Initial support combined type anchor rod

Abstract

The invention provides a preliminary bracing combined type anchor rod which comprises a reinforcement cage, an isolation ring of the reinforcement cage is a thick-wall steel pipe with the inner diameter of 50 mm, one ring is welded to a longitudinal steel bar and a positioning steel bar in the longitudinal direction per meter, and a construction method of the combined type anchor rod comprises the following steps that (1) after a drilling machine is in place, measurement positioning and drilling are conducted; (2) a combined type anchor rod and a grouting pipe are installed, the combined type anchor rod is hoisted through a simple supporting frame, the first section of the combined type anchor rod slowly falls into a pile hole to be in place after being hoisted through manual cooperation, it is guaranteed that the elevation and perpendicularity of a supporting system are correct by means of self-weight, steel bars are lengthened through a connector every time the combined type anchor rod is placed at the position of a steel bar connector, and grouting is conducted; the steel bar connection needs to meet design and corresponding specification requirements; and (3) slurry is prepared, grouting is carried out, and slurry is supplemented for multiple times. The foundation reinforced through the method has good uniformity and self-supporting performance.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, in particular to an initial support composite anchor rod. Background Art

[0002] Anchor rods are the most basic component of contemporary tunnel support. They reinforce the surrounding rock of the tunnel so that the surrounding rock can support itself. Anchor rods are not only used in mines, but also in engineering technology to reinforce the main body of slopes, tunnels, and dams. As a tensile member that penetrates deep into the stratum, one end of the anchor rod is connected to the engineering structure, and the other end penetrates deep into the stratum. The entire anchor rod is divided into a free section and an anchoring section. The free section refers to the area where the tension at the anchor rod head is transmitted to the anchor body. Its function is to apply prestress to the anchor rod. However, the current anchor rod support range is small, and the construction cost is high. Summary of the invention

[0003] The technical problem solved by the present invention is to provide an initial support composite anchor rod to solve the problems raised in the above background technology.

[0004] The technical problem solved by the present invention is achieved by the following technical solution: an initial support composite anchor rod, comprising: a steel cage, wherein the steel cage isolation ring is a thick-walled steel pipe with an inner diameter of 50 mm, and one ring is welded to the longitudinal steel bars and the positioning steel bars per meter in the longitudinal direction. The composite anchor rod construction method comprises the following steps:

[0005] Step (1). After the drilling rig is in place, measurement, positioning and drilling are performed;

[0006] Step (2). Install the composite anchor and grouting pipe. The composite anchor is suspended by a simple support frame. The first section is lifted manually and then slowly dropped into the pile hole. The elevation and verticality of the support system are ensured to be correct by self-weight. Each time it is placed in a steel bar connector position, the connector is used to connect the long steel bar. The steel bar connection should meet the design and corresponding specification requirements.

[0007] Step (3): prepare slurry, perform grouting and make up slurry multiple times.

[0008] Furthermore, the composite anchor rod should be prevented from twisting and bending during hoisting, aligned with the hole position during installation, hoisted straight and steady, lowered slowly to avoid collision with the hole wall, and fixed immediately after being in place.

[0009] Furthermore, the grouting pipe is lowered at the same time as the composite anchor rod is placed, and the length of the grouting pipe section is 3 to 6 meters. The grouting pipe is a φ20mm seamless steel pipe, and the connection is a threaded connection.

[0010] Furthermore, before the composite anchor pile drilling construction, grouting reinforcement is performed on the soil 4m below the ground surface within the anchor pile driving range to prevent the collapse of the hole from affecting the existing buildings and structures. The grouting pipe adopts a DN32*2.75 small conduit with a plum blossom-shaped 1.0m*1.0m layout. The grouting material uses cement single-liquid slurry. The diffusion radius of the slurry is 750mm, and the grouting pressure is controlled within 0.2MP. The grouting pressure should be strictly controlled during construction to avoid excessive pressure from causing damage to surrounding buildings and pipelines.

