CN209277905U - Tunnel bilayer I-steel preliminary bracing structure - Google Patents

Abstract

A tunnel double-layer I-beam primary support structure. It includes inner support frame, outer support frame, steel wire mesh and initial support layer; the inner support frame is composed of a plurality of inner arch rods arranged on the inner side of the surrounding rock at intervals along the extension direction of the tunnel; The layer support frame is composed of a plurality of outer layer arched rods arranged on the inner side of the surrounding rock at intervals along the extension direction of the tunnel. An inner layer arched rod is placed between two adjacent outer layer arched rods, and the outer layer arched rod The radial positions of the inner arch rods are staggered from each other and the outer arch rods are closer to the surrounding rock; the steel wire mesh is hung on the surrounding rock; the initial support layer is sprayed on the steel wire mesh and the inner layer support It is formed after the concrete on the retaining frame and the outer layer support frame has solidified. The utility model has the advantages: it can prevent adverse geological conditions such as primary branch deformation, cracking, collapse, roof fall, excavation surface flow collapse, and tunnel water leakage due to the adverse geological conditions of fully weathered water-rich granite during tunnel construction, ensuring that the tunnel Construction safety and permanent operation safety.

Description

Tunnel double-layer I-beam primary support structure

technical field

The utility model belongs to the technical field of tunnel construction protection facilities, in particular to a tunnel double-layer I-beam primary support structure.

Background technique

A tunnel is an engineering building buried in the ground, and it is a form of human use of underground space. In the process of tunnel construction, the commonly used initial support structure is to use a single-layer I-beam support to excavate in the dark after the long pipe shed is constructed, and no strengthening measures are taken. However, if the tunnel has weak fully weathered granite, large water seepage, In the case of unfavorable geological conditions such as shallow burial depth, such conventional methods may cause unfavorable geological conditions such as primary support deformation, cracking, collapse, and roof fall. Therefore, there are relatively large safety risks and permanent operational safety risks.

Contents of the invention

In order to solve the above problems, the purpose of this utility model is to provide a tunnel double-layer I-beam primary support structure.

In order to achieve the above purpose, the tunnel double-layer I-beam initial support structure provided by the utility model includes an inner support frame, an outer support frame, a steel wire mesh sheet and an initial support layer; wherein, the inner support The support frame is composed of a plurality of inner arch rods arranged at intervals along the tunnel extension direction on the inner side of the surrounding rock; the outer layer support frame is also composed of a plurality of outer layer arch rods arranged at intervals along the tunnel extension direction on the inner side of the surrounding rock Rods, an inner arched rod is placed between two adjacent outer arched rods, the positions of the outer arched rod and the inner arched rod are staggered from each other in the radial direction of the tunnel and the outer arched rods are closer Surrounding rock; the steel wire mesh is hung on the surrounding rock in the area where the inner layer support frame and the outer layer support frame are set; the initial support layer is sprayed on the steel wire mesh sheet, the inner layer support frame and the outer layer support It is formed after the concrete on the frame solidifies.

The inner arched rod adopts I18 I-beam; the outer arched rod adopts I20a I-beam.

The distance between the adjacent inner layer arched rods and outer layer arched rods is 0.6 meters in the tunnel extension direction, and 0.3 meters in the radial direction of the tunnel.

The tunnel double-layer I-beam primary support structure provided by the utility model has the following advantages: it can prevent primary support deformation, cracking, collapse, roof fall, and excavation surface flow during tunnel construction due to adverse geological conditions of fully weathered water-rich granite. To ensure the safety of tunnel construction and permanent operation safety.

Description of drawings

Fig. 1 is a schematic diagram of the transverse section of the tunnel adopting the double-layer I-beam initial support structure provided by the utility model.

Fig. 2 is a sectional view along line I-I in Fig. 1 .

Fig. 3 is a schematic diagram of the longitudinal section of the tunnel adopting the double-layer I-beam initial support structure provided by the utility model.

Detailed ways

The utility model is described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1-3, the tunnel double-layer I-beam initial support structure provided by the utility model includes an inner layer support frame 1, an outer layer support frame 2, a steel wire mesh sheet and an initial support layer 3; , the inner layer support frame 1 is composed of a plurality of inner layer arched rods arranged at intervals along the tunnel extension direction on the inner side of the surrounding rock; The outer arched rods on the inner side of the surrounding rock are formed, and an inner arched rod is placed between two adjacent outer layered arched rods. Staggered and the outer arched rods are closer to the surrounding rock; the steel wire mesh is hung on the surrounding rock in the area where the inner support frame 1 and the outer support frame 2 are set; the initial support layer 3 is sprayed on the steel wire mesh The sheet and the concrete on the inner layer support frame 1 and the outer layer support frame 2 are solidified and formed.

The inner arched rod adopts I18 I-beam; the outer arched rod adopts I20a I-beam.

The distance between the adjacent inner layer arched rods and outer layer arched rods is 0.6 meters in the tunnel extension direction, and 0.3 meters in the radial direction of the tunnel.

The construction method of the tunnel double-layer I-beam initial support structure provided by the utility model is described as follows:

(1) The tunnel is excavated step by step, and then the initial support structure is started. Firstly, the first inner arch rod on the inner support A steel wire mesh is hung on the surrounding rock on the outer side of the arched bar of the first layer, and then sprayed concrete on the above-mentioned steel mesh and the first inner arched bar;

(2) The support of the first inner arch rod is completed. The first outer arch rod on the outer support frame 2 is supported at 0.6 meters behind it and the locking foot anchor pipe is installed. The outer arch The positions of the shaped rods and the inner arched rods are staggered from each other in the radial direction of the tunnel, and the outer arched rods are closer to the surrounding rock, and the distance between the adjacent inner layer arched rods and the outer layer arched rods in the radial direction of the tunnel is 0.3 meters; Then hang a steel wire mesh sheet on the surrounding rock outside the first outer layer arched rod, and then spray concrete on the above steel wire mesh sheet and the first outer layer arched rod;

(3) Steps (1) and (2) are repeated until all inner layer arched rods and outer layer arched rods are set, and the primary support layer 3 can be formed after the concrete solidifies.

Claims (3)

1. A tunnel double-layer I-beam initial support structure, characterized in that: the tunnel double-layer I-beam initial support structure comprises an inner layer support frame (1), an outer layer support frame (2) , steel wire mesh sheet and primary support layer (3); wherein, the inner layer support frame (1) is composed of a plurality of inner layer arch rods arranged on the inner side of the surrounding rock at intervals along the extension direction of the tunnel; The layer support frame (2) is also composed of a plurality of outer layer arched rods arranged at intervals along the tunnel extension direction on the inner side of the surrounding rock, and an inner layer arched rod is placed between two adjacent outer layer arched rods. The positions of the outer arch rod and the inner arch rod are staggered from each other in the radial direction of the tunnel, and the outer arch rod is closer to the surrounding rock; the steel wire mesh is hung on the inner support frame (1) and the outer support frame (2) On the surrounding rock of the set area; the initial support layer (3) is formed by the solidification of concrete sprayed on the steel wire mesh sheet and the inner support frame (1) and the outer support frame (2) . 2. The tunnel double-layer I-beam initial support structure according to claim 1, characterized in that: the inner arched rod adopts I18 I-beam; the outer arched rod adopts I20a I-beam. 3. The tunnel double-layer I-beam initial support structure according to claim 1, characterized in that: the distance between the adjacent inner layer arched rods and outer layer arched rods in the direction of tunnel extension is 0.6 meters , the distance in the radial direction of the tunnel is 0.3 meters.