Construction structure and method of parallel pilot tunnel for TBM side-crossing highway tunnel in mountainous area

Abstract

The present invention provides a parallel pilot tunnel construction structure and method for TBM-assisted lateral tunneling on mountainous highways. The structure features a drilled-and-blasted branch tunnel and a drilled-and-blasted portal platform, a TBM branch tunnel and portal platform, a mainline tunnel, a parallel pilot tunnel, a blocking area, and a vehicle-carrying cross tunnel. This method utilizes a dual-branch tunnel entry scheme to avoid traffic interference between the TBM access tunnel and the mainline tunnel. Combining drilled-and-blasted with TBM methods, this method addresses the challenges of TBM assembly, launch, and entry on mountainous highways, where forward entry is difficult. When applied to the construction of extra-long tunnels, this method can shorten construction cycles and significantly improve socioeconomic benefits.

Description

Technical Field

[0001] The present invention relates to a TBM (Transport Machine) tunnel entry method for mountain tunnels in the technical field of tunnel construction, and more specifically to a parallel pilot tunnel construction structure and method for TBM lateral level crossing mountain highway tunnel excavation. Background Art

[0002] The TBM is a highly mechanized and automated complete set of equipment for large-scale tunnel excavation and lining. It boasts numerous advantages, including rapid construction, labor savings, safety, economy, and one-step completion. It is the most promising machine for rock tunneling. Currently, in mountainous highway construction, TBMs are primarily used for parallel pilot tunnel construction in extra-long tunnels exceeding 10 km.

[0003] Mountain highways often use a bridge-tunnel design, but TBMs require a parallel pilot tunnel with an outward portal extending at least 60 meters in length and no less than 25 meters in width to meet the TBM assembly site requirements. When the portal is located on a steep cliff, auxiliary engineering measures such as steel platforms are needed to meet the TBM assembly site requirements. When the height difference between the portal and the ground is too large, using a steel platform as the assembly site is costly, has poor technical and economic performance, and poses significant safety risks. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a parallel pilot tunnel construction structure and method for TBM side-crossing mountain highway tunnel excavation; it is suitable for TBM level crossing tunnel excavation construction where it is difficult to adopt a forward entry scheme.

[0005] The present invention is achieved by constructing a parallel pilot tunnel construction structure for TBM lateral level crossing mountain highway tunnel excavation, characterized in that the construction structure comprises a drill-blast branch tunnel and a drill-blast portal platform, a TBM branch tunnel and a TBM portal platform, a main line tunnel, a parallel pilot tunnel, a blocking area, and a vehicle cross tunnel.

[0006] According to the present invention, a TBM lateral level crossing mountain highway tunnel excavation parallel pilot tunnel construction method is characterized in that: the TBM branch tunnel includes a drilling and blasting section and a TBM section; wherein the drilling and blasting section is 170m long, including a 25m long starting tunnel and a 145m long stepping tunnel.

[0007] According to the present invention, a parallel pilot tunnel construction method for TBM lateral level crossing mountain highway tunnel excavation is characterized in that: the length of the drilling and blasting portal platform along the axis of the portal section of the drilling and blasting branch tunnel is not less than 15m, and the width is not less than 20m, and the drilling and blasting portal platform includes the drilling and blasting portal and the drilling and blasting portal site; the length of the TBM portal platform along the axis of the portal section of the TBM branch tunnel is not less than 50m, and the width is not less than 25m, and the TBM portal platform includes the TBM portal and the assembly starting site.

[0008] According to the present invention, a parallel pilot tunnel construction method for TBM lateral level crossing mountain highway tunnel excavation is characterized in that: the main line tunnel includes a tunnel advance section and a tunnel post-opening section; the parallel pilot tunnel includes a level guide drilling and blasting section, a level guide TBM section and a level guide post-opening section.