[0011] Furthermore, the foundation reinforced with the composite anchor rods should have good uniformity and self-sustaining properties. The grouting effect should be tested in time after the grouting is completed. Its unconfined compressive strength should not be less than 0.8Mpa, and the permeability coefficient should be ≤1.0e-6cm / s.

[0012] Furthermore, the calculation formula for the grouting volume of a single hole of the composite anchor is as follows: Q = πR 2 Lηαβ, where: Q is the grouting volume of a single hole in m3; R is the diffusion radius of the slurry; η is the formation porosity; α is the effective filling coefficient of the slurry in the formation, 0.7 to 0.9; β is the slurry loss, which is 1.0 to 1.2; L is the grouting length in m.

[0013] Furthermore, the drilling is performed by dry drilling with a fully hydraulic anchor drill rig, each drill rod is 1.5 meters long, and the drilling is performed while the earth is being dug out. After the drilling is completed, the steel cage and grouting pipe are promptly placed, and cement slurry is injected at the same time.

[0014] Furthermore, during the grouting reinforcement, grouting begins after the drill rod is pulled out and the steel bars are lowered. Three grouting pipes are used for grouting. The material of the grouting pipes is φ20mm plastic pipe. The first grouting pipe is not provided with a slurry outlet hole, and the slurry is directly discharged from the bottom of the pipe. The second and third grouting pipes are provided with 4 φ4mm slurry outlet holes, and the four holes are vertically staggered by 150mm.

[0015] Compared with the prior art, the beneficial effects of the present invention are: the reinforced foundation of the present invention has good uniformity and self-sustainability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the construction process of the present invention. DETAILED DESCRIPTION

[0017] In order to make the technical means for realizing the present invention, the creative features, the objectives and effects to be achieved easy to understand, the present invention is further explained below in conjunction with specific diagrams. In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection, or an integral connection can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two elements.

[0018] Example 1

[0019] like Figure 1 As shown, an initial support composite anchor bolt comprises: a steel cage, wherein the steel cage isolation ring is a thick-walled steel pipe with an inner diameter of 50 mm, and one ring is welded to the longitudinal steel bars and the positioning steel bars per meter in the longitudinal direction. The composite anchor bolt construction method comprises the following steps:

[0020] Step (1). After the drilling rig is in place, measurement, positioning and drilling are performed;

[0021] Step (2). Install the composite anchor and grouting pipe. The composite anchor is suspended by a simple support frame. The first section is lifted manually and then slowly dropped into the pile hole. The elevation and verticality of the support system are ensured to be correct by self-weight. Each time it is placed in a steel bar connector position, the connector is used to connect the long steel bar. The steel bar connection should meet the design and corresponding specification requirements.

[0022] Step (3). Prepare slurry, perform grouting and multiple grouting. The composite anchor rod should be prevented from twisting and bending during lifting. It should be aligned with the hole position during installation, lifted straight and steady, and lowered slowly to avoid collision with the hole wall. It should be fixed immediately after it is in place. The grouting pipe is lowered at the same time as the composite anchor rod is placed. The length of the grouting pipe section is 3 to 6 meters. The grouting pipe adopts φ20mm seamless steel pipe, and the connection adopts threaded connection.

[0023] Example 2

[0024] like Figure 1 As shown, an initial support composite anchor bolt comprises: a steel cage, wherein the steel cage isolation ring is a thick-walled steel pipe with an inner diameter of 50 mm, and one ring is welded to the longitudinal steel bars and the positioning steel bars per meter in the longitudinal direction. The composite anchor bolt construction method comprises the following steps:

[0025] Step (1). After the drilling rig is in place, measurement, positioning and drilling are performed;

[0026] Step (2). Install the composite anchor and grouting pipe. The composite anchor is suspended by a simple support frame. The first section is lifted manually and then slowly dropped into the pile hole. The elevation and verticality of the support system are ensured to be correct by self-weight. Each time it is placed in a steel bar connector position, the connector is used to connect the long steel bar. The steel bar connection should meet the design and corresponding specification requirements.

