A reserved protection device for the construction end of a locking foot anchor pipe and a construction method thereof

Abstract

The present invention provides a reserved protection device for the construction end of a locking foot anchor pipe and a construction method thereof. The reserved protection device comprises a protective sleeve, a fixed disk, a push piece, a protective disk and a protective cover. The protective sleeve is provided with a first mounting hole and a first mounting groove, and the first mounting hole and the first mounting groove are arranged and connected along the axial direction; the fixed disk is arranged in the first mounting groove, and the fixed disk is provided with a threaded hole, and the threaded hole is coaxially arranged and connected with the first mounting hole; the first end of the push piece is inserted in the first mounting hole, the middle part of the push piece is threadedly connected with the threaded hole, and the second end of the push piece is provided with an operating part, and the push piece can rotate relative to the protective sleeve and the fixed disk; the protective disk blocks the first mounting groove, and the protective disk is provided with a second mounting hole, and the second end of the push piece extends outward through the second mounting hole, and the operating part is located on the outside of the protective sleeve; the protective cover is wrapped on the second end of the push piece, and the operating part is located in the protective cover. The present invention can protect the construction end of the locking foot anchor pipe and can be easily demoulded.

Description

Technical Field

[0001] The invention relates to the field of initial tunnel support construction, and in particular to a reserved protection device for a construction end of a locking foot anchor pipe and a construction method thereof. Background Art

[0002] In tunnel construction, the foot-locking construction technology is a conventional technical measure in the industry and is widely used in earth tunnels and broken rock tunnels. Foot-locking mainly refers to the process of fixing the foot of the steel arch frame after the upper step excavation is completed and the steel arch frame is erected. The foot-locking anchor pipe is different from the anchor rod. Its main function is to limit the rigid body displacement of the steel arch frame as much as possible, so that it can bear the pressure caused by the deformation of the surrounding rock as soon as possible, and improve the stability of the initial support of the tunnel.

[0003] In the current construction in the industry, construction units can ensure timely construction according to requirements for the construction of lock-foot anchor pipes, but there is a lag in the grouting of anchor pipes. This is mainly due to the fact that the lock-foot grouting operation of the lock-foot anchor pipe is carried out after the arch frame is installed. Since the overall grouting process takes a long time, the surrounding rock is exposed for a long time from excavation to the start of concrete spraying, which will inevitably lead to relaxation of the surrounding rock. If the surrounding rock stability of the face is poor, a long wait will inevitably cause the working face to become unstable or even collapse.

[0004] Therefore, in order to meet the requirements of rapid closure of surrounding rock and primary support and speed up the closed loop and closure time, the grouting process of the lock-foot anchor pipe is no longer strictly required to be controlled during the steel frame installation process. Instead, the grouting process of the lock-foot anchor pipe is adjusted and optimized to after the sprayed primary support concrete construction, that is, after the primary support steel arch frame is installed, the lock-foot anchor pipe is drilled and welded immediately, and then the sprayed concrete construction of this cycle is carried out immediately. When the drilling process of the next cycle is carried out, the grouting of the lock-foot anchor pipe is carried out synchronously. On the whole, the process is "overlapping", which can not only ensure the timely drilling of the anchor pipe, but also ensure the completion of grouting reinforcement within the effective time, and ultimately ensure the construction quality and control effect of the lock-foot.

[0005] However, during the operation, when grouting construction is carried out after spraying the initial support concrete, a problem needs to be solved, that is, how to protect the pre-connected grouting port of the locking anchor pipe to avoid the tedious operation of covering it with sprayed concrete and then chiseling it off. Summary of the invention

[0006] The first object of the present invention is to provide a reserved protection device for the construction end of the locking foot anchor pipe which can protect the construction end of the locking foot anchor pipe during the initial concrete construction and can be easily demoulded after the initial concrete construction.

[0007] The second object of the present invention is to provide a construction method comprising the above-mentioned reserved protection device.

