Tunnel section sudden change construction supporting structure and construction method thereof

Abstract

The invention discloses a tunnel section sudden change construction supporting structure and a construction method thereof.The supporting structure comprises a primary support, a temporary middle partition wall and a temporary inverted arch which are arranged in a three-line tunnel, the top and the bottom of the three-line tunnel are transversely separated through the temporary inverted arch, and the top of the three-line tunnel is vertically separated through the temporary middle partition wall; a first excavation area and a second excavation area are formed, the bottom of the three-line tunnel is sequentially divided into a third excavation area, a fifth excavation area and a fourth excavation area from left to right, and middle core soil is reserved in the fifth excavation area; the construction method comprises the following steps that S1, the tunnel face of the three-line tunnel is excavated through a hexagonal construction method; s2, when the three-line tunnel is suddenly changed into the double-line tunnel, excavating a tunnel face of the double-line tunnel through a three-step temporary cross brace method; and S3, when the double-track tunnel is suddenly changed into the single-track tunnel, the tunnel face of the single-track tunnel is excavated through a short step method. The method has the advantage that the safety and progress of tunnel primary support construction can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to a construction support structure for sudden change of tunnel cross-section and its construction method. Background Art

[0002] With the vigorous development of railway construction in China, mountainous route selection is becoming more and more common, and tunnel construction in mountains is becoming more and more obvious. Due to terrain restrictions in some difficult mountainous areas, part of the station line needs to enter the tunnel, resulting in a multi-segment cross-section at the tunnel entrance, mostly designed as a three-track to two-track to single-track tunnel. For the current relevant specifications for the design and construction of railway tunnels in China, only the design and construction of single-track and double-track railway tunnels have corresponding regulations. For three-track railway tunnels, at present, more exploration designs and constructions are still carried out on the basis of drawing on the experience of double-track railway tunnels and highway large-section tunnels. For three-track railway tunnels, the experience in construction and supervision is extremely lacking.

[0003] Therefore, a construction support structure for sudden change of tunnel cross-section and its construction method that can solve the above problems are needed. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction support structure for sudden change of tunnel cross-section and its construction method according to the deficiencies of the above-mentioned prior art. The support structure is provided with primary support, temporary middle wall and temporary inverted arch in the three-track tunnel. The construction method excavates the heading face of the three-track tunnel by the six-character method. When the three-track tunnel suddenly changes to a two-track tunnel, the heading face of the two-track tunnel is excavated by the three-step temporary cross brace method. When the two-track tunnel suddenly changes to a single-track tunnel, the heading face of the single-track tunnel is excavated by the short bench method, which can improve the construction safety and progress of the primary support of the tunnel.

[0005] The purpose of the present invention is achieved by the following technical solutions: A construction support structure for sudden change of tunnel cross-section, the support structure includes primary support, temporary middle wall and temporary inverted arch provided in the three-track tunnel. The top and bottom of the three-track tunnel are horizontally separated by the temporary inverted arch, and the top of the three-track tunnel is vertically separated by the temporary middle wall to form a first excavation area and a second excavation area. The bottom of the three-track tunnel is divided into a third excavation area, a fifth excavation area and a fourth excavation area from left to right, and the fifth excavation area is the reserved middle core soil.

[0006] There are two temporary inverted arches, and the temporary inverted arches are connected to the primary support.

[0007] The top of the temporary middle wall is connected to the primary support and the bottom is connected to the temporary inverted arch.

[0008] The outside of the primary support is provided with advanced support.

[0009] A construction method for a construction support structure with a sudden change in tunnel cross-section, the construction method comprising the following steps: S1: Excavate the heading face of a three-track tunnel by the six-character method; Among them, the construction steps of the six-character method are as follows: S1.1: Excavate the left side of the upper bench of the heading face of the three-track tunnel, and after excavating the left side of the upper bench, construct the corresponding initial support, temporary middle partition, and first temporary invert; S1.2: Excavate the right side of the upper bench of the heading face of the three-track tunnel, and after excavating the right side of the upper bench, construct the corresponding initial support and second temporary invert; S1.3: Excavate half of the left side of the lower bench of the heading face of the three-track tunnel, and after excavating half of the left side of the lower bench, construct the corresponding initial support; S1.4: Excavate half of the right side of the lower bench of the heading face of the three-track tunnel, and after excavating half of the right side of the lower bench, construct the corresponding initial support; S1.5: Demolish the temporary middle partition, the first temporary invert, and the second temporary invert, excavate the reserved middle core soil, and after excavating the reserved middle core soil, construct the corresponding initial support and invert lining; S2: When the three-track tunnel suddenly changes to a two-track tunnel, excavate the heading face of the two-track tunnel by the three-bench temporary cross brace method; S3: When the two-track tunnel suddenly changes to a single-track tunnel, excavate the heading face of the single-track tunnel by the short bench method.

