A soil nail for a soil-nail wall slope support and a construction method thereof

Abstract

The application discloses a soil nailing wall slope supporting soil nailing and a construction method, and relates to the technical field of slope supporting; the soil nailing comprises a soil nailing body and a sealing assembly arranged on the peripheral wall of the soil nailing body; the sealing assembly comprises a clamping spring, an extension rod, a C-shaped opening elastic steel framework and a water-swelling rubber ring; the sealing assembly is fixed by being clamped into the annular clamping groove of the peripheral wall of the soil nailing body through the clamping spring, and the outer diameter of the sealing assembly in a natural state is greater than the drilling diameter; in the application, the sealing assembly divides the annular space between the outer wall of the soil nailing body and the hole wall of the drilling into a plurality of independent closed grouting sections; each sealing assembly completes the plugging of the transverse section of the annular space before grouting starts, so that the external underground water cannot seep into the section from the hole wall of the drilling or the outer wall of the steel pipe, a static water environment free from seepage interference is provided for the slurry, and the problems of cement particle loss and stone body strength reduction caused by seepage washing in traditional grouting are solved.

Description

Technical Field

[0001] This invention relates to the field of slope protection technology, and in particular to a soil nailing wall slope protection soil nail and construction method. Background Technology

[0002] Soil nailing is an in-situ soil reinforcement technology. It involves placing dense soil nails in the excavated slope and combining them with a shotcrete surface layer to form a composite support structure similar to a gravity retaining wall, which is used to maintain the stability of the excavation face.

[0003] Patent CN210737558U discloses a grouting concrete soil nail, which solves the problem of grout leakage from the hole opening by setting an expansion ring at the tail end of the soil nail to seal the hole opening. However, in coastal areas with high groundwater levels, the impact of groundwater seepage on grouting quality is not limited to the hole opening. External water can seep directly from the borehole wall in the middle and rear section of the borehole into the annular space between the outer wall of the steel pipe and the borehole wall, scouring and diluting the cement grout that has not yet solidified. This leads to the loss of cement particles, an increase in the water-cement ratio, and ultimately a decrease in the strength of the grout after solidification. The bonding and anchoring force between the soil nail and the soil is insufficient, which may cause local slope slippage or even overall instability in severe cases. Summary of the Invention

[0004] This invention solves the following technical problem: groundwater seepage easily washes away and segregates cement slurry, leading to a decrease in the strength of the slurry after solidification.

[0005] The technical solution of the present invention is as follows: A soil nail for slope protection of a soil nail wall includes a soil nail body, wherein the soil nail body is a hollow steel pipe with a soil nail cavity inside, and multiple sets of grout outlets are opened on the outer circumferential surface of the soil nail body, the grout outlets being spaced apart along the axial direction of the soil nail body. It also includes multiple sets of sealing components, wherein multiple annular grooves are opened on the outer circumferential wall of the soil nail body, the annular grooves being disposed between two adjacent grout outlets, and the sealing components being correspondingly installed in the annular grooves. The outer diameter of the sealing components in their natural state is larger than the borehole diameter. The sealing components include:

[0006] A retaining ring is inserted into the annular groove;

[0007] The telescopic rod has one end connected to the outer circumferential surface of the retaining spring;

[0008] The elastic steel frame is a C-shaped open ring structure, and its inner circumferential surface is connected to the other end of the telescopic rod.

[0009] A water-swellable rubber ring is disposed on the outer circumferential surface of the elastic steel frame.

[0010] Preferably, the water-swellable rubber ring includes a flanged portion, the cross-section of the water-swellable rubber ring is L-shaped, its outer ring portion is bonded to the outer peripheral surface of the elastic steel frame, and the flanged portion extends inward and fits the outer peripheral surface of the soil nail body.

[0011] Preferably, an inverted T-shaped steel bar is fixedly installed at the top of the soil nail body, a cross-shaped steel bar is fixedly installed at the top of the T-shaped steel bar, and steel mesh hooks are provided at all four ends of the cross-shaped steel bar.

[0012] Preferably, the vertical height of the T-shaped steel bar is equal to the thickness of the shotcrete on the slope.