[0008] In order to achieve the above-mentioned first purpose, the present invention provides a reserved protection device for the construction end of a locking foot anchor pipe, comprising a protective sleeve, a fixed plate, a push piece, a protective plate and a protective cover, the protective sleeve is provided with a first mounting hole and a first mounting groove, the first mounting hole and the first mounting groove are arranged axially and pass through both ends of the protective sleeve; the fixed plate is arranged in the first mounting groove, the fixed plate is provided with a threaded hole, the threaded hole is coaxially arranged and connected with the first mounting hole; the first end of the push piece can be rotatably inserted in the first mounting hole, the middle part of the push piece is threadedly connected with the threaded hole, the second end of the push piece is provided with an operating part, and the push piece can rotate relative to the protective sleeve and the fixed plate; the protective plate is blocked at the notch of the first mounting groove, the protective plate is provided with a second mounting hole, the second end of the push piece extends outward through the second mounting hole, and the operating part is located on the outside of the protective plate; the protective cover is wrapped on the second end of the push piece, and the operating part is located inside the protective cover.

[0009] It can be seen from the above scheme that the end pipe opening of the locking foot anchor pipe is blocked by setting a protective sleeve to prevent the primary support concrete from covering or blocking the locking foot anchor pipe when spraying the primary support concrete, thereby affecting the normal grouting operation of the subsequent locking foot anchor pipe; by setting a push piece and a fixed plate threaded connection, when demoulding, the push piece is twisted to make the fixed plate and the protective sleeve move along their own axial direction, thereby realizing easy demoulding of the reserved protective device. The present invention also has the advantages of simple operation, reusability and strong practicality.

[0010] A further solution is that the outer diameter of the first end of the protective sleeve is smaller than the outer diameter of the second end of the protective sleeve, and the first mounting groove is located at the second end of the protective sleeve; the first mounting hole includes a first hole section, a second hole section and a third hole section in sequence, the diameter of the first hole section is larger than the diameter of the third hole section, the second hole section is set to be conical, the length of the first hole section is larger than the total length of the second hole section and the third hole section, and the third hole section is connected to the first mounting groove.

[0011] It can be seen from the above scheme that by setting the outer diameter of one end of the protective sleeve buried in the primary support concrete to be smaller than the outer diameter of the other end, the pipe opening of the locking foot anchor pipe can be blocked, and the contact area between the protective sleeve and the primary support concrete can be minimized, thereby reducing the difficulty of later demoulding.

[0012] A further solution is that the pushing member also includes a pushing head and a threaded rod, the pushing head and the operating part are respectively arranged at both ends of the threaded rod, and the length of the threaded rod is greater than the total length of the second hole section, the threaded hole and the second mounting hole.

[0013] It can be seen from the above solution that by providing a sufficiently long threaded rod, the pushing member can push the protective sleeve to move a sufficient displacement, thereby ensuring that the protective sleeve is completely separated from the primary concrete.

[0014] A further solution is that the protective cover and the protective plate are both made of rubber, and the fixing plate is made of metal material.

[0015] It can be seen from the above scheme that the protective sleeve made of rubber material can effectively prevent liquid concrete from flowing out of the mold; the fixed plate made of metal material can help ensure that the strength of the fixed plate meets the design requirements, so that the protective sleeve can be smoothly ejected from the mold when the push piece rotates.

[0016] A further solution is that a second mounting groove is provided on the inner side of the protective cover, the second mounting groove includes a first groove section and a second groove section, one end of the first groove section has an opening, and the other end of the first groove section is connected to the second groove section; the first groove section is clearance-matched with the middle part of the pushing member, and the second groove section is interference-fitted with the operating part, or the first groove section is threadedly connected with the middle part of the pushing member, and the second groove section is cooperatively connected with the operating part.

