Geobear was contracted by Dover Harbour Board to deliver some urgent works at berths 8 & 9 at their Dover Docks.
Following a presentation to representatives of the Port of Dover Authority we were asked to visit the site where they were experiencing the problems. There was a major issue for the client operating the docks where the off ramp had sunk to a degree that caused off loading lorries to hit the ramp as they were disembarking. Uretek was approached to stabilise the ground beneath the slabs and extend the life of the ferry berths.
Following the Uretek investigation, it became apparent that there was an issue with the ground beneath four slabs in the run off area. The fines beneath the concrete slabs had washed out on the ramps to berths 8 & 9 and they had settled by up to 40mm, this affected the safe vehicle passage on and off the ferries.
The Uretek engineering team designed a solution that could be achieved in two days with minimal impact to operations. The design of works involved injection of a Uretek geo-polymer directly beneath the slab; the process required drilling of 16mm holes through the slab at 1.5m centres and we then injected in our expanding geo-polymers. The material enters as a liquid and reacts to expand and become solid – this expansion forces out any water and completely fills voids. As it expands the material follows the path of least resistance, which means ultimately it will began to expand vertically to lift the slabs. The material Uretek uses is also hydro insensitive and forms a permanent water barrier to prevent further problems.
Over two days, on-site technicians delivered the ground stabilisation and relevelling treatment over 90m2 and recorded the process using laser monitoring. The monitoring system is accurate to 0.25mm and enabled us to ensure the slabs were raised by 40mm and leveled across the area. The technical teams used existing utility plans to ensure drilling and injecting would not hit any electricity cabling.
Our work was completed around the normal ferry operations to minimise any disruption to the terminal. The Uretek solution is fast curing, meaning areas of stabilisation could be used again within 15 minutes of treatment and with our mobile work units we could also extract technical teams and all equipment to and from site within 15 minutes. During the programme of works we could efficiently move in and out of the work site in between ferry dockings.
The versatility of Uretek solutions enabled the port to continue normal operations while the ground improvement work was carried out, the innovation and speed of the Uretek solution resulted in us being awarded a commendation at their AGM.