Static pressure expansion chemical anchoring type anchor rod and construction method thereof

Abstract

The application provides a static pressure expansion chemical anchoring type anchor rod and a construction method thereof. The static pressure expansion chemical anchoring type anchor rod is composed of a chemical expansion inner core, a metal thin-wall outer cylinder and a concrete partition section. The static pressure expansion chemical anchoring type anchor rod is provided with a plurality of chemical expansion inner cores which are separated by the concrete partition section in the metal thin-wall outer cylinder. The anchor rod is placed in a pre-drilled hole, and a static pressure is applied at the tail part, so that the pre-fragmented outer wall of the chemical expansion inner core is extruded and deformed outward, and a bite effect is generated with the surrounding soil. Meanwhile, the static pressure crushes the chemical expansion inner core, and the chemical expansion inner core fragments, the metal thin-wall outer cylinder and the concrete partition section are cemented and fixed in the hole by a special chemical adhesive in the chemical inner core, so that the anchoring of the anchor rod is realized. The static pressure expansion chemical anchoring type anchor rod can be used in slope reinforcement engineering, excavation free face reinforcement and other engineering, effectively controls the stability of the slope, and is simple, fast and convenient to operate, and can save a large amount of construction material cost.

Description

Technical Field

[0001] This invention relates to a static pressure expansion chemical anchor bolt and its construction method, belonging to the technical fields of retaining structure reinforcement, foundation pit engineering and slope reinforcement. Background Technology

[0002] A landslide is a natural phenomenon in which soil or rock masses on a slope slide downhill, either as a whole or in parts, under the influence of gravity, due to factors such as river erosion, groundwater activity, rainwater soaking, earthquakes, and artificial slope cutting. The mechanism of a landslide is that the shear stress on a certain sliding surface exceeds the shear strength of that surface. The basic conditions for a landslide are that there is space for sliding in front of the slope and cutting surfaces on both sides. For example, in southwestern China, especially in the hilly and mountainous areas, the most basic topographical features are numerous mountains, steep slopes, loose soil structure, easy water accumulation, and gullies and rivers running through the mountains, cutting against them, thus forming numerous slopes and cutting surfaces with sufficient space for sliding. The basic conditions for landslides are widespread, and landslide disasters are quite frequent. In urban construction, the protection of excavated soil such as foundation pits and trenches, whether temporary or semi-permanent, also involves the need for soil anchoring. Chemical anchors are a new type of anchor that emerged after expansion anchors. They are composite components that use a special chemical adhesive to bond the bolt to a drilled hole in a concrete substrate, thus achieving anchoring of the fixed component. Existing technologies, within a certain price range, cannot achieve a sufficiently strong bond between the anchor and the soil. Therefore, there is a need to invent a hydrostatic expansion chemical anchor and a corresponding construction method. Summary of the Invention

[0003] Purpose of the invention: The first purpose of this invention is to provide a hydrostatic expansion chemical anchor bolt, and the second purpose of this invention is to provide a construction method for the hydrostatic expansion chemical anchor bolt.

[0004] Technical solution: The present invention discloses a hydrostatic expansion chemical anchor bolt, which includes a chemical expansion inner core, a thin-walled metal outer cylinder, and concrete partition sections. Multiple chemical expansion inner cores separated by concrete partition sections are arranged inside the thin-walled metal outer cylinder. Each chemical expansion inner core contains a chemical tube. The chemical expansion inner core can deform or break the thin-walled metal to achieve anchoring.

[0005] The chemically expanded inner core is made of a metal slotted tube. The inner wall has a milled ring along the middle section and evenly distributed milled grooves along the axial direction of the inner wall. Only a thin layer of metal is left to connect them. The milled ring and milled grooves form the pre-fragments of the chemically expanded inner core.

[0006] The chemical expansion core also contains a chemical drug tube.

[0007] The chemical tube is sealed with glass and contains vinyl resin, quartz particles, and a curing agent.

[0008] The thin-walled metal outer cylinder is a circular tube made of a highly malleable metal material with a closed top.

[0009] The static pressure expansion chemical anchor bolt has two or more chemical expansion cores.

[0010] The length of the chemically expanded core is determined based on the frictional resistance between the slope soil and the anchor. When the frictional resistance is large, the length of the chemically expanded core is small, and when the frictional resistance is small, the length of the chemically expanded core is large. The length of the chemically expanded core is sufficient to achieve the anchoring force required by the design. The length of the concrete partition is the total length of the anchor minus the length of the chemically expanded core.