[0017] In order to achieve the above-mentioned second purpose, the present invention provides a construction method of a reserved protection device for the construction end of a locking foot anchor pipe, including the above-mentioned reserved protection device, and the method comprises the following steps:

[0018] After installing the primary steel arch frame, install the locking foot anchor pipe so that one end of the locking foot anchor pipe protrudes outside the primary steel arch frame;

[0019] Install the reserved protection device, specifically: first install the protection cover, the fixing plate and the protection plate together, then install the push piece so that the push piece is located at one end of the first installation hole, then put the protection cover on the end of the locking foot anchor pipe so that the push piece is adjacent to the end of the locking foot anchor pipe, and then install the protection cover;

[0020] Spraying the primary support concrete, so that the primary support steel arch frame is immersed in the primary support concrete, and the protective cover and the jacking member partially protrude outside the primary support concrete;

[0021] After the primary support concrete is initially solidified, the reserved protection device is removed. Specifically, the protective cover is first removed, and then the push piece is twisted so that the push piece abuts against the locking foot anchor pipe and drives the protective cover to separate from the primary support concrete.

[0022] A further solution is that when the push piece is turned, the protective sleeve moves outward along its own axial direction, so that an end groove is formed on the surface of the primary concrete, and the end groove matches the shape of one end of the protective sleeve.

[0023] A further solution is to weld a connecting joint at the end of the locking foot anchor pipe, connect the connecting joint to the grouting pipe, and the grouting pipe injects grout into the tunnel surrounding rock through the locking foot anchor pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the installation position of the locking foot anchor pipe in the tunnel construction of the present invention.

[0025] Figure 2 It is a partial diagram of an embodiment of a reserved protection device of the present invention.

[0026] Figure 3 It is a cross-sectional view of an embodiment of a reserved protection device of the present invention.

[0027] Figure 4 It is an exploded view of an embodiment of a reserved protection device of the present invention.

[0028] Figure 5 It is a structural schematic diagram of installing a reserved protection device in an embodiment of the construction method of the present invention.

[0029] Figure 6 It is a schematic diagram of the structure after spraying the initial support concrete in the construction method embodiment of the present invention.

[0030] Figure 7 It is a schematic structural diagram of the reserved protection device during demoulding in the construction method embodiment of the present invention.

[0031] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0032] Pre-protection device embodiment

[0033] See also Figure 1 and Figure 2 During the tunnel construction process, four locking foot anchor pipes 1 are generally required to be set on the left and right sides of the tunnel. The four locking foot anchor pipes 1 on the same side are set in pairs at the bottom wall and the middle of the tunnel side wall. The two locking foot anchor pipes 1 in the same group intersect at a first preset angle θ1, and one of the locking foot anchor pipes 1 intersects with the vertical direction or the horizontal direction at a second preset angle θ2. In this embodiment, the first preset angle and the second preset angle are both 20°. The first end of the locking foot anchor pipe 1 penetrates deep into the tunnel surrounding rock to facilitate grouting deep into the tunnel surrounding rock; the second end of the locking foot anchor pipe 1 passes through the primary support steel arch frame 2 and extends to the center of the tunnel.

[0034] See also Figure 3 to Figure 4 The reserved protection device for the construction end of the locking foot anchor pipe provided in this embodiment is used, on the one hand, to block and protect the pipe opening of the second end of the locking foot anchor pipe 1 to prevent the primary support concrete 8 from blocking the locking foot anchor pipe 1 when the primary support concrete 8 is sprayed; on the other hand, after the primary support concrete 8 is sprayed, the reserved protection device can be quickly and easily removed.

[0035] The reserved protection device comprises a protection sleeve 3, a fixing plate 4, a pushing member 5, a protection plate 6 and a protection cover 7.

[0036] The protective sleeve 3 is set to a truncated cone structure. The outer diameter of the first end of the protective sleeve 3 is smaller than the outer diameter of the second end of the protective sleeve 3. The first end of the protective sleeve 3 faces the tunnel surrounding rock and is adjacent to the primary support steel arch frame 2. The inner side of the protective sleeve 3 is provided with a first mounting hole 31 and a first mounting groove 32. The first mounting hole 31 and the first mounting groove 32 are arranged along the axial direction of the protective sleeve 3 and pass through the two ends of the protective sleeve 3. The first mounting groove 32 is located at the second end of the protective sleeve 3. The first mounting hole 31 extends axially from the first end of the protective sleeve 3 to the first mounting groove 32. The first mounting hole 31 is coaxially arranged and connected with the first mounting groove 32. The first mounting groove 32 is set to be circular, and the shape of the fixing plate 4 matches the first mounting groove 32.

