Construction method for middle pilot tunnel of double-track tunnel by excavating pilot hole in advance and thereafter performing excavation

A double-track tunnel and construction method technology, applied in tunnels, tunnel linings, earthwork drilling and mining, etc., can solve problems such as ineffective construction, achieve the effects of reducing construction costs, increasing tunnel excavation speed, and saving construction period

Active Publication Date: 2020-06-19
CHINA RAILWAY CONSTR BRIDGE ENG BUREAU GRP OF THE FIFTH ENG +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to cater for the construction of these tunnels, many tunnel construction methods have been born, such as TBM construction method, middle partition method, cross middle partition method, and shield method; time; none of the above methods can effectively carry out the construction

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] The present invention is realized through the following technical scheme, the construction method of excavating the pilot pit first and then excavating in the double-line tunnel, excavating a pilot tunnel first in the tunnel design section, and waiting for the pilot tunnel to penetrate or excavate a length of 300-500M in advance, according to Excavation, support and other operations are carried out on the designed section of the tunnel; the specific steps are as follows:

[0037] Step S1: advance support for the pilot pit and set the ventilation mode;

[0038] Step S2: Excavation of the intermediate pilot pit, expansion of the intermediate pilot pit and initial support;

[0039] Step S3: Invert arch excavation and support;

[0040] Step S4: Inverted arch concrete construction, backfilling and concrete base construction.

[0041] It should be noted that, through the above improvements, the advance pilot pit re-excavation method can conduct uninterrupted geological surv...

Embodiment 2

[0045] This embodiment is further optimized on the basis of the above embodiments. Further, in order to better realize the present invention, the step S1 specifically refers to: using the lock I-shaped steel door frame as the first circular erected steel The frame is used as the advance support of the tunnel; the diameter of the advance small conduit steel pipe is 50mm, the length is 5m, the spacing is 30-40mm, and the external insertion angle is 10-20°.

[0046] It should be noted that, through the above improvements, the end-to-end length of the leading small conduit steel pipes is no less than 1.0m.

[0047] Cement-water glass double-liquid grouting is adopted, the volume ratio of cement-water glass is 1:0.8, 325 ordinary Portland cement is used, the water-cement ratio is 1:1, the concentration of water glass is 25-30 degrees Baume, and the grouting pressure is 0.5 ~5MPa.

[0048] Other parts of this embodiment are the same as those of the foregoing embodiments, so details...

Embodiment 3

[0050] This embodiment is further optimized on the basis of the above embodiments. Further, in order to better realize the present invention, the step S2 specifically includes the following steps:

[0051] Step S21: Use full-section excavation and smooth blasting to excavate the intermediate pilot pit. Set anchors with a diameter of 22mm around the intermediate pilot pit, the length of the anchors is 2.5m, and the spacing is 1m*1m; The steel mesh with a diameter of 6mm has a grid spacing of 25cm*25cm; the arch wall is sprayed with 15cm thick concrete with a strength of C25; for some relatively broken sections, grid steel frames are added to ensure construction safety. The grid steel frame processing is processed according to the detail size of the grid steel frame in the front hole.

[0052] Step S22: Excavating the upper part of the intermediate pilot pit and initial support;

[0053] Step S23: Excavation and initial support of the left and right sides of the pilot pit.

[...

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PUM

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Abstract

The invention belongs to the technical field of double-track tunnel construction and particularly discloses a construction method for a middle pilot tunnel of a double-track tunnel by excavating a pilot hole in advance and thereafter performing excavation. The pilot hole is excavated in advance in a tunnel design section, and after the pilot hole is through or the length of the advanced excavationis 300-500 M, excavation expanding, support and other operations are carried out according to the tunnel design section. The construction method has the beneficial effects that the double-track tunnel construction is suitable for poor geological conditions, the tunneling speed of the tunnel can be effectively increased, the construction period is saved, and the construction cost is reduced.

Description

technical field [0001] The invention relates to the technical field of tunnel pilot pit excavation, in particular, it relates to a construction method in which the pilot pit is excavated first and then excavated in a double-track tunnel. Background technique [0002] In recent years, with the rapid development of highway and subway construction in our country, tunnel construction has entered a period of rapid development. In order to solve the growing traffic pressure, my country has successively built some ultra-long tunnels and super-long-span flat tunnels. In order to cater for the construction of these tunnels, many tunnel construction methods have been born, such as TBM construction method, middle partition method, cross middle partition method, and shield method; When; above-mentioned method all can not effectively carry out construction. Contents of the invention [0003] The purpose of the present invention is to provide a construction method of pilot pit first a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21D9/01E21D9/00E21D9/14E21D11/00E21D11/10E21D11/15E21D11/18E21D20/00E21F16/02E21F7/00
CPCE21D9/006E21D9/14E21D11/003E21D11/105E21D11/152E21D11/18E21D20/00E21F7/00E21F16/02E21D9/01
Inventor 何十美马天昌徐少平饶胜斌苏春生朴占华周文郭建强郝玉峰卫守峰赵辉石先火汤振亚梁朋刚
Owner CHINA RAILWAY CONSTR BRIDGE ENG BUREAU GRP OF THE FIFTH ENG
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