阅读说明：本技术 一种大断面t型交叉隧道洞群的施工方法 (Construction method of large-section T-shaped cross tunnel hole group ) 是由 王岩 李金会 赵耀 张立强 任利军 金鑫 王磊 于 2021-01-04 设计创作，主要内容包括：本发明公开了一种大断面T型交叉隧道洞群的施工方法,其包括大断面隧道初期支护施工；拆除大断面隧道与小断面隧道交叉口位置的临时拱架；在大断面隧道与小断面隧道交叉口位置安装门式加强支架；在小断面隧道顶部打设超前大管棚；小断面隧道开挖；双拼型钢拱架制作与安装；大断面隧道与小断面隧道交叉口位置变形监测。本发明提供的一种大断面T型交叉隧道洞群的施工方法,其步骤合理,通过T型交叉隧道进洞安全控制施工,保证了大断面隧道进入小断面隧道的施工安全；通过T型交叉口结构加强施工方法,提高T型交叉口处二次衬砌结构强度,进而提高结构整体的承载能力与抗变形能力。(The invention discloses a construction method of a large-section T-shaped cross tunnel hole group, which comprises the primary support construction of a large-section tunnel; removing a temporary arch frame at the intersection of the large-section tunnel and the small-section tunnel; installing a portal reinforcing support at the intersection of the large-section tunnel and the small-section tunnel; constructing an advanced large pipe shed at the top of the small-section tunnel; excavating a small-section tunnel; manufacturing and installing a double-spliced steel arch frame; and monitoring the deformation of the intersection position of the large-section tunnel and the small-section tunnel. The construction method of the large-section T-shaped cross tunnel hole group provided by the invention has reasonable steps, and ensures the construction safety of the large-section tunnel entering the small-section tunnel by controlling the construction through the entrance safety of the T-shaped cross tunnel; through the reinforced construction method of the T-shaped intersection structure, the strength of the secondary lining structure at the T-shaped intersection is improved, and further the integral bearing capacity and the deformation resistance of the structure are improved.)

1. A construction method of a large-section T-shaped cross tunnel cave group is characterized by comprising the following steps:

step one, primary support construction of a large-section tunnel;

step two, dismantling a temporary arch at the intersection of the large-section tunnel and the small-section tunnel;

step 21: cutting the temporary arch frame according to the outline of the intersection of the large-section tunnel and the small-section tunnel;

step 22: chiseling off the cut temporary arch;

step three, installing a gate type reinforcing support at the intersection of the large-section tunnel and the small-section tunnel;

step 31: setting bedrock at the bottom of the door type reinforcing bracket to support the door type reinforcing bracket;

step 32: connecting the top of the door type reinforcing support with the cutting position of the upper arch frame;

fourthly, constructing an advanced large pipe shed at the top of the small-section tunnel;

step five, excavating the small-section tunnel;

sixthly, manufacturing and installing a double-spliced steel arch frame;

and seventhly, monitoring the deformation of the intersection position of the large-section tunnel and the small-section tunnel.

2. The construction method of a large-section T-shaped cross tunnel cave dwelling as claimed in claim 1, wherein before the temporary arch is removed, a locking anchor is installed at each arch at the temporary arch removal position.

3. The construction method of a large-section T-shaped cross tunnel cave group according to claim 2, characterized in that the foot-locking anchor rod is a T51 self-advancing foot-locking anchor rod.

4. The construction method of the large-section T-shaped cross tunnel hole group according to claim 1, further comprising a structure reinforcing construction of an intersection of the large-section tunnel and the small-section tunnel, wherein the construction is combined in a mode of combining a secondary lining reinforcing ring beam and a longitudinal reinforcing hidden beam, so that the structural strength of a secondary lining at the intersection is improved.

5. The construction method of the large-section T-shaped cross tunnel cave group according to claim 4, wherein the structure strengthening construction of the tunnel intersection comprises the following steps:

erecting a support, and constructing a reinforcing ring beam and a secondary lining of a small-section tunnel with the length of 1m at the interface;

after the concrete reaches the design strength, dismantling the support, installing a lateral truss, and pouring a reinforcing beam and lining the side wall of the main structure in the range of the reinforcing beam;

and after the concrete reaches the design strength, removing the side wall support, and sequentially pouring the rest secondary lining at the intersection position by using a secondary lining trolley.

6. The method as claimed in claim 4, wherein the longitudinal reinforcing hidden beams are symmetrically arranged on the upper side of the reinforcing ring beam and have a thickness of 500 mm.

7. The construction method of a large-section T-shaped cross tunnel cave group according to claim 6, characterized in that the reinforcing ring beam is of a non-uniform thickness symmetrical structure, and the wall thickness of the downward part of the two sides of the reinforcing ring beam is larger than the wall thickness of other parts.

