Demand for deep excavations is growing but new projects need to make more use of instrumentation and innovative techniques in order to meet cost and technical challenges according to Arup director Duncan Nicholson.
Nicholson made the comments during his opening address at GE’s annual Basements and Underground Structures Conference in London today, where he also looked at the growth potential for the next 12 months. “The economic climate is difficult but in the UK there are plenty of high specification residential projects in planning that will call for deep excavations and demand for residential basement construction is also growing, especially in London,” he said before highlighting the large potential for growth globally.
During his presentation, Nicholson discussed the cost and time savings that are currently being delivered on excavations at Tottenham Court Road for Crossrail through removal of one level of strutting. “Shape arrays were used for real time monitoring of the excavation to ensure the reality matches predicted design deformations.
“Future developments will need to consider use of new technology such as BIM to integrate ground investigation data with the structural design and follow the Japanese lead on use of raked steel sheet piled retaining walls to reduce active earth pressures to remove the need for strutting and make excavations safer. Monitoring of prop forces also needs to be more widely used, along with greater care to avoid wall defects from tremmied concrete with wider use of techniques such as Pile Dynamics Thermal Integrity Profiler to check as built construction.”