[0013] Preferably, multiple slurry outlets within the same group are evenly distributed circumferentially along the outer periphery of the soil nail body. The slurry outlets are formed by cutting and turning up the pipe wall of the soil nail body. The cut and turned-up sheet-like structure constitutes the barb of the soil nail. The root of the barb of the soil nail is integrally formed with the bottom end of the slurry outlet, and the end is raised outward.

[0014] Preferably, the bottom end of the soil nail body is provided with a pointed conical end cap.

[0015] A construction method for soil nailing for slope protection of a soil nailing wall includes the following steps:

[0016] S1: When the soil nail is inserted into the pre-drilled hole, the elastic steel frame is compressed radially by the hole wall, and the telescopic rod is compressed.

[0017] S2: After the soil nail is in place, let it stand for 5 to 10 minutes to allow the water-swellable rubber ring to expand when it comes into contact with water. At the same time, the telescopic rod releases its elastic force to push the elastic steel frame outward, and the elastic steel frame abuts against the borehole wall.

[0018] S3: Insert the grouting pipe into the soil nail cavity to the bottom of the hole, and start the grouting pump to inject grout;

[0019] S4: During grouting, the grouting pipe is pulled out from the bottom of the hole to the opening at a uniform speed. When the grouting pipe passes through a grout outlet, the grout is injected into the corresponding grouting section through that outlet. The grouting sections are sealed by a sealing component.

[0020] S5: The grouting pipe is pulled to the borehole opening, and grouting ends after grout overflows from the opening.

[0021] Preferably, after grouting is completed, the steel mesh is hung on the steel mesh hook, and the vertical height of the T-shaped steel bar is used as the reference for controlling the grout thickness before spraying the surface concrete.

[0022] Preferably, in step S4, the grouting pipe pulling speed ,in This represents the actual output flow rate of the grouting pump. The diameter of the borehole. This refers to the outer diameter of the soil nail body.

[0023] Preferably, the grouting pressure in step S4 satisfy ,in The spring stiffness of the telescopic rod. This refers to the pre-compression amount of the telescopic rod. The diameter of the borehole. This refers to the contact width between the water-swellable rubber ring and the hole wall. The expansion pressure of the water-swellable rubber ring. For groundwater pressure, This is for the safety factor.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. In this invention, the sealing component divides the annular space into several independent sealed grouting sections. Before grouting begins, the sealing component seals the cross-section of the annular space, preventing external groundwater from seeping into the section along the borehole wall or the outer wall of the steel pipe. This provides a static water environment for the subsequently injected grout, which is undisturbed by seepage. The grout solidifies stably in this environment, solving the problems of cement particle loss and grout strength reduction after solidification caused by seepage scouring in traditional grouting.

[0026] 2. In this invention, the cross-shaped steel bar serves as the force-bearing surface when the soil nail is driven into the borehole, and the steel mesh hooks at its four ends are used to hang the steel mesh and control the thickness of the protective layer; the vertical length of the T-shaped steel bar is equal to the thickness of the shotcrete, and its top end is used as the control reference for the shotcrete surface layer during construction; the three are integrated on the same structural component at the top of the soil nail, eliminating the need to set separate thickness control rods or protective layer pads, thus simplifying the construction process.

[0027] 3. In this invention, the tube pulling speed is precisely controlled by a quantitative formula. Workers only need to read the flow count value to calculate the upper limit of the tube pulling speed, so that each section can get sufficient grouting time. Compared with the qualitative requirement of "slow and uniform speed" and the empirical practice of "pausing for 5 seconds per section" in the prior art, the quantitative control of this invention makes the grouting quality calculable and controllable, and avoids local grouting incompleteness caused by improper tube pulling speed. Attached Figure Description

[0028] Figure 1 This is a perspective view of the soil nail used for support in this invention;

[0029] Figure 2 This is a schematic diagram of the sealing assembly when the water-swellable rubber ring separates.

[0030] Figure 3 This is a cross-sectional view of the mating point between the sealing component and the soil nail body;

[0031] Figure 4This is a partial three-dimensional structural diagram of the soil nail body.

