SIXTEEN FAMILIES were homeless this week after a crater opened up in a Reading street damaging the carriageway and nearby houses.
It is thought the 200m3 hole resulted from the collapse of an old chalk mine or historic fortifications.
Reading Borough Council and insurers called in local consulting engineer Peter Brett Associates to investigate the collapse and find a repair solution.
Peter Brett geotechnical engineer John Talbot said: ‘We have drilled 20 dynamic probe holes in the area surrounding the subsidence, many extending to more than 20m in depth. Preliminary results show the ground conditions in most of the surrounding area to be weak to around 15m below ground level.’
Further exploratory holes are being undertaken to define the full extent of the problem. Initial analysis of the results and historical maps point to a backfill failure.
Peter Brett and other ground treatment specialists are considering stabilising the ground with a combination of compaction and pressure grouting methods before services reinstatement and reconstruction work can be started.
Residents noticed a water leak in the road at 5am on 4 January and reported it to Thames Water. Subsidence occurred later that afternoon.
Thames Water said it was unlikely that a mains leak caused the hole to open up unless the main had been leaking for a long time.