Internal supporting type grouting anchor rod and coarse particle soil slope grouting construction method

Abstract

The internal supporting type grouting anchor rod comprises a pushing rod, a drill bit and a pressing locking piece, a first liquid guiding channel is formed in the pushing rod, a first grouting hole is formed in the outer wall of the pushing rod, and an external expansion acting inclined face is formed at the connecting end of the pushing rod; a second liquid guide channel which is aligned and communicated with the first liquid guide channel is formed in the drill bit, a plurality of second grouting holes are formed in the outer wall of the drill bit in the circumferential direction, and an external expansion guide inclined plane which is bonded and connected with the external expansion acting inclined plane is formed at the connecting end of the drill bit; when the extrusion force applied between the pushing rod and the drill bit exceeds a preset value, the pushing rod moves relative to the drill bit, and the external expansion guide inclined plane guides the external expansion action inclined plane, so that the connecting end of the pushing rod expands outwards; the pressing locking piece is connected to the end, away from the drill bit, of the pushing rod. Compared with the prior art, the friction effect between the anchor rod and a soil body is increased, formation of an anchoring layer is facilitated, larger pre-tightening force can be conveniently applied to the anchor rod, and therefore a more stable pressure arch is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of slope construction, in particular to an internal support type grouting anchor rod and a coarse-grained soil slope grouting construction method. BACKGROUND

[0002] The stability control of coarse-grained soil slope has always been a problem in the field of geotechnical engineering because of the loose structure of the soil body and the weak inter-particle bonding force. Under the action of dynamic load or hydrology, such slope is prone to sliding instability. Grouting reinforcement is a common treatment method, but due to the large gap between coarse-grained soils, the existing anchor rod will guide the grout into the coarse-grained soil slope, and the grout will easily seep along the gap under the action of gravity, making it difficult to form an effective bonding layer between the coarse-grained soils, resulting in low friction between the coarse-grained soils and the anchor rod, and making it difficult to apply pre-tightening force to the surface of the coarse-grained soil slope, further reducing the anchoring effect of the anchor rod. SUMMARY

[0003] In view of the deficiencies in the prior art, the purpose of the present application is to provide an internal support type grouting anchor rod and a coarse-grained soil slope grouting construction method to solve the problem of poor anchoring effect of the anchor rod for coarse-grained soil slope in the prior art.

[0004] To achieve the above-mentioned purpose, the first aspect of the present application adopts the following technical solution: an internal support type grouting anchor rod, comprising:

[0005] a push rod, a first liquid guide channel is formed in the push rod along its axial direction, and a first grouting hole is formed in the outer wall of the push rod along its circumferential direction and axial direction, and the connecting end of the push rod is formed with an outward expansion inclined surface;

[0006] a drill bit, the drill bit has a second liquid guide channel for aligning and communicating with the first liquid guide channel, and a second grouting hole is arranged circumferentially on the outer wall of the drill bit and communicates with the second liquid guide channel, and the connecting end of the drill bit is formed with an outward expansion guide inclined surface bonded to the outward expansion inclined surface; when the extrusion force between the push rod and the drill bit exceeds a preset value, the push rod moves relative to the drill bit and the outward expansion guide inclined surface guides the outward expansion inclined surface so that the connecting end of the push rod expands outward;

[0007] a pressing locking member connected to the end of the push rod away from the drill bit.

[0008] The internal support type grouting anchor rod in use is:

[0009] The inner support type grouting anchor rod is rotated along the direction perpendicular to the coarse-grained soil slope until the drill bit is rotated into the solid soil layer after passing through the coarse-grained soil layer; the drill bit is subjected to greater friction resistance due to the increase in the density of the solid soil layer; when the friction resistance acting on the drill bit exceeds the bonding strength between the drill bit and the pushing rod, the drill bit is stuck in the solid soil layer and cannot move forward any more;

[0010] The pushing rod continues to rotate forward under the action of subsequent pushing force, the outer expansion guide slope of the drill bit guides the outer expansion action slope to make the connecting end of the pushing rod expand outward to form a radial expansion structure, and the installation of the anchor rod is completed;