8. The construction method of the large-section T-shaped cross tunnel hole group according to claim 1, wherein in the seventh step, deformation joints are arranged at the intersections of the large-section tunnel and the small-section tunnel, and deformation of the intersections of the large-section tunnel and the small-section tunnel is monitored by detecting changes of the deformation joints.

9. The method as claimed in claim 8, wherein the number of the deformation joints is plural, and the variation of the deformation joints is monitored by collecting the image of the deformation joints and comparing the image with historical data.

10. The construction method of the large-section T-shaped cross tunnel hole group according to claim 1, wherein in the seventh step, a strain gauge is arranged at the intersection of the large-section tunnel and the small-section tunnel, and deformation of the intersection of the large-section tunnel and the small-section tunnel is monitored by monitoring the change of the strain gauge.

Technical Field

The invention belongs to the technical field of tunnel excavation, and relates to a construction method of a large-section T-shaped cross tunnel group.

Background

In the building engineering, the tunnel intersection means that two main tunnels are intersected, and in the construction process of a large-section tunnel intersection, the stability of the large-section tunnel intersection is extremely poor because surrounding rocks are in a complex three-dimensional space stress state. When a T-shaped cross tunnel hole group enters a small-section tunnel from a large-section tunnel to be constructed, stress distribution at the cross opening is concentrated, and stress conversion in the supporting process is complex, so that the structural safety is difficult to guarantee.

However, relevant specifications, detailed rules and the like in China still lack relevant regulations, a plurality of design houses do not carry out relevant detailed design on the structures at the large-section intersection of soft rock, construction units carry out construction only according to respective construction experiences, and great hidden dangers are brought to the tunnel construction process and later-period safe operation.

Therefore, a construction method for a large-section T-shaped cross tunnel cave group is needed to solve the technical problems in the prior art.

Disclosure of Invention

The invention aims to solve at least some technical problems in the prior art to a certain extent, and provides a construction method of a large-section T-shaped cross tunnel hole group, which is suitable for the construction of the T-shaped cross tunnel hole group from a large-section tunnel into a small-section tunnel; through the reinforced construction method of the T-shaped intersection structure, the strength of the secondary lining structure at the T-shaped intersection is improved, and further the integral bearing capacity and the deformation resistance of the structure are improved.

In order to solve the technical problem, the invention provides a construction method of a large-section T-shaped cross tunnel hole group, which comprises the following steps:

step one, primary support construction of a large-section tunnel;

step two, dismantling a temporary arch at the intersection of the large-section tunnel and the small-section tunnel;

step 21: cutting the temporary arch frame according to the outline of the intersection of the large-section tunnel and the small-section tunnel;

step 22: chiseling off the cut temporary arch;

step three, installing a gate type reinforcing support at the intersection of the large-section tunnel and the small-section tunnel;

step 31: setting bedrock at the bottom of the door type reinforcing bracket to support the door type reinforcing bracket;

step 32: connecting the top of the door type reinforcing support with the cutting position of the upper arch frame;

fourthly, constructing an advanced large pipe shed at the top of the small-section tunnel;

step five, excavating the small-section tunnel;

sixthly, manufacturing and installing a double-spliced steel arch frame;

and seventhly, monitoring the deformation of the intersection position of the large-section tunnel and the small-section tunnel.

As a preferred embodiment, before the temporary arch is dismantled, a locking anchor rod is required to be arranged at each arch where the temporary arch is dismantled.

In a preferred embodiment, the foot-locking anchor rod is a T51 self-advancing foot-locking anchor rod.

As a preferred embodiment, the construction method of the large-section T-shaped cross tunnel group further comprises a structure reinforcing construction of the intersection of the large-section tunnel and the small-section tunnel, and the construction is combined in a manner of combining a secondary lining reinforcing ring beam and a longitudinal reinforcing hidden beam, so that the structural strength of the secondary lining at the intersection position is improved.

As a preferred embodiment, the structure reinforcing construction of the tunnel intersection includes:

erecting a support, and constructing a reinforcing ring beam and a secondary lining of a small-section tunnel with the length of 1m at the interface;

after the concrete reaches the design strength, dismantling the support, installing a lateral truss, and pouring a reinforcing beam and lining the side wall of the main structure in the range of the reinforcing beam;

and after the concrete reaches the design strength, removing the side wall support, and sequentially pouring the rest secondary lining at the intersection position by using a secondary lining trolley.

As a preferred embodiment, the longitudinal reinforcing hidden beams are symmetrically arranged on the upper side of the reinforcing ring beam, and the thickness of the longitudinal reinforcing hidden beams is 500 mm.

