A self-advancing rod body and method for tunnel soft and hard interbedded rock mass grouting construction

Abstract

The application relates to a self-advancing rod body and method for tunnel soft and hard interbedded rock mass grouting construction. The self-advancing rod body comprises a supporting rod body for supporting the whole self-advancing rod body in the process of connecting and driving the self-advancing rod body into the tunnel soft and hard interbedded rock mass by an impact drill; a grouting pipe body which is sleeved on the supporting rod body and is left in the tunnel soft and hard interbedded rock mass hole for grouting after the self-advancing rod body enters the tunnel soft and hard interbedded rock mass and the supporting rod body is drawn out; and a drill bit fixed on the supporting rod body. The self-advancing rod body for tunnel soft and hard interbedded rock mass grouting construction is used as a whole as the self-advancing rod body, has high overall strength, and after the whole structure is pushed to the rock layer of a specified depth by the pneumatic impact drill in the soft and hard interbedded tunnel rock layer, the supporting rod body can be drawn and recycled for reuse.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, specifically to a self-propelled rod and grouting method for grouting construction in alternating soft and hard rock masses in tunnels. Background Technology

[0002] Interbedded soft and hard rock masses pose a significant challenge to tunnel support construction. Due to the presence of numerous uneven, discontinuous, and irregularly distributed rock fissures, their strength, deformation, and stability are significantly weaker than those of a single surrounding rock mass, increasing the difficulty of support construction. When conducting conventional anchor bolt support operations, if drilling is performed first, and the anchor bolt is inserted along the hole after drilling, the borehole is prone to collapse when encountering interbedded soft and hard rock masses, making it difficult to reach the bottom of the hole. To overcome the problems of large-scale collapse of the borehole wall during drilling, resulting in borehole collapse, inability to insert the bolt, and incomplete grouting, a self-drilling hollow anchor bolt construction method is commonly used, integrating drilling, anchor bolt installation, grouting, and anchoring into one process. Currently, the main problems with this method are: the anchor bolt tube wall is thin, and the overall strength of the bolt is low. If a self-drilling bolt drilling method is used, the bolt is prone to bending deformation and failure due to insufficient strength.

[0003] Drilling tools (self-drilling rods and drill bits) are adaptable to both soft and hard rock formations, depending on the selection of the drilling tools and the optimization of drilling parameters. However, for formations with alternating soft and hard rock, the construction of self-drilling rods still carries a high risk. Conventional self-drilling hollow grouting anchor bolts use thick-walled seamless steel pipes and disposable drill bits, but in actual drilling operations in formations with alternating soft and hard rock, stuck drill bits and broken seamless steel pipes often occur. The main reason for this is that seamless steel pipes are prone to breakage due to insufficient rod strength, and the drill bit's side teeth and lateral teeth suffer severe wear, especially in areas with well-developed fractures in alternating soft and hard rock formations, where stuck drill bits occur more frequently. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a self-advancing rod for grouting construction in alternating soft and hard rock masses in tunnels, comprising a support rod for connecting to an impact drill and for supporting the self-advancing rod as a whole during the process of the impact drill driving the self-advancing rod into the alternating soft and hard rock masses in the tunnel.

[0005] A grouting pipe that is fitted onto a support rod and remains in the hole of the interbedded soft and hard rock mass of the tunnel for grouting after the self-advancing rod enters the tunnel and the support rod is pulled out;

[0006] And the drill bit fixed to the support rod body.

[0007] Based on the above scheme, an adhesive part for supporting the grouting pipe body is provided between the grouting pipe body and the support rod body.

[0008] Based on the above scheme, the adhesive part shown is a polyurethane material or a high-strength duct grout that is injected between the grouting pipe and the support rod and solidifies.

[0009] Based on the above scheme, a stop is fixedly connected to the side of the support rod away from the drill bit to prevent relative sliding between the grouting pipe and the support rod during the process of the self-advancing rod being driven into the rock formation.

