Construction technology for soft rock large-deformation tunnel by de-stressing method and matched bracket

Abstract

The invention discloses construction technology for a soft rock large-deformation tunnel by a de-stressing method and a matched bracket, and belongs to a high-burial depth large-deformation soft rock tunnel method and a support. The technology comprises the following steps: 1, performing tunnel tunneling construction and tunneling; 2, constructing mesh beam and shotcrete supports of the tunnel; 3, excavating a bottom plate de-stressing groove backwards from the tunneled working surface at the tunneled tunnel bottom plate; 4, constructing a tunnel wall de-stressing groove at the wall position of the tunnel; 5, setting up the matched bracket from the rear to the front; and 6, concreting at the bottom plate of the tunnel. The construction technology has the advantages that: 1, the de-stressing groove is excavated at a bottom groove, so that the tunnel is positioned in a low stress region at the initial stage of the excavation and the influence on and damage to the tunnel due to high stress are reduced after the tunnel excavation; 2, an enclosed structure where a full section and the tunnel section are adapted has high deformation resistance; 3, the bracket has a multi-stage variable bearing structure, and can prolong the time in the tunnel; and 4, an intensity-controlled buffer cushion block controls the variation rate of the bracket timely. In addition, the construction technology also has the advantages of simple structure and strong engineering practicability.

Description

technical field [0001] The invention relates to a high buried depth and large deformation soft rock roadway method and support under complex geological conditions, in particular to a soft rock large deformation roadway pressure relief method construction technology and supporting supports. Background technique [0002] At present, the support of roadways in complex structural areas and buried deep and high ground stress surrounding rocks has always been a difficult problem in roadway support. Generally, there are conventional support, U-shaped steel retractable support, anchor mesh cable or anchor grouting support. The above support methods are difficult to meet the support stability requirements of complex areas and buried deep high ground stress surrounding rock roadway, which seriously restricts the production efficiency of mine excavation, delays the mine commissioning period, affects the improvement of economic benefits, and poses a serious threat to safe production. ...

AI Technical Summary

Problems solved by technology

[0002] At present, the support of roadways in complex structural areas and buried deep and high ground stress surrounding rocks has always been a difficult problem in roadway support. Generally, there are conventional support, U-shaped steel retractable support, anchor mesh cable or anchor grouting support. The above-mentioned support methods are difficult to meet the support stability requirements of tunnels in complex areas and buried deep high ground stress surrounding rock, which seriously restricts the production efficiency of mine excavation, delays the mine production period, affects the improvement of economic benefits, and poses a serious threat to safe production

[0003] The pressure of the conventional support on the surrounding rock depends on the strength of the support itself to maintain the rock mass space it maintains. After the support is stressed, the structure of the support will change, and the section of the maintained roadway will be reduced. It is necessary to continuously repair the roadway, resulting in A lot of waste of money and material resources

[0004] When the U-shaped steel shrinkable support is used in soft rock roadway support, the initial shrinkable support has certain adaptability to the deformation of the roadway. As the surrounding rock of the roadway further expands, the shrinkable support is difficult to bear the influence of the total amount of surrounding rock In addition, if you encounter soft rock rich in expansive mineral components, the rock mass will react with humid air or engineering water after exposure, and it will easily muddy and soften, and the strength of the surrounding rock will continue to decrease, and the self-weight and stress of the surrounding rock will be quickly transferred to the support. , resulting in rapid deformation of the bracket and the need for constant maintenance

[0005] Anchor mesh cable or anchor-grouting support cannot adapt to the influence of large deformation of the roadway. The elongation rate of the anchor rod is generally not more than 16%, and the elongation rate of the anchor cable is generally not higher than 6%. Fractures will break in large numbers and need to be repaired in time

The surrounding rock mass of the soft rock roadway is rich in expansive mineral components, and the anchoring and grouting support method of conventional cement slurry will cause the rock mass to expand, which has little effect on the roadway support

[0006] Existing pressure relief measures such as loose blasting around the roadway and the bottom plate have destroyed the integrity of the surrounding rock to a certain extent. The lack of matching follow-up support means weakens the strength of the rock mass around the roadway, and the roadway is easily in disrepair under the action of high-stress environment or mining

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