[0011] The fast-drying cement slurry is injected into the pushing rod, and under the action of gravity and injection pressure, the slurry penetrates into the solid soil layer around the drill bit through the first and second liquid guide channels and the second grouting hole, and forms an anchoring layer after rapid solidification, and the second grouting hole is sealed; a small amount of fast-drying cement slurry may penetrate into the coarse-grained soil layer outside the middle part of the pushing rod from the first grouting hole;

[0012] The fast-drying cement slurry is continuously injected into the pushing rod, and the injection pressure is increased, the slurry penetrates into the coarse-grained soil layer outside the middle part of the pushing rod through the first liquid guide channel and the first grouting hole, and the slurry penetrates into the gap of the coarse-grained soil layer to form a seepage barrier;

[0013] The ordinary cement slurry is then injected into the pushing rod, and the slurry penetrates into the coarse-grained soil layer outside the middle part of the pushing rod through the first liquid guide channel and the first grouting hole; the slurry is solidified outside the middle part of the pushing rod to form an anti-sliding reinforcement layer because the fast-drying cement in the previous step has blocked the seepage channel of the slurry;

[0014] The compression locking member is locked on the end of the pushing rod exposed outside the coarse-grained soil slope, and the compression locking member is pre-tightened by the post-tensioning method; as the locking degree of the compression locking member increases, the anchor rod axial force gradually increases, and a pressure arch is formed between the anchoring layer, the anti-sliding reinforcement layer and the compression locking member, which improves the density of the soil and increases the mechanical friction between the coarse-grained soil, thereby improving the stability of the coarse-grained soil slope.

[0015] Further, the drill bit comprises:

[0016] The outer guide section gradually increases in diameter from one end to the other end so that the outer surface forms the outer expansion guide slope;

[0017] The drill bit action section gradually increases in diameter from one end to the other end and is connected to the large end of the outer guide section, the second liquid guide channel extends from the small end of the outer guide section to the inside of the drill bit action section in the axial direction of the outer guide section without penetrating through, and a plurality of second grouting holes are distributed on the drill bit action section.

[0018] Further, the pressing locking piece comprises:

[0019] Anchorage, which is detachably fixedly connected to the advancing rod;

[0020] A tray, which is movably sleeved on the advancing rod and located between the anchorage and the drill bit.

[0021] Further, the cross-sectional area of the tray along the direction of the tray surface is greater than the cross-sectional area of the anchorage along the direction of the tray surface.

[0022] Further, the end of the advancing rod connected with the drill bit is uniformly provided with a plurality of barbs.

[0023] The second aspect of the present application adopts the following technical solution: a coarse-grained soil slope grouting construction method, which is implemented by using a plurality of the internal bracing type grouting anchor rods as described in the first aspect of the present application and grouting, and comprises the following steps:

[0024] Step S1, anchor rod installation: a plurality of internal bracing type grouting anchor rods are distributed in an array and vertically rotated into the coarse-grained soil slope until the drill bit reaches the solid soil layer, and the end of the advancing rod connected with the drill bit is outwardly braced to form a radial expansion structure;

[0025] Step S2, layered grouting, which is implemented by the advancing rod to form an anchoring layer in the expansion area outside the drill bit and a skid-resistant reinforcing layer outside the middle section of the advancing rod;

[0026] Step S3, prestress construction, which is implemented by installing a pressing locking piece on the exposed end of the advancing rod outside the coarse-grained soil slope and applying an axial pretightening force to form a continuous pressure arch structure between the anchoring layer, the skid-resistant reinforcing layer and the pressing locking piece.

