Advanced pipe shed structure of tunnel portal

Abstract

The utility model relates to a tunnel portal advance pipe shed structure, and relates to the technical field of tunnel construction.The tunnel portal advance pipe shed structure comprises multiple sets of mounting holes formed in a tunnel portal guide wall at intervals and pipe shed steel pipes facilitating concrete pouring in the mounting holes, and multiple sets of grouting holes are formed in the pipe shed steel pipes; the utility model discloses a reinforcement cage for improving pipe shed steel pipe supporting strength. The pipe shed steel pipes are installed in the installation holes in a sealed mode, the reinforcement cage is installed in the pipe shed steel pipes, meanwhile, the reinforcement cage does not affect pouring of cement mortar in the pipe shed steel pipes, and then gaps between the pipe shed steel pipes and the installation holes are tightly filled with the cement mortar through the pipe shed steel pipes; the interiors of the pipe shed steel pipes are jointly supported through the reinforcement cage and the cement mortar, then the rigidity and strength of a single set of pipe shed steel pipes are improved, the multiple sets of pipe shed steel pipes jointly form the advance pipe shed, finally, the supporting acting force of the advance pipe shed on a soil body at a tunnel portal is improved, and the probability that the pipe shed deforms is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of tunnel construction, and in particular to an advanced pipe-roof structure at a tunnel entrance. Background Art

[0002] This method is used before tunnel excavation to increase the bearing capacity of the ground and ensure construction safety. This method involves pre-installing steel pipes or other supporting materials in front of the tunnel excavation face to form an arched continuum. This reinforces the ground ahead of the excavation face and uses its supporting force to maintain the stability of the soil ahead, reducing surface settlement.

[0003] At present, the construction steps of the advanced pipe roof at the tunnel entrance mainly include: first, using different drilling tool combinations according to different stratum conditions, and then using pipe roof steel pipes with casting holes to cast the drilled holes according to the geological conditions and the needs of the grouting process, so as to form the advanced pipe roof.

[0004] However, since the advanced pipe roof needs to bear the load at the tunnel entrance, it requires a strong supporting force. The combination of the pipe roof steel pipes and concrete alone makes the pipe roof prone to deformation under the long-term action of the soil at the tunnel entrance, thereby reducing the stability of the soil at the tunnel entrance. Utility Model Content

[0005] In order to increase the supporting force of the advance pipe roof on the soil at the tunnel entrance and reduce the probability of deformation of the pipe roof, the present application provides a tunnel entrance advance pipe roof structure.

[0006] This application provides a tunnel entrance advance pipe roof structure, which adopts the following technical solutions:

[0007] A tunnel entrance advance pipe-roof structure includes a plurality of groups of mounting holes spaced apart on a guide wall of the tunnel entrance, wherein pipe-roof steel pipes are provided in the mounting holes for facilitating pouring concrete in the mounting holes, a plurality of groups of grouting holes are provided on the pipe-roof steel pipes, and a steel cage is provided in the pipe-roof steel pipes for increasing the supporting strength of the pipe-roof steel pipes.

[0008] By adopting the above technical solution, the pipe-roof steel pipe is sealed and installed in the installation hole, and the steel cage is installed in the pipe-roof steel pipe. At the same time, the steel cage does not affect the pouring of cement mortar in the pipe-roof steel pipe. Then, the gap between the pipe-roof steel pipe and the installation hole is tightly filled with cement mortar through the pipe-roof steel pipe. The steel cage and cement mortar jointly support the inside of the pipe-roof steel pipe, thereby improving the stiffness and strength of a single group of pipe-roof steel pipes. Multiple groups of pipe-roof steel pipes together form an advanced pipe-roof, which ultimately improves the supporting force of the advanced pipe-roof on the soil at the tunnel entrance and reduces the probability of deformation of the pipe-roof.

[0009] Furthermore, the steel cage comprises:

[0010] Fixed rings, with multiple groups of fixed rings spaced apart and arranged inside the steel pipes of the pipe roof;

[0011] Connecting steel bars are connected to multiple groups of fixing rings, and multiple groups of connecting steel bars are arranged in a circular array on the fixing rings.

