Large-span spherical dome excavation method

Abstract

The invention relates to a large-span spherical dome excavation method, which solves the problems of high drilling control difficulty, poor drilling precision and poor safety when a spherical curved surface of a dome is excavated by a cross excavation method, a fan-shaped strip block method and an annular center column method. A middle vertical guide hole is excavated upwards at the terminal of a flat guide hole, namely the middle shaft of the spherical dome, after the middle vertical guide hole is excavated to the spherical dome, dome middle top arch anchor rod and sprayed concrete layer construction is conducted immediately, then the peripheral areas of the dome are excavated, and the peripheral area of the first dome is excavated to form a spherical curved surface; excavating a first reserved protective layer near the spherical curved surface, when the first reserved protective layer is excavated, obliquely drilling from the center to the periphery along the annular curved surface of the dome, then charging, blasting and excavating, and after the first reserved protective layer is excavated, removing rock ballast to the bottom of the middle vertical guide hole; and the steps are repeated to excavate and support the peripheral area of the lower-layer dome and the reserved protective layer of the lower-layer dome until all excavation and support are completed.

Description

technical field [0001] The invention relates to the field of underground cavern excavation construction, in particular to a large-span spherical dome excavation construction method. Background technique [0002] In underground engineering buildings such as hydropower stations, spherical domes are often designed, that is, underground caverns with spherical curved top arches, such as surge wells, vortex chambers and vortex wells of hydropower stations. The construction methods of the dome position mainly include the cross excavation method, the fan-shaped block method, the annular center column method, etc. During the construction, it is necessary to drill horizontal holes along the spherical surface of the dome. The hole control is difficult and the drilling accuracy is poor, which affects the excavation and forming quality of the spherical curved surface of the dome. At the same time, during the excavation of reserved rock pillars, the excavation span is greatly increased, ...

AI Technical Summary

Problems solved by technology

The construction methods of the dome mainly include the cross excavation method, the fan-shaped strip method, and the circular center column method. During construction, horizontal holes need to be drilled along the spherical surface of the dome. Since the depth and angle of the drilling are different at different heights of the spherical surface of the dome, drilling The hole control is difficult and the drilling accuracy is poor, which affects the excavation quality of the spherical curved surface of the dome

At the same time, when the reserved rock pillar is excavated, the excavation span is greatly increased, resulting in a substantial increase in the deformation of the surrounding rock, and a great safety risk

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