[0027] Further, the step S2 specifically comprises:

[0028] Step S21, low-pressure quick-drying cement grouting stage: injecting quick-drying cement slurry through the advancing rod under low pressure, and the slurry penetrates into the solid soil layer outside the drill bit through the second grouting hole to form an anchoring layer;

[0029] Step S22, high-pressure quick-drying cement grouting stage: continuing to inject quick-drying cement slurry under high pressure, and the slurry penetrates into the coarse-grained soil layer outside the middle section of the advancing rod through the first grouting hole to form an anti-seepage barrier;

[0030] Step S23, high-pressure reinforcing grouting stage: continuing to inject ordinary cement slurry under high pressure, and the slurry penetrates into the coarse-grained soil layer outside the middle section of the advancing rod through the first grouting hole to form a skid-resistant reinforcing layer.

[0031] Further, the low pressure is 0.2-0.5 MPa.

[0032] Furthermore, the high pressure is 1-2 MPa.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. When this internally braced grouting anchor is in use, the end of the push rod connected to the drill bit is pushed outward under the action of thrust, which increases the friction between the anchor and the soil, helps to form the anchoring layer, and makes it easier to apply a greater pre-tightening force to the anchor, thereby forming a more stable pressure arch.

[0035] 2. In this coarse-grained soil slope grouting construction method, a step-by-step grouting method is adopted to form an anchoring layer, a seepage barrier and an anti-sliding reinforcement layer in the coarse-grained soil slope in sequence. With the enhancement of the pre-tightening force on the anchor rod, a pressure arch is formed in the soil, which improves the stability of the coarse-grained soil slope.

[0036] 3. Using a step-by-step grouting method can effectively reduce the impact of grout seepage on the support effect. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of an internally supported grouting anchor rod according to an embodiment of the present invention;

[0038] Figure 2 for Figure 1 A schematic diagram of the structure after outward expansion to form a radially expanding structure;

[0039] Figure 3 for Figure 1 A schematic diagram of the structure formed within a coarse-grained soil slope;

[0040] Figure 4 This is a schematic diagram of the structure formed in a coarse-grained soil slope after the construction of a grouting method for a coarse-grained soil slope according to an embodiment of the present invention.

[0041] The reference numerals in the accompanying drawings include: push rod 101, first grouting hole 1021, second grouting hole 1022, barb 103, adhesive layer 104, drill bit 105, tray 106, anchor 107, anti-slip reinforcement layer 201, anchoring layer 202, pressure combination arch 300, tray pressure arch 301, and anchoring layer pressure arch 302. Detailed Implementation

[0042] The present invention will be further described in detail below through specific embodiments:

[0043] like Figure 1 and Figure 2As shown, the embodiment of the present application provides an inner support type grouting anchor rod, which comprises a pushing rod 101, a drill bit 105 and a pressing locking piece, the pushing rod 101 is formed with a first liquid guide channel in the axial direction thereof and the outer wall of the pushing rod 101 is formed with a plurality of first grouting holes 1021 which are in communication with the first liquid guide channel and are arranged in the circumferential direction and the axial direction of the pushing rod 101, and the connecting end of the pushing rod 101 is formed with an outward expansion action slope; the drill bit 105 is provided with a second liquid guide channel which is in communication with the first liquid guide channel and the outer wall of the drill bit 105 is circumferentially arranged with a plurality of second grouting holes 1022 which are in communication with the second liquid guide channel, and the connecting end of the drill bit 105 is formed with an outward expansion guide slope which is connected to the outward expansion action slope by bonding; when the extrusion force between the pushing rod 101 and the drill bit 105 exceeds a preset value, the pushing rod 101 moves relative to the drill bit 105 and the outward expansion guide slope guides the outward expansion action slope so that the connecting end of the pushing rod 101 is expanded outwardly; and the pressing locking piece is connected to the end of the pushing rod 101 which is away from the drill bit 105.

[0044] In order to better understand the present scheme, the structure of the drill bit 105 and the pressing locking piece will be optimized as follows.

[0045] First of all, the drill bit 105.

[0046] Among them, the drill bit 105 comprises an outer guide section and a drill bit 105 action section, the outer guide section gradually increases in diameter from one end to the other end thereof so that the outer surface thereof forms the outward expansion guide slope; the drill bit 105 action section gradually increases in diameter from one end to the other end thereof and the large end thereof is connected to the large end of the outer guide section, the second liquid guide channel extends from the small end of the outer guide section to the inside of the drill bit 105 action section in the axial direction of the outer guide section without penetrating through, and a plurality of second grouting holes 1022 are distributed on the drill bit 105 action section.

