Anti-floating anchor rod construction structure and construction method thereof

Abstract

The application discloses an anti-floating anchor rod construction structure and a construction method thereof. The anchor rod is located at the center of a hole, and a plurality of anchor rod steels are fixed symmetrically on the outer periphery of the anchor rod. Positioning steels are arranged on the outer side of the anchor rod steels along the radial direction of the hole, and the outer ends of the positioning steels are fixed on the hole wall of the anchor rod. The anchor rod, the anchor rod steels and the positioning steels are fixed in the hole of the anchor rod by cement mortar. Expansion water-stopping strips are arranged on the outer periphery surface of the anchor rod steels and the anti-floating anchor rod at the opening of the top of the hole, and water-resistant plates are arranged on the top. The construction method comprises the following steps: construction preparation, hole forming by a drilling machine, anchor rod manufacturing, anchor rod grouting, anchor rod maintenance and detection. The anchor rod is accurately positioned and stable, and the overall structure has excellent anti-floating performance. The follow-up pipe drilling method can effectively avoid the hole collapse phenomenon during and after the hole forming, and the floor elevation can be measured before the hole forming, the drilling depth can be accurately calculated, the drilled depth can be calculated according to the length of each follow-up pipe, and the hole forming depth can be accurately controlled to meet the requirements.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building construction, especially to the technical field of underground building construction, and relates to an anti-floating anchor rod construction structure and a construction method thereof. BACKGROUND

[0002] With the rapid development of urbanization, people's demand for underground space is becoming more and more urgent. The development and utilization of underground space can greatly improve the space utilization rate of urban land and alleviate the contradiction between urban development and land resources. However, in the process of developing underground space, the self-weight of underground structure is often less than the buoyancy of underground water. How to ensure the safety of underground space structure, especially in areas with rich underground water, the buoyancy generated by underground water cannot be ignored. Generally, multi-storey buildings often adopt the foundation form of single foundation plus waterproof board, and the anti-floating anchor rod is often used as the anti-floating measure. However, as an elongated member anchored in the soil layer, the anti-floating anchor rod is difficult to construct in water-rich strata, and there are many quality problems that affect safety and functionality during construction. Therefore, further research is needed on the construction of anti-floating anchor rods, and a safer and more effective anti-floating anchor rod structure needs to be provided. SUMMARY

[0003] The present application aims to solve the problems existing in the prior art and provides an anti-floating anchor rod construction structure and a construction method thereof.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0005] Firstly, the present application provides an anti-floating anchor rod construction structure, which is erected in an anti-floating construction pit and a pre-drilled anchor rod hole. The anti-floating anchor rod construction structure is characterized in that:

[0006] The anti-floating anchor rod is located at the center of the anchor rod hole, and a plurality of anchor rods are symmetrically welded and fixed outside the circumference of the anti-floating anchor rod. Each anchor rod is provided with a positioning steel bar outside along the radial direction of the anchor rod hole, and the outer end of the positioning steel bar is positioned and fixed on the wall of the anchor rod hole. The anti-floating anchor rod, the anchor rod and the positioning steel bar are cemented in the inner part of the anchor rod hole.

[0007] Expansion waterstop strips are arranged on the outer circumferential surface of the anti-floating anchor rod and the anchor rod outside the opening at the top of the anchor rod hole, and a water-resistant plate is arranged on the top of the anti-floating construction pit. The top of the anti-floating anchor rod and the anchor rod is the bottom plate of the basement.

[0008] One symmetrical arrangement structure of the anchor rod is that three anchor rods forming an equilateral triangle are symmetrically welded and fixed outside the circumference of the anti-floating anchor rod.

[0009] Another symmetrical arrangement structure of the anchor rod is that four anchor rods forming a square are symmetrically welded and fixed outside the circumference of the anti-floating anchor rod.

[0010] The top of the anchor rod steel bar is bent, and the bending position of the anchor rod steel bar is located at the top of the water resisting plate and is in supporting contact and fixation with the bottom position of the basement bottom plate.