[0012] By adopting the above technical solution, multiple groups of fixing rings and multiple groups of connecting steel bars cooperate with each other to form a steel cage, which supports the concrete inside the pipe-roof steel pipe, thereby improving the stiffness and strength of the pipe-roof steel pipe, and ultimately improving the stiffness and strength of the pipe-roof steel pipe, and reducing the probability of deformation of the pipe-roof steel pipe.

[0013] Furthermore, the pipe roof steel pipe includes:

[0014] A front end of the steel pipe is disposed in the mounting hole near the bottom, and the front end of the steel pipe is tapered near the bottom of the mounting hole;

[0015] The middle section of the steel pipe is arranged on the side of the front end of the steel pipe away from the bottom of the installation hole and is hollow inside. The multiple groups of grouting holes are arranged at intervals on the middle section of the steel pipe, and the multiple groups of grouting holes are arranged in a plum blossom shape;

[0016] The tail end of the steel pipe is arranged on a side of the middle section of the steel pipe away from the front end of the steel pipe, and the tail end of the steel pipe does not contain a grouting hole.

[0017] By adopting the above technical solution, the tapered front end of the steel pipe is easy to insert into the installation hole, and the middle section of the steel pipe with multiple groups of grouting holes is mainly used to evenly inject the cement mortar in the pipe-roof steel pipe into the installation hole. The tail end of the steel pipe is easy to seal tightly with the installation hole to ensure tight pouring in the installation hole, and it is also easy to connect detachably with the grouting machine.

[0018] Furthermore, a plurality of groups of support blocks slidably arranged on the inner side wall of the pipe-roof steel pipe are arranged at intervals on the fixed ring located inside the front end of the steel pipe, the width of the support block away from the fixed ring is greater than the width of the end close to the fixed ring, and a plurality of groups of connecting steel bars are provided with a bending portion near the front end of the steel pipe, and the bending angle of the bending portion is the same as the taper of the front end of the steel pipe.

[0019] By adopting the above technical solution, multiple groups of support blocks are supported on the inner wall of the front end of the steel pipe, so as to improve the coaxiality between the steel cage and the pipe-roof steel pipe. At the same time, the bending portion and the inner wall of the conical structure of the front end of the steel pipe are pressed against each other, thereby further improving the coaxiality between the steel cage and the pipe-roof steel pipe.

[0020] Furthermore, a filling layer is provided on the side of the mounting hole away from the bottom to seal and fill the gap between the outer wall of the rear end of the steel pipe and the mounting hole, and the filling layer is composed of hemp and an anchoring agent.

[0021] By adopting the above technical solution, before pouring into the installation hole, hemp wire is tied to the outer wall of the tail end of the steel pipe, so that the side of the hemp wire away from the pipe rack steel pipe is pressed tightly against the installation hole, and then the gap between the hemp wires is further sealed by the anchor agent, and finally the gap between the installation hole and the tail end of the steel pipe is tightly sealed.

[0022] Furthermore, a pressure gauge for detecting the grouting pressure in the pipe-roof steel pipe is detachably provided on the pipe-roof steel pipe.

[0023] By adopting the above technical solution, the pressure gauge is fixedly installed on the grouting machine. When the grouting machine is sealed and connected to the corresponding pipe-roof steel pipe, the pressure gauge can detect the pressure value inside the pipe-roof steel pipe.

[0024] Furthermore, a reinforcement body is tightly arranged inside the pipe-roof steel pipe, the steel cage is arranged inside the reinforcement body and supports and fixes the inside of the pipe-roof steel pipe, and the reinforcement body is tightly filled with M30 cement mortar.

[0025] By adopting the above technical solution, higher strength cement mortar is used to tightly fill the inside of the pipe-roof steel pipe, so that the formed reinforcement body has higher strength, and then cooperates with the steel cage to improve the rigidity and strength of the pipe-roof steel pipe.

[0026] Furthermore, the plurality of mounting holes are drilled using a skip-hole drilling method.

[0027] By adopting the above technical solution and using the skip hole drilling method to drill the installation holes, the stress concentration phenomenon is reduced and the drilling quality is improved.

[0028] Furthermore, test holes are provided on both sets of arch feet of the tunnel entrance guide wall, and the test holes are used to find out the characteristics of the stratum and conduct grouting and mortar filling tests.

