The primary task of tunnel construction is to ensure stable and safe operation in the later stages, which relies heavily on handling various issues during construction. Tunnel roof collapse is a serious problem, mainly caused by factors such as excessively high groundwater content and loose, fragmented geological conditions. The following discussion focuses on how to address tunnel roof collapse issues.

1. Rock Removal

Use an excavator to remove the rubble and soil from the collapsed tunnel face. During removal, pay attention to changes in the arch and surrounding rock mass to prevent secondary collapses. Different treatment methods are selected based on the scale of the collapse; temporary supports can be erected for small-scale collapses, while large-scale collapses require grouting reinforcement.

2. Shotcrete

 After clearing the landslide mass, shotcrete is applied to the tunnel face, and the surrounding rock surface is sealed to prevent further landslides during secondary excavation. If geological conditions are poor, anchoring and grouting reinforcement measures are necessary.

3. Anchor Drilling

For collapsed rock masses, reinforcement support must be implemented during reconstruction. Traditional tunnel support often uses casing drilling, while new self-drilling hollow grouting anchor bolts offer faster construction efficiency, eliminate the need for casing, and allow for simultaneous drilling and grouting.

4. Simultaneous Drilling and Grouting
Self-drilling hollow grouting anchors can be used with specialized drilling rigs and are suitable for various loose and fractured strata. Grouting during drilling appropriately enlarges the hole diameter, thereby increasing pull-out force and bearing capacity, achieving better hole formation and force results than other reinforcement methods.

Tunnel roof collapse can cause significant harm and impact on project schedule, cost, personal safety, and quality. Project safety issues require professional management, with strict requirements on design, materials, and construction to prevent roof collapse and other problems. Henglong's self-drilling anchors are developed to make soil and rock anchoring faster, more economical, and safer!