[0011] The top of the anti-floating anchor rod is located at the top of the water resisting plate and is in supporting contact and fixation with the bottom position of the basement bottom plate, and the bottom end of the anti-floating anchor rod and the bottom end of the anchor rod steel bar are consolidated in the anchor rod hole.

[0012] The application further provides the anti-floating anchor rod construction method, which comprises the following steps:

[0013] Step one, construction preparation: three-way leveling is performed on the construction site, anchor rod design parameters are determined, axis marking and measurement lofting are performed;

[0014] Step two, drilling machine hole forming: after the drilling machine is installed in place and drilled to form a hole, wall fixing and hole cleaning are performed;

[0015] Step three, anchor rod manufacturing: the anchor rod body is composed of a plurality of threaded hot-rolled steel bars with a diameter of 22 mm, and the whole bundle of anchor rod bodies is straight and does not intersect;

[0016] Step four, anchor rod grouting: the grouting pipe is connected by a 4-part steel pipe and a hard plastic grouting pipe, the grouting end is 0.2 m away from the hole bottom, and the grouting slurry is M30 cement slurry;

[0017] Step five, anchor rod maintenance and detection: after the anchor rod construction is completed, the anchor rod is maintained for fifteen days, and after the maintenance period, the anchor rod is subjected to a pull-out test, and the grouted concrete is subjected to a test block compressive strength test.

[0018] Further, the axis marking and measurement lofting comprises:

[0019] Step 11, positioning is performed by using a total station according to the main control point, and each axis control point is determined;

[0020] Step 12, each axis control point is guided to a relatively stable position and is protected until the completion acceptance;

[0021] Step 13, double control is adopted according to each axis control point after rechecking and qualification to perform pile position lofting, and the pile position error is not greater than 20 mm.

[0022] Further, in step two, the drilling machine is an MGJ-50 type drilling machine, the hole forming is performed by using a full casing follow-up construction technology, the drilling machine, the crown block, the trolley and the drilling tool form a plumb line, and the center offset distance of the anchor rod hole position is less than 10 mm.

[0023] Further in the step two, when the drill bit of the drilling machine reaches the designed depth, whether there is underground water in the anchor hole is observed, when there is much underground water, the anchor rod hole is cleaned by using pressure water through the grouting pipe, when there is little underground water or no underground water, the residual in the anchor hole is cleaned by using the air compressor pipe.

[0024] Further in the step two, when the drill bit of the drilling machine reaches the designed depth, whether there is underground water in the anchor hole is observed, when there is much underground water, the anchor rod hole is cleaned by using pressure water through the grouting pipe, when there is little underground water or no underground water, the residual in the anchor hole is cleaned by using the air compressor pipe.

[0025] Further in the step five, the number of the pull-out test should not be less than 5% of the total number of the anchor rods and should not be less than six, and the acceptance pull-out force is twice the designed value of the anchor rod pull-out bearing capacity.

[0026] The present application has the following beneficial effects:

[0027] The anti-floating anchor rod construction structure can conveniently and stably position and fix the whole anchor rod structure in the foundation pit hole, can guarantee the positioning accuracy and the stability after the structure is positioned and fixed, can improve the anti-floating performance of the whole structure, and can guarantee the structural safety of the underground space. The construction method can effectively avoid the hole collapse phenomenon in the hole forming process and after the hole forming, can accurately calculate the drilling depth by measuring the floor elevation before the hole forming, can calculate the drilled depth according to the length of each following pipe, can accurately control the hole forming depth to meet the requirements, the construction structure and method can improve the anti-floating anchor rod construction efficiency by 20%, shorten the construction period by more than 10%, reduce the construction cost by not less than 3%, reduce the management personnel by more than 20%, and has good economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the whole structure schematic diagram of the present application;

[0029] Figure 2 It is the anchor rod reinforcement triangular distribution structure plan view of the present application;

[0030] Figure 3 It is the anchor rod reinforcement square distribution structure plan view of the present application;

[0031] Figure 4 It is the flow chart of the anti-floating anchor rod construction method of the present application.