[0029] By adopting the above technical solution, the characteristics of the stratum are first found through the test hole before pouring, and then the grouting and mortar filling tests are carried out through the test hole, and then the appropriate grouting pressure value and mortar ratio are selected according to the stratum at that location.

[0030] In summary, this application includes at least one of the following beneficial technical effects:

[0031] The pipe shed steel pipe is sealed and installed in the installation hole, the steel reinforcement cage is installed in the pipe shed steel pipe, meanwhile the steel reinforcement cage does not affect the pouring of the cement mortar in the pipe shed steel pipe, then the pipe shed steel pipe and the installation hole are tightly filled with the cement mortar through the pipe shed steel pipe, meanwhile the rigidity and the strength of the reinforced body are enhanced through the steel reinforcement cage, the steel reinforcement cage and the reinforced body jointly support the inside of the pipe shed steel pipe, thereby the rigidity and the strength of the single pipe shed steel pipe are improved, multiple pipe shed steel pipes jointly form the advanced pipe shed, and finally the supporting force of the advanced pipe shed on the soil at the tunnel portal is improved, and the probability of deformation of the pipe shed is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a tunnel portal advanced pipe shed structure of the present application;

[0033] Figure 2 is a pipe shed steel pipe of the present application, wherein a steel reinforcement cage is placed in the pipe shed steel pipe;

[0034] Figure 3 is a steel reinforcement cage structure of the present application.

[0035] The drawings show that: 1, a tunnel portal guide wall; 11, a core soil platform; 12, an installation hole; 13, a test hole; 2, a pipe shed steel pipe; 21, a front end of the steel pipe; 22, a middle section of the steel pipe; 221, a grouting hole; 23, a tail end of the steel pipe; 3, a steel reinforcement cage; 31, a fixing ring; 311, a support block; 32, a connecting steel bar; 321, a bent part; 4, a filling layer. DETAILED DESCRIPTION

[0036] The drawings are briefly described as follows: Figure 1-3 The present application is further described in detail.

[0037] The present application discloses a tunnel portal advanced pipe shed structure.

[0038] Reference is made to Figure 1 and Figure 2 A tunnel portal advanced pipe shed structure comprises multiple installation holes 12 which are spaced apart and arranged on a tunnel portal guide wall 1, a pipe shed steel pipe 2 is arranged in each installation hole 12, the pipe shed steel pipe 2 is used for facilitating pouring of concrete in the installation hole 12, multiple grouting holes 221 are arranged on the pipe shed steel pipe 2, and a steel reinforcement cage 3 is arranged in the pipe shed steel pipe 2 and used for improving the supporting strength of the pipe shed steel pipe 2.

[0039] Reference is made to Figure 1 At the tunnel portal, concrete is used for tunnel portal guide wall 1 construction, after the concrete of the tunnel portal guide wall 1 reaches the design strength, a crawler-type down-the-hole drill is used for drilling, a core soil platform 11 is reserved inside the tunnel portal, and the drill is arranged on the reserved core soil platform 11, so as to facilitate drilling construction of the tunnel portal guide wall 1; the drill bit diameter of the present embodiment is φ127 mm.

[0040] Reference Figure 1 Before drilling the installation holes 12, mark the positions where the holes need to be drilled on the tunnel entrance guide wall 1 in advance, and then number the points where the holes need to be drilled in order from high hole positions to low hole positions, so as to divide the multiple groups of installation holes 12 set at intervals into odd-numbered holes and even-numbered holes. Then, adopt the skipping hole drilling method, drill the odd-numbered holes first, and after all the odd-numbered holes are drilled, cast the odd-numbered holes first; after the casting construction of the odd-numbered holes is completed and the slurry in the holes is solidified, drill the even-numbered holes in the same way, and finally cast the even-numbered holes.

