Abstract:

The ventilation shaft of New Qidaoliang Tunnel on LanzhouLintao expressway is 171.16m deep and the clearance diameter of the ventilation shaft is 6m. The lining of the ventilation shaft is constructed with insitucast concrete rings installed step by step from the shaft bottom toward the shaft head. The separation wall of the ventilation shaft is constructed onceforall from the shaft bottom toward the shaft head when the lining construction of the shaft is completed. Compared to the construction method of immediate lining during shaft excavation, the above construction method has such advantages as simple construction procedure, little construction interference, less concrete joints and little water leakage from the surrounding rock. This construction method can provide reference for similar projects in the future.

Key words: ventilation shaft  , separation wall  , lining