UK Roads - Road Trips - Mam Tor - Plaque

Plaque

 DERBYSHIRE COUNTY COUNCIL

MAM TOR
THE PROBLEM

1. The landslide originated at least 3000 years ago determined from radio carbon dating on material recovered from slide.
   The slide is recognised as one of the major land movements in the British Isles.
2. In 1802 the Machester and Sheffield Turnpike Company decided to by-pass the then existing road through Winnatts Pass by constructing a new road at an easier gradient across the Mam Tor landslip.
3. Since the construction of the road, major works have been carried out in 1912, 1933, 1946, 1952 and 1966. On the latter occasion the road was closed for six weeks. The movements relate closely to periods of heavy rain determined from rainfall records.
4. The combination of a hot dry summer in 1976 followed by heavy winter weather rains resulted in a major movement occurring in February 1977.
5. The 1977 movement resulted in 600mm (2ft) steps appearing in the carriageway and on the downhill side of the upper road cracks appeared leaving a 2.5m (8ft) unsupported face adjacent to the uphill lane.
6. The road was patched and limited to a single lane over the affected area and kept open until 1979. In 1979 the road was closed to through traffic.

ERIC HOOK C.ENG., M.I.C.E., M.I.H.T.
County Surveyor

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