stirred, it is pressurized and injected into the pile hole by a grouting machine; the grouting pressure is 0.3-0.5Mpa;

[0059] Step 8: After the pile is constructed, the mud in the cast-in-place grass is removed and the ring beam is constructed according to the design. The ring beam construction must first break the cast-in-place pile head to expose the steel bar for a sufficient anchoring length, then pour the cushion layer, tie the ring beam steel bar, and set up the formwork; pour the ring beam concrete;

[0060] Step 9: Ring beam construction, install the measuring beam 301 and the positioning beam 302 in sequence, and fix them together with the fixing bolts 303. After the ring beam construction is completed, backfill the soil; after the concrete strength reaches the specified value, excavation is carried out, and drainage equipment is configured to prevent water gushing or water accumulation in the foundation pit from affecting the construction;

[0061] Step 10: Quality inspection and acceptance. During the construction process, each process is quality inspected according to relevant standards and design requirements. The installation of the overall support device is judged by the sensor at the top of the pillar 2, and the pillar 2 is adjusted for the second time according to the offset value of the sensor. After the foundation pit support construction is completed, a completion acceptance is carried out.

[0062] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A reinforcement support device for a deep foundation pit, comprising a foundation pit (1), characterized in that: A plurality of pillars (2) are vertically inserted at equal intervals inside the foundation pit (1), and support brackets (3) are horizontally arranged between the tops of the pillars (2); The support column (2) is composed of a plurality of support rods (201) connected coaxially, one end of the support rod (201) is provided with a threaded joint (202), and the other end of the support rod (201) is internally provided with an internal thread (203) corresponding to the threaded joint (202); Two through holes (204) are horizontally penetrated through the middle of the support rod (201), and the two through holes (204) are symmetrically distributed with respect to the support rod (201).

2. A reinforcement support device for a deep foundation pit according to claim 1, characterized in that: The plurality of support rods (201) are connected to each other through the cooperation between the threaded joint (202) and the internal thread (203).

3. A reinforcement support device for a deep foundation pit according to claim 1, characterized in that: The outer surface of the support rod (201) is vertically provided with a plurality of convex strips (205), and the plurality of convex strips (205) are distributed in parallel.

4. A reinforcement support device for a deep foundation pit according to claim 1, characterized in that: The support (2) also includes an end head (206), and the end head (206) is installed on the lower end of the support (2) through a threaded connection.

5. A reinforcement support device for a deep foundation pit according to claim 1, characterized in that: The support bracket (3) is composed of two cross beams (301), a plurality of positioning beams (302) and a plurality of fixing bolts (303), the two cross beams (301) are arranged in parallel, and the positioning beams (302) are installed above the cross beams (301) at equal distances.

6. A reinforcement support device for a deep foundation pit according to claim 1, characterized in that: Both ends of each positioning beam (302) are connected to the cross beam (301) via a plurality of fixing bolts (303).

7. A reinforcement support device for a deep foundation pit according to claim 1, characterized in that: The pillars (2) are arranged in a square shape and at equal intervals in the middle of the support bracket (3).

8. A reinforcement support device for a deep foundation pit according to claim 1, characterized in that: A sensor unit is installed at the top of each support (2), and the sensor unit is configured as one or more of a displacement sensor, a distance sensor, and an inclination monitoring sensor.

9. A construction process for the reinforcement support device for a deep foundation pit as claimed in any one of claims 1 to 8, characterized in that: The specific steps include: Step 1: Construction preparation, clear or relocate underground obstacles and pipelines in the enclosure construction area; lay out the enclosure centerline according to the design drawings and coordinate reference points, and review the coordinate data; Step 2: On-site treatment, conduct on-site preparation work near the pile site, including cleaning and leveling the construction area, and surface soil treatment; check the engineering geological report, foundation depth and surrounding construction environment, determine the support form, place positioning steel, and place the pile according to the design drawings and measurement control points to ensure that the pile plane deviation is within the allowable range; Step 3: Use a drilling machine to perform vertical drilling operations according to the pile position, then move the pile mixing machine to the working position, adjust the verticality of the pile frame, and use the theodolite to calibrate the verticality of the drill rod. The inclination rate must be less than 1%; Step 4: Steel casing is buried. The casing is made of 8mm thick steel plate, with an inner diameter 10-20cm larger than the pile diameter. One or two overflow holes are opened on the top. When burying the casing, the casing hole is 40-50cm larger than the casing. The surrounding and bottom are backfilled and compacted with clay to prevent penetration. The casing is buried 1.5-2.0m deep. If the upper soil layer is thicker, it should pass through the loose soil layer to protect the hole opening and prevent hole collapse. Step 5: assembling the foundation piles, selecting a corresponding number of support rods (201) according to the required foundation pile length, and connecting and fixing them through threaded joints (202) and internal threads (203), and installing a terminal (206) at the lower end of the lowest support rod (201), and fixing the installed foundation pile on the pile driver; Step 6: Support piling, carry out piling construction according to design requirements; Step 7: Grouting. The grouting material is prepared according to the ratio of cement to fly ash = 1:7, and after being fully stirred, it is pressurized and injected into the pile hole by a grouting machine; the grouting pressure is 0.3-0.5Mpa; Step 8: After the pile is constructed, the mud in the cast-in-place grass is removed and the ring beam is constructed according to the design. The ring beam construction must first break the cast-in-place pile head to expose the steel bar for a sufficient anchoring length, then pour the cushion layer, tie the ring beam steel bar, and set up the formwork; pour the ring beam concrete; Step 9: Ring beam construction, install the measuring beam (301) and the positioning beam (302) in sequence, and fix the two together through the fixing bolts (303). After the ring beam construction is completed, backfill the soil; after the concrete strength reaches the specified value in the design, excavation is carried out, and drainage equipment is configured to prevent water gushing or water accumulation in the foundation pit from affecting the construction; Step 10: Quality inspection and acceptance. During the construction process, quality inspection is carried out on each process in accordance with relevant standards and design requirements. The installation of the overall support device is judged by the sensor at the top of the support (2). The support (2) is adjusted for the second time according to the offset value of the sensor. After the foundation pit support construction is completed, a completion acceptance is carried out.

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