using compressible insertions

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Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling (E21D15/00 - E21D23/00 take precedence; specially for shafts E21D5/00; ; lining pressure water galleries, linings therefor E02B9/06) > Lining with building materials (E21D11/02, E21D11/14 take precedence ) > using compressible insertions