Excavation of Loess Tunnel with Large Section and Rapid Closing and Ring Forming Method of Primary Support

A primary support and loess tunnel technology, which is applied in tunnels, earthwork drilling, tunnel lining, etc., can solve problems such as inability to effectively protect construction safety, improve the construction environment for workers, ensure normal traffic, and quickly close primary support Effect

Active Publication Date: 2019-01-11
CHINA RAILWAY 12TH BUREAU GRP +1
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0006] In order to solve the problem in the construction of large-section loess tunnels that lacks the technology of quickly closing the initial support and forming a ring after excavation, so that the construction safety cannot be effectively protected, the present invention provides a large-section loess tunnel excavation and initial support that quickly closes and forms a ring method

Method used

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  • Excavation of Loess Tunnel with Large Section and Rapid Closing and Ring Forming Method of Primary Support
  • Excavation of Loess Tunnel with Large Section and Rapid Closing and Ring Forming Method of Primary Support
  • Excavation of Loess Tunnel with Large Section and Rapid Closing and Ring Forming Method of Primary Support

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Embodiment

[0058] The Wanrong Tunnel constructed by our group is designed as a single-hole and double-track, with a total length of 7,683 meters, of which Ⅴ and Ⅵ-level surrounding rocks account for 97.66%, and the maximum buried depth is 90.25 meters. A total of 33 tunnels pass through roads and villages, and the surface roads are crisscross, the villages are dense, and the yellow irrigation system is staggered. In particular, the tunnel body passes through new loess and silty sand layers, and there are extremely high landslides and sand surges. Security Risk.

[0059] In order to effectively prevent landslides and sand gushing during construction and solve a series of construction problems such as "quick excavation, fast branching, fast sealing, and fast strengthening" in new loess and silty sand strata, our department combined the Wanrong Tunnel Engineering and geological characteristics According to the quality, safety, and construction period risk control requirements, the height an...

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Abstract

The invention is an excavation of a large section loess tunnel and preliminary bracing rapid closure of a ring forming technology. The problem of lack of construction technology which is high in safety performance and simple in technology in construction of excavation of the large section loess tunnel is solved, the technology comprises the following steps that S1, the height and the length of each bench are determined and measurement lofting is conducted according to the tunnel surrounding rock environment; and S2, upper bench excavation, bracing; middle bench excavation, bracing; lower bench excavation, bracing; the arc excavation face of the upper bench, the arc excavation face of the middle bench and the arc excavation face of the lower bench are re-jetted concrete; and inverted arch excavation bracing. According to the excavation of the large section loess tunnel and preliminary bracing rapid closure of the ring forming technology, construction progress reaches to about 70 meters of drill footage per month, the duration is 5 months ahead of schedule, more than 3 million yuan of various management costs are saved, about 20 million yuan of project investment is saved, and economic and social benefits are remarkable.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a large-section loess tunnel excavation and primary support rapid closure ring forming method. technical background [0002] Loess is mainly distributed in Northwest my country and North China, covering a total area of ​​635,000 square meters. Loess has the characteristics of rapid development of vertical cracks and low shear strength, which leads to sudden collapse of soil and excessive deformation of supporting structures when excavating tunnels in loess strata. The mechanical properties of large-section loess tunnels determine that only step-by-step excavation and sub-support methods can be used. At present, the construction methods commonly used in large-section loess tunnels include arc-shaped pilot pit (reserved core soil) method, CD method (middle partition method), CRD method (middle wall cross method), single-side wall pilot pit method, Double-side-wall pil...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21D11/10E21D9/00
CPCE21D9/00E21D11/00E21D11/105
Inventor 田晓峰赵香萍鲍海荣赵西民李五红张朝亮张华都强徐磊
Owner CHINA RAILWAY 12TH BUREAU GRP
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