[0032] Figure label:

[0033] 1. Soil nail body; 11. Soil nail cavity; 12. Annular groove; 13. Grout outlet; 14. Soil nail barb; 15. Conical end cap; 2. Sealing assembly; 21. Elastic steel frame; 22. Telescopic rod; 23. Snap ring; 24. Water-swellable rubber ring; 241. Flanged edge; 3. T-shaped steel bar; 4. Cross steel bar; 41. Steel mesh hook. Detailed Implementation

[0034] Example 1

[0035] Reference Figures 1-4 A soil nailing wall slope support soil nail includes a soil nail body 1, which is a hollow steel pipe with an internal cavity called a soil nail cavity 11. Three sets of grout outlets 13 are provided on the pipe wall of the soil nail body 1. The three sets of grout outlets 13 are spaced apart along the axial direction of the soil nail body 1. The three grout outlets 13 in the same set are evenly distributed along the circumferential direction of the outer circumference of the soil nail body 1, so that the grout flows out from the inside of the steel pipe and is evenly distributed in the circumferential direction of the annular space.

[0036] Two annular grooves 12 are provided on the outer peripheral wall of the soil nail body 1. Each annular groove 12 is located between two adjacent grout outlets 13. A sealing component 2 is provided in the annular groove 12. In this embodiment, three sets of grout outlets 13 and two sets of sealing components 2 are provided. A sealing component 2 is provided between two adjacent sets of grout outlets 13.

[0037] The sealing assembly 2 includes a retaining ring 23, a telescopic rod 22, an elastic steel frame 21, and a water-swellable rubber ring 24. The retaining ring 23 is inserted into the annular groove 12. The sealing assembly 2 is installed on the outer peripheral wall of the soil nail body 1 by the retaining ring 23 being inserted into the annular groove 12. The retaining ring 23 is a C-shaped open annular structure made of spring steel. Its inner diameter is adapted to the bottom diameter of the annular groove 12. After the retaining ring 23 is inserted into the annular groove 12, its outer peripheral surface is fixedly connected to the telescopic rod 22. The telescopic rod 22 is a compression spring. One end of it is fixedly connected to the outer peripheral surface of the retaining ring 23, and the other end is fixedly connected to the inner peripheral surface of the elastic steel frame 21. The telescopic rod 22 is arranged radially along the retaining ring 23.

[0038] The elastic steel frame 21 is a C-shaped open ring structure made of spring steel sheet. In its natural state, the outer diameter of the elastic steel frame 21 is larger than the borehole diameter D, with the excess being 2 to 4 mm.

[0039] A water-swellable rubber ring 24 is disposed on the outer peripheral surface of the elastic steel frame 21. The cross-section of the water-swellable rubber ring 24 is L-shaped, including an outer ring portion and a flange portion 241. The outer ring portion is disposed on the outer peripheral surface of the elastic steel frame 21, and the flange portion 241 extends inward to the inner peripheral surface of the elastic steel frame 21 and is pressed against the outer peripheral wall of the soil nail body 1 by the retaining spring 23.

[0040] In this embodiment, the engagement of the snap ring 23 and the annular groove 12 provides radial locking force, preventing the entire sealing assembly 2 from moving axially along the steel pipe during soil nailing and grouting.

[0041] The telescopic rod 22 is in an extended state in its natural state. When the soil nail is driven into the borehole, it is compressed and stores elastic potential energy. After it is in place, it is released immediately and actively pushes the elastic steel frame 21 against the borehole wall, thus establishing the initial sealing pressure before grouting begins.

[0042] The elastic steel frame 21 has a C-shaped opening structure. When it is squeezed by the borehole wall, its C-shaped opening can close to reduce the outer diameter, making it easier to push into the borehole. After being pushed into place, the elastic steel frame 21 expands outward under the action of its own elastic restoring force and the thrust of the telescopic rod 22.