[0032] LEGEND:

[0033] 1 is the anti-floating construction foundation pit, 2 is the anchor rod hole forming, 3 is the anti-floating anchor rod, 4 is the anchor rod reinforcement, 5 is the positioning reinforcement, 6 is the filling layer, 7 is the expansion water stop strip, 8 is the water resistance plate, and 9 is the basement bottom plate. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific embodiments. These specific embodiments are further explanations of the principles of the present invention and are not intended to limit the present invention in any way. Any technology that is the same as or similar to the present invention does not exceed the scope of protection of the present invention.

[0035] Refer to the attached diagram.

[0036] like Figures 1 to 3 The anti-buoyancy anchor construction structure shown includes an anti-buoyancy construction pit 1, an anchor hole 2 set in the anti-buoyancy construction pit 1, an anti-buoyancy anchor 3 set at the center of the anchor hole 2, an anchor bar 4 fixedly connected to the outer surface of the anti-buoyancy anchor 3, a filling layer 6 set in the anchor hole 2, and an expansion waterstop strip 7 set near the top of the anchor hole 2 and on the outer surface of the anti-buoyancy anchor 3 and the anchor bar 4, a water-resistant plate 8 set at the top of the anti-buoyancy construction pit 1, and a basement floor slab 9 set on the anti-buoyancy construction pit 1 and above the anti-buoyancy anchor 3.

[0037] When using anti-buoyancy anchor bolts in construction, a drilling rig is used to drill holes at the anti-buoyancy construction pit 1 to form anchor bolt holes 2. The anchor bolt holes 2 are then cleaned. Positioning steel bars 5 are welded to anchor bolt steel bars 4, and then anchor bolt steel bars 4 are welded to anti-buoyancy anchor bolts 3. The anti-buoyancy anchor bolts 3 are then inserted into the holes and positioned using positioning steel bars 5, ensuring the accuracy of anchor bolt positioning. After positioning, grouting is performed, and after grouting, natural fixation is allowed to complete the construction of anti-buoyancy anchor bolts 3. Multiple anchor bolts can be set in one area to form an integrated structure, thereby improving the overall protective performance of the base plate.

[0038] In a further embodiment, the anchor rod 4 is fixedly connected to the anti-buoyancy anchor 3 by welding. The anchor rod 4 can be configured as three equilateral triangles or four squares, such as... Figure 2 As shown, the anchor rod reinforcement 4 is set in three positions forming an equilateral triangle, as follows: Figure 3 The anchor rod reinforcement 4 shown is set in a square arrangement of four. The arrangement of multiple anchor rod reinforcement 4 can improve the stability of the anti-buoyancy anchor rod 3 structure, effectively cope with the situation of weak interlayers in some water-rich strata, improve the structural strength of the construction structure, and thus ensure the stability and safety of the overall anchor rod structure. Different forms of distribution installation can be selected according to different needs.

[0039] In a further embodiment, the diameter of the anti-buoyancy anchor rod 3 is 160mm, and the insertion depth of the anchor rod reinforcement 4 is 22mm. The combination of the anti-buoyancy anchor rod 3 and the anchor rod reinforcement 4 can effectively improve the anti-buoyancy and leak-proof effect of the bottom plate.

[0040] Further, the outer surface of the anchor rod reinforcement 4 is fixedly connected with a positioning reinforcement 5. The positioning reinforcement 5 can ensure that the anchor rod reinforcement 4 can be accurately positioned, so that the anti-floating anchor rod 3 can be accurately positioned in the hole, thereby ensuring the accuracy and stability of the entire construction installation.

[0041] Further, the top of the anchor rod reinforcement 4 is bent, and the bending position of the anchor rod reinforcement 4 corresponds to the top position of the water-resistant plate 8 and the bottom position of the basement bottom plate 9. The anchor rod reinforcement 4 can improve the structural strength of the entire anti-floating anchor rod 3 and improve the stability of the overall structure.

[0042] Further, the material of the filling layer 6 is M30 cement mortar. The cement mortar filling can ensure the stability of the anchor rod structure positioning and fixation, thereby effectively dealing with the leakage in the water-rich stratum and improving the waterproof construction quality.