In a preferred embodiment, the reinforcing ring beam is of a non-uniform-thickness symmetrical structure, and the wall thickness of the reinforcing ring beam at the lower parts of two sides of the reinforcing ring beam is larger than that of other parts.

As a preferred embodiment, in the seventh step, deformation joints are arranged at the intersections of the large-section tunnel and the small-section tunnel, and deformation of the intersections of the large-section tunnel and the small-section tunnel is monitored by detecting changes of the deformation joints.

As a preferred embodiment, the number of the deformation joints is multiple, and the deformation joints are monitored by acquiring images of the deformation joints and comparing the images with historical data to monitor changes of the deformation joints.

In the seventh step, strain gauges are arranged at the intersections of the large-section tunnels and the small-section tunnels, and deformation of the intersections of the large-section tunnels and the small-section tunnels is monitored by monitoring changes of the strain gauges.

The invention has the beneficial effects that:

the construction method of the large-section T-shaped cross tunnel hole group provided by the invention has reasonable steps, and ensures the construction safety of the large-section tunnel entering the small-section tunnel by controlling the construction through the entrance safety of the T-shaped cross tunnel; through the reinforced construction method of the T-shaped intersection structure, the strength of the secondary lining structure at the T-shaped intersection is improved, and further the integral bearing capacity and the deformation resistance of the structure are improved.

Drawings

The above advantages of the present invention will become more apparent and more readily appreciated from the detailed description set forth below when taken in conjunction with the drawings, which are intended to be illustrative, not limiting, of the invention and in which:

FIG. 1 is a flow chart of a construction method of a large-section T-shaped cross tunnel cave group according to the invention;

FIG. 2 is a schematic diagram of the construction of a large-section T-shaped cross tunnel cave group according to the invention;

FIG. 3 is a cross-sectional view of the intersection of a large cross-section tunnel and a small cross-section tunnel in accordance with the present invention;

FIG. 4 is a flow chart of a structure-reinforced construction of an intersection of a large-section tunnel and a small-section tunnel according to the present invention;

fig. 5 is a schematic view of the reinforcing ring beam and the longitudinal reinforcing hidden beam of the invention.

In the drawings, the reference numerals denote the following components:

10. a temporary arch; 20. a portal reinforcing support; 30. advancing a large pipe shed; 40. locking the anchor rod; 50. reinforcing the ring beam; 60. longitudinally reinforcing the hidden beam; 70. double pin type steel bow member.

Detailed Description

Fig. 1 to 5 are related schematic diagrams of a construction method of a large-section T-shaped cross tunnel cave group according to the present application, and the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

The examples described herein are specific embodiments of the present invention, are intended to be illustrative and exemplary in nature, and are not to be construed as limiting the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification of the present application, and these technical solutions include technical solutions which make any obvious replacement or modification for the embodiments described herein.

The drawings in the present specification are schematic views to assist in explaining the concept of the present invention, and schematically show the shapes of respective portions and their mutual relationships. It is noted that the drawings are not necessarily to the same scale so as to clearly illustrate the structures of the various elements of the embodiments of the invention. Like reference numerals are used to denote like parts.

The invention relates to a flow chart of a construction method of a large-section T-shaped cross tunnel hole group, which is shown in figure 1. The construction method of the large-section T-shaped cross tunnel hole group comprises the following steps:

step one, primary support construction of a large-section tunnel;

building a temporary arch frame 10 of the large-section tunnel to form a primary support of the large-section tunnel;

step two, dismantling the temporary arch 10 at the intersection of the large-section tunnel and the small-section tunnel;

step 21: cutting the temporary arch 10 according to the outline of the intersection of the large-section tunnel and the small-section tunnel;

step 22: chiseling off the already cut temporary arch 10;

step three, installing a gate type reinforcing bracket 20 at the intersection of the large-section tunnel and the small-section tunnel;

step 31: a bedrock is provided at the bottom of the door-type reinforcing bracket 20 shown in fig. 2 to support the door-type reinforcing bracket;

step 32: connecting the top of the door type reinforcing support with the cutting position of the upper arch frame;

fourthly, arranging an advanced large pipe shed 30 shown in the figure 3 on the top of the small-section tunnel;

specifically, the top of the transverse passage is provided with an advanced large pipe shed 30 for excavation guiding, and the self-stability capability of the surrounding rock at the position is improved.

Step five, excavating the small-section tunnel;

sixthly, manufacturing and installing a double-spliced steel arch frame;

the double-spliced steel arch frame 70 shown in fig. 3 can strengthen primary support at the intersection position and ensure construction safety.

And seventhly, monitoring the deformation of the intersection position of the large-section tunnel and the small-section tunnel.