[0011] The construction method of the hydrostatic expansion chemical anchor bolt of the present invention includes the following steps:

[0012] (1) Based on the slope shape and soil parameters, the slope stability limit equilibrium method is used to determine the location of the slope surface that needs to be anchored and the potential sliding surface, and to determine the installation location and depth of the static pressure expansion chemical anchor bolt.

[0013] (2) Drill holes in advance at the locations where anchoring is required, and clean the holes;

[0014] (3) Multiple chemically expanded inner cores are inserted into a thin-walled metal outer cylinder, separated by a concrete partition, and the static pressure expansion chemical anchor bolts are placed into the drilled holes.

[0015] (4) Apply static pressure to the tail of the hydrostatic expansion chemical anchor bolt, squeeze the pre-fragments of the chemical expansion core outward radially, crush the chemical tubes in the chemical expansion core, and continue to apply static pressure until the chemical agent solidifies, thus completing one hydrostatic anchor bolt and forming a hydrostatic anchor bolt.

[0016] (5) Continue to insert the hydrostatic expansion chemical anchor bolt for hydrostatic pressure again, repeat steps (4) and (5) until the drilled hole is filled.

[0017] In step (2), the thin-walled metal outer cylinder is a round tube made of a highly malleable metal material with a closed top. When the chemical expansion inner core pre-fractured piece is extruded radially outward, the thin-walled metal outer cylinder is pushed out and deformed or ruptured, forming an interlock with the surrounding soil.

[0018] In step (3), the concrete partition section is a concrete segment used to separate the chemically expanded inner core within the thin-walled metal outer cylinder during the filling process. The filling volume of the concrete segment is calculated based on the length of the concrete segment and the diameter of the anchor bolt. The length of the concrete segment needs to be determined according to the actual soil conditions of the site. For sites with poor soil conditions (lower cohesion, internal friction angle, and density), the concrete segment length should be smaller, and vice versa.

[0019] In step (4), during static pressing, the chemical expansion core will bulge outward radially after static pressing, and its length will decrease. Therefore, after the first static pressing, if the hole is not filled, a shorter static expansion chemical anchor rod will be inserted for static pressing again. Thus, steps (4) and (5) are repeated until the hole is filled.

[0020] In step (1), the slope is a slope with a low stability safety factor that needs to be reinforced to increase stability, and the soil parameters of the slope are lower than the parameter values ​​required for slope stability.

[0021] In step (1), the anchoring location is determined based on whether the slope stability can meet the design requirements. Based on the survey data and the physical and mechanical parameters of the slope soil, static pressure expansion chemical anchoring rods are installed at locations where the slope stability design requirements cannot be met. The installation depth is required to penetrate to the potential sliding surface depth of the slope.

[0022] This invention relates to a hydrostatic expansion chemical anchor bolt, comprising a chemically expanded inner core, a thin-walled metal outer cylinder, and concrete partitions. Multiple chemically expanded inner cores are housed within the thin-walled metal outer cylinder, separated by concrete partitions. This hydrostatic expansion chemical anchor bolt is used in the reinforcement of rocky or soil slopes prone to landslides. Multiple chemically expanded inner cores are placed within the thin-walled metal outer cylinder, separated by concrete partitions. The anchor bolt is inserted into a pre-drilled hole in the soil, and hydrostatic pressure is applied to its tail. This causes the pre-fragmented outer walls of the chemically expanded inner core to deform outwards, interlocking with the surrounding soil. Simultaneously, the hydrostatic pressure crushes the chemically expanded inner core. A specially formulated chemical adhesive within the chemically expanded inner core bonds and fixes the fragments of the chemically expanded inner core to the thin-walled metal outer cylinder and concrete partitions within the drilled hole, thus achieving anchoring.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0024] This invention utilizes the mechanical interlocking effect of fragment anchoring combined with the anchoring force generated by chemical consolidation. Multiple chemically expanded inner cores are set within a thin-walled metal outer cylinder, separated by concrete partitions, resulting in a static pressure expansion chemical anchor bolt. Used in reinforcement projects for rocky or soil slopes prone to landslides, static pressure is applied at the tail end, causing the pre-fragmented outer walls of the chemically expanded inner cores to deform outwards, interlocking with the surrounding soil. Simultaneously, the static pressure crushes the chemically expanded inner cores. A specially formulated chemical adhesive within the inner cores bonds the chemically expanded inner core fragments to the thin-walled metal outer cylinder and concrete partitions, fixing them in place within the drilled hole, thus achieving anchoring. It can be used in slope reinforcement projects, excavation face reinforcement, and other similar projects, effectively controlling slope stability. Modular prefabrication makes operation simple, quick, and convenient. Attached Figure Description

