A new installation technology of large diameter deeply-buried caissons: Practical application and observed performance

The development of installation technologies open caissons has been lagging behind increasingly complex construction conditions. For such purpose, a new technology large diameter deeply-buried (LDDB) developed and then used for twin LDDB into undrained ground with stiff soils in Zhenjiang, China. To assess the effects filed performance, monitoring program was presented to document variations total jacking forces provided by shaft driven method, water level (GWL) around caisson shaft, inclination angles shafts radial displacements surrounding as well surface settlements existing nearby facilities. It is observed that data during falls almost entirely within design criteria, reported limited impacts on induced movements, depending variation GWL, interaction between excavation-induced unloading effect. Moreover, increase approximately stepwise shape depth increases; change law highly similar those showing their close correlation; larger are mainly encountered earlier phase, but controllable. Further discussion movements caused various confirms feasibility technology. Both compared results give greater confidence use practice.