[0047] The drill bit 105 is composed of the outer guide section and the drill bit 105 action section, on the one hand, the drill bit 105 action section forms a sharp tip, which facilitates the easy rotation of the present inner support type grouting anchor rod into the soil body; on the other hand, the outer guide section is formed, which is guided by the outward expansion guide slope to the outward expansion action slope, so that the connecting end of the pushing rod 101 is expanded outwardly to form a radial expansion structure during use, thereby improving the friction between the present inner support type grouting anchor rod and the soil body, which is helpful for the formation of the anchoring layer 202 and facilitates the application of greater pre-tightening force to the anchor rod, thereby forming a more stable pressure arch.

[0048] Further, the outward expansion guide slope and the outward expansion action slope are connected by bonding through a bonding layer 104, and the strength of the bonding layer 104 can be selected according to the actual engineering.

[0049] Secondly, the pressing locking piece.

[0050] The pressing locking member comprises an anchor 107 and a tray 106, the anchor 107 is detachably fixedly connected to the advancing rod 101, in the embodiment, the anchor 107 is threadedly connected to the advancing rod 101; the tray 106 is movably sleeved on the advancing rod 101 and located between the anchor 107 and the drill bit 105.

[0051] The cross-sectional area of the tray 106 along the direction of the disc surface is greater than the cross-sectional area of the anchor 107 along the direction of the disc surface of the tray 106.

[0052] The advancing rod 101 is inserted through the tray 106, the tray 106 is anchored on the coarse-grained soil slope by the anchor 107 through the pre-tightening force, and the contact surface is increased through the tray 106, which is more conducive to the formation of the pressure arch.

[0053] In order to further improve the friction between the inner bracing type grouting anchor rod and the soil body, a plurality of barbs 103 are uniformly distributed on the end of the advancing rod 101 connected with the drill bit 105, which helps to form the anchoring layer 202 and facilitates the application of greater pre-tightening force to the anchor rod, thereby forming a more stable pressure arch.

[0054] The inner bracing type grouting anchor rod is used as follows:

[0055] The inner bracing type grouting anchor rod is rotated in the direction perpendicular to the coarse-grained soil slope, and the tray 106 is anchored on the surface of the coarse-grained soil slope until the drill bit 105 is rotated into the solid soil layer after penetrating the coarse-grained soil layer; due to the increase in the density of the solid soil layer, the drill bit 105 is subjected to greater frictional resistance; when the frictional resistance acting on the drill bit 105 exceeds the bonding strength of the adhesive layer 104, the drill bit 105 is clamped in the solid soil layer and cannot continue to move forward;

[0056] The advancing rod 101 continues to rotate forward under the action of subsequent thrust, and the outward expansion guide slope of the drill bit 105 guides the outward expansion of the connecting end of the advancing rod 101 to form a radial expansion structure (such as Figure 2 ) to complete the installation of the anchor rod;

[0057] The quick-drying cement slurry is injected into the advancing rod 101, and under the action of gravity and injection pressure, the slurry penetrates into the solid soil layer around the drill bit 105 through the first and second liquid channels and the second grouting hole 1022 after rapid solidification to form the anchoring layer 202, and the second grouting hole 1022 is sealed; a small amount of quick-drying cement slurry will penetrate into the coarse-grained soil layer outside the middle part of the advancing rod 101 from the first grouting hole 1021;

[0058] Continue to inject quick-drying cement grout into the push rod 101 and increase the injection pressure. After passing through the first liquid guiding channel, the grout seeps from the first grouting hole 1021 into the coarse-grained soil layer outside the middle of the push rod 101. The grout seeps into the gaps of the coarse-grained soil layer to seal and form a seepage barrier.

