Dilatometer

The Flat Dilatometer Test (DMT) is an in-situ testing method used to determine the strength and deformation characteristics of fine-grained soils. This method involves a stainless blade shaped probe with a thin circular steel membrane mounted on one side. The blade has