[0043] The water-swellable rubber ring 24 is made of water-swellable rubber conforming to GB / T 18173.3-2014 standard. After contact with water, its volume expands to 150% to 600% of its original volume, and it can generate a contact pressure of 0.3 to 1.5 MPa in a confined space. The cross-section of the water-swellable rubber ring 24 is L-shaped. Its outer ring is pressed against the borehole wall to form an external seal, and the flange 241 is pressed against the outer peripheral wall of the soil nail body 1 by the retaining spring 23 to form an internal seal. The two sealing directions are perpendicular to each other, respectively blocking the infiltration of external groundwater from the borehole wall direction and from the C-shaped opening of the steel frame along the outer wall of the steel pipe into the section.

[0044] After the water-swellable rubber ring 24 expands and adheres tightly to the borehole wall, each sealing component 2 longitudinally divides the annular space between the outer wall of the soil nail body 1 and the borehole wall into three independent sealed grouting sections. Each sealed grouting section corresponds to a set of grout outlets 13. After the annular space is divided, each section becomes an independent micro-grouting chamber during grouting. Grout is injected into the section from the corresponding grout outlet 13, and both ends are sealed by the sealing components 2, preventing external groundwater from seeping in. It should be noted that the water-swellable rubber ring 24 is also C-shaped with a small opening to accommodate the elastic deformation of the elastic steel frame 21. When the water-swellable rubber ring 24 absorbs groundwater and expands, this opening closes without affecting the sealing effect.

[0045] The bottom end of the soil nail body 1 is provided with a pointed cone head 15, which is used to split the soil and reduce resistance when it is driven into the borehole.

[0046] The top of the soil nail body 1 is welded with a T-shaped steel bar 3, and the upper end of the T-shaped steel bar 3 is welded with a cross steel bar 4. The cross steel bar 4 serves as the pressure-bearing part of the soil nail when it is driven into the slope. First, the soil nail body 1 is placed on the guide rail support of the mechanical drill rod so that the soil nail body 1 and the mechanical drill rod are on the same center. The mechanical drill rod is then aligned with the cross steel bar 4, and the soil nail is driven into the hole that has been drilled in the slope.

[0047] The four ends of the cross steel bar 4 are provided with steel mesh hooks 41. When constructing the shotcrete surface layer on the slope, steel mesh needs to be laid. The steel mesh is made of longitudinal and transverse steel bars tied or welded together and laid on the slope as the skeleton of the shotcrete surface layer. The longitudinal and transverse steel bars of the steel mesh are respectively placed into the steel mesh hooks 41. At this time, the steel mesh hooks 41 play the role of fixing the steel mesh.

[0048] The vertical length of T-shaped steel bar 3 is equal to the thickness of the shotcrete on the slope. During construction, the top of T-shaped steel bar 3 is used as the surface control benchmark for the shotcrete layer. The design thickness is achieved when the shotcrete covers the top of T-shaped steel bar 3. The setting of T-shaped steel bar 3 solves the problem of needing to set a separate thickness control benchmark in traditional shotcrete construction. It is itself a structural component at the top of the soil nail, and at the same time undertakes the dual functions of force connection and thickness control. There is no need to set an additional thickness control component, which simplifies the construction process.

[0049] The grout outlet 13 is formed by cutting and turning up the pipe wall of the soil nail body 1. The cut and turned-up sheet-like structure constitutes the soil nail barb 14. The root of the soil nail barb 14 is integrally formed with the bottom end of the grout outlet 13, and the end is raised outward. The soil nail barb 14 is integrally formed with the pipe wall of the soil nail body 1. After the soil nail barb 14 is raised outward, its end is embedded in the soil of the hole wall, which increases the mechanical interlocking force between the soil nail and the soil and improves the pull-out bearing capacity of the soil nail.