[0025] Figure 1 A schematic diagram of a chemically expanded core;

[0026] Figure 2 A schematic diagram of the combination of a hydrostatically expanded chemical core and a concrete partition section;

[0027] Figure 3 This is a schematic diagram of the chemically expanded core after hydrostatic deformation.

[0028] Figure 4 This is a schematic diagram showing the anchorage formed after static pressure.

[0029] Figure 5 This is a schematic diagram of the construction of a hydrostatic expansion chemical anchor bolt.

[0030] Figure 6 This is a schematic diagram showing the static pressure anchor bolts formed after construction is completed. Detailed implementation method:

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0032] Example 1

[0033] like Figure 1-2 As shown, the hydrostatic expansion chemical anchor bolt of this invention comprises three parts: a chemically expanded inner core 1, a thin-walled metal outer cylinder 5, and a concrete partition section 6. Three sections of the chemically expanded inner core 1 are installed within the thin-walled metal outer cylinder 5, separated by the concrete partition section 6. The diameter of the thin-walled metal outer cylinder 5 is the designed anchor bolt diameter. The chemically expanded inner core 1 is tightly fitted into the thin-walled metal outer cylinder 5. The length of the chemically expanded inner core 1 is the designed length that meets the anchoring force requirements. The length of the concrete partition section 6 is the total anchor bolt length minus the length of the chemically expanded inner core.

[0034] The chemical expansion core 1 is made of a metal slotted tube. The inner wall of the metal slotted tube has a milled ring 2 along the middle section and evenly distributed milled grooves along the axial direction of the inner wall. Only a thin layer of metal is left to connect them. The milled ring 2 and the milled grooves complete the pre-fragment 3 of the chemical expansion core 1. At the same time, a chemical tube 4 is also sandwiched in the chemical expansion core 1. The chemical tube 4 is sealed with glass and contains vinyl resin, quartz particles, curing agent and other agents.

[0035] Among them, the thin-walled metal outer cylinder 5 is a round tube made of highly malleable metal material with a closed top. It can be made of materials such as aluminum alloy. When the pre-fractured pieces 3 of the chemical expansion inner core 1 are extruded radially outward, the thin-walled metal outer cylinder 5 is pushed out and deformed or ruptured, forming an interlock with the surrounding soil.

[0036] The concrete dividing section 6 is a concrete section used to divide the chemically expanded inner core 1 in the thin-walled outer cylinder 5 when filling it into the thin-walled outer cylinder 5. Its length is the total length of the anchor rod minus the length of the chemically expanded inner core.

[0037] The construction method of the static pressure expansion chemical anchor bolt of the present invention:

[0038] like Figure 3-6 As shown:

[0039] (1) Based on the slope shape and soil parameters, the location of the slope surface to be anchored and the potential sliding surface 7 are determined by the limit equilibrium method, and the installation location and depth of the static pressure expansion chemical anchor bolt are determined.

[0040] (2) Drill holes 8 in advance at the locations where anchoring is required, and clean the holes 8.

[0041] (3) Multiple chemical expansion inner cores 1 are spaced into the thin-walled metal outer cylinder 5, separated by a concrete partition 6, and the static pressure expansion chemical anchoring anchor is placed into the drilled hole.

[0042] (4) Apply static pressure to the tail of the static pressure expansion chemical anchor bolt, squeeze the pre-fragment 3 of the chemical expansion core 1 outward along the radial direction, crush the chemical tube 4 in the chemical expansion core 1 at the same time, and continue to apply static pressure until the chemical agent in the chemical tube 4 is solidified, thus completing one static pressure anchoring and forming a static pressure anchor bolt 9.

[0043] (5) Continue to insert the hydrostatic expansion chemical anchor bolt for hydrostatic pressure again, repeat steps (4) and (5) until the drilled hole is filled.

