PROPERTIES OF CHALK REVEALED BY DEEP INSPECTION PITS

A new method of examining the in-situ properties of chalk, by excavating large pits and using a manned inspection cage, is described. This method was adopted for a 23km extension of the M3 in Hampshire. The 3m square pits were excavated up to depths in excess of 20m. An example of the log produced by a geologist in an inspection cage is given. It includes records of the soil type, fracture spacing, bedding, weathering, fossil types, micro faulting and flint distributions. The dip and stribe of all exposed joints, bedding planes and fractures were measured and the results plotted on a polar net. The pole concentrations indicate whether any of the joint sets will cause instability in road cuttings. A correlation between the chalk grade and standard penetration test in value for the chalk was established. Correlations between the modulus of elasticity and chalk grade were obtained using a Menard pressuremeter. It is hoped to use the correlations to design footings and cutting on the basis of standard penetration test results. /TRRL/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00174653
• Corporate Authors:

  Foundation Publications Limited

  7 Ongar Road
  Brentwood CM15 9AU, Essex,   England 
• Publication Date: 1974-4

Language

• English

Media Info

• Features: Figures; Photos;
• Pagination: p. 50
• Serial:
  • GROUND ENGINEERING
  • Volume: 7
  • Issue Number: 3
  • Publisher: EMAP CONSTRUCT LIMITED
  • ISSN: 0017-4653

Subject/Index Terms

• TRT Terms: Chalks; Design; Fault location; Footings; Fracture mechanics; Geological surveying; Inspection; Logging (Recording); Modulus of elasticity; Pits; Properties of materials; Road construction; Soil penetration test
• Uncontrolled Terms: Fracture
• Old TRIS Terms: Geologic investigations; Pits (Excavations)
• ITRD Terms: 4120: Chalk; 3674: Equipment; 5702: Excavation pit; 5520: Failure; 4068: Fault (geomorphol); 4170: Flint; 2998: Joint (structural); 5919: Modulus of elasticity; 6200: Particle size distribution; 8119: United Kingdom; 5281: Weathering
• Subject Areas: Design; Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00081351
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: May 1 1975 12:00AM