Experience counts when the unexpected happens
Client: A local building contractor
View Road Highgate, London
Purkelly were quick to solve the problem when a 3m test bore filled up and collapsed.
This was a piling only contract for an underpinning raft slab subsequently constructed by the building contractor. It is a good example of problem solving when the unexpected is encountered.
The original estimate was for open boring, but following a test bore on site with an auger bore track drilling machine, ground water entered the borehole at a depth of approximately 3.0 m and quickly rose to within 1.0 m of the surface. This was in spite of clay being encountered which was thought to be susceptible to shrinkage and heave. The bore collapsed when the augers were extracted.
Purkelly then proposed a successful alternative which involved 150 mm diameter steel cased driven piles installed inside a pre-bored 200 mm diameter sleeved hole. The sleeving provided full heave protection to the steel cased piles.
To cater for the specified pile loadings a total of 19. piles were installed using a Grundomat vibratory piling machine to depths varying from 5.50 m to 9.00 m.
