CN102587366A - Self-drilling type spiral anchor rod and construction process using self-drilling type spiral anchor rod for grouting along with drilling, stirring and curing - Google Patents

Abstract

The invention discloses a self-drilling spiral anchor rod and a construction technique of grouting, stirring and solidifying while drilling, which is suitable for supporting engineering of anchored slopes in soft soil areas. The rod body of the spiral anchor is provided with a slurry hole, the front end of the anchor rod body is closed, the spiral blade is welded to the front end of the anchor rod body, and the stirring plate is welded on the anchor rod body behind the spiral blade. The grouting-while-drilling mixing and solidification construction technology using the spiral bolt is to inject grout while drilling the bolt body, grouting while drilling, so that the slurry is injected from the grout hole of the bolt body, and it is connected with the front end of the spiral bolt. The soil cut by the blades is mixed together, and the stirring blade set behind the helical blades can evenly mix the soil and cement slurry, and form irregular anchors after solidification to increase its anchoring force. The invention integrates drilling and grouting, avoids the influence of post-grouting on the side wall of the foundation pit, and can effectively control the grouting pressure to ensure the quality of grouting.

Description

A self-drilling screw bolt and its construction technology of grouting and stirring while drilling

technical field

The invention relates to construction equipment and a construction method for foundation pit support engineering in building construction, in particular to a self-drilling screw bolt and its construction technology of grouting, stirring and curing while drilling, which is suitable for the support of anchor-drawn slopes in soft soil areas Engineering, especially suitable for foundation pit support engineering of foundation construction in soft soil areas like the Yellow River Delta.

Background technique

The Yellow River Delta area is an alluvial plain composed of cohesive soil, silt and silt sand recently deposited in the Quaternary, and the buried depth of groundwater is relatively shallow, generally not exceeding 1m.

For soft soil areas with rich groundwater, in order to keep the environment outside the foundation pit unaffected, precipitation outside the pit is generally not allowed. In the case that the dewatering outside the pit cannot be carried out, the pre-formed hole prestressed anchor bolt construction technology adopted in the traditional foundation pit support project, due to the cumbersome construction procedures and complicated mechanical operations, is prone to water leakage and quicksand and low construction efficiency. make it difficult to achieve. In the case of no precipitation outside the pit, the ramming technology is very suitable for the foundation pit support bolt construction in the soft soil area with abundant groundwater, but in this kind of area, the ramming type is used to drive the prestressed anchor rod to support the foundation pit. However, there are certain disadvantages. The front end of this kind of bolt is flat, and there is a grout hole on the rod body, which is first rammed into the ground and then injected with grout. During the grouting process, it is difficult to control the grouting time, grouting pressure, and grouting volume, which greatly affects the grouting effect and fails to achieve the expected prestressing effect. At present, the commonly used anchor rods on the construction site also have pre-hole anchor rods. This kind of anchor rods are drilled on the wall of the foundation pit according to the length required by the design. After drilling, steel strands or steel bars together with grouting pipes, such as PVC pipes , together into the hole, and then grouting. The construction cost of this technology is low, but it is easy to cause hole collapse after pre-forming holes in saturated soft soil areas, which seriously reduces work efficiency, and the grouting effect of post-grouting is not ideal.

Contents of the invention

The purpose of the present invention is to provide a self-drilling screw bolt and its construction technology of grouting, stirring and curing while drilling, which can be used in the foundation pit support engineering of the soft ground in the soft soil area of the Yellow River Delta. It solves the problems of poor anchor grouting effect and insufficient tensile force in foundation pit support engineering in soft soil areas.

Technical solution of the present invention is:

A self-drilling screw bolt includes a bolt body, which is provided with a grout hole, the front end of the bolt body is closed, the spiral blade is welded to the front end of the bolt body, and the bolt body behind the spiral blade is welded Stir the flakes.

A self-drilling helical bolt grouting stirring and curing construction technology, the multifunctional drilling rig and the grouting pipe are connected to the rear end of the bolt body or connected to the rear end of the extended bolt body, and drilled in the bolt body At the same time, the grout is injected, and the grout is injected while drilling, so that the grout is injected from the grout hole of the anchor rod body, and mixed with the soil cut by the front helical blade. The body and the cement slurry are evenly stirred, and after curing, an irregular anchor body is formed to increase its anchoring force.