[0010] In step S2, the construction steps of the three-bench temporary cross brace method are as follows: S2.1: After steps S1.1 and S1.2 are completed, excavate the left and right sides of the upper bench of the heading face of the two-track tunnel, and after excavating the left and right sides of the upper bench, construct the corresponding initial support and first temporary cross brace; S2.2: Excavate the left and right sides of the middle bench of the heading face of the two-track tunnel, and after excavating the left and right sides of the middle bench, construct the corresponding initial support and second temporary cross brace; S2.3: Excavate the left and right sides of the lower bench of the heading face of the two-track tunnel, and after excavating the left and right sides of the lower bench, demolish the first temporary cross brace and the second temporary cross brace, and construct the corresponding initial support and invert lining.

[0011] In step S3, the construction steps of the short bench method are as follows: S3.1: After the completion of steps S2.1 and S2.2, excavate the left and right sides of the upper bench of the heading face of the single-track tunnel. After excavating the left and right sides of the upper bench, construct the corresponding initial support and the third temporary cross brace. S3.2: Excavate the left and right sides of the lower bench of the heading face of the single-track tunnel. After excavating the left and right sides of the lower bench, demolish the third temporary cross brace and construct the corresponding initial support and invert lining.

[0012] In step S1, when excavating the left side of the upper bench of the heading face of the three-track tunnel, arrange the first monitoring points on the left arch crown, left arch waist of the three-track tunnel and the left side of the temporary middle wall; when excavating the right side of the upper bench of the heading face of the three-track tunnel, arrange the second monitoring points on the right arch crown, right arch waist of the three-track tunnel and the right side of the temporary middle wall; when excavating half of the left side of the lower bench of the heading face of the three-track tunnel, arrange the third monitoring points on the left arch bottom of the three-track tunnel; when excavating half of the right side of the lower bench of the heading face of the three-track tunnel, arrange the fourth monitoring points on the right arch bottom of the three-track tunnel.

[0013] The advantages of the present invention are as follows: 1. Simple structure and convenient construction; 2. Adopting the six-character construction method can effectively ensure the construction of large-span rock surrounding rock by drill and blast method, ensure the construction space and construction safety, and improve the construction progress of large-span rock surrounding rock; 3. Simple construction method and strong practicability, which can improve the construction safety and progress of the initial support of the tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view of the tunnel of the present invention; Figure 2 It is a schematic diagram of the heading face of the three-track tunnel of the present invention; Figure 3 It is a schematic diagram of the arrangement of the monitoring points on the three-track tunnel of the present invention; As Figures 1 to 3 shown, the marks in the figure are respectively represented as: Initial support 1, temporary middle wall 2, first temporary invert 3, second temporary invert 4, three-track tunnel 5, double-track tunnel 6, single-track tunnel 7, first excavation area A, second excavation area B, third excavation area C, fourth excavation area D, fifth excavation area E, first monitoring point a, second monitoring point b, third monitoring point c, fourth monitoring point d. DETAILED DESCRIPTION OF THE INVENTION

[0015] The features of the present invention and other related features will be further described in detail below with reference to the accompanying drawings through embodiments for the understanding of those skilled in the same industry: Embodiment: As Figures 1 to 3 shown, this embodiment relates to a construction support structure for a sudden change in tunnel cross-section, which mainly includes a primary support 1, a temporary middle wall 2, and a temporary invert disposed in a three-line tunnel 5. Moreover, an advanced support is provided outside the primary support 1. The top and bottom of the three-line tunnel 5 are horizontally separated by a temporary invert, and the top of the three-line tunnel 5 is vertically separated by a temporary middle wall 2 to form a first excavation area A and a second excavation area B. There are two temporary inverts, namely a first temporary invert 3 and a second temporary invert 4. The temporary inverts are connected to the primary support 1. The top of the temporary middle wall 2 is connected to the primary support 1, and the bottom is connected to the temporary invert. The bottom of the three-line tunnel 5 is sequentially divided into a third excavation area C, a fifth excavation area E, and a fourth excavation area D from left to right, and the fifth excavation area E is the reserved middle core soil.

[0016] As Figures 1 to 3 shown, this embodiment also has a construction method for a construction support structure for a sudden change in tunnel cross-section. The construction method mainly includes the following steps: S1: Excavate the face of the three-line tunnel 5 by the six-character method.

