Described here is the development and operation of horizontal inclinometers for measuring the verticle movements of the soil in the vicinity of foundations as the foundations are installed and loaded. The transducer around which the inclinometers have been designed is an electrolytic liquid level. It is used to record changes in the inclination to the horizontal at various locations along small holes bored from a trench outside the soil zone affected by the foundation. Two of the inclinometer instruments have been employed successfully to determine the soil displacements during the installation and test loading of an instrumented steel tube pile 168 mm diameter and 3.5 m long in London clay. Large numbers of a simpler version have been prepared for the simultaneous recording of the movement around a group of three similar piles at the same site. The technique is capable of considerable development. The observation is made that there are no reasons why similar inclinometers should not be operated from a lined shaft or between two or more large diameter bored piles. In a discussion of electrolytic levels, consideration is given to the effects of temperature and the effect of inclination to the vertical. Details are given of the instrument itself and the operation of the inclinometers. Other aspects discussed include calibration, assessment of the inclinometers, installation, the effect of boreholes on behavior of clay, and field experience. The inclinometers described here are capable of measuring inclinations in the ground to an accuracy of a few seconds of arc. They have been used in short-term loading tests of an instrumented pile without significantly affecting the behavior of the soil. Sufficient observations have been made for complete soil displacement profiles under working load conditions to be determined with an accuracy of the order of plus or minus 0.02 mm.

Media Info

  • Features: Figures; References;
  • Pagination: p. 23-31

Subject/Index Terms

Filing Info

  • Accession Number: 00263199
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Nov 12 1974 12:00AM