[0059] Next, ordinary cement grout is injected into the push rod 101. After passing through the first liquid guiding channel, the grout seeps into the coarse-grained soil layer outside the middle part of the push rod 101 through the first grouting hole 1021. Because the medium-speed dry cement in the previous step blocked the seepage channel of the grout, the grout solidifies outside the middle part of the push rod 101 and forms an anti-sliding reinforcement layer 201.

[0060] Anchor 107 is locked onto the exposed end of the push rod 101 outside the coarse-grained soil slope. A pre-tensioning force is applied to the anchor 107 using the post-tensioning method (an existing construction method in the building field, not described in detail here). As the tightness of the anchor 107 increases, the axial force of this internally braced grouting anchor gradually increases, forming a pressure arch (such as...) between the anchoring layer 202, the anti-slip reinforcement layer 201, and the pressing locking element. Figure 3 This increases the density of the soil, enhances the mechanical friction between coarse soil particles, and improves the stability of coarse soil slopes.

[0061] According to another embodiment of the present invention, the above-mentioned internally braced grouting anchor is applied to the grouting construction process of coarse-grained soil slopes, and the grouting construction method for coarse-grained soil slopes includes the following steps:

[0062] Step S1, Anchor installation: Several internally braced grouting anchors are arranged in an array and vertically screwed into the coarse-grained soil slope, and the tray 106 in each internally braced grouting anchor is anchored on the surface of the coarse-grained soil slope until the drill bit 105 reaches the solid soil layer, and the push rod 101 is connected to the drill bit 105 and one end is stretched outward to form a radial expansion structure.

[0063] Step S2: Layered grouting. Grouting is carried out in stages through the push rod 101. First, an anchoring layer 202 is formed in the expansion zone outside the drill bit 105, and then an anti-slip reinforcement layer 201 is formed outside the middle section of the push rod 101.

[0064] Step S3: Prestressed construction. A pressing and locking component is installed at the end of the exposed push rod 101 on the coarse-grained soil slope and an axial preload is applied to form a continuous pressure arch structure between the anchoring layer 202, the anti-sliding reinforcement layer 201, and the pressing and locking component.

[0065] Specifically, step S2 is as follows:

[0066] Step S21, Low-pressure quick-drying cement grouting stage: Quick-drying cement grout is injected through the push rod 101 under a pressure of 0.2-0.5MPa. The grout penetrates through the second grouting hole 1022 into the solid soil layer around the drill bit 105 to form the anchoring layer 202.

[0067] Step S22, High-pressure quick-drying cement grouting stage: Continue to inject quick-drying cement grout under a pressure of 1-2MPa. The grout penetrates through the first grouting hole 1021 to the coarse-grained soil layer around the middle of the push rod 101 to form a seepage barrier.

[0068] Step S23, High-pressure reinforcement grouting stage: Continue to inject ordinary cement grout under a pressure of 1-2 MPa. The grout penetrates through the first grouting hole 1021 into the coarse-grained soil layer around the middle of the push rod 101 to form an anti-sliding reinforcement layer 201.

[0069] In the above:

[0070] Several internally braced grouting anchors are arranged in a coarse-grained soil slope, and the pressure arches formed by the individual internally braced grouting anchors are combined to form a pressure composite arch 300 (e.g. Figure 4 The soil density is significantly improved, and the mechanical friction between soil particles is increased, thus improving the stability of the slope. Under the action of pre-tightening force, a pressure arch is formed between the pallet 106 and the anti-slip reinforcement layer 201, and a pressure arch is formed between the anchoring layer 202 and the anti-slip reinforcement layer 201.

[0071] It should be noted that:

[0072] Both the quick-drying cement slurry and the ordinary cement slurry are processed from existing formulas. The quick-drying cement slurry can be made by mixing water and quick-drying cement in a certain proportion, and the ordinary cement slurry can be made by mixing water and ordinary cement in a certain proportion.