The present invention has following remarkable effect:

The invention can integrate the advantages of the pre-drilled anchor rod and the ramming type anchor rod, is suitable for the situation where there is no precipitation outside the pit, adopts the grout hole and the grouting stirring and solidification process while drilling, and has good grouting effect. Drilling with self-drilling screw bolts and pile-anchor support means short construction period and low engineering cost, and does not affect the construction of the basement structure. The integration of drilling and grouting of the self-drilling screw anchor avoids the pressure effect of post-grouting on the side wall of the foundation pit, and at the same time can effectively control the grouting pressure to ensure the quality of grouting. By applying prestress to the helical anchor, the soil deformation can be actively controlled, and the stress state of the soil can be adjusted, which is beneficial to the stability of the slope. The self-drilling screw bolt has high construction safety, strong pull-out resistance, and can better ensure the safety of the surrounding environment. mainly reflects in:

1. The self-drilling helical bolt in the present invention is easy to manufacture and has a simple structure. By welding the helical blade at the end of the bolt, the blade has extremely strong penetrating power in soft soil areas, which reduces the difficulty of drilling, and the helical The structural form of the blade can effectively improve the pullout resistance of the anchor rod in each soil layer. the

2. In the present invention, the threaded seamless steel pipe material is used to improve the side frictional resistance of the bolt body while cooperating with the helical blade to complete the drilling.

3. The grout hole on the self-drilling helical bolt of the present invention is located at the rear side of the helical blade. Pressure grouting is performed during the process of the bolt rotating and pushing the soil layer. The soil is mixed together, and the stirring blade is set behind the spiral blade, which can evenly stir the soil and the cement slurry, so that the soil and the slurry are fully combined, and an irregular anchor is formed after solidification, which increases its anchoring force and ensures its Effectiveness of support works.

4. The structure design of the present invention is simple, easy to construct, and the construction process is safe and reliable. Through the implementation of the invention, the construction efficiency and construction quality are improved, and the economic benefits are improved.

Description of drawings

The accompanying drawing is a structural schematic diagram of the self-drilling screw bolt of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings. Referring to the accompanying drawings, a self-drilling screw anchor includes an anchor rod body 3, which is provided with a grout hole 2, and the front end of the anchor rod body 3 is closed. The blade 1 is welded on the front end of the anchor rod body 3 , and the stirring piece 4 is welded on the anchor rod body 3 behind the helical blade 1 . In one embodiment, the slurry outlet hole 2 is set on the anchor rod body 3 on the rear side of the helical blade 1, and its hole diameter is 4mm-8mm, such as 5mm, 7mm, 8mm and so on. When the grout hole 2 is directly arranged on the anchor rod body 3, its aperture will be smaller, which can increase its spraying capacity and prevent the soil body from blocking the grout hole 2. The slurry outlet hole 2 of another embodiment is a slurry outlet pipe welded on the anchor rod body 3, and is arranged on the rear side of the spiral blade 1. The slurry outlet pipe is a straight pipe or a tapered pipe, and the diameter of the nozzle is 8mm-12mm, such as 9mm, 10mm, etc., use a welded slurry outlet pipe as the slurry outlet 2, which is more conducive to preventing mud from clogging. The anchor rod body 3 is a seamless threaded steel pipe, and its front end is provided with at least one helical blade 1, the helical blade 1 is 10cm-15cm away from the front end of the anchor rod body 3, which is more conducive to drilling; the distance between the helical blades 1 is 25cm -35cm, the helical angle between the helical blade 1 and the anchor rod body 3 is between 28°-32°; a stirring piece 4 is set at 15cm-25cm behind the helical blade 1. Stirring pieces 4 are arranged staggeredly on the anchor rod body 3, at least three pieces are arranged, the distance between the stirring pieces 4 is between 15cm-25cm, and the included angle with the anchor rod body 3 is between 40°-50°. The illustrated spiral blade 1 is provided with 2 pieces, and the stirring blade 4 is provided with 4 pieces. The rear end of the anchor rod body 3 is connected to the lengthened anchor rod 6 through the connecting sleeve 5, which is more suitable for deep and large foundation pit support projects.