[0037] The fixing plate 4 is arranged in the first mounting groove 32, a plurality of first connecting members 33 are arranged on the groove wall of the first mounting groove 32, a plurality of first connecting holes 42 are arranged on the peripheral wall of the fixing plate 4, and the first connecting members 33 are matched and connected with the corresponding first connecting holes 42. A threaded hole 41 is opened in the middle of the fixing plate 4, and the threaded hole 41 is coaxially arranged and connected with the first mounting hole 31.

[0038] The push member 5 includes a push head 51, a threaded rod 52 and an operating portion 53, which are respectively arranged at both ends of the threaded rod 52. The push head 51 is arranged in the first mounting hole 31 and is loosely matched with the first mounting hole 31; the threaded rod 52 is threadedly connected to the threaded hole 41; the operating portion 53 is arranged as a hexagonal column, and the maximum width of the operating portion 53 is smaller than the outer diameter of the threaded rod 52. The worker can control the entire push member 5 to rotate relative to the fixed plate 4 and the protective cover 3 through the operating portion 53.

[0039] The protection plate 6 is blocked at the notch of the first mounting groove 32. A plurality of second connecting members 61 are arranged on the protection plate 6. A plurality of second connecting holes 43 are provided on the end surface of the fixed plate 4. The second connecting members 61 are connected to the second connecting holes 43 in a one-to-one correspondence, so that the protection plate 6, the fixed plate 4 and the protective sleeve 3 are connected as a whole. A second mounting hole 62 is provided in the middle of the protection plate 6. The diameter of the second mounting hole 62 is larger than the diameter of the threaded hole 41, that is, the threaded rod 52 is loosely matched with the second mounting hole 62 to prevent the threaded rod 52 from rubbing against the hole wall of the second mounting hole 62 when rotating, thereby avoiding damage to the protection plate 6 after long-term use, which is conducive to improving its service life. The threaded rod 52 extends outward through the second mounting hole 62, and the operating part 53 is located on the outside of the protection plate 6.

[0040] The protective cover 7 is wrapped around the second end of the push member 5 , and the protective cover 7 blocks the gap between the second mounting hole 62 and the push member 5 to prevent concrete slurry from entering. The operating part 53 is located in the protective cover 7 .

[0041] Specifically, the first mounting hole 31 includes a first hole section 311, a second hole section 312 and a third hole section 313 in sequence, the diameter of the first hole section 311 is larger than the diameter of the third hole section 313, the second hole section 312 is set to be a cone that matches the shape of the push head 51, the length of the first hole section 311 is larger than the total length of the second hole section 312 and the third hole section 313, and the third hole section 313 is connected to the first mounting groove 32. The length of the threaded rod 52 is larger than the total length of the third hole section 313, the threaded hole 41 and the second mounting hole 62, ensuring that the operating portion 53 of the push member 5 is on the outside of the protective plate 6 during the demoulding process of the rotating push protection sleeve 3, so as to facilitate the operation of the worker.

[0042] The protective sleeve 3 and the protective plate 6 are both made of rubber material, which is convenient for demoulding. The fixing plate 4 is made of metal material, preferably steel, so that the fixing plate 4 has sufficient strength, especially the thread in the threaded hole 41 has sufficient strength to drive the protective sleeve 3 to demould.

[0043] A second installation groove 71 is provided inside the protective cover 7. The second installation groove 71 includes a first groove section 711 and a second groove section 712. The first groove section 711 opens toward one end of the protective plate 6, and the other end of the first groove section 711 is connected to the second groove section 712. The first groove section 711 is clearance-matched with the threaded rod 52, and the second groove section 712 is interference-matched with the operating portion 53, or the first groove section 711 is threadedly connected with the threaded rod 52, and the second groove section 712 is cooperatively connected with the operating portion 53, so as to facilitate the installation and removal of the protective cover 7.

