Auxiliary grouting platform and construction method for crossing large karst caves during excavation of existing tunnels

Abstract

The invention discloses an auxiliary grouting platform for passing through a large karst cave in the expanding excavation of an existing tunnel, a grouting rack with a steel framework structure is adopted, a material channel penetrating front and back is arranged at the middle part of the steel framework structure, steel plates are respectively fixedly arranged on the top wall, the left side walland the right side wall of the steel framework structure, drilling machine ascending and descending rack temporary ramps are respectively arranged between the left side and the right side of the grouting platform and a previous expanding excavation completion section of the large karst cave, and a space formed by the upper part of the grouting rack and the top part of the large karst cave forms agrouting operation space of a drilling machine. Meanwhile, the invention further provides a construction method for passing through the large karst cave in the expanding excavation of the existing tunnel. The grouting rack with the material channel designed again is combined with the drilling machine ascending and descending rack temporary ramps distributed on the left side and the right side of the grouting rack, then the parallel operations of treatment and expanding excavation of a cavity of the large karst cave are conducted, the expanding excavation efficiency of the tunnel is obviously improved, the construction period is shortened, the auxiliary grouting platform is safe and reliable and is strong in operability, and the construction safety is guaranteed.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a construction method for crossing a large-scale karst cave when expanding and excavating an existing small-section tunnel into a large-section tunnel, and an auxiliary construction platform for grouting the upper half of the tunnel when crossing a large-scale karst cave . Background technique [0002] In the past, the treatment of large-section dissolved cavities was mainly carried out in newly excavated tunnels. When large-section tunnels pass through large-scale dissolved cavities, excavation can be carried out in steps. For example, the upper half of the tunnel is excavated first, and then the tunnel is excavated The lower half section, and then the whole section, shall be used as the tunnel slurry wall. After the construction of the grout stop wall is completed, the drilling rig is used to carry out curtain grouting on the tunnel face and construct the pipe shed...

AI Technical Summary

Problems solved by technology

Therefore, when the lower half section is filled with tunnel slag for karst cave treatment, it greatly affects the logistics traffic of the lower half section tunnel, thereby affecting the excavation of the next section of the large karst cave, reducing the efficiency of expansion and excavation, and prolonging the construction period

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