Preliminary bracing construction method for tunnel with surrounding rocks containing collapsible loess and soft rocks

A technology of collapsible loess and initial support, applied in tunnels, tunnel linings, earth-moving drilling, etc., can solve the problems of increased tunnel support, increased construction difficulty, poor self-stabilizing ability, etc., and avoid long-term suffering. Excessive force, low construction cost, and the effect of releasing surrounding rock stress

CN103410527AInactive Publication Date: 2013-11-27CENT SOUTH UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2013-11-27
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a preliminary bracing construction method for a tunnel with surrounding rocks containing collapsible loess and soft rocks. The method includes the following steps that a plurality of layers of advanced pipe sheds are arranged on a collapsible loess layer, and a single layer of advanced pipe shed is arranged on a soft rock layer; after the advanced pipe shed is set up, a working face is closed through sprayed concrete, a system anchor bolt is arranged on the soft rock layer, a foot locking small guide pipe is arranged at the arch springing position of the tunnel, and grouting is conducted on the rocks through permeation of the system anchor bolt and the foot locking small guide pipe; a pre-fabricated reinforcing mesh is paved on a concrete initial spraying layer formed by concrete initial spraying in a fluctuation mode, and a reinforcing mesh arranged at the collapsible loess layer is encrypted; a steel arch support is set on the collapsible loess layer, a reinforcing steel bar grid is set up at the soft rock layer, and the connecting position of the reinforcing steel bar grid and the steel arch support is welded; repeated spraying is conducted by adopting concrete spraying, and construction of tunnel preliminary bracing is finished. By means of the method, stress releasing and deformation coordination of two layers of surrounding rocks can be well controlled, operability is good, construction cost is low, and the safety is good.
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Description

technical field

[0001] The invention relates to a construction method for initial support of tunnels, in particular to a construction method for initial support of tunnels with collapsible loess and soft rock in the cross section. Background technique

[0002] Compared with tunnel surrounding rocks of grades I to III, layered surrounding rocks containing collapsible loess and soft rocks have low strength, large deformation, and poor self-stabilization ability, and there are differences in the characteristics of the upper and lower rock and soil layers, especially It is because the excavation area of ​​the tunnel is greatly increased, and the construction difficulty increases sharply. The disturbance to the surrounding rock during construction may cause the surrounding rock to loosen or enter a stage of large deformation, resulting in an increase in the difficulty of the initial support of the tunnel. Therefore, a reasonable The initial support technology is particularly impo...

Examples

Embodiment

[0030] A construction method for primary support of a tunnel with collapsible loess and soft rock in the surrounding rock of the present invention, there are two types of rock-soil layers on the cross-section of the tunnel surrounding rock, that is, the tunnel surrounding rock contains collapsible loess and soft rock at the same time. The loess layer 3 and the soft rock layer 4, and the collapsible loess layer 3 is located above the soft rock layer 4, the construction method of the present embodiment specifically includes the following steps:

[0031] (1) Construction advanced pipe shed

[0032] Such as figure 1 As shown, the concrete arch is constructed outside the outline of the open cave as a guide wall, the I-beam is pre-embedded in the arch, and the guide steel pipe is accurately placed according to the designed hole position. The I-beam and the guide steel pipe are welded as a whole. Use the theodolite to determine the plane position of the orifice pipe on the I-beam wi...