[0050] In this embodiment, the soil nailing device is used by a drilling rig to push the soil nail into a pre-drilled hole. During the pushing process, the elastic steel frame 21 is squeezed by the borehole wall, its C-shaped opening closes, its outer diameter decreases, and the telescopic rod 22 is compressed. After being pushed into place, it is left to stand for 5-10 minutes to allow the water-swellable rubber ring 24 to fully contact the groundwater and begin to expand. At the same time, the telescopic rod 22 releases its elastic potential energy, pushing the elastic steel frame 21 outward against the borehole wall. After the water-swellable rubber ring 24 contacts the groundwater in the borehole, its volume expands, and its outer ring adheres tightly to the borehole wall to form a main seal. The flanged part is held in place by the retaining spring 2. 3. The secondary seal is formed by pressing the outer peripheral wall of the soil nail body 1. As the telescopic rod 22 continuously provides active thrust, the water-swellable rubber ring 24 is always pressed against the borehole wall. Even under the condition of groundwater pressure fluctuation, the sealing pressure can remain stable, ensuring effective isolation between each sealed grouting section. This blocks the seepage path of external groundwater along the borehole wall or the outer wall of the steel pipe into the section. It solves the problem of external dynamic water environment washing away and diluting uncured cement grout in traditional grouting, so that the grout can be stably cured under static water conditions in each sealed section, ensuring the compactness and strength of the grout body.

[0051] Example 2

[0052] This embodiment provides a construction method for soil nailing in slope protection of a soil nailing wall, including the following steps:

[0053] Step 1: Drilling Holes and Installing Soil Nails

[0054] After the slope is trimmed, a thin layer of concrete is sprayed to seal the slope and prevent the soil from collapsing. The location of the soil nail holes is then marked out, and a small drilling rig is used to drill the holes. The drilling depth matches the length of the soil nail body 1. After drilling, the assembled soil nail is placed on the guide rail support of the drilling rig, so that the soil nail and the drill rod are on the same center line. The drilling rig pushes the cross steel bar 4 to push the soil nail into the hole. During the pushing process, the elastic steel frame 21 is squeezed by the hole wall, and its C-shaped opening closes to reduce the outer diameter. The telescopic rod 22 is compressed, and the soil nail smoothly enters the hole until the opening of the soil nail body 1 is flush with the soil surface.

[0055] Step 2: Allow to stand and expand

[0056] After the soil nails are in place, they are left to stand for 5 to 10 minutes. During this period, the water-swellable rubber ring 24 comes into contact with the groundwater in the borehole and begins to expand to 150% to 600% of its original volume. The outer ring gradually adheres to the borehole wall. At the same time, the telescopic rod 22 releases its elastic potential energy and continuously pushes the elastic steel frame 21 outward against the borehole wall, so that the water-swellable rubber ring 24 is pressed tightly against the borehole wall. The active expansion of the water-swellable rubber and the active thrust of the telescopic rod work together to establish a reliable initial seal for the sealing component 2 before grouting begins.

[0057] Step 3: Determining Grouting Parameters

[0058] Insert the grouting pipe into the soil nail cavity 11 to the bottom of the hole, with the end of the grouting pipe no more than 200mm from the bottom of the hole. The actual output flow rate of the grouting pump. The flow rate is read in real time by the flow meter on the pump.

[0059] Before grouting, the sealing capacity of the sealing components must be verified. The sealing contact pressure consists of three superimposed parts: the contact pressure generated by the spring preload of the telescopic rod 22, and the expansion pressure of the water-swellable rubber ring 24. and grouting pressure The sum of these three factors must be greater than the groundwater pressure. With safety factor The product of, i.e.:

[0060] ;

[0061] The contact pressure generated by the spring preload is , The spring stiffness of the telescopic rod 22, This refers to the pre-compression amount of the telescopic rod 22. The diameter of the borehole. The contact width between the water-swellable rubber ring 24 and the hole wall; The product testing report shall be provided in accordance with GB / T 18173.3-2014. According to the geological survey report, the safety factor is determined to be... Take 1.5 to 2.0.

[0062] Taking a coastal foundation pit project as an example: the borehole diameter D = 0.15m, the contact width of the water-swellable rubber ring W = 0.05m, and the spring stiffness of the telescopic rod... =15N / mm, pre-compression amount =8mm, then the contact pressure generated by the spring preload is 15×8 / (π×0.15×0.05)≈0.005MPa; the expansion pressure of water-swellable rubber. =0.8MPa (provided by the manufacturer's test report), grouting pressure =0.5MPa, the sum of the three is approximately 1.305MPa, groundwater pressure =0.3MPa (provided by the geological survey report), with a safety factor of 1.5. · =0.45MPa, which means the sealing contact pressure of 1.305MPa is much greater than 0.45MPa, indicating that the seal is safe and reliable.