[0044] Construction method example

[0045] See also Figures 5 to 7 The construction method of the reserved protection device for the construction end of the locking foot anchor pipe provided in this embodiment includes the reserved protection device of the above embodiment, and the construction method includes the following steps:

[0046] Step 1: After installing the primary steel arch frame 2, use a drilling rig to drill holes at both ends of the bottom of the primary steel arch frame 2, install the locking foot anchor pipe 1, and weld the locking foot anchor pipe 1 to the primary steel arch frame 2 firmly in accordance with the construction inspection requirements, so that one end of the locking foot anchor pipe 1 protrudes from the surface of the primary steel arch frame 2 toward the center of the tunnel.

[0047] Step 2, install the reserved protection device. Specifically: first install the protective sleeve 3, the fixed plate 4 and the protective plate 6 together to form an integral component; then install the push piece 5 so that the push head 51 of the push piece 5 is located in the second hole section 312 of the first mounting hole 31, and the threaded rod 52 of the push piece 5 partially passes through the second mounting hole 62 of the protective plate 6, and the operating part 53 is also located outside the second mounting hole 62; then the integral component is sleeved on the end of the locking foot anchor pipe 1, so that the locking foot anchor pipe 11 is inserted into the first mounting hole 31 and adjacent to the end face of the push piece 5. In this process, the end face of the protective sleeve 3 should be as close to the primary support steel arch frame 2 as possible. On the one hand, the primary support steel arch frame 2 is used to block the gap between the protective sleeve 3 and the locking foot anchor pipe 11 to prevent concrete from entering. On the other hand, the end face of the locking foot anchor pipe 11 can be abutted against the end face of the push piece 5 to reduce the moving distance of the push piece 5 in its own axial direction and improve the demoulding efficiency. Then install the protective cover 7 so that the protective cover 7 wraps around the end of the push member 5 and the protective cover 7 should be as close to the surface of the protection plate 6 as possible to prevent concrete from entering the protective cover 7 from the gap between the protective cover 7 and the protection plate 6.

[0048] Step three, spraying the primary support concrete 8, so that the primary support steel arch frame 2 is immersed in the primary support concrete 8, and the protective cover 3 and the push piece 5 partially protrude from the primary support concrete 8. In this embodiment, the first end of the protective cover 3 is buried in the primary support concrete 8, and the middle part of the protective cover 3 and the second end are both located outside the primary support concrete 8.

[0049] Step 4: After the primary support concrete 8 is initially solidified, remove the reserved protective device. Specifically: first remove the protective cover 7, then manually or by using a tool to twist the operating part 53 and then twist the entire push piece 5, so that the push piece 5 abuts against the locking foot anchor pipe 1 and drives the protective sleeve 3 to separate from the primary support concrete 8. The worker drives the operating part 53 to rotate around the axial direction of the push piece 5. Since one end of the protective sleeve 3 is fixedly connected to the primary support concrete 8, the primary support concrete 8 limits the rotation of the guarantee sleeve, and the first connecting member 33 limits the rotation of the fixed disk 4, so that when the push piece 5 rotates, the protective sleeve 3 and the fixed disk 4 can move along the axial direction of the push piece 5. Since the protective sleeve 3 is sleeved on the locking foot anchor pipe 1, the end face of the push piece 5 abuts against the locking foot anchor pipe 11, so that the protective sleeve 3 and the fixed disk 4 can only move in the direction away from the primary support concrete 8 to achieve demoulding. Tools with hexagonal holes can be used when twisting.

[0050] After the protective sleeve 3 is demoulded, an end groove is formed on the surface of the primary supporting concrete 8, and the end groove matches the shape of one end of the protective sleeve 3, reserving sufficient operating space for subsequent welding connection joints and connecting grouting pipe operations.

[0051] Step five, a connecting joint is welded at the end of the locking foot anchor pipe 1 , the connecting joint is connected to the grouting pipe, and the grouting pipe injects grout into the tunnel surrounding rock through the locking foot anchor pipe 1 .

[0052] In summary, the present invention blocks the end pipe opening of the locking foot anchor pipe by setting a protective sleeve to prevent the primary support concrete from covering or blocking the locking foot anchor pipe when spraying the primary support concrete, thereby affecting the normal grouting operation of the subsequent locking foot anchor pipe; by setting a threaded connection between the push piece and the fixed plate, when demoulding, the push piece is twisted to make the fixed plate and the protective sleeve move together along their own axial direction, thereby realizing easy demoulding of the reserved protective device. The present invention also has the advantages of simple operation, reusability and strong practicality.