[0027] Step (3): prepare slurry, perform grouting and make up slurry multiple times.

[0028] Before the composite anchor pile drilling construction, the soil 4m below the ground surface within the anchor pile driving range is grouting reinforced to prevent the collapse of the hole from affecting the existing buildings and structures. The grouting pipe uses a DN32*2.75 small conduit, a plum blossom-shaped 1.0m*1.0m layout, and cement single-liquid slurry. The diffusion radius of the slurry is 750mm. The grouting pressure is controlled within 0.2MP. The grouting pressure should be strictly controlled during construction to avoid excessive pressure from causing damage to surrounding buildings and pipelines. The foundation reinforced by the composite anchor should have good uniformity and self-sustaining properties. After the grouting is completed, the grouting effect should be tested in time. Its unconfined compressive strength should not be less than 0.8Mpa, and the permeability coefficient is ≤1.0e-6cm / s.

[0029] Example 3

[0030] like Figure 1 As shown, an initial support composite anchor bolt comprises: a steel cage, wherein the steel cage isolation ring is a thick-walled steel pipe with an inner diameter of 50 mm, and one ring is welded to the longitudinal steel bars and the positioning steel bars per meter in the longitudinal direction. The composite anchor bolt construction method comprises the following steps:

[0031] Step (1). After the drilling rig is in place, measurement, positioning and drilling are performed;

[0032] Step (2). Install the composite anchor and grouting pipe. The composite anchor is suspended by a simple support frame. The first section is lifted manually and then slowly dropped into the pile hole. The elevation and verticality of the support system are ensured to be correct by self-weight. Each time it is placed in a steel bar connector position, the connector is used to connect the long steel bar. The steel bar connection should meet the design and corresponding specification requirements.

[0033] Step (3): prepare slurry, perform grouting and make up slurry multiple times.

[0034] The calculation formula for the single hole grouting volume of the composite anchor is as follows: Q = πR 2 Lηαβ

[0035] Q—single hole grouting volume m3;

[0036] R—slurry diffusion radius; (take 750mm);

[0037] η—formation porosity (0.4 is used);

[0038] α—Effective filling coefficient of slurry in the formation 0.7~0.9; (0.8 in this scheme)

[0039] β—Slurry loss, take 1.0~1.2; (take 1.2 in this scheme)

[0040] L—grouting length m; (4m)

[0041] Q=π×0.752×4×0.4×0.8×1.2×2.71m 3 .

[0042] Example 4

[0043] like Figure 1 As shown, an initial support composite anchor bolt comprises: a steel cage, wherein the steel cage isolation ring is a thick-walled steel pipe with an inner diameter of 50 mm, and one ring is welded to the longitudinal steel bars and the positioning steel bars per meter in the longitudinal direction. The composite anchor bolt construction method comprises the following steps:

[0044] Step (1). After the drilling rig is in place, measurement, positioning and drilling are performed;

[0045] Step (2). Install the composite anchor and grouting pipe. The composite anchor is suspended by a simple support frame. The first section is lifted manually and then slowly dropped into the pile hole. The elevation and verticality of the support system are ensured to be correct by self-weight. Each time it is placed in a steel bar connector position, the connector is used to connect the long steel bar. The steel bar connection should meet the design and corresponding specification requirements.

[0046] Step (3): prepare slurry, perform grouting and make up slurry multiple times.

[0047] The drilling process is to use a fully hydraulic anchor drill to dry drill holes. Each drill rod is 1.5 meters long, and the holes are excavated while drilling. After the drilling is completed, the steel cage and grouting pipe are placed in time, and cement slurry is injected at the same time. The drilling should be carried out strictly in accordance with the design parameters. The hole position and angle deviation of the drilling hole meet the relevant specifications. If the hole position of the on-site drilling cannot meet the design requirements due to objective conditions, it should be shifted and the parameters should be calculated to determine. If necessary, the hole should be supplemented. During the drilling construction process, the drilling rig should be stabilized and drilled steadily. It is required to have experienced drill operators to operate, and inexperienced novices should not operate rashly. Before each shift, the mechanical equipment should be inspected, and it is strictly forbidden to operate the machine with defects; at the same time, the drilling tools should be inspected, and drill rods and drill bits with good quality and performance should be used. It is strictly forbidden to use defective drilling tools. The slag in the hole is uniformly transported to the slag bin of the site by electric tricycles. When excavating, pay attention to prevent pollution of the road surface.