[0063] Step 4: Segmented grouting

[0064] Start the grouting pump, grouting pressure The pressure should be controlled at 0.4–0.6 MPa, and the grouting pipe should be pulled out from the bottom of the hole to the opening at a uniform speed. Grouting pipe pulling speed. satisfy:

[0065] ;

[0066] in, This represents the actual output flow rate of the grouting pump. The diameter of the borehole. The outer diameter of the soil nail body 1.

[0067] In this embodiment, the actual output flow rate of the grouting pump =15L / min=2.5×10 -4 m³ / s, borehole diameter =0.15m, outer diameter of soil nail body 1 =0.048m, then ≈0.0158m / s≈0.95m / min. On site, the grouting pipe is pulled out at a uniform speed of 0.8m / min, leaving a safety margin.

[0068] As the grouting pipe passes through a grout outlet 13, the grout is injected into the corresponding sealed grouting section through that outlet 13. Since both ends of each sealed grouting section are sealed by the sealing component 2, external groundwater cannot seep into the annular space of that section from the borehole wall in the later part of the borehole. The grout is stably filled and solidified in the sealed environment. Compared with the traditional grouting process of pausing for about 5 seconds after each section is pulled out, this embodiment ensures that each section has sufficient grouting time by quantitatively controlling the pipe pulling speed, thus avoiding local grouting incompleteness caused by uneven pipe pulling speed.

[0069] During grouting, the grouting pressure Simultaneously, the elastic steel skeleton 21 of the sealing component 2 is pushed further outward against the borehole wall, so that the water-swellable rubber ring 24 is pressed more tightly. The higher the grouting pressure, the tighter the seal, forming a positive feedback effect of grout pressure self-locking. This mechanism ensures that the sealing effect will not weaken under grouting pressure fluctuations, but will instead be enhanced as the pressure increases.

[0070] Step 5: Finishing

[0071] Pull the grouting pipe to the borehole opening, and stop grouting after fresh grout steadily overflows from the borehole opening. Hang the steel mesh on the steel mesh hook 41, and use the vertical height of the T-shaped steel bar 3 as the control benchmark for the grout thickness. Spray the surface concrete to cover the top of the T-shaped steel bar 3 to achieve the designed grout thickness.

[0072] In traditional grouting processes, external groundwater continuously seeps into the annular space along the borehole wall, scouring and diluting the uncured cement grout, leading to cement particle loss, increased water-cement ratio, and decreased strength after grout curing. In this embodiment, the annular space is divided into several independent sealed grouting sections by the sealing component 2. The telescopic rod 22 provides active thrust to keep the water-swellable rubber ring 24 tightly attached to the borehole wall. The grouting pressure further strengthens the seal, achieving reliable blocking of external seepage paths. This allows the grout to solidify stably under static water conditions in each sealed section, ensuring the compactness and strength of the entire grout body.

[0073] At the same time, each sealed grouting section is independent of the others. If a grouting defect occurs in one section due to special circumstances, it will not affect other sections, thus avoiding the risk of single-point failure leading to full-length failure in traditional processes.

Claims

1. A soil nail for slope protection of a soil nail wall, comprising a soil nail body (1), wherein the soil nail body (1) is a hollow steel pipe with a soil nail cavity (11) inside, and multiple sets of grout outlets (13) are provided on the outer circumferential surface of the soil nail body (1), and the grout outlets (13) are spaced apart along the axial direction of the soil nail body (1), characterized in that: It also includes multiple sets of sealing components (2). The outer peripheral wall of the soil nail body (1) is provided with multiple annular grooves (12). The annular grooves (12) are located between two adjacent grout outlets (13). The sealing components (2) are installed in the annular grooves (12). The outer diameter of the sealing components (2) in its natural state is larger than the borehole diameter. The sealing components (2) include: The snap ring (23) is inserted into the annular slot (12); The telescopic rod (22) is connected at one end to the outer circumferential surface of the retaining ring (23); The elastic steel frame (21) is a C-shaped open ring structure, and its inner circumferential surface is connected to the other end of the telescopic rod (22). A water-swellable rubber ring (24) is disposed on the outer circumferential surface of the elastic steel frame (21).

