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2. Deere, D., Gamble, J., 1971. Durability-plasticity classification of shales and indurated clay. In: Proceedings of the 22nd Annual Highway Geology Symposium; Norman, Oklahoma, pp. 37–52.
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4. Hollmann, F., 2014. Evaluation of Soil and Rock for Clogging and Disintegration of Fines for mechanised Tunnel Drives (In German: Bewertung von Boden und Fels auf Verklebungen und Feinkornfreisetzung beim maschinellen Tunnelvortrieb). Dissertation, Ruhr-University Bochum, Institute for Tunnelling and Construction Management.
5. Assessment method for clay clogging and disintegration of fines in mechanised tunnelling;Hollmann;TUST,2013