[0048] Example 5

[0049] like Figure 1As shown, an initial support composite anchor bolt comprises: a steel cage, wherein the steel cage isolation ring is a thick-walled steel pipe with an inner diameter of 50 mm, and one ring is welded to the longitudinal steel bars and the positioning steel bars per meter in the longitudinal direction. The composite anchor bolt construction method comprises the following steps:

[0050] Step (1). After the drilling rig is in place, measurement, positioning and drilling are performed;

[0051] Step (2). Install the composite anchor and grouting pipe. The composite anchor is suspended by a simple support frame. The first section is lifted manually and then slowly dropped into the pile hole. The elevation and verticality of the support system are ensured to be correct by self-weight. Each time it is placed in a steel bar connector position, the connector is used to connect the long steel bar. The steel bar connection should meet the design and corresponding specification requirements.

[0052] Step (3): prepare slurry, perform grouting and make up slurry multiple times.

[0053] During the grouting reinforcement, grouting begins after the drill rod is pulled out and the steel bars are lowered. Three grouting pipes are used for grouting. The material of the grouting pipes is φ20mm plastic pipe. No slurry outlet holes are set in the first grouting pipe, and slurry is discharged directly from the bottom of the pipe. Four φ4mm slurry outlet holes are set in the second and third grouting pipes, and the four holes are vertically staggered by 150mm.

[0054] When the grouting pipe is installed vertically, the end of the first grouting pipe is not closed, and the ends of the second and third grouting pipes are closed. The ends of the first and third grouting pipes are 0.1m away from the bottom of the hole. The second grouting pipe is L / 4m shorter than the first and third ones. When grouting the first pipe, the slurry holes of the second and third pipes are isolated with plastic tape to prevent the slurry from sealing the slurry holes during grouting.

[0055] Before grouting construction, 1-2 hole grouting tests should be carried out on site to check and adjust the grouting parameters. Attention should be paid to adjusting the slurry ratio and pressure to ensure that the grouting achieves a good grouting effect. Subsequent grouting construction should be carried out according to the parameters obtained from the grouting test.

[0056] In order to achieve the purpose of grouting consolidation, the slurry needs to be prepared in a certain order.

[0057] Cement slurry dilution: Add the required amount of water to the mixing barrel each time, start the mixer, then add cement and stir for more than 3 minutes. Strictly follow the ratio when preparing the slurry.

[0058] Grouting pump trial run: After confirming that all parts of the grouting system are correctly connected, start the grouting pump for water pressure test to check the hydraulic condition of the grouting pump, whether there is any leakage in the system pipeline, and whether the pipeline is unobstructed.

[0059] Slurry injection: The grouting construction adopts compaction grouting, and the grouting is divided into three times: the first grouting adopts normal pressure grouting with a grouting pressure of 0.2~0.5MPa. The grouting is ended when the hole overflows, and the water-cement ratio of cement slurry is 1:1; the second grouting adopts medium-high pressure grouting with a grouting pressure of 0.5~1.0MPa. It is carried out 10~15 hours after the first grouting, and the water-cement ratio of cement slurry is 1:1; the third grouting pressure is 1.0~1.5MPa, which is carried out 5~10 hours after the second grouting, and the water-cement ratio of cement slurry is 1:1.

[0060] The reinforced foundation should have good uniformity and self-sustaining properties, with an unconfined compressive strength of 1.0-1.2Mpa and a permeability coefficient of ≤1.0e-6cm / s. After the reinforcement construction is completed, the reinforced body must be cored to ensure the grouting effect.

