Tunnel shield construction is a type of underground construction method for subway projects. During the construction process, tunnel shields are a material that must be used. What are the functions of tunnel shields?
Enhance the strength of the surrounding rock mass
Enhance the strength of the surrounding rock soil, improve the soil bearing capacity of the excavation line arch, reinforce the tunnel surrounding rock, and ensure the safety of tunnel construction. The grouting fluid is pressurized into the surrounding rock fractures through the pipe wall holes, causing the loose rock mass to cement and solidify, thereby improving the physical and mechanical properties of the soft (fractured) surrounding rock, enhancing the self-bearing capacity of the surrounding rock, and achieving the reinforcement of the pipeline. The purpose of the棚围 surrounding rock is. When the tunnel passes through fractured zones, loose areas, weak strata, water gushing, sand gushing, and other sections, the role of the pipe shed becomes more pronounced.
Ensure construction safety
The support rigidity of the pipe shed is quite high. If a landslide occurs again during construction, the collapsed slag will also fall onto the rock slag above the pipe shed, serving as a buffer. Even if the pipe shed is unstable, its destruction is relatively slow.
3. Control land subsidence
When tunnelling passes beneath existing lines and structures, the primary role of the pipe shed is to control ground settlement, prevent damage to the existing lines, buildings, and structures due to tunnel excavation, and ensure the safety of the existing lines, buildings, and structures as well as the smooth progress of tunnel excavation. In such cases, the diameter of the steel pipe in the pipe shed may be too large (φ299).
4. Control rock mass instability and collapse
Pre-fabricated pipe shields are supported by the front and rear surrounding rock for anchoring, forming a beam-like structure. Together, they create a shell-like structure around the tunnel contour, effectively preventing surrounding rock from loosening and collapsing.