[0043] As shown in Figure 4 The construction method embodiment is described by taking a certain number of land plots of a certain city second ring road north section apartment construction project.

[0044] The apartment construction project plans to construct a net land area of about 25,000 square meters, with a total construction area of about 110,000 square meters. The foundation form is column independent foundation, wall strip foundation, and raft foundation. Anti-floating anchor rods are arranged except for the raft part, and the anchor rod construction is carried out after the completion of the foundation cushion construction.

[0045] The following is the anti-floating anchor rod construction method, which includes the following steps:

[0046] Step 1, construction preparation: three-way leveling is performed at the construction site, the anchor rod design parameters are determined, and the axis marking and measurement lofting are performed;

[0047] Specifically, before the anti-floating anchor rod construction, the excavator is used to excavate and level the site to be constructed, so as to facilitate the drilling machinery to control the perpendicularity and positioning, and to achieve the conditions of water passage, electricity passage and road passage. The anchor rod design parameters are determined according to the drawings, the plane and elevation control points provided by the owner are introduced to the construction site by the surveyor, the construction II plane control network and elevation control network are established, and the axis marking and measurement lofting are performed. The axis marking and measurement lofting includes:

[0048] Step 11, positioning is performed according to the main control point, and each axis control point is measured by a total station;

[0049] Step 12, introduce each axis control point to a relatively stable position and protect it to the completion acceptance;

[0050] Step 13, according to the re-inspection of each axis control point using double control to carry out pile position setting out, the pile position error is not more than 20mm.

[0051] Step two, drill hole: after the drill installation in place and drilling hole, solid wall hole cleaning;

[0052] Specific, hole forming machinery using MGJ-50 drill. Steel pipe and wood board to drill platform, drill in place, the drill, trolley, pulley, drill into a plumb line, and the anchor hole center offset distance is less than 10mm. Hole forming using full casing follow-up construction technology construction.

[0053] Drill in place, first use 3-4m long core tube, to ensure the straight line shape of the drill. Drilling speed depending on the rock, 30-40cm / min is appropriate. Each time the drill should check the drill diameter, the degree of wear of the drill bit, the steering device of the drill bit, the serious wear should be repaired in time.

[0054] Anchor hole after hole forming, drill bit to the design depth, observation of the anchor hole without groundwater, when the groundwater, use pressure water through the grouting pipe to clean the anchor hole when there is no groundwater or less groundwater, using air compressor pipe cleaning anchor hole residue.

[0055] Step three, anchor rod production: anchor rod main body using 3 diameter 22mm hot rolled steel bar combination, the whole bundle anchor rod main body straight without crossing.

[0056] Specific, anchor rod lengthening using mechanical sleeve connection, joint located below the anchor hole and staggered.

[0057] Step four, anchor rod grouting: grouting pipe using 4 steel pipe and hard plastic grouting pipe connection, grouting end distance from the hole bottom 0.2m, grouting slurry using M30 cement slurry;

[0058] Specific, after filling gravel pressure grouting, its grouting pressure is 0.5-1.0MPa. Grouting material using P.0.42.5R ordinary portland cement, according to the water-cement ratio 0.5-1.0 preparation of cement mortar, hole overflow grout slowly after lifting grouting pipe, then repeatedly grouting, until the hole grout full no empty. Anchor rod filling gravel grouting body compressive strength is not less than 30MPa, that is, M30. The slurry should be stirred evenly, with stirring, slurry should be used before initial setting.

[0059] After grouting, the anchor rod main body with rust paint to avoid rusting of the anchor rod main body. The upper end of the anchor rod main body is bent under the top steel reinforcement, the hole is provided with expansion rubber water stop.

[0060] Step five, anchor rod maintenance, detection: after the completion of the anchor rod construction maintenance fifteen days, maintenance period after the anchor rod pullout test, the grouting of concrete block compressive strength test.

[0061] Specific, pullout test number should not be less than the total number of anchor rod percentage and not less than six, acceptance pullout force is twice the anchor rod uplift bearing capacity design value; the strength of the test block for each 30 anchor rod not less than a group, each group of six test blocks.