Using a self-drilling helical bolt grouting stirring and curing construction technology, the multifunctional drilling rig and the grouting pipe are connected to the rear end of the bolt body 3 or to the rear end of the extended bolt 6, and the When the rod body 3 is drilled, the grout is injected, and the grout is injected while drilling, so that the grout is shot out from the grout hole 2 of the anchor rod body 3, and mixed with the soil cut by the front helical blade 1, and the helical blade 1 The stirring plate 4 arranged at the back evenly stirs the soil body and the cement slurry, and forms an irregular anchoring body after solidification to increase its anchoring force. The grouting pressure while drilling when grouting is 2 Mpa-5Mpa, and the grouting pressure can be adjusted according to the actual size of the anchor and the location of the formation; the water-cement ratio of the grout is 0.45:1-0.50:1.

According to the construction characteristics of the self-drilling screw bolt, the multifunctional drilling rig model MDL-120D1 is used as the drilling construction equipment and grouting at the same time. When in use, connect the power connection sleeve of the MDL-120D1 multifunctional drilling rig to the rear end of the anchor rod body 3 or to the rear end of the lengthened anchor rod 6, connect the anti-drilling joint at the rear end of the power connection sleeve to the grouting pipe and It is connected to the grouting equipment through the grouting pipe.

After the anchor reaches the designed strength requirements, prestress is applied to the spiral anchor. First, hang the channel steel on the anchor rod. In order to make the anchor rod and the waist beam work together, add a lining plate on the tension side of the channel steel, and lock it with bolts after tension. Tension locking should pay attention to the tight combination of all parts, and the bolts should be locked for ten minutes after the prestress is applied to ensure that the applied prestress meets the design requirements.

Claims (8)

1. A self-drilling screw bolt, comprising a bolt body (3), on which a grout hole (2) is provided, characterized in that the front end of the bolt body (3) is closed, and the helical blade (1 ) is welded on the front end of the anchor rod body (3), and the stirring plate (4) is welded on the anchor rod body (3) behind the helical blade (1). 2. A self-drilling screw bolt according to claim 1, characterized in that the slurry outlet hole (2) is set on the bolt body (3) on the rear side of the helical blade (1), and its hole diameter is It is 4mm-8mm. 3. A self-drilling screw bolt according to claim 1, characterized in that, the slurry outlet hole (2) is a slurry outlet pipe welded on the bolt body (3), and is arranged on the helical blade (1) On the rear side, the slurry outlet pipe is a straight pipe or a tapered pipe, and the diameter of the nozzle is 8mm-12mm. 4. A self-drilling screw bolt according to claim 1, 2 or 3, characterized in that, the bolt body (3) is a seamless threaded steel pipe, and its front end is provided with at least one helical blade ( 1), the spiral blade (1) is 10cm-15cm away from the front end of the anchor rod body (3); the distance between the spiral blades (1) is 25cm-35cm, and the distance between the spiral blade (1) and the anchor rod body (3) The included angle of the spiral is between 28°-32°; a stirring plate (4) is arranged at 15cm-25cm behind the spiral blade (1). 5. A self-drilling screw bolt according to claim 4, characterized in that, the stirring pieces (4) are arranged staggeredly on the bolt body (3), at least 3 pieces are provided, and the stirring pieces ( 4) The distance between them is between 15cm-25cm, and the included angle with the anchor rod body (3) is between 40°-50°. 6. A self-drilling screw bolt according to claim 5, characterized in that, the rear end of the bolt body (3) is connected to the extended bolt (6) through a connecting sleeve (5). 7. A self-drilling helical bolt grouting stirring and solidifying construction process according to claim 1, characterized in that the grout is injected while the bolt body (3) is drilling, and the grouting is performed while drilling, so that The slurry is injected from the slurry hole (2) of the anchor rod body (3), and mixed with the soil cut by the front helical blade (1), and the stirring blade (4) arranged behind the helical blade (1) Stir the soil and cement slurry evenly, and form an irregular anchor after solidification. 8. The grouting-while-drilling stirring and curing construction process according to claim 7, characterized in that, the grouting-while-drilling pressure during the grouting is 2 Mpa-5Mpa, and the water-cement ratio of the grout is 0.45:1- 0.50:1.

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