Authors: J.P. Davis, F.A. Loveridge, J. Perry, D. Patterson, D. Carder
Plenary session of 12th Pan-American Conference on Soil Mechanics & Geotechnical Engineering & 39th US Rock Mechanics Symposium, 2003
Abstract
This paper describes the lessons learnt in the assessment, stabilization and subsequent monitoring of a landslide, which mobilized over 90,000 m3 of material and threatened to completely close England’s busiest highway, the M25 around London. The wedge shaped slide occurred on the 19th December 2000 and extended some 80m up the slope with a slip surface up to 10 m below the ground surface. Due to the strategic importance of the M25, the design and construction was fast tracked to be completed before the fall rains when further movements would be inevitable. The adopted solution used a combination of 1050 mm diameter augered piles, a deep cutoff trench and counterforts at the toe and was extensively instrumented.
The collected data for the winter 2001/02 demonstrates that not only were the remedial works successful in stabilizing the slope but that the proposed design method can accurately predict the bending moments and forces produced in the piles.