[0061] Pressure and grouting volume control: Observe the grouting pressure through the pressure gauge and check the pressure change with the increase of grouting volume. Two-way control is adopted during the grouting process, that is, stop grouting after reaching the designed grouting volume; or stop grouting after abnormal conditions occur when the designed grouting volume is not reached but the designed grouting pressure is reached.

[0062] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An initial support composite anchor, characterized in that: include: The steel cage, the steel cage isolation ring is a thick-walled steel pipe with an inner diameter of 50 mm, one ring per meter in the longitudinal direction is welded with the longitudinal steel bars and the positioning steel bars. The composite anchor construction method includes the following steps: Step (1). After the drilling rig is in place, measurement, positioning and drilling are performed; Step (2). Install the composite anchor and grouting pipe. The composite anchor is suspended by a simple support frame. The first section is lifted manually and then slowly dropped into the pile hole. The elevation and verticality of the support system are ensured to be correct by self-weight. Each time it is placed in a steel bar connector position, the connector is used to connect the long steel bar. The steel bar connection should meet the design and corresponding specification requirements. Step (3): prepare slurry, perform grouting and make up slurry multiple times.

2. The composite anchor bolt for initial support according to claim 1, characterized in that: The composite anchor rod should be prevented from twisting and bending during hoisting. During installation, it should be aligned with the hole position, hoisted straight and held steady, and lowered slowly to avoid collision with the hole wall. It should be fixed immediately after being in place.

3. The initial support composite anchor according to claim 1, characterized in that: The grouting pipe is lowered simultaneously with placing the composite anchor rod, and the length of the grouting pipe section is 3 to 6 meters. The grouting pipe is made of φ20mm seamless steel pipe and the connection is made of threaded connection.

4. The initial support composite anchor according to claim 1, characterized in that: Before the composite anchor pile drilling construction, grouting reinforcement is carried out on the soil 4m below the ground surface within the anchor pile driving range to prevent the collapse of the hole from affecting the existing buildings and structures. The grouting pipe adopts a DN32*2.75 small conduit with a plum blossom-shaped 1.0m*1.0m layout. The grouting material is cement single-liquid slurry. The diffusion radius of the slurry is 750mm. The grouting pressure is controlled within 0.2MP. The grouting pressure should be strictly controlled during construction to avoid excessive pressure from causing damage to surrounding buildings and pipelines.

5. The initial support composite anchor according to claim 1, characterized in that: The foundation reinforced with the composite anchor rods should have good uniformity and self-sustaining properties. The grouting effect should be tested in time after the grouting is completed. The unconfined compressive strength should not be less than 0.8Mpa, and the permeability coefficient should be ≤1.0e-6cm / s.

6. The initial support composite anchor according to claim 1, characterized in that: The calculation formula for the single hole grouting volume of the composite anchor is as follows: Q = πR 2 Lηαβ, where: Q is the grouting volume of a single hole in m3; R is the diffusion radius of the slurry; η is the formation porosity; α is the effective filling coefficient of the slurry in the formation, 0.7 to 0.9; β is the slurry loss, which is 1.0 to 1.2; L is the grouting length in m.

7. The initial support composite anchor according to claim 1, characterized in that: The drilling process adopts a fully hydraulic anchor drilling rig to dry drill the hole. Each drill rod is 1.5 meters long. The hole is drilled in and out of the earth at the same time. After the drilling is completed, the steel cage and grouting pipe are placed in time, and cement slurry is injected at the same time.

8. The initial support composite anchor according to claim 1, characterized in that: During the grouting reinforcement, grouting begins after the drill rod is pulled out and the steel bars are lowered. Three grouting pipes are used for grouting. The material of the grouting pipes is φ20mm plastic pipe. No slurry outlet holes are set in the first grouting pipe, and slurry is discharged directly from the bottom of the pipe. Four φ4mm slurry outlet holes are set in the second and third grouting pipes, and the four holes are vertically staggered by 150mm.

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