Construction structure for underground excavation tunnel in hilly area and rapid tunnel entering method

Abstract

The invention discloses a construction structure for a subsurface tunnel in a hilly area and a rapid hole entering method. The method comprises the following steps that (1) a site is leveled; (2) constructing fender posts and a top ring beam; (3) in the range of the fender posts, excavation and supporting are carried out, and excavation is carried out to the elevation of an underground excavation protection arch foundation; (4) the open-cut foundation pit is synchronously excavated to the elevation of the construction ramp, and supporting is carried out while excavation is carried out; (5) a sleeve arch foundation bracket is constructed, and fender posts are used as bracket supports; 6) pouring a cover arch and constructing a pipe shed; and (7) carrying out tunnel-entering construction. Compared with a conventional open excavation working well hole entering method, the number of constructed fender posts can be reduced, underground excavation construction can be carried out as early as possible, and therefore the workload is reduced and the working time is shortened on the premise that construction safety is guaranteed; compared with a conventional mining method for tunnel portal side upward slope tunnel entering, the temporary occupied area of portal slope construction can be reduced, the fender posts are used as the cover arch foundation, the cover arch foundation can be ensured to be stable, and waste of transverse space caused by conventional foundation expansion is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a construction structure for a dark tunnel in a hilly area and a rapid tunnel entry method. Background Art

[0002] Rapid tunnel entry refers to shortening the time as much as possible when passing through the tunnel portal stage during the tunnel construction process to improve work efficiency. It is a complex and challenging task, facing many technical and environmental difficulties, such as: unstable geological conditions at the portal and changes in the strata, complex connection between open-cut tunneling and dark-cut tunneling, instability of the portal caused by insufficient initial support or lack of coordination between excavation and support, various restrictions on the adaptation and matching of machinery during the construction process and the enclosure stage, drainage and seepage problems, construction safety risks and cost losses, etc., covering many aspects. At present, the open-cut and dark-cut tunnel entry conversion method is still to set up a working well at the end of the open excavation, and then carry out dark excavation construction after the main structure of the working well is completed or the frame beam is completed. The construction period is long, the process is complex, the cost is relatively high, and there is a greater risk of collapse when breaking the retaining piles, and the construction risk and design difficulty are greater; while the conventional side slope entry method has problems such as large land area and difficulty in connecting with the open excavation section. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a construction structure and a rapid tunnel entry method for dark tunnels in hilly areas to address the deficiencies in the prior art.

[0004] In order to achieve the above object, the present invention is achieved through the following technical solutions:

[0005] Provided is a construction structure for dark-cut tunnels in hilly areas, comprising retaining piles, back slope support and advanced pipe shed arch protection, wherein the retaining piles are vertically supported on opposite sides of a foundation pit and a back slope at an entrance to a tunnel, the bottom surfaces of the retaining piles are located below the excavation line at the bottom of an open-cut foundation pit, the top surfaces of the retaining piles are provided with top ring beams, the top surfaces of the top ring beams are flush with the ground, the back slope support is located at the end of the open-cut foundation pit, the advanced pipe shed arch protection is located at the boundary between open and dark excavation, and the advanced pipe shed is provided at the arch portion of the dark-cut tunnel.

[0006] As described in the construction structure for dark tunnels in hilly areas, wherein the opposite sides of the retaining piles are respectively provided with corbel-type arch protection foundations, and the bottom end of the advanced pipe-roof arch protection is erected on the corbel-type arch protection foundations.

[0007] As described above, the construction structure for dark tunnels in hilly areas also includes a plurality of anchor cables, and the opposite sides of the retaining piles are respectively provided with a plurality of horizontally arranged steel waist beams, one end of the anchor cable is fixed on the steel waist beam, and the retaining piles are anchored by the anchor cables.

[0008] A method for quickly entering a dark tunnel in a hilly area is provided, which is implemented based on any construction structure as described in any one of the above, and includes the following steps:

[0009] S1. Level the site;

[0010] S2. Construct retaining piles and top ring beams;

[0011] S3. Support the back slope of the dark excavation hole as you dig within the retaining pile range, and excavate to the elevation of the dark excavation arch foundation;

[0012] S4. Simultaneously excavate the open excavation pit to the construction ramp elevation, and provide support as you dig;

[0013] S5. Construct the arch foundation corbels and use the retaining piles as corbel supports;

[0014] S6. Cast the sleeve arch and construct the pipe shed;

[0015] S7. Start construction in the cave.