[0041] Reference Figure 1 and Figure 2 The pipe-roof steel pipe 2 includes a steel pipe front end 21, a steel pipe middle section 22 and a steel pipe tail end 23, wherein the steel pipe front end 21 and the steel pipe tail end 23 are respectively fixedly connected to the two ends of the steel pipe middle section 22, and the steel pipe front end 21 has a conical structure near the bottom of the mounting hole 12; the steel pipe middle section 22 is hollow inside, and a plurality of groups of grouting holes 221 are arranged on the steel pipe middle section 22 at intervals, and the plurality of grouting holes 221 are arranged in a plum blossom shape; the steel pipe tail end 23 is hollow inside and communicates with the interior of the steel pipe middle section 22, and does not contain grouting holes 221 on the steel pipe tail end 23; when cement mortar is injected into the steel pipe tail end 23, the cement mortar is injected into the steel pipe middle section 22 through the interior, and the cement mortar in the pipe-roof steel pipe 2 is discharged into the mounting hole 12 through the plurality of grouting holes 221, thereby pouring concrete in the mounting hole 12; the outer diameter of the pipe-roof in this embodiment is φ108 mm, wherein the pipe-roof steel pipe 2 is prefabricated in advance.

[0042] Reference Figure 2 and Figure 3 In order to improve the supporting strength of the pipe-roof steel pipe 2, a steel cage 3 is provided in the pipe-roof steel pipe 2. The steel cage 3 is placed in the pipe-roof steel pipe 2 and is used to improve the supporting strength of the pipe-roof steel pipe 2. The steel cage 3 includes a fixing ring 31 and a connecting steel bar 32. There are multiple groups of fixing rings 31, and the multiple groups of fixing rings 31 are installed at intervals in the pipe-roof steel pipe 2. The axes of the multiple groups of fixing rings 31 coincide with each other; the connecting steel bars 32 are fixedly connected to the multiple groups of fixing rings 31. The connecting steel bars 32 are located on the outer side walls of the multiple groups of fixing rings 31. There are multiple groups of connecting steel bars 32, and the multiple groups of connecting steel bars 32 are installed in a circular array on the fixing rings 31; the fixing rings 31 of this embodiment are made of a stirrup steel pipe with a diameter of 42 mm and a width of 5 mm, and the connecting steel bars 32 are composed of steel bars with a diameter of 18 mm. There are 4 groups of connecting steel bars 32 in this embodiment.

[0043] Reference Figure 2 and Figure 3, because there is no supporting structure on the side of the steel cage 3 near the front end 21 of the steel pipe, when the steel cage 3 is placed in the pipe-roof steel pipe 2, the front end of the steel cage 3 is completely pressed against the side wall of the front end 21 of the steel pipe under the action of gravity, which eventually reduces the coaxiality between the steel cage 3 and the pipe-roof steel pipe 2; multiple groups of support blocks 311 are installed at intervals on the fixing ring 31 finally located in the front end 21 of the steel pipe, and the multiple groups of support blocks 311 are in sliding contact with the inner wall of the pipe-roof steel pipe 2, wherein the support block 311 is an arc structure near the side of the pipe-roof steel pipe 2, so as to facilitate sliding on the inner wall of the pipe-roof steel pipe 2, in order to prevent it from being stuck in the grouting hole 221 during movement, and at the same time ensure the normal flow of cement mortar when pouring into the pipe-roof steel pipe 2, the support block 31 The width of the end away from the fixing ring 31 is greater than the width of the end close to the fixing ring 31, and the width of the support block 311 at the end away from the fixing ring 31 is greater than the diameter of the grouting hole 221. At the same time, since the conical structure of the front end 21 of the steel pipe is hollow, a bending portion 321 is provided on the side of the multiple groups of connecting steel bars 32 close to the front end 21 of the steel pipe, and the bending angle of the bending portion 321 is the same as the taper of the front end 21 of the steel pipe. When the steel cage 3 is installed, the bending portion 321 is tightly pressed against the inner wall of the front end 21 of the steel pipe, further improving the coaxiality between the steel cage 3 and the pipe-roof steel pipe 2, ultimately improving the reinforcing effect of the steel cage 3 on the strength of the pipe-roof steel pipe 2, and reducing the influence of the steel cage 3 on the cement mortar during cement mortar pouring.

[0044] Reference Figure 1 and Figure 2 After the installation hole 12 is drilled, the pipe-roof steel pipe 2 and the steel cage 3 placed in the pipe-roof steel pipe 2 are placed into the installation hole 12. The tapered front end 21 of the steel pipe facilitates the insertion of the pipe-roof steel pipe 2 into the installation hole 12, thereby realizing the installation of the pipe-roof steel pipe 2 and the steel cage 3.