[0009] According to the present invention, a TBM parallel pilot tunnel construction method for side-crossing mountain highway tunnel excavation is characterized by the following operating steps and methods:

[0010] Step 1, construction design:

[0011] 1) Select gentle slopes or terraces near the main tunnel entrance to plan drill-blast branch tunnels and drill-blast entrance platforms, TBM branch tunnels, and TBM entrance platforms; and the following requirements must be met;

[0012] - There should be no cross-working interference between the drilling and blasting portal platform and the TBM portal platform;

[0013] -- The drill-and-blast branch tunnel is located on the side of the TBM branch tunnel close to the main tunnel entrance, intersecting with the main tunnel and parallel pilot tunnel. The drill-and-blast branch tunnel should be excavated uphill with a longitudinal slope of no more than 8%;

[0014] The tail section of the TBM branch tunnel intersects the main line tunnel with a circular curve and is tangent to the parallel pilot tunnel. The radius of the circular curve should be no less than 800m. The TBM branch tunnel should be controlled with a longitudinal slope of no more than 5%, and the longitudinal slope should be designed according to uphill excavation.

[0015] 2) The main tunnel is affected by the TBM branch tunnel and is extended 30m to both ends to form the main tunnel back-opening section; the parallel pilot tunnel is affected by the TBM branch tunnel and is extended 30m to the tunnel entrance to form the parallel pilot back-opening section;

[0016] 3) A blocking area shall be set up at the openings formed by TBM branch tunnels and drill-blast branch tunnels passing through the arch wall of the main line tunnel, the arch wall of the parallel pilot tunnel, etc. The blocking area shall be controlled to have a radial thickness of no less than 5m in the main line tunnel and the parallel pilot tunnel.

[0017] Step 2, Construction Preparation: Level the drilling and blasting portal platform and the TBM portal platform, lay out the drilling and blasting portal and the TBM portal, build the assembly starting site, and arrange the portal facilities;

[0018] Step 3: construct drill-blast branch holes and drill-blast sections;

[0019] Step 4: Construction of the remaining sections of the drill-blast branch tunnels, TBM sections, mainline tunnels, and parallel pilot tunnels;

[0020] 1) TBM construction: The TBM is assembled and advanced simultaneously until the entire machine is assembled and debugged, then it enters the launch tunnel. This completes the TBM's advanced and initial operations, and the TBM enters normal excavation, completing the TBM branch tunnel and the horizontal pilot TBM section in sequence.

[0021] 2) Drilling and blasting: The remaining sections of the drilled and blasted branch tunnels are constructed using the drilled and blasted method. At the intersections of the drilled and blasted branch tunnels with the main line tunnel and parallel pilot tunnels, new working faces are added to excavate the tunnel advance sections and parallel pilot drilled and blasted sections at both ends.

[0022] 3) Newly added working surface in the tunnel:

[0023] During the excavation of the first tunnel section, the completed first tunnel section, the horizontal guide TBM section and the vehicle cross tunnel are used as a passage to construct the first tunnel section of another tunnel;

[0024] After the parallel pilot TBM section is completed, the TBM equipment exits the tunnel and uses the parallel pilot tunnel to construct a vehicle-carrying cross tunnel to connect to the main line tunnel. A new working face is added to realize the staged excavation of the tunnel's advance section.

[0025] Step 5: Use the mold-casting method to fill the blockage area with rubble concrete;

[0026] Step 6: Drill and blast the tunnel back section and the flat pilot back section;

[0027] Step 7: Complete the remaining construction of the main line tunnel.

[0028] The present invention provides a parallel pilot tunnel construction structure and method for TBM side-on level crossing mountain highway tunnel excavation, which is suitable for TBM level crossing tunnel excavation where forward tunneling is not easy to adopt. It has the following advantages:

[0029] (1) This method combines the drilling and blasting method with the TBM method, solving the problem of TBM assembly and entry, which is difficult to achieve using a forward entry method on highways in mountainous areas. When applied to the construction of extra-long tunnels, this method can shorten the construction period and significantly improve social and economic benefits.

[0030] (2) When the tunnel entrance is located on a steep cliff, this method can reduce engineering costs and construction safety risks compared to building a steel platform as the starting site for TBM assembly, and has better technical and economic benefits.