[0016] As described in the rapid tunnel entry method for dark-cut tunnels in hilly areas, in step S2, the construction of retaining piles is extended to the transition area of ​​the dark-cut tunnel section.

[0017] The beneficial effects of the technical solution of the present invention are:

[0018] 1. Reduce the process of dark excavation for conversion of open and dark excavation wells. The construction can be started before the construction of the open excavation main structure. The unexcavated open excavation section can be used to form a ramp to provide parallel transportation conditions, which can ultimately speed up the overall construction period and improve construction efficiency;

[0019] 2. Compared with the work well, it can reduce a row of retaining piles, anchor cables, water-stop curtains, etc., thus improving economic benefits;

[0020] 3. Reduce the intersection of dark excavation and open excavation, avoid the risk of soil collapse and leakage when vertical retaining piles are removed, and reduce the risk during construction;

[0021] 4. Compared with the conventional mining method of tunnel entrance with upslope, the temporary construction area of ​​the entrance slope can be reduced;

[0022] 5. Using retaining piles as the arch foundation can ensure the stability of the arch foundation and reduce the waste of lateral space caused by conventional foundation expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To further illustrate the above-mentioned objectives, structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Figure 1 This is a longitudinal cross-sectional view of a hole in a preferred embodiment of the present invention;

[0025] Figure 2 This is a transverse cross-sectional view of a hole in a preferred embodiment of the present invention;

[0026] In the figure: 1. Guarding piles; 2. Advanced pipe shed arch protection; 3. Top ring beam; 4. Corbel arch protection foundation; 5. Anchor cable; 6. Steel waist beam. DETAILED DESCRIPTION

[0027] The terms "invention", "present invention" and "the present invention" used in this specification are intended to refer broadly to all subject matter of this specification and any patent claims below. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of any patent claim below. In addition, this specification does not attempt to describe or limit the subject matter covered by any claim of any specific component, paragraph, statement or figure of this application. The subject matter should be understood with reference to the entire specification, all drawings and any claims below. The present invention may have other embodiments and be practiced or implemented in other ways. Moreover, it should be understood that the words and terms used herein are for illustrative purposes and should not be considered as limiting.

[0028] The details of the present invention will now be discussed with reference to the accompanying drawings which illustrate the present invention by way of example only. In the accompanying drawings, similar features or components may be marked with the same reference numerals.

[0029] The use of "including," "having," and "comprising" and variations thereof herein is meant to encompass the items listed thereafter and their equivalents and additional items. Although reference may be made to directions such as above, below, upward, downward, rearward, bottom, top, front, rear, etc., in describing the drawings, for convenience, reference is made relative to the drawings. These directions are not intended to literally accept or limit the present invention in any form. In addition, terms such as "first," "second," "third," etc., are used herein for illustrative purposes and are not intended to indicate or imply importance or significance.

[0030] See also Figure 1 , Figure 2 As shown, in a preferred embodiment, the construction structure of the invention for a dark tunnel in a hilly area includes a retaining pile 1, a back slope support and an advanced pipe shed arch 2, the retaining pile 1 is vertically supported on opposite sides of the foundation pit and the back slope of the tunnel entrance, the retaining pile 1 is vertically supported on opposite sides of the foundation pit and the back slope of the tunnel entrance, the bottom surface of the retaining pile 1 is located below the excavation line at the bottom of the open pit, the top surface of the retaining pile 1 is provided with a top ring beam 3, the top surface of the top ring beam 3 is flush with the ground, the back slope support is located at the end of the open pit, the advanced pipe shed arch 2 is located at the boundary between the open and dark excavation, and the advanced pipe shed is provided at the arch of the dark tunnel.

[0031] The opposite sides of the retaining piles 1 are respectively provided with corbel-type arch protection foundations 4 , and the bottom ends of the advanced pipe-roof arch protection 2 are erected on the corbel-type arch protection foundations 4 .