[0053] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A reserved protection device for the construction end of a locking foot anchor pipe, characterized in that: include: A protective sleeve, wherein the protective sleeve is provided with a first mounting hole and a first mounting groove, wherein the first mounting hole and the first mounting groove are arranged in an axial direction and pass through two ends of the protective sleeve; A fixing plate, the fixing plate is arranged in the first mounting groove, the fixing plate is provided with a threaded hole, and the threaded hole is coaxially arranged and connected with the first mounting hole; A push member, wherein the first end of the push member is rotatably inserted into the first mounting hole, the middle portion of the push member is threadedly connected to the threaded hole, the second end of the push member is provided with an operating portion, and the push member can rotate relative to the protective cover and the fixed plate; A protection plate, the protection plate is sealed at the notch of the first mounting groove, the protection plate is provided with a second mounting hole, the second end of the push member extends outward through the second mounting hole, and the operating portion is located on the outside of the protection plate; A protective cover, the protective cover is wrapped around the second end of the push member, and the operating part is located in the protective cover; The outer diameter of the first end of the protective sleeve is smaller than the outer diameter of the second end of the protective sleeve, and the first mounting groove is located at the second end of the protective sleeve; The first mounting hole includes a first hole segment, a second hole segment and a third hole segment in sequence, the diameter of the first hole segment is larger than the diameter of the third hole segment, the second hole segment is set to be tapered, the length of the first hole segment is larger than the total length of the second hole segment and the third hole segment, and the third hole segment is connected to the first mounting groove; A second installation groove is provided on the inner side of the protective cover, the second installation groove includes a first groove section and a second groove section, one end of the first groove section is provided with an opening, and the other end of the first groove section is connected with the second groove section; The first groove section is clearance-matched with the middle part of the pushing member, and the second groove section is interference-matched with the operating portion, or the first groove section is threadedly connected with the middle part of the pushing member, and the second groove section is cooperatively connected with the operating portion.

2. The reserved protection device according to claim 1, characterized in that: The pushing member further includes a pushing head and a threaded rod, wherein the pushing head and the operating part are respectively arranged at two ends of the threaded rod, and the length of the threaded rod is greater than the total length of the second hole section, the threaded hole and the second mounting hole.

3. The reserved protection device according to claim 1, characterized in that: The protective sleeve and the protective plate are both made of rubber, and the fixing plate is made of metal material.

4. A construction method for a reserved protection device for the construction end of a locking foot anchor pipe, comprising the reserved protection device as described in any one of claims 1 to 3 above, characterized in that: The method comprises the following steps: After installing the primary steel arch frame, installing the locking foot anchor pipe so that one end of the locking foot anchor pipe protrudes outside the primary steel arch frame; Install the reserved protection device, specifically: first install the protection cover, the fixing plate and the protection plate together, then install the push piece so that the push piece is located at one end of the first installation hole, then put the protection cover on the end of the locking foot anchor pipe so that the push piece is adjacent to the end of the locking foot anchor pipe, and then install the protection cover; Spraying primary support concrete so that the primary support steel arch frame is immersed in the primary support concrete and the protective cover and the push piece partially protrude out of the primary support concrete; After the primary support concrete is initially solidified, the reserved protection device is removed. Specifically, the protection cover is first removed, and then the push piece is twisted so that the push piece abuts against the locking foot anchor pipe and drives the protection cover to separate from the primary support concrete.

5. The construction method according to claim 4, characterized in that: When the jacking member is turned, the protective sleeve moves outward along its own axial direction, so that an end groove is formed on the surface of the primary concrete, and the end groove matches the shape of one end of the protective sleeve.

6. The construction method according to claim 4, characterized in that: A connecting joint is welded at the end of the locking foot anchor pipe, and the connecting joint is connected to a grouting pipe, and the grouting pipe injects grout into the tunnel surrounding rock through the locking foot anchor pipe.

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