[0017] Among them, the construction steps of the six-character method are as follows: S1.1: Excavate the left side of the upper bench (the first excavation area A) of the face of the three-line tunnel 5. After excavating the left side of the upper bench, construct the corresponding primary support 1, temporary middle wall 2, and first temporary invert 3.

[0018] S1.2: Excavate the right side of the upper bench (the second excavation area B) of the face of the three-line tunnel 5. After excavating the right side of the upper bench, construct the corresponding primary support 1 and second temporary invert 4.

[0019] S1.3: Excavate half of the left side of the lower bench (the third excavation area C) of the face of the three-line tunnel 5. After excavating half of the left side of the lower bench, construct the corresponding primary support 1.

[0020] S1.4: Excavate half of the right side of the lower bench (the fourth excavation area D) of the face of the three-line tunnel 5. After excavating half of the right side of the lower bench, construct the corresponding primary support 1.

[0021] S1.5: Demolish the temporary middle wall 2, the first temporary invert 3, and the second temporary invert 4, excavate the reserved middle core soil (the fifth excavation area E), and after excavating the reserved middle core soil, construct the corresponding primary support 1 and invert lining.

[0022] As Figure 3As shown in the figure, to ensure construction safety, when excavating the heading face of the three-track tunnel 5 using the six-character method, it is necessary to arrange monitoring measurement points, which are used to measure the settlement and convergence of the three-track tunnel 5. When excavating the left side of the upper bench (the first excavation area A) of the heading face of the three-track tunnel 5, the first monitoring measurement point a is arranged on the left arch crown, left arch waist of the three-track tunnel 5, and the left side of the temporary middle wall 2; when excavating the right side of the upper bench (the second excavation area B) of the heading face of the three-track tunnel 5, the second monitoring measurement point b is arranged on the right arch crown, right arch waist of the three-track tunnel 5, and the right side of the temporary middle wall 2; when excavating half of the left side of the lower bench (the third excavation area C) of the heading face of the three-track tunnel 5, the third monitoring measurement point c is arranged on the left arch bottom of the three-track tunnel 5; when excavating half of the right side of the lower bench (the fourth excavation area D) of the heading face of the three-track tunnel 5, the fourth monitoring measurement point d is arranged on the right arch bottom of the three-track tunnel 5.

[0023] S2: When the three-track tunnel 5 suddenly changes to a two-track tunnel 6, the heading face of the two-track tunnel 6 is excavated by the three-bench temporary cross brace method.

[0024] Among them, the construction steps of the three-bench temporary cross brace method are as follows: S2.1: After steps S1.1 and S1.2 are completed, the left and right sides of the upper bench of the heading face of the two-track tunnel 6 are excavated, and after excavating the left and right sides of the upper bench, the corresponding initial support and the first temporary cross brace are constructed.

[0025] S2.2: The left and right sides of the middle bench of the heading face of the two-track tunnel 6 are excavated, and after excavating the left and right sides of the middle bench, the corresponding initial support and the second temporary cross brace are constructed.

[0026] S2.3: The left and right sides of the lower bench of the heading face of the two-track tunnel 6 are excavated, and after excavating the left and right sides of the lower bench, the first temporary cross brace and the second temporary cross brace are removed, and the corresponding initial support and invert lining are constructed.

[0027] S3: When the two-track tunnel 6 suddenly changes to a single-track tunnel 7, the heading face of the single-track tunnel 7 is excavated by the short bench method.

[0028] Among them, the construction steps of the short bench method are as follows: S3.1: After steps S2.1 and S2.2 are completed, the left and right sides of the upper bench of the heading face of the single-track tunnel 7 are excavated, and after excavating the left and right sides of the upper bench, the corresponding initial support and the third temporary cross brace are constructed.

[0029] S3.2: The left and right sides of the lower bench of the heading face of the single-track tunnel 7 are excavated, and after excavating the left and right sides of the lower bench, the third temporary cross brace is removed, and the corresponding initial support and invert lining are constructed.

[0030] The beneficial technical effects of this embodiment are as follows: 1. Simple structure and convenient construction; 2. The six-character construction method is adopted, which can effectively ensure the construction of large-span rocky surrounding rock by drilling and blasting method, ensure the construction space and safety, and improve the construction progress of large-span rocky surrounding rock; 3. Simple construction method and strong practicability, which can improve the construction safety and progress of the initial support of the tunnel.

[0031] Although the above embodiments have detailed the concept and implementation of the object of the present invention with reference to the drawings, those of ordinary skill in the art can recognize that various improvements and transformations can still be made to the present invention without departing from the scope defined by the claims, so they will not be elaborated one by one here.