[0010] Based on the above scheme, a soft pad is provided between the stop part and the grouting pipe body to provide a certain sliding space between the grouting pipe body and the support rod body during the process of the self-advancing rod body being driven into the rock strata.

[0011] Based on the above scheme, the side of the grouting pipe body closest to the drill bit is the grouting section, and several grouting holes for grouting are provided on the wall of the grouting section of the grouting pipe body; the end of the grouting pipe body away from the drill bit is provided with a reinforcing hoop to prevent the tail end of the grouting pipe body from cracking during the process of the self-advancing rod entering the soft and hard interlayered rock mass of the tunnel.

[0012] Based on the above scheme, the grouting pipe body narrows at the end near the drill bit to form a cone head; the outer diameter of the support rod and the drill bit is smaller than the minimum inner diameter of the grouting pipe body at the cone head.

[0013] This application also provides a method for grouting construction in tunnels with alternating layers of soft and hard rock, comprising the following steps:

[0014] (1) Sleeve the grouting pipe body over the outside of the support rod body, so that the tail end of the grouting pipe body abuts against the soft pad body;

[0015] (2) Inject polyurethane material or high-strength grouting material between the grouting pipe and the support rod;

[0016] (3) Fix the drill bit to the support rod at the front end of the support rod; and connect the support rod to the impact drill at the rear end of the support rod.

[0017] (4) Use an impact drill to drive the connected self-advancing rod into the soft and hard alternating rock strata of the tunnel at the designed location on the tunnel rock wall.

[0018] (5) After the self-advancing rod enters the design position, the support rod is pulled out of the grouting pipe and grout is injected using the grouting pipe.

[0019] Based on the above scheme, before the grouting pipe is fitted onto the outside of the support rod, grease is first applied to the outer wall of the support rod.

[0020] Based on the above scheme, before filling the grouting pipe body and the support rod body with polyurethane material or high-strength grouting material, the grouting hole is first sealed with a plug; after solidification, the plug is removed.

[0021] The self-propelled rod used in this application for grouting construction in alternating soft and hard rock formations of tunnels is used as a single unit, possessing high overall strength. In tunnels with alternating soft and hard rock formations, after the integral structure is pushed to a designated depth by a pneumatic impact drill, the support rod can be cored and reused. In the self-propelled rod structure of this invention, the drill bit is connected to the support rod; when the support rod is pulled out, the drill bit can be retrieved simultaneously. This self-propelled rod and grouting method effectively solve the problems of easy hole collapse during self-propelled grouting with small guide pipes in alternating soft and hard rock formations and the insufficient overall strength of self-propelled operations. Furthermore, the reusability of the drill bit effectively reduces construction costs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural schematic diagram of the self-advancing rod of this application;

[0024] Figure 2 This is a schematic diagram of the grouting pipe body in the self-propelled rod body of this application;

[0025] Figure 3 for Figure 1 Schematic diagram of sectional view along the AA direction (without plug);

[0026] Figure 4 for Figure 1 Schematic diagram of cross section AA (with plug).

[0027] Figure 5 for Figure 1 A magnified structural diagram of part B in the middle section;

[0028] Figure 6 This is a structural schematic diagram of the support rod in the self-advancing rod of this application. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] In the grouting construction of tunnels with alternating layers of soft and hard rock, grouting holes need to be drilled in the rock mass first, and then grouting pipes (small guide pipes) are inserted along the holes for grouting. In tunnels with alternating layers of soft and hard rock, borehole collapse is common after drilling, making it difficult to reach the bottom of the hole with the grouting small guide pipe. If a self-propelled grouting small guide pipe is used, its thin wall and low overall strength make it prone to bending deformation and failure during impact drilling due to insufficient strength.

[0032] Therefore, such as Figure 1 , Figure 2 and Figure 6 As shown, this application provides a self-advancing rod for grouting construction in a tunnel with alternating layers of soft and hard rock, including a support rod 1 for supporting the self-advancing rod as a whole during the process of the impact drill driving the self-advancing rod into the alternating layers of soft and hard rock in the tunnel.

