DETERMINATION OF COMPRESSION CHARACTERISTICS OF DEEP CLAY STRATA BY MEANS OF CONTROLLED LOWERING OF THE GROUND WATER LEVEL

BESTAEMMING AV KOMPRESSIONSEGENSKAPER HOS DJUPA LERLAGER GENOM KONTROLLERAD GRUNDVATTENSAENKNING

A new field method of determining the preconsolidation pressure and other compression characteristics of clay is presented. This method is based on the idea of pumping groundwater in order to apply a load to the deeper portion of a thick clay stratum. As long as this load is below the preconsolidation pressure the change in pore water pressure is rapid but above that pressure the change is slow which makes it possible to determine the pore water pressure. The method has been thoroughly tested at angered, a suburb of gothenburg, where the expected lowering of the groundwater table exceeds 20 M and the soil consists of overconsolidated clay with thin silt layers. The tests were performed for two years and divided into four stages with alternating pumping and recovery periods. During the whole test the groundwater level in the sand layer underlying the clay stratum was determined as well as the pore water pressure at four levels. Settlements and raisings of the ground surface were also measured. The outcome of the investigation was satisfactory. The main advantage of this method is that the results can be obtained within a few months. /TRRL/

• Corporate Authors:

  Statens Raad Foer Byggnadsforskning

  St Goeransgatan 66
  Stockholm,   Sweden 
• Authors:
  • Alte, B
• Publication Date: 1976

Language

• Swedish

Media Info

• Features: Figures; References;
• Pagination: 31 p.

Subject/Index Terms

• TRT Terms: Clay; Compression; Consolidations; Drawdown (Hydraulics); Field tests; Ground settlement; Groundwater; Loads; Lowering; Measurement; Mineral deposits; Pore water pressures; Preconsolidation pressure; Pressure; Pumps; Water table
• Old TRIS Terms: Deep clay deposits; Groundwater level; Preconsolidation
• Subject Areas: Geotechnology; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 00149907
• Record Type: Publication
• Source Agency: Swedish National Road and Traffic Research Institute
• Report/Paper Numbers: Report R12:1976 Monograph
• Files: ITRD, TRIS
• Created Date: Jun 17 1977 12:00AM