Reconstruction technology of underground engineering based on dismantled area in soft clays in Ningbo, China

In recent years, the reconstruction projects of underground engineering in existed basement are frequently appeared. The efficiently dismantlement technology and safety construction technology of diaphragm wall trench are the mainly problems in these projects. Based on the reconstruction project of North Square of Ningbo South Railway Station in China, the reconstruction technology of deep braced excavation based on the existed basement is proposed. The reconstruction technology contains technology for pulling out the existed piles, backfill technology of the holes leaved by pulling out piles, shallow reinforcement technology of diaphragm wall trench in soft clays and the control technology of high water head difference between inside and outside the existed basement for diaphragm wall construction. From the field application, the reconstruction technologies ensure the construction safety and quality, and can be applied to the similar projects. © 2016 ejge.