[0033] The grouting pipe 2 is left in the hole of the interbedded soft and hard rock mass of the tunnel after the self-advancing rod enters the tunnel and the support rod 1 is pulled out;

[0034] The grouting pipe 2 is sleeved on the outside of the support rod 1;

[0035] A drill bit 3 is provided at the end of the support rod 1.

[0036] An adhesive part 4 is provided between the grouting pipe body 2 and the support rod body 1. The adhesive part 4 shown is made of polyurethane material or high-strength grouting material.

[0037] The adhesive part 4 has two main functions. One is to provide support between the grouting pipe body 2 and the support rod body 1, enhance the integrity of the self-advancing rod body, and prevent the grouting pipe body 2 from deforming during the process of the self-advancing rod body entering the soft and hard interlayered rock mass of the tunnel. The other is to bond the grouting pipe body 2 and the support rod body 1 together, so as to minimize the relative sliding between the two during the process of the self-advancing rod body entering the soft and hard interlayered rock mass of the tunnel.

[0038] To enhance the overall strength of the support rod 1, the support rod 1 of this application uses a solid high-strength steel rod with a diameter of 22mm, a length of 4-8m, and a load-bearing capacity of approximately 600KN.

[0039] The grouting pipe body 2 is located on the side near the drill bit 3 as the grouting section, and several grouting holes 2-1 for grouting are provided on the wall of the grouting section of the grouting pipe body 2.

[0040] The grouting pipe 2 tapers at the end near the drill bit 3, forming a conical head 2-2. The conical head 2-2 reduces the resistance of the rock formation to the grouting pipe 2 during the self-propelled rod's insertion into the rock formation.

[0041] During the process of driving the self-propelled rod of this application into the rock formation using an impact drill, the thin wall of the grouting pipe 2 makes it prone to cracking at the tail end, i.e., the end of the grouting pipe 2 away from the drill bit 3. To solve this technical problem, a reinforcing hoop 2-3 is provided at the end of the grouting pipe 2 away from the drill bit 3. The use of the reinforcing hoop 2-3 can effectively prevent cracking at the tail end of the grouting pipe 2.

[0042] As a specific implementation plan, the grouting pipe body 2 is made of hot-rolled seamless steel pipe (diameter 38mm, wall thickness 5mm, load-bearing capacity approximately 400KN). The front end of the grouting pipe body 2 is made into a conical shape (cone head 2-2), and the tail end is welded with a tightening clamp 2-3 to prevent the pipe end from cracking during installation, thus affecting the connection of the grouting pipe. The tail length of the grouting pipe body 2 is 1m long and is designated as a section without drilling. The remaining part is the grouting section, and four rows of φ10mm holes are drilled around the pipe wall, with a hole spacing of 15cm, arranged in a quincunx pattern.

[0043] During the process of driving the self-propelled rod of this application into the rock formation using an impact drill, the large resistance formed by the borehole wall on the grouting pipe 2 causes relative sliding between the grouting pipe 2 and the support rod 1. This sliding prevents the grouting pipe 2 from reaching the predetermined depth. To solve this technical problem, the support rod 1 of this application has a stop 5 fixedly connected to the side away from the drill bit 3 to prevent relative sliding between the grouting pipe 2 and the support rod 1 during the driving of the self-propelled rod into the rock formation. Specifically, the stop 5 uses a metal ring of a certain thickness, which is directly fixed to the support rod 1 by welding, allowing for repeated use.

