Concept

Description and procedure

 The pressuremeter test is an in-situ testing method used to achieve a quick measure of the in-situ stress-strain relationship of the soil. In principle, the pressuremeter test is performed by applying pressure to the sidewalls of a borehole and observing the corresponding deformation.

The pressuremeter consists of two parts, the read-out unit which rests on the ground surface, and the probe that is inserted into the borehole (ground). The original Ménard-type pressuremeter was designed to be lowered into a performed hole and to apply uniform pressure to the borehole walls by means of inflatable flexible membrane. As the pressure increases, the borehole walls deform. The pressure is held constant for a given period and the increase in volume required for maintaining the constant pressure is recorded. A load-deformation diagram and soil characteristics can be deduced by measurement of the applied pressure and change in the volume of the expanding membrane.

The major difference between categories of pressuremeter lies in the method f installation of the instrument into the ground. Three main types of pressuremeters are:

• The borehole pressuremeter: The instrument is inserted into a performed hole.
• The self-boring pressuremeter: The instrument is self-bored into the ground with the purpose of minimizing the sol disturbance caused by insertion.
• Displacement pressuremeters: The instrument is pushed into the ground from base of a borehole. The soil displaced by the probe during insertion enters the body of instrument, reducing the disturbance to the surrounding soil (see Cone-pressuremeter).

There are different approaches the interpretation of results and the determination of material properties from pressuremeter tests. In general, these approaches rely either on empirical correlations to allow measured co-ordinates of pressure and displacement to be inserted directly into design equations, or on solving the boundary problem posed by the pressuremeter test.

Standards

• BSI BS 5930 Code of practice for site investigations
• ASTM D4719 - 07 Standard Test Method for Prebored Pressuremeter Testing in Soils Link

References - External Links

1. The pressuremeter test principle, Bautechnische Versuchs- und Forschungsanstalt Salzburg
2. Detailed description of different types of pressuremeters, Site Investigation - Chapter 9: In-situ Testing, C.R.I. Clayton, M.C. Matthews and N.E. Simons, Department of Civil Engineering, University of Surrey
3. General description of the pressuremeter test and interpretation of results, Bryan M. Waisnor, Angelle Ducote-Price, Ben Jarosz, J. Michael Duncan, and Charles J. Smith, Geotechnical Engineering within the Piedmont Physiographic Province, Appendix A, Report of a study performed by the Virginia Tech Center for Geotechnical Practice and Research, August 2001 
4. A general description of the soil pressuremeter test with photos, Roger A. Failmezger, In-Situ Soil Testing, L.C.