Claims

1. A construction support structure for sudden change of tunnel section, characterized in that: The support structure includes the primary support, temporary middle diaphragm, and temporary invert provided in the three-track tunnel. The top and bottom of the three-track tunnel are horizontally separated by the temporary invert, and the top of the three-track tunnel is vertically separated by the temporary middle diaphragm, forming a first excavation area and a second excavation area. The bottom of the three-track tunnel is divided into a third excavation area, a fifth excavation area, and a fourth excavation area from left to right in sequence, and the fifth excavation area is the reserved middle core soil.

2. The construction support structure for sudden change of tunnel cross-section according to claim 1, characterized in that: There are two temporary inverts, and the temporary inverts are connected to the primary support.

3. The construction support structure for sudden change of tunnel cross-section according to claim 1, characterized in that: The top of the temporary middle diaphragm is connected to the primary support, and the bottom is connected to the temporary invert.

4. The construction support structure for sudden change of tunnel section according to claim 1, characterized in that: An advanced support is provided outside the primary support.

5. The construction method of a construction support structure for sudden change of tunnel cross-section according to any one of claims 1 to 4, characterized in that: The construction method includes the following steps: S1: Excavate the face of the three-track tunnel by the six-character method; Among them, the construction steps of the six-character method are as follows: S1.1: Excavate the left side of the upper bench of the face of the three-track tunnel, and after excavating the left side of the upper bench, construct the corresponding primary support, temporary middle diaphragm, and first temporary invert; S1.2: Excavate the right side of the upper bench of the face of the three-track tunnel, and after excavating the right side of the upper bench, construct the corresponding primary support and second temporary invert; S1.3: Excavate half of the left side of the lower bench of the face of the three-track tunnel, and after excavating half of the left side of the lower bench, construct the corresponding primary support; S1.4: Excavate half of the right side of the lower bench of the face of the three-track tunnel, and after excavating half of the right side of the lower bench, construct the corresponding primary support; S1.5: Demolish the temporary middle diaphragm, the first temporary invert, and the second temporary invert, excavate the reserved middle core soil, and after excavating the reserved middle core soil, construct the corresponding primary support and invert lining; S2: When the three-track tunnel suddenly changes to a two-track tunnel, excavate the face of the two-track tunnel by the three-bench temporary cross brace method; S3: When the two-track tunnel suddenly changes to a single-track tunnel, excavate the face of the single-track tunnel by the short bench method.

6. The construction method of a construction support structure for sudden change of tunnel cross-section according to claim 5, characterized in that: In step S2, the construction steps of the three-bench temporary cross brace method are as follows: S2.1: After steps S1.1 and S1.2 are completed, excavate the left and right sides of the upper bench of the face of the two-track tunnel, and after excavating the left and right sides of the upper bench, construct the corresponding primary support and first temporary cross brace; S2.2: Excavate the left and right sides of the middle bench of the face of the two-track tunnel, and after excavating the left and right sides of the middle bench, construct the corresponding primary support and second temporary cross brace; S2.3: Excavate the left and right sides of the lower bench of the face of the two-track tunnel, and after excavating the left and right sides of the lower bench, demolish the first temporary cross brace and the second temporary cross brace, and construct the corresponding primary support and invert lining.

7. The construction method of a construction support structure for sudden change of tunnel cross-section according to claim 6, characterized in that: In step S3, the construction steps of the short bench method are as follows: S3.1: After steps S2.1 and S2.2 are completed, excavate the left and right sides of the upper bench of the face of the single-track tunnel, and after excavating the left and right sides of the upper bench, construct the corresponding primary support and third temporary cross brace; S3.2: Excavate the left and right sides of the lower bench of the heading face of the single-track tunnel, and after excavating the left and right sides of the lower bench, remove the third temporary cross brace, and construct the corresponding initial support and invert lining.

8. The construction method of a construction support structure for sudden change of tunnel cross-section as claimed in claim 5, characterized in that: In step S1, when excavating the left side of the upper bench of the heading face of the three-track tunnel, arrange the first monitoring points on the left arch crown, left arch waist of the three-track tunnel and the left side of the temporary middle partition wall; when excavating the right side of the upper bench of the heading face of the three-track tunnel, arrange the second monitoring points on the right arch crown, right arch waist of the three-track tunnel and the right side of the temporary middle partition wall; when excavating half of the left side of the lower bench of the heading face of the three-track tunnel, arrange the third monitoring points on the left arch bottom of the three-track tunnel; when excavating half of the right side of the lower bench of the heading face of the three-track tunnel, arrange the fourth monitoring points on the right arch bottom of the three-track tunnel.

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