[0045] Reference Figure 1 and Figure 2 Before pouring the mounting hole 12, high-pressure gas is introduced into the mounting hole 12 to clean the mounting hole 12, and then a filling layer 4 is arranged on the outer wall of the steel pipe tail end 23 near the end of the mounting hole 12 away from the bottom. The gap between the outer wall of the steel pipe tail end 23 and the inner wall of the mounting hole 12 is sealed and filled by the filling layer 4 to ensure the quality of subsequent grouting; the filling layer 4 of this embodiment is composed of hemp fiber and anchoring agent.

[0046] Reference Figure 1 and Figure 2 Before pouring the installation hole 12, in order to find out the characteristics of the stratum, a group of test holes 13 are opened on the two groups of arch feet of the tunnel hole guide wall. The stratum characteristics are found through the test holes 13, and then the test holes 13 are subjected to grouting and mortar filling tests.

[0047] Reference Figure 1and Figure 2 A pressure gauge is detachably installed outside the hole of the installation hole 12 when the pipe shed steel pipe 2 is located, and the grouting pressure in the pipe shed steel pipe 2 can be monitored in real time through the pressure gauge; the pressure gauge of the embodiment is fixedly installed on the grouting machine, and when the grouting machine is sealingly connected with the corresponding pipe shed steel pipe 2, the pressure gauge can detect the pressure value in the pipe shed steel pipe 2.

[0048] Referring to Figure 1 and Figure 2 When the installation hole 12 is grouted, the odd holes in the installation hole 12 are grouted first, the grouting sequence is from bottom to top, the grouting method is to grout first dilution and then concentration, and the pressure value in the pipe shed steel pipe 2 is detected in real time through the pressure gauge during grouting, so that the grouting pressure value is controlled within the range of 0.5-1MPa, so that the grouting enters the gap between the pipe shed steel pipe 2 and the installation hole 12 through the multiple grouting holes 221 on the pipe shed steel pipe 2, so as to tightly fill the gap between the pipe shed steel pipe 2 and the installation hole 12 with cement mortar, and enhance the connection strength between the pipe shed and the tunnel portal guide wall 1; the cement mortar of M20 is used between the pipe shed steel pipe 2 and the gap of the installation hole 12 in the embodiment.

[0049] Referring to Figure 1 and Figure 2 The pipe shed steel pipe 2 is tightly provided with a reinforcing body, and the steel reinforcement cage 3 is located in the reinforcing body, which supports and fixes the inside of the pipe shed steel pipe 2 through the steel reinforcement cage 3 and the reinforcing body, so as to improve the support strength of the pipe shed steel pipe; the reinforcing body in the embodiment is tightly filled with M30 cement mortar, and the specific pouring process is as follows: after the grouting of the gap between the pipe shed steel pipe 2 and the installation hole 12 is completed, the slurry in the pipe shed steel pipe 2 is cleaned with clean water in time, and after cleaning, M30 cement mortar is used for tight filling, and the steel reinforcement cage 3 in the pipe shed steel pipe 2 enhances the rigidity and strength of the reinforcing body, and through the cooperation of the reinforcing body and the steel reinforcement cage 3, the rigidity and strength of the pipe shed steel pipe 2 are enhanced.

[0050] Referring to Figure 1 and Figure 2 First, the odd holes in the installation hole 12 are drilled and poured, and then the even holes in the installation hole 12 are drilled and poured, so that the tunnel portal can ensure good support effect during drilling and pouring, and after all the installation holes 12 are poured and the quality inspection is qualified, the grouting machine is cleaned, so as to realize the construction of the advanced pipe shed structure.

[0051] The working principle of the embodiment of the application is as follows:

[0052] By sealing and installing the pipe-roof steel pipe 2 in the installation hole 12, and installing the steel cage 3 in the pipe-roof steel pipe 2, while the steel cage 3 does not affect the pouring of cement mortar in the pipe-roof steel pipe 2, and then the gap between the pipe-roof steel pipe 2 and the installation hole 12 is tightly filled with cement mortar through the pipe-roof steel pipe 2, and at the same time, the rigidity and strength of the reinforcement body are enhanced by the steel cage 3, and the steel cage 3 and the reinforcement body jointly support the inside of the pipe-roof steel pipe 2, thereby improving the rigidity and strength of a single group of pipe-roof steel pipes 2. Multiple groups of pipe-roof steel pipes 2 together constitute an advanced pipe-roof, which ultimately improves the supporting force of the advanced pipe-roof on the soil at the tunnel entrance and reduces the probability of deformation of the pipe-roof.

[0053] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A tunnel entrance advanced pipe roof structure, characterized by: The invention comprises a plurality of groups of mounting holes (12) arranged at intervals on a guide wall (1) at a tunnel entrance, wherein a pipe-roof steel pipe (2) is arranged in the mounting hole (12) for facilitating pouring concrete in the mounting hole (12), a plurality of groups of grouting holes (221) are arranged on the pipe-roof steel pipe (2), and a steel cage (3) is arranged in the pipe-roof steel pipe (2) for improving the supporting strength of the pipe-roof steel pipe (2); The steel cage (3) comprises: Fixed rings (31), with multiple groups of fixed rings (31) arranged at intervals in the pipe-roof steel pipe (2); Connecting steel bars (32), the connecting steel bars (32) being connected to a plurality of sets of fixing rings (31), the connecting steel bars (32) being provided in a plurality of sets and being arranged in a circumferential array on the fixing rings (31); The pipe roof steel pipe (2) comprises: A steel pipe front end (21), the steel pipe front end (21) being arranged in a side close to the bottom of the mounting hole (12), and the side close to the bottom of the mounting hole (12) of the steel pipe front end (21) being in a conical structure; A steel pipe middle section (22), the steel pipe middle section (22) is arranged on a side of the steel pipe front end (21) away from the bottom of the mounting hole (12) and is hollow inside, and a plurality of groups of grouting holes (221) are arranged at intervals on the steel pipe middle section (22), and the plurality of groups of grouting holes (221) are arranged in a plum blossom shape; A steel pipe tail end (23), the steel pipe tail end (23) being arranged on a side of the steel pipe middle section (22) away from the steel pipe front end (21), and the steel pipe tail end (23) does not contain a grouting hole (221); A plurality of groups of support blocks (311) are arranged at intervals on the fixing ring (31) located inside the front end (21) of the steel pipe and are slidably arranged on the inner side wall of the pipe-roof steel pipe (2). The width of the support block (311) at one end away from the fixing ring (31) is greater than the width at one end close to the fixing ring (31). A plurality of groups of connecting steel bars (32) are provided with a bending portion (321) on a side close to the front end (21) of the steel pipe. The bending angle of the bending portion (321) is the same as the taper of the front end (21) of the steel pipe. The support block (311) is an arc structure on the side close to the pipe-roof steel pipe (2). The width of the support block (311) away from the fixing ring (31) is greater than the diameter of the grouting hole (221); A filling layer (4) is provided on the side of the mounting hole (12) away from the bottom to seal the gap between the outer wall of the steel pipe tail end (23) and the mounting hole (12), and the filling layer (4) is composed of hemp and an anchoring agent; M20 cement mortar is used between the gap between the pipe-roof steel pipe (2) and the installation hole (12); A reinforcement body is tightly arranged inside the pipe-roof steel pipe (2), the steel cage (3) is arranged inside the reinforcement body and supports and fixes the inside of the pipe-roof steel pipe (2), and the reinforcement body is tightly filled with M30 cement mortar.

2. The tunnel entrance advanced pipe roof structure according to claim 1, characterized in that: A pressure gauge for detecting the grouting pressure in the pipe-roof steel pipe (2) is detachably provided on the pipe-roof steel pipe (2).

3. The tunnel entrance advanced pipe roof structure according to claim 1, characterized in that: When multiple groups of mounting holes (12) are opened, a skip hole drilling method is used for drilling.

4. The tunnel entrance advanced pipe roof structure according to claim 1, characterized in that: Test holes (13) are provided on both sets of arch feet of the tunnel entrance guide wall (1). The test holes (13) are used to find out the characteristics of the stratum and to conduct grouting and mortar filling tests.

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