Geotechnical aspects of underground construction in soft ground IX proceedings of the 9th International Symposium on Geotechnical Aspects of Underground Construction in Soft Grounds (IS-Sao Paulo 2017), April 4-6, 2017, Sao Paulo, Brazil - Bilfinger, Werner; Cecílio, Marlísio O.; Negro, Arsenio (CRC Press, 2017)