INSTRUMENTATION OF FLOOD DEFENSE BANKS ALONG THE RIVER THAMES

The paper which outlines some of the problems associated with the instrumentation of flood defense banks, also describes instruments which have been installed and discusses ideas to be incorporated in the programme of instrumentation. A cross-section through a typical bank is described and the types and positions of instruments on a typical installation are illustrated in a figure. The factors are outlined which determine the type of piezometer used in the measurement of the pore water pressure. Vertical standpipes comprising plastic tubes, with diameters from 12.5 to 20 mm and fitted with porous ceramic tips have been used extensively for measuring the changes in pore water pressure in layers of sand and gravel which have a direct connection with the river. The advantages and disadvantages of this type of instrument are discussed. Extensive use has been made of twin-tube closed system hydraulic piezometers to measure pore water pressures in studies of various aspects of the stability of flood banks. Pneumatic piezometers, although not affected by water pressures and temperature changes of the connecting tube, may give higher readings owing to the presence of methane gas on the organic oils. Details are given of these instruments and their installation. Measurements are described which were made in order to study the movements of banks before the onset of obvious failures. The types of instruments and techniques used in the measurement of internal movements in the ground (vertical and lateral movements) are described. Conclusions drawn from the study are presented.

Media Info

  • Features: Figures; References;
  • Pagination: p. 45-56

Subject/Index Terms

Filing Info

  • Accession Number: 00263195
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Nov 12 1974 12:00AM