In an embodiment of the present invention, before the temporary arch 10 is removed, a locking anchor is installed at each arch 10 at the removal position of the temporary arch 10. Preferably, the foot-locking anchor rod is a T51 self-advancing foot-locking anchor rod.

FIG. 2 is a schematic diagram of the construction of a large-section T-shaped cross tunnel group, and the construction of the T-shaped cross tunnel entrance safety control is realized by combining a portal reinforced support, a double-spliced steel arch frame and an advanced large pipe shed.

As an aspect of the present embodiment, the door-type reinforcing bracket 20 includes an arc-shaped steel frame, and the double-spliced steel arch 70 is disposed outside the arc-shaped steel frame and the bottom thereof abuts against the bottom of the arc-shaped steel frame. Specifically, the double-split steel arch 70 is composed of a pair of steel arches arranged in parallel, and the distance between the adjacent steel arches is 40 mm. The primary support at the intersection position can be strengthened by the arrangement of the double-spliced steel arch frame 70, and the safety of subsequent construction is guaranteed.

In fig. 3, the leading large pipe shed 30 is disposed obliquely to the axis of the small-section tunnel and toward the outside of the small-section tunnel. The included angle between the advanced large pipe shed 30 and the axis of the small-section tunnel is 5-15 degrees. Preferably, the angle between the advanced large pipe shed 30 and the axis of the small-section tunnel is 8 °.

In one aspect of this embodiment, the advanced large pipe shed 30 is made of steel pipes with a diameter of 108mm, and the steel pipes are uniformly arranged along the position of the self-crossing at intervals. In the invention, the self-stability capability of the surrounding rock at the part is improved by digging and guiding the advanced large pipe shed 30 arranged at the top of the small-section tunnel.

And seventhly, arranging deformation joints at the intersections of the large-section tunnel and the small-section tunnel, and monitoring the deformation of the intersections of the large-section tunnel and the small-section tunnel by detecting the changes of the deformation joints. Specifically, the deformation joint number is a plurality of, and it is through gathering the image of deformation joint and comparing with historical data in order to monitor the change of deformation joint. Preferably, an image acquisition device such as a CCD (charge coupled device) can be selected to realize the image acquisition of the deformation joint. The monitoring of the deformation of the intersection positions of the large-section tunnel and the small-section tunnel can prevent the intersection positions from being accidentally influenced by the construction safety.

As a variation of this embodiment, in step seven, a strain gauge is disposed at the intersection of the large-section tunnel and the small-section tunnel, and the strain gauge monitors the deformation of the intersection of the large-section tunnel and the small-section tunnel by monitoring the change of the strain gauge.

As another embodiment of the present invention, the construction method of the large cross section T-shaped intersecting tunnel cave depot further includes a structural reinforcement construction of the intersection of the large cross section tunnel and the small cross section tunnel, which adopts a combined construction of a secondary lining reinforcement ring beam and a longitudinal reinforcement hidden beam to improve the structural strength of the secondary lining at the intersection position.

Fig. 4 is a structural reinforcement construction flow chart of the intersection of the large-section tunnel and the small-section tunnel according to the present invention, and the structural reinforcement construction of the tunnel intersection includes:

s10: erecting a support, and constructing a reinforcing ring beam and a secondary lining of a small-section tunnel with the length of 1m at the interface;

s20: after the concrete reaches the design strength, dismantling the support, installing a lateral truss, and pouring a reinforcing beam and lining the side wall of the main structure in the range of the reinforcing beam;

s30: and after the concrete reaches the design strength, removing the side wall support, and sequentially pouring the rest secondary lining at the intersection position by using a secondary lining trolley.

In fig. 5, the longitudinal reinforcing hidden beam 60 is symmetrically arranged on the upper side of the reinforcing ring beam 50, and the thickness of the longitudinal reinforcing hidden beam is 500 mm. The reinforcing ring beam 50 is of a non-uniform-thickness symmetrical structure, and the wall thickness of the two sides of the reinforcing ring beam is larger than that of other parts, so that the strength of the reinforcing ring beam 50 is ensured.

Compared with the defects and shortcomings of the prior art, the construction method of the large-section T-shaped cross tunnel hole group provided by the invention has reasonable steps, and the construction safety of the large-section tunnel entering the small-section tunnel is ensured by the safety control construction of the T-shaped cross tunnel entering the hole; through the reinforced construction method of the T-shaped intersection structure, the strength of the secondary lining structure at the T-shaped intersection is improved, and further the integral bearing capacity and the deformation resistance of the structure are improved.

The present invention is not limited to the above embodiments, and any other products in various forms can be obtained by the teaching of the present invention, but any changes in the shape or structure thereof, which are the same as or similar to the technical solutions of the present invention, fall within the protection scope of the present invention.