Sandwich arch suitable for surrounding rock support of high-stress soft rock tunnel and construction method thereof

Abstract

The invention discloses a sandwich arch suitable for surrounding rock support of a high-stress soft rock tunnel and a construction method of the sandwich arch. The sandwich arch comprises a surrounding rock outer ring bearing arch, an interlayer anchor rod reinforcing arch and a surrounding rock inner ring bearing arch, wherein the surrounding rock outer ring bearing arch, the interlayer anchor rod reinforcing arch and the surrounding rock inner ring bearing arch are anchored together by anchoring cable bundles to finally form an integral anchor shell sandwich arch support structure. The surrounding rock outer ring bearing arch is characterized in that a deep surrounding rock mass in front of a tunneling head is crushed according to a deep hole pre-splitting blasting method, and grouting is carried out to re-consolidate a deep fractured rock body and a crushed rock layer to form a crushed stone reinforced arch. The interlayer anchor rod reinforcing arch is characterized in that anchorrods are densely and evenly installed in a surrounding rock shallow rock layer to form a uniform-thickness layer compression zone. The surrounding rock inner ring bearing arch is a high-strength grating steel arched frame and concrete built arched bracket. The sandwich arch significantly improves the bearing capacity of surrounding rock deep and shallow rock masses, is high in supporting strengthand large in range, provides a reliable stress foundation for the anchoring cable bundles, and can realize the long-term stability of surrounding rock of the high-stress soft rock tunnel.

Description

technical field [0001] The invention relates to the field of tunnel roadway surrounding rock control, in particular to a sandwich arch suitable for high-stress soft rock tunnel roadway surrounding rock support and a construction method. Background technique [0002] The biggest problem faced by tunnel construction under the condition of high-stress soft rock is the large deformation of surrounding rock. Large deformation will lead to cracking and failure of surrounding rock support, even landslides, and more seriously, it may cause permanent damage to the support. If the construction method is improper, it will not only increase the project cost, but also have considerable hidden dangers to the construction and operation safety. According to statistics, the actual repair ratio of high-stress soft rock tunnel roadway is as high as 90%, and its deformation characteristics are as follows: Surrounding rock deformation speed is fast and the deformation amount is large, so exca...

AI Technical Summary

Problems solved by technology

At present, many engineering experts at home and abroad have proposed many solutions for the tunnel support under the condition of high-stress soft rock, such as scaffolding, passive support of masonry, active support of anchor cables, anchor net spraying, and step-by-step joint support. Control and other methods have played a certain role in inhibiting the large deformation of the surrounding rock, but the supporting effect is not obvious. The surrounding rock collapses in layers, and the wedge-shaped caving outside the anchorage area leads to permanent failure of the support structure, which seriously affects the safe construction and traffic of the tunnel roadway

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