The effects of tunnelling in soft ground consisting mainly of Singapore marine clay were recently monitored to establish ground response characteristics. A sewer tunnel of 2.1 m square section was driven at a depth of 6.3 m in this soil by jacking conventional shield and face supports against installed timber lining. Ground response was monitored by an assortment of field instruments read over several weeks\u27 duration. Peck\u27s proposal (1969) of fitting a normal distribution profile to lateral surface settlement field plots when a heading is well past, and the suggestion by Oshikoshi et al 0978) that similar profiles may be drawn across an error function fitted to longitudinal surface settlement field plots, have been confirmed for the site. In addition, similar relationships to the above were found to apply with depth. Thus, taking into account Lo\u27 s (1982) determination of standard deviation and ground loss volume for marine clay based on the relationships proposed by Peck (1969) and Yoshikoshi et al (1980), it should, in principle, be possible to determine the vertical ground displacement pattern associated with any tunnel excavation in this soil
