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Landslipping is part of the normal erosion process in many rock strata and particularly in steep sided valleys in clays and shales. This can have far reaching effects on urban development and The programme looks at the valley of the River Severn near Ironbridge which has had a history of slope instability. The famous Ironbridge, the first ever constructed of brittle cast iron by Abraham Darby in 1776 is used as an indicator of landslip movements along the valley. Cracks in the stone abutments and the iron arches are clear evidence of unstable foundations and have resulted in expensive conservation measures. Just downstream from Ironbridge the last major landslip in the Severn valley is looked at in detail. Part of the village of Jackfield slipped into the river in 1951, and the scientific investigation of its causes are examined. Some of the methods used in giving numbers to the forces which result in shear surfaces developing are shown in the Engineering Geology Laboratory at Durham University.
Metadata describing this Open University video programme
Module code and title: S333, Earth science topics and methods
Item code: S333; 10
First transmission date: 1976
Published: 1976
Rights Statement: Rights owned or controlled by The Open University
Restrictions on use: This material can be used in accordance with The Open University conditions of use. A link to the conditions can be found at the bottom of all OUDA web pages.
Duration: 00:25:00
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Producer: Neil Cleminson
Contributors: P. B. Attewell; David Williams
Publisher: BBC Open University
Keyword(s): 1951; Conservation measures; Durham University; Engineering Geology Laboratory; Erosion process; Ironbridge; Jackfield; River Severn; Scientific investigation; Urban development
Footage description: Shots of the Severn Valley near Ironbridge. Dave Williams, in the studio, introduces the programme. David Williams at Ironbridge. He parts of the old bridge for signs due to landslip. Further shots of the valley area, particularly of buildings which show severe damage from landslip. Commentary by Williams. Shots of the old road leading to the village of Jackfield. Williams points out the landslip damage. Williams, in the studio, discusses the and severity of the 1951 landslip at Jackfield which devastated much of the village. An animated map shows the progress and extent of the landslip. Peter Attewell explains why it is necessary to do shear tests on core samples from likely landslip areas. A shear box, an apparatus which measures residual shear-strength of soft rock samples, is demonstrated. David Williams (voice over) explains what is happening. Peter Attewell points out some of the inherent disadvantages of the shear box test. Shots of a demonstration of a trexial test which overcomes many of the disadvantages of the shear box. Williams, in the studio, examines a Mohr diagram which plots the shearing strength of materials tested in the triaxial test above. Williams, with a simple model, demonstrates slope stability at a potential failure surface within a large mass of clay. Williams briefly sums up. Film shots of Jackfield from the air.
Master spool number: 6HT/2093
Production number: 00525_1216
Videofinder number: 1376
Available to public: no