[0044] Based on the aforementioned self-advancing rod with a stop 5, after the self-advancing rod is driven into the rock stratum, the support rod 1 and drill bit 3 need to be withdrawn from the grouting pipe 2. However, since an adhesive part 4 is provided between the grouting pipe 2 and the support rod 1, the grouting pipe 2 will move outward together during withdrawal. In order to withdraw the support rod 1 and drill bit 3 from the grouting pipe 2, the adhesive part 4 between the grouting pipe 2 and the support rod 1 needs to cease its function of bonding the two. In this application, the self-advancing rod only requires the adhesive part 4 to play a supporting and bonding role during the process of driving into the rock stratum; after driving, during the withdrawal of the support rod 1, the adhesive part 4 needs to cease its function. To solve this technical problem, such as Figure 1 and 5 As shown, this application provides a soft pad 6 between the stop 5 and the grouting pipe 2 to provide a certain limited sliding space (0.5-1.5cm) between the grouting pipe 2 and the support rod 1 during the process of the self-propelled rod being driven into the rock stratum. The soft pad 6 can be made of thick rubber gaskets and is fitted onto the support rod 1. When the impact drill drives the self-propelled rod into the rock stratum, the self-propelled rod moves as a whole into the rock stratum. At the same time, the friction between the grouting pipe 2 and the rock stratum will cause a tendency for relative sliding between the grouting pipe 2 and the support rod 1. If the grouting pipe 2 directly abuts against the stop 5, the stop 5 will counteract the friction and prevent relative sliding between the two. However, the padding 6 provides some space for sliding between the two, allowing the grouting pipe 2 to slide and misalign with the support rod 1 during the self-propelled rod's penetration into the rock strata (the size of the misalignment is determined by factors such as the thickness of the padding 6). This relative sliding will cause the grouting pipe 2 and the support rod 1 to break free from the adhesive constraint of the adhesive part 4, preparing for the subsequent extraction of the support rod 1. To facilitate the extraction of the support rod 1, grease is applied to the outer wall of the support rod 1, so that the adhesive part 4 only serves a supporting function between the grouting pipe 2 and the support rod 1. In addition, the padding 6 also protects the tail end of the grouting pipe 2 during the self-propelled rod's penetration into the rock strata, preventing it from cracking.

[0045] The extracted support rod 1 and drill bit 3 can be reused, greatly saving costs. The tail end of the support rod 1 is provided with a threaded part 1-1 for threaded connection with the impact drill. At the same time, the support rod 1 and drill bit 3 can be connected by welding or threading.

[0046] The outer diameters of the support rod 1 and the drill bit 3 are smaller than the minimum inner diameter of the grouting pipe 2 at the cone head 2-2. This is to facilitate core sampling after the drilling tool has been excavated.

[0047] Example 2

[0048] Based on the self-advancing rod in Embodiment 1, this application provides a method for grouting construction in tunnels with alternating soft and hard layers, specifically including the following steps:

[0049] (1) The grouting pipe body 2 is sleeved on the outside of the support rod body 1, so that the tail end of the grouting pipe body 2 abuts against the soft pad body 6.

[0050] (2) Inject polyurethane material or high-strength grouting material between the grouting pipe body 2 and the support rod body 1;

[0051] (3) Fix the drill bit 3 to the support rod 1 at the front end of the support rod 1; and connect the support rod 1 to the impact drill at the tail end of the support rod 1.

[0052] (4) Use an impact drill to drive the connected self-advancing rod into the soft and hard alternating rock strata of the tunnel at the designed location on the tunnel rock wall.

[0053] (5) After the self-advancing rod enters the design position, the support rod 1 is pulled out from the grouting pipe 2 and grouting is performed using the grouting pipe 2.

[0054] In order to facilitate the removal of the support rod 1, as a specific implementation plan, in step (1), before the grouting pipe 2 is fitted onto the outside of the support rod 1, grease is first applied to the outer wall of the support rod 1.

[0055] In step (2), when filling polyurethane material or high-strength grouting material into the grouting hole 2-1, the material will enter the grouting hole 2-1, solidify, and block the grouting hole 2-1. This will affect the grouting effect in the later grouting process. To solve this technical problem, before filling polyurethane material or high-strength grouting material between the grouting pipe body 2 and the support rod body 1, the grouting hole 2-1 is first blocked with a plug 7; after solidification, the plug 7 is removed.