2. The soil nailing method for slope protection of a soil nailing wall according to claim 1, characterized in that, The water-swellable rubber ring (24) includes a flange (241). The cross-section of the water-swellable rubber ring (24) is L-shaped. Its outer ring is bonded to the outer circumference of the elastic steel frame (21). The flange (241) extends inward and fits the outer circumference of the soil nail body (1).

3. The soil nailing method for slope protection of a soil nailing wall according to claim 1, characterized in that, The top of the soil nail body (1) is fixedly provided with an inverted T-shaped steel bar (3), and the top of the T-shaped steel bar (3) is fixedly provided with a cross steel bar (4). The four ends of the cross steel bar (4) are provided with steel mesh hooks (41).

4. The soil nailing method for slope protection of a soil nailing wall according to claim 3, characterized in that, The vertical height of the T-shaped steel bar (3) is equal to the thickness of the concrete for the slope shotcrete.

5. The soil nailing method for slope protection of a soil nailing wall according to claim 1, characterized in that, Multiple grout outlets (13) within the same group are evenly distributed circumferentially along the outer periphery of the soil nail body (1). The grout outlets (13) are formed by cutting and turning up the pipe wall of the soil nail body (1). The cut and turned-up sheet-like structure constitutes the soil nail barb (14). The root of the soil nail barb (14) is integrally formed with the bottom end of the grout outlet (13), and the end is raised outward.

6. A soil nailing method for slope protection of a soil nailing wall according to any one of claims 1 to 5, characterized in that, The bottom end of the soil nail body (1) is provided with a pointed cone head (15).

7. A construction method for soil nailing for slope protection of a soil nailing wall, comprising the soil nailing method for slope protection of a soil nailing wall as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: The soil nail is inserted into the pre-drilled hole. The elastic steel frame (21) is compressed radially by the hole wall, and the telescopic rod (22) is compressed. S2: After the soil nail is in place, let it stand for 5 to 10 minutes to allow the water-swellable rubber ring (24) to expand when it comes into contact with water. At the same time, the telescopic rod (22) releases its elastic force to push the elastic steel frame (21) outward, and the elastic steel frame (21) abuts against the borehole wall. S3: Insert the grouting pipe into the soil nail cavity (11) to the bottom of the hole, and start the grouting pump to grout; S4: During grouting, the grouting pipe is pulled out from the bottom of the hole to the opening at a uniform speed. When the grouting pipe passes through a grout outlet (13), the grout is injected into the corresponding grouting section through the grout outlet (13). The grouting sections are sealed by the sealing component (2). S5: The grouting pipe is pulled to the borehole opening, and grouting ends after grout overflows from the opening.

8. The construction method of soil nailing for slope protection of a soil nailing wall according to claim 7, characterized in that, After grouting is completed, the steel mesh is hung on the steel mesh hook (41), and the vertical height of the T-shaped steel bar (3) is used as the reference for controlling the grout thickness, and the surface concrete is sprayed.

9. A construction method for soil nailing for slope protection of a soil nailing wall according to claim 7, characterized in that, In step S4, the grouting pipe pulling speed ,in This represents the actual output flow rate of the grouting pump. The diameter of the borehole. The outer diameter of the soil nail body (1) is given.

10. A construction method for soil nailing for slope protection of a soil nailing wall according to claim 7, characterized in that, Grouting pressure in step S4 satisfy ,in The spring stiffness of the telescopic rod (22) is... The pre-compression amount of the telescopic rod (22) The diameter of the borehole. The contact width between the water-swellable rubber ring (24) and the hole wall. The expansion pressure of the water-swellable rubber ring (24) is... For groundwater pressure, This is for the safety factor.

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