[0073] In the low-pressure quick-drying cement grouting stage, quick-drying cement grout is injected under a pressure of 0.2-0.5 MPa. It has been proven through testing that under this pressure, the quick-drying cement grout can basically penetrate from the second grouting hole 1022 into the solid soil layer around the drill bit 105 to form the anchoring layer 202.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An internally supported grouting anchor bolt, characterized in that, include: The push rod has a first liquid guiding channel formed inside it along its axial direction and a plurality of first grouting holes connected to the first liquid guiding channel along its circumferential and axial directions on its outer wall. The connecting end of the push rod has an outward expansion inclined surface. The drill bit has a second fluid channel that is aligned and connected with the first fluid channel, and its outer wall is circumferentially arranged with a plurality of second grouting holes that communicate with the second fluid channel. The connecting end of the drill bit forms an outward expansion guide slope that is bonded to the outward expansion slope. When the compressive force between the push rod and the drill bit exceeds a preset value, the push rod moves relative to the drill bit and the outward expansion guide slope guides the outward expansion slope to cause the connecting end of the push rod to expand outward. A pressing and locking element is connected to the end of the push rod away from the drill bit.

2. The internally supported grouting anchor bolt according to claim 1, characterized in that, The drill bit includes: An outer guide section, wherein the diameter of the outer guide section gradually increases from one end to the other end so that its outer surface forms the outwardly expanding guide slope; The drill bit working section has a diameter that gradually increases from one end to the other end, and its large end is connected to the large end of the outer guide section. The second fluid guiding channel extends from the small end of the outer guide section along the axial direction of the outer guide section into the drill bit working section without penetrating it, and several second grouting holes are distributed on the drill bit working section.

3. The internally supported grouting anchor bolt according to claim 1, characterized in that, The pressing and locking component includes: An anchor, which is detachably and fixedly connected to the push rod; The tray is movably mounted on the push rod and located between the anchor and the drill bit.

4. The internally supported grouting anchor bolt according to claim 3, characterized in that, The cross-sectional area of ​​the pallet along its surface direction is greater than the cross-sectional area of ​​the anchor along the pallet surface direction.

5. A type of internally supported grouting anchor bolt according to any one of claims 1-4, characterized in that, The end of the push rod connected to the drill bit has several barbs evenly distributed on its outer side.

6. A method for grouting a coarse-grained soil slope, comprising grouting with a plurality of internally braced grouting anchors as described in any one of claims 1-5, characterized in that, Includes the following steps: Step S1, Anchor Installation: Several internally braced grouting anchors are arranged in an array and vertically screwed into the coarse-grained soil slope until the drill bit reaches the solid soil layer, and the end of the push rod connected to the drill bit is stretched outward to form a radial expansion structure. Step S2: Layered grouting. Grouting is carried out in stages through the push rod. First, an anchoring layer is formed in the expansion zone outside the drill bit, and then an anti-slip reinforcement layer is formed outside the middle section of the push rod. Step S3: Prestressed construction. Install pressing and locking components on the exposed ends of the push rods on the coarse-grained soil slope and apply axial prestress to form a continuous pressure arch structure between the anchoring layer, the anti-sliding reinforcement layer, and the pressing and locking components.

7. The method for grouting construction of coarse-grained soil slopes according to claim 6, characterized in that, Step S2 specifically involves: Step S21, Low-pressure quick-drying cement grouting stage: Quick-drying cement grout is injected under low pressure through the push rod. The grout penetrates into the solid soil layer around the drill bit through the second grouting hole to form an anchoring layer. Step S22, High-pressure quick-drying cement grouting stage: Continue to inject quick-drying cement grout under high pressure. The grout penetrates through the first grouting hole to the coarse-grained soil layer around the middle of the push rod to form a seepage barrier. Step S23, High-pressure reinforcement grouting stage: Continue to inject ordinary cement grout under high pressure. The grout penetrates through the first grouting hole into the coarse-grained soil layer around the middle of the push rod to form an anti-sliding reinforcement layer.

8. The method for grouting construction of coarse-grained soil slopes according to claim 7, characterized in that, The low pressure is 0.2-0.5 MPa.

9. A method for grouting coarse-grained soil slopes according to claim 7, characterized in that, The high pressure is 1-2 MPa.

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