[0056] When using the plug 7 for sealing, the plug 7 needs to be inserted into the grouting hole 2-1 and pressed against the support rod 1. This ensures that the grouting hole 2-1 is open after the support rod 1 is pulled out, thus not affecting the subsequent grouting.

[0057] Where the method in this embodiment is not described in detail, please refer directly to the content in Embodiment 1.

[0058] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A self-propelled rod for grouting construction in tunnels with alternating layers of soft and hard rock, characterized in that, Includes a support rod (1) used to connect the impact drill and to support the self-advancing rod as a whole during the process of the impact drill driving the self-advancing rod into the soft and hard interbedded rock mass of the tunnel. A grouting pipe (2) is installed on the support rod (1) and left in the hole of the soft and hard interbedded rock mass of the tunnel for grouting after the self-advancing rod enters the tunnel soft and hard interbedded rock mass and is pulled out of the support rod (1). And the drill bit (3) fixed to the end of the support rod (1); An adhesive part (4) supporting the grouting pipe body (2) is provided between the grouting pipe body (2) and the support rod body (1). The support rod (1) is fixedly connected to a stop (5) on the side away from the drill bit (3) to prevent relative sliding between the grouting pipe (2) and the support rod (1) during the process of the self-advancing rod being driven into the rock stratum. A soft pad (6) is provided between the stop part (5) and the grouting pipe body (2) to provide a certain sliding space between the grouting pipe body (2) and the support rod body (1) during the process of the self-advancing rod body being driven into the rock layer. The grouting pipe (2) has a grouting section on the side near the drill bit (3). Several grouting holes (2-1) for grouting are provided on the wall of the grouting section of the grouting pipe (2). The end of the grouting pipe (2) away from the drill bit (3) is provided with a reinforcing hoop (2-3) to prevent the tail end of the grouting pipe (2) from cracking during the process of the self-advancing rod entering the soft and hard interlayered rock mass of the tunnel. The grouting pipe (2) narrows at the end near the drill bit (3) to form a conical head (2-2); the outer diameter of the support rod (1) and the drill bit (3) is smaller than the minimum inner diameter of the grouting pipe (2) at the conical head (2-2).

2. The self-advancing rod for grouting construction in alternating soft and hard rock masses in tunnels according to claim 1, characterized in that, The adhesive part (4) shown is a polyurethane material or high-strength grouting material that is injected between the grouting pipe (2) and the support rod (1) and solidifies.

3. A method for grouting construction in tunnels with alternating layers of soft and hard rock, characterized in that, Using the self-advancing rod body according to any one of claims 1-2, the following steps are included: (1) Sleeve the grouting pipe (2) over the outside of the support rod (1) so that the tail end of the grouting pipe (2) abuts against the soft pad (6); (2) Inject polyurethane material or high-strength grouting material between the grouting pipe (2) and the support rod (1); (3) Fix the drill bit (3) to the support rod (1) at the front end of the support rod (1); and connect the support rod (1) to the impact drill at the tail end of the support rod (1); (4) Use an impact drill to drive the connected self-advancing rod into the soft and hard alternating rock strata of the tunnel at the designed location on the tunnel wall; (5) When the self-advancing rod enters the design position, the support rod (1) is pulled out from the grouting pipe (2) and grout is injected using the grouting pipe (2).

4. The method for grouting construction in tunnels with alternating layers of soft and hard rock, as described in claim 3, is characterized in that... In step (1), before the grouting pipe (2) is fitted onto the outside of the support rod (1), grease is applied to the outer wall of the support rod (1).

5. A method for grouting construction in tunnels with alternating layers of soft and hard rock, as described in claim 3, characterized in that... In step (2), before filling the grouting pipe (2) and the support rod (1) with polyurethane material or high-strength grouting material, the grouting hole (2-1) is first sealed with a plug (7); after solidification, the plug (7) is removed.

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