[0062] Among them, the anchor rod position selection principle:

[0063] a. According to the geological exploration of the most unfavorable geological conditions of the position.

[0064] b. The same geological conditions of at least three groups, and different length, step by step growth.

Claims

1. A method of construction of an anti-float anchor, characterised in that: The anti-buoyancy anchor is erected in the pre-drilled anchor hole within the anti-buoyancy construction pit. The anti-buoyancy anchor is located at the center of the anchor hole. Three anchor bars forming an equilateral triangle or four anchor bars forming a square are symmetrically welded and fixed to the outer periphery of the anti-buoyancy anchor. A positioning bar is installed radially along the anchor hole on the outer side of each anchor bar, with its outer end positioned and fixed against the periphery of the anchor hole. The anti-buoyancy anchor, anchor bars, and positioning bars within the anchor hole are solidified with cement mortar. An expansion seal strip is installed at the top opening of the anchor hole and on the outer surface of the anti-buoyancy anchor and anchor bars. A water-resistant board is installed on the top of the anti-buoyancy construction pit. The basement floor slab lies above the water-resistant board and above the anti-buoyancy anchor and anchor bars. Includes the following steps: Step 1: Construction Preparation: Level the site, determine the anchor bolt design parameters, mark the axis, and conduct surveying and layout. Step 2, Drilling: After the drilling rig is installed and the hole is drilled, the hole is cleaned and the wall is solidified. Step 3, Anchor Bolt Fabrication: The main body of the anchor bolt is composed of multiple 22mm diameter threaded hot-rolled steel bars, and the entire anchor bolt bundle is straight and does not cross. Step 4, Anchor Bolt Grouting: The grouting pipe is made of 1 / 4-point steel pipe and hard plastic grouting pipe connected together. The grouting end is 0.2m away from the bottom of the hole. The grouting slurry is M30 cement mortar. Step 5: Anchor Bolt Curing and Testing: After the anchor bolts are installed, they should be cured for 15 days. After the curing period, pull-out tests should be conducted on the anchor bolts, and compressive strength tests should be conducted on the grouted concrete.

2. The anti-floating anchor construction method according to claim 1, characterized in that: The top of the anchor bar is bent, and the bent position of the anchor bar is located at the top of the water-resistant slab and is supported and fixed at the bottom of the basement floor slab.

3. The anti-floating anchor construction method according to claim 2, characterized in that: The top of the anti-buoyancy anchor is located at the top of the water-resistant slab and is supported and fixed at the bottom of the basement floor slab. The bottom of the anti-buoyancy anchor and the bottom of the anchor bar are fixed in the anchor hole.

4. The anti-floating anchor construction method according to claim 3, characterized in that: The axis marking and measurement layout in step one are as follows: Step 11: Based on the main control points, use a total station to locate and determine the control points of each axis; Step 12: Transfer each axis control point to a relatively stable position and protect it until final acceptance. Step 13: Based on the verified and qualified control points of each axis, use double control to lay out the pile positions, and the pile position error shall not exceed 20mm.

5. The anti-floating anchor construction method according to claim 3, characterized in that: In step two, the drilling rig used is an MGJ-50 type drilling rig, and the hole is formed using a full casing follow-up construction process. The drill rig, the overhead crane, the pulley, and the drilling tools are aligned with a vertical line, and the offset from the center of the anchor hole is less than 10mm.

6. The anti-floating anchor construction method according to claim 3, characterized in that: In step two, after the drill bit of the drilling rig reaches the designed depth, observe whether there is groundwater in the anchor hole. If there is water, use pressurized water to clean the anchor hole through the grouting pipe. If there is no water, use an air compressor duct to clean the residue in the anchor hole.

7. The anti-floating anchor construction method according to claim 3, characterized in that: The anchor bolts are extended using mechanical sleeve connections, with the joints located below the anchor holes and staggered from each other.

8. The anti-floating anchor construction method according to claim 3, characterized in that: In step five, the number of anchor rods tested shall not be less than five percent of the total number of anchor rods and shall not be less than six. The acceptance pull-out force shall be twice the design value of the anchor rod's pull-out bearing capacity.

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