[0044] Example 2

[0045] For a certain slope project, the slope height is 11m and the slope angle is 60°. Based on the site survey data and indoor geotechnical tests, the weight of the slope soil is 1950 kg / m³.3 With a cohesion of 20 kPa and an internal friction angle of 26°, the slope safety factor before reinforcement was 1.43 according to the slope stability calculation results. After conventional anchor reinforcement with a horizontal and vertical spacing of 2 m and a depth penetrating to the potential sliding surface of the slope, the slope safety factor increased to 1.62. However, after reinforcement with the static pressure expansion chemical anchor bolts described in Example 1 of this invention, the slope safety factor increased to 1.75. It can be seen that the slope stability safety factor is significantly improved after reinforcement with the static pressure expansion chemical anchor bolts of this invention.

Claims

1. A hydrostatic expansion chemical anchor bolt, characterized in that, The static pressure expansion chemical anchor bolt includes a chemical expansion inner core (1), a thin-walled metal outer cylinder (5), and a concrete partition section (6). Multiple chemical expansion inner cores (1) separated by concrete partition sections (6) are set inside the thin-walled metal outer cylinder (5). A chemical tube (4) is sandwiched inside the chemical expansion inner core (1). The chemical expansion inner core (1) can deform or break the thin-walled metal outer cylinder (5) to achieve anchoring. The chemical expansion inner core (1) is made of a metal seam tube. The inner wall of the metal seam tube has a milling ring (2) along the middle section. The inner wall is provided with evenly distributed milling grooves, with only a thin layer of metal connected. The milling ring (2) and the milling grooves form the pre-fragments (3) of the chemical expansion inner core.

2. The hydrostatic expansion chemical anchor bolt according to claim 1, characterized in that, A chemical tube (4) is also sandwiched inside the chemical expansion core (1).

3. The hydrostatic expansion chemical anchor bolt according to claim 1, characterized in that, The chemical tube (4) is sealed with glass and contains vinyl resin, quartz particles and curing agent.

4. The hydrostatic expansion chemical anchor bolt according to claim 1, characterized in that, The thin-walled metal outer cylinder (5) is a round tube made of a highly malleable metal material with a closed top.

5. The hydrostatic expansion chemical anchor bolt according to claim 1, characterized in that, The number of chemically expanded inner cores (1) in the static pressure expansion chemical anchor bolt is more than two.

6. The hydrostatic expansion chemical anchor bolt according to claim 1, characterized in that, The length of the chemically expanded inner core (1) is determined based on the frictional resistance between the slope soil and the anchor. When the frictional resistance is large, the length of the chemically expanded inner core (1) is small, and when the frictional resistance is small, the length of the chemically expanded inner core is large. The length of the chemically expanded inner core (1) is sufficient to achieve the anchoring force required by the design. The length of the concrete dividing section (6) is the total length of the anchor minus the length of the chemically expanded inner core (1).

7. The construction method of the hydrostatic expansion chemical anchor bolt according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Based on the slope shape and soil parameters, the slope stability limit equilibrium method is used to determine the location of the slope surface that needs to be anchored and the potential sliding surface (7), and to determine the installation location and depth of the static pressure expansion chemical anchor bolt. (2) Drill holes (8) in advance at the locations where anchoring is required, and clean the holes (8). (3) Insert multiple chemically expanded inner cores (1) into the thin-walled metal outer cylinder (5) at intervals, separated by a concrete partition section (6) in the middle, and put the static pressure expansion chemical anchor bolt into the drilled hole. (4) Apply static pressure to the tail of the hydrostatic expansion chemical anchor bolt, squeeze the pre-fragment (3) of the chemical expansion core (1) outward radially, and crush the chemical tube (4) inside the chemical expansion core (1). Continue to apply static pressure until the chemical agent inside the chemical tube (4) solidifies, complete one hydrostatic anchoring, and form a hydrostatic anchor bolt (9). (5) Continue to insert the hydrostatic expansion chemical anchor bolt for hydrostatic pressure again, repeat steps (4) and (5) until the drilled hole is filled.

8. The construction method according to claim 7, characterized in that, In step (1), the slope is a slope with a low stability safety factor that needs to be reinforced to increase stability, and the soil parameters of the slope are lower than the parameter values ​​required for slope stability.

9. The construction method according to claim 7, characterized in that, In step (1), the anchoring location is determined based on whether the slope stability can meet the design requirements. Based on the survey data and the physical and mechanical parameters of the slope soil, static pressure expansion chemical anchoring rods are installed at locations where the slope stability design requirements cannot be met. The installation depth is required to penetrate the potential sliding surface of the slope.

Images