[0032] Continuing to refer to the figure, it also includes multiple anchor cables 5. The opposite sides of the retaining pile 1 are respectively provided with a plurality of horizontally arranged steel waist beams 6. One end of the anchor cable 5 is fixed on the steel waist beam 6, and the retaining pile 1 is anchored by the anchor cable 5.

[0033] The fast tunnel entry method for dark-dig tunnels in hilly areas of the present invention is implemented based on the above-mentioned construction structure and includes the following steps:

[0034] S1. The site is level.

[0035] Level the site at the tunnel entrance to ensure the flatness and stability of the construction site. If necessary, construct a first-level side slope to the fixed height of the retaining piles.

[0036] S2. Construct retaining piles and top ring beam.

[0037] Construct retaining piles in the open-cut tunnel section and extend the construction of retaining piles to the transition area of ​​the dark-cut tunnel section to ensure the continuity and stability of the retaining structure.

[0038] S3. Support the back slope of the dark excavation hole as you dig within the range of the retaining piles, and excavate to the elevation of the dark excavation arch foundation.

[0039] Under the protection of retaining piles, only the back slope within the width of the foundation pit can be excavated, reducing the slope range and improving safety.

[0040] S4. Simultaneously excavate the open excavation pit to the construction ramp elevation and provide support as you dig.

[0041] According to the excavation scope, steel purlins and anchor cables are constructed, and the excavation is completed to cast a hardened ramp at the elevation to facilitate the construction of the dark excavation. Preferably, the construction slope is less than 12%.

[0042] S5. Construct the arch foundation corbel and use the retaining piles as corbel supports.

[0043] For the two retaining piles at the foundation position, pre-embedded connecting steel bars are used to cast the arch foundation corbels and connect them with the retaining piles. These serve as corbel supports, which can reduce the space occupied by the shallow foundation arch corbels, avoid the risks of weak foundations, and avoid the settlement and deformation of the arch during dark tunnel excavation.

[0044] S6. Cast the sleeve arch and construct the pipe shed;

[0045] S7. Start construction in the cave.

[0046] This method can be used in the construction of tunnels in and out of hilly areas in cities with undulating terrain. According to the unique topographical characteristics of the hilly areas, the method simplifies the construction scale and cost to form stable upslope entry conditions.

[0047] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A construction structure for dark tunneling in hilly areas, characterized in that: It includes retaining piles, back slope support and advanced pipe shed arch protection. The retaining piles are vertically supported on opposite sides of the foundation pit and the back slope of the tunnel entrance. The bottom surface of the retaining piles is located below the excavation line at the bottom of the open-cut foundation pit. The top surface of the retaining piles is provided with a top ring beam, and the top surface of the top ring beam is flush with the ground. The back slope support is located at the end of the open-cut foundation pit, the advanced pipe shed arch protection is located at the boundary between open and dark excavation, and the advanced pipe shed is arranged on the arch of the dark excavation tunnel.

2. The construction structure for dark tunneling in hilly areas as claimed in claim 1, characterized in that: The opposite sides of the guard piles are respectively provided with corbel-type arch protection foundations, and the bottom end of the advanced pipe-roof arch protection is erected on the corbel-type arch protection foundations.

3. The construction structure for dark tunneling in hilly areas as claimed in claim 2, characterized in that: It also includes a plurality of anchor cables. The opposite sides of the retaining piles are respectively provided with a plurality of horizontally arranged steel waist beams. One end of the anchor cable is fixed on the steel waist beam, and the retaining piles are anchored by the anchor cables.

4. A method for rapid entry into a dark tunnel in a hilly area, based on the construction structure as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Level the site; S2. Construct retaining piles and top ring beams; S3. Support the back slope of the dark excavation hole as you dig within the retaining pile range, and excavate to the elevation of the dark excavation arch foundation; S4. Simultaneously excavate the open excavation pit to the construction ramp elevation, and provide support as you dig; S5. Construct the arch foundation corbels and use the retaining piles as corbel supports; S6. Cast the sleeve arch and construct the pipe shed; S7. Start construction in the cave.

5. The rapid tunneling method for dark excavation in hilly areas as claimed in claim 1, characterized in that: In step S2, the construction of retaining piles is extended to the transition area of ​​the dark excavation tunnel section.

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