[0031] (3) This method adopts a dual-branch tunneling scheme of drilling and blasting branch tunnels and TBM branch tunnels to avoid traffic interference between the TBM channel and the main line tunnel, facilitate construction organization, and speed up the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a construction process flow chart of the present invention;

[0033] Figure 2It is a construction design plan layout drawing of the present invention;

[0034] Figure 3 yes Figure 2 A large sample picture in the figure;

[0035] Figure 4 It is the excavation sequence diagram of the present invention;

[0036] Figure 5 This is a schematic plan view of the TBM working branch tunnel sealing area;

[0037] Figure 6 It is a plan view of the main line tunnel, parallel pilot tunnel and drilled and blasted branch tunnel sealing area after penetration.

[0038] Among them: drilling and blasting branch tunnel 1, drilling and blasting tunnel entrance platform, TBM branch tunnel 3, drilling and blasting section 301, TBM section 302, TBM tunnel entrance platform 4, main line tunnel 5, tunnel advance section 501, tunnel rear section 503, parallel pilot tunnel 6, flat pilot drilling and blasting section 601, flat pilot TBM section 602, flat pilot rear section 603, blocking area 7, vehicle cross tunnel 8. DETAILED DESCRIPTION

[0039] The following will be combined with the Figures 1-6 The present invention is described in detail, and the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] The present invention provides a TBM parallel pilot tunnel construction method for side-crossing mountain highway tunnel excavation. Figure 2-Figure 6 As shown, it can be implemented as follows;

[0041] like Figure 2-Figure 3 As shown, the construction design includes a drill-blast branch tunnel 1 and a drill-blast portal platform 2, a TBM branch tunnel 3 and a TBM portal platform 4, a main line tunnel 5, a parallel pilot tunnel 6, a blocking area 7, a vehicle cross tunnel 8, etc.; wherein, the drill-blast portal platform 2 is not less than 15m long and 20m wide along the portal section axis of the drill-blast branch tunnel 1, and includes the drill-blast portal and the drill-blast portal site; wherein, the TBM portal platform 4 is not less than 50m long and 25m wide along the portal section axis of the TBM branch tunnel 3, and includes the TBM portal and the assembly starting site; wherein, as Figure 2 and Figure 5As shown, the TBM branch tunnel 3 includes a drilling and blasting section 301 and a TBM section 302. The drilling and blasting section 301 is 170 m long and includes a 25 m long launch tunnel and a 145 m long step-in tunnel. Figure 5 As shown, the main line tunnel 5 includes a tunnel leading section 501 and a tunnel rear opening section 503; wherein, the parallel pilot tunnel 6 includes a flat pilot drilling and blasting section 601, a flat pilot TBM section 602 and a flat pilot rear opening section 603;

[0042] like Figure 1 As shown, the construction process and operation points of the present invention are as follows:

[0043] Step 1, construction design:

[0044] 1) If Figure 2 , select a gentle slope or terrace near the entrance of the main line tunnel 5 to plan the drill-blast branch tunnel 1 and drill-blast entrance platform 2, TBM branch tunnel 3 and TBM entrance platform 4; and meet the following requirements;

[0045] - There should be no cross-working interference between the drilling and blasting portal platform 2 and the TBM portal platform 4;

[0046] -- The drill-and-blast branch tunnel 1 is located on the side of the TBM branch tunnel 3 close to the mainline tunnel 5 entrance, intersecting the mainline tunnel 5 and the parallel pilot tunnel 6. The drill-and-blast branch tunnel 1 should be excavated uphill at a longitudinal slope of no more than 8%;

[0047] The tail section of the TBM branch tunnel 3 intersects the main line tunnel 5 with a circular curve and is tangent to the parallel pilot tunnel 6. The radius of the circular curve should be no less than 800m. The TBM branch tunnel 3 should be controlled with a longitudinal slope of no more than 5%, and the longitudinal slope should be designed according to uphill excavation.

[0048] 2) If Figure 3 The main line tunnel 5 is affected by the TBM branch tunnel 3 and is extended 30m to both ends to form the main line tunnel rear section 501; the parallel pilot tunnel 6 is affected by the TBM branch tunnel 3 and is extended 30m to the tunnel entrance to form the parallel pilot rear section 603;

[0049] 3) If Figure 3 The TBM branch tunnel 3 and the drill-blast branch tunnel 1 pass through the main line tunnel 5 arch wall, the parallel pilot tunnel 6 arch wall and other places to form the openings to set up the blocking area 7. The blocking area 7 is controlled to be no less than 5m in thickness in the radial direction of the main line tunnel and the parallel pilot tunnel.

[0050] Step 2, construction preparation: leveling the drilling and blasting portal platform 2 and the TBM portal platform 4, setting out the drilling and blasting portals and the TBM portals, building the assembly starting site, and arranging portal facilities;

[0051] Step 3, such as Figure 4 In the excavation sequence 1, drill and blast branch tunnel 1 and drill and blast section 301 are constructed;

[0052] Step 4, such as Figure 4 In the excavation sequence 2 to 4, the remaining section of the drill-blast branch tunnel 1, TBM section 302, mainline tunnel 5, and parallel pilot tunnel 6 are constructed;

[0053] 1) TBM construction: The TBM is assembled and advanced simultaneously until the entire machine is assembled and debugged, then it enters the launch tunnel. This completes the TBM's advanced and initial operations, and then normal TBM excavation begins. Operations in TBM branch tunnel 3 and horizontal guide TBM section 602 are completed in sequence.

[0054] 2) Drilling and blasting: The remaining section of branch tunnel 1 will be constructed using the drilling and blasting method. At the intersection of branch tunnel 1 with the main line tunnel 5 and parallel pilot tunnel 6, new working faces will be added to excavate the tunnel advance section 501 and the parallel pilot section 601 at both ends.

[0055] 3) Newly added working surface in the tunnel:

[0056] During the excavation of the tunnel advance section 501, the completed tunnel advance section 501, the parallel TBM section 602 and the vehicle cross tunnel 8 are used as a passage to construct the tunnel advance section 501 of another tunnel;

[0057] After the parallel guide TBM section 602 is completed, the TBM equipment exits the tunnel and uses the parallel guide tunnel 6 to construct the vehicle-carrying cross tunnel 8 to connect to the main line tunnel 5. A new working face is added to realize the segmented excavation of the tunnel advance section 501.

[0058] Step 5, such as Figure 5 , the molded filling stone concrete is used to construct the blocking area 7;

[0059] Step 6, such as Figure 5-Figure 6 The tunnel rear section 503 and the flat pilot rear section 603 were constructed by drilling and blasting methods;

[0060] Step 7: Complete the remaining construction of the main line tunnel 5.

[0061] The present invention has the following improvements and advantages:

[0062] First, this method combines drill and blast with the TBM method, solving the challenges of TBM assembly, launch, and tunneling on mountainous highways, where forward tunneling is difficult. When applied to the construction of extra-long tunnels, this method can shorten construction periods and significantly improve socioeconomic benefits.

[0063] Secondly, when the tunnel entrance is on a steep cliff, this method can reduce engineering costs and construction safety risks compared to building a steel platform as the starting site for TBM assembly, and has better technical and economic benefits.

[0064] Thirdly, this method adopts a dual-branch tunnel entry scheme of drilling and blasting branch tunnels and TBM branch tunnels to avoid traffic interference between the TBM channel and the main line tunnel, facilitate construction organization, and speed up the construction period.

[0065] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A TBM parallel pilot tunnel construction method for side-by-side tunneling of a mountain highway, characterized by: The construction method adopts the following construction structure, which comprises a drill-blast branch tunnel (1) and a drill-blast tunnel entrance platform (2), a TBM branch tunnel (3) and a TBM tunnel entrance platform (4), a main line tunnel (5), a parallel pilot tunnel (6), a blocking area (7), and a vehicle-carrying cross tunnel (8); and is suitable for TBM level crossing tunnel excavation construction where a forward tunneling scheme is not easily adopted; The steps of this construction method are as follows: Step 1, construction design: 1) Select a gentle slope or terrace near the main tunnel (5) entrance to plan a drill-blast branch tunnel (1), a drill-blast entrance platform (2), a TBM branch tunnel (3), and a TBM entrance platform (4); and meet the following requirements: There should be no cross-working interference between the drilling and blasting portal platform (2) and the TBM portal platform (4); The drill-blast branch tunnel (1) is set on the side of the TBM branch tunnel (3) close to the main line tunnel (5) entrance, intersecting with the main line tunnel (5) and the parallel pilot tunnel (6). The drill-blast branch tunnel (1) should be set uphill with a longitudinal slope of no more than 8%; The tail section of the TBM branch tunnel (3) intersects the main line tunnel (5) with a circular curve and is tangent to the parallel pilot tunnel (6). The radius of the circular curve is not less than 800m. The TBM branch tunnel (3) should be controlled with a longitudinal slope of no more than 5%, and the longitudinal slope should be designed according to uphill excavation. 2) The main line tunnel (5) is affected by the TBM branch tunnel (3) and is extended 30m to both ends to form the main line tunnel rear opening section; the parallel pilot tunnel (6) is affected by the TBM branch tunnel (3) and is extended 30m to the tunnel entrance to form the parallel pilot rear opening section (603); 3) A blocking area (7) is set up at the opening formed by the TBM branch tunnel (3) and the drill-blast branch tunnel (1) passing through the arch wall of the main tunnel (5) and the arch wall of the parallel pilot tunnel (6). The blocking area (7) is controlled to be no less than 5m thick in the radial direction of the main tunnel and the parallel pilot tunnel; Step 2, construction preparation: leveling the drilling and blasting portal platform (2) and the TBM portal platform (4), setting out the drilling and blasting portal and the TBM portal, building the assembly starting site, and arranging the portal facilities; Step 3, constructing drill-blast branch holes (1) and drill-blast sections (301); Step 4, construct the remaining section of the drill-blast branch tunnel (1), the TBM section (302), the main line tunnel (5), and the parallel pilot tunnel (6); 1) TBM construction: The TBM is assembled and advanced simultaneously until the whole machine is assembled and debugged and then enters the starting tunnel. The TBM’s advanced and launching operations are completed and the TBM enters normal excavation. The TBM branch tunnel (3) and the horizontal guide TBM section (602) are completed in sequence. 2) Drilling and blasting construction: The remaining section of the drilled and blasted branch tunnel (1) is constructed by the drilled and blasted method. At the intersection of the drilled and blasted branch tunnel (1) and the main line tunnel (5) and the parallel pilot tunnel (6), new working surfaces are added to the tunnel advance section (501) and the parallel pilot drilled and blasted section (601) at both ends. 3) Newly added working surface in the tunnel: During the excavation of the tunnel advance section (501), the completed tunnel advance section (501), the parallel TBM section (602) and the vehicle cross tunnel (8) are used as a passage to construct the tunnel advance section (501) of another tunnel; After the parallel guide TBM section (602) is completed, the TBM equipment exits the tunnel and uses the parallel guide tunnel (6) to construct a vehicle-carrying cross tunnel (8) to connect to the main line tunnel (5), and a new working face is added to realize the segmented excavation of the tunnel advance section (501); Step 5: Fill the sealing area with stone concrete using the mold-casting method (7); Step 6, constructing the tunnel rear opening section (503) and the horizontal guide rear opening section (603) by drilling and blasting method; Step 7: Complete the remaining construction of the main line tunnel (5).

2. The method for parallel pilot tunneling of a TBM-assisted tunnel for a mountain highway according to claim 1, characterized in that: The TBM branch tunnel (3) comprises a drilling and blasting section (301) and a TBM section (302); wherein the drilling and blasting section (301) is 170 m long and comprises a 25 m long launch tunnel and a 145 m long step-in tunnel.

3. The method for parallel pilot tunneling of a TBM-assisted tunnel for a mountain highway according to claim 1, characterized in that: The drilling and blasting portal platform (2) has a length of not less than 15 m and a width of not less than 20 m along the axial direction of the portal section of the drilling and blasting branch tunnel (1), and includes a drilling and blasting portal and a drilling and blasting portal site; the TBM portal platform (4) has a length of not less than 50 m and a width of not less than 25 m along the axial direction of the portal section of the TBM branch tunnel (3), and includes a TBM portal and an assembly starting site.

4. The method for constructing a parallel pilot tunnel for a TBM-assisted lateral tunnel crossing a mountainous highway according to claim 1, characterized in that: The main line tunnel (5) includes a tunnel leading section (501) and a tunnel rear opening section (503); the parallel pilot tunnel (6) includes a parallel pilot drilling and blasting section (601), a parallel pilot TBM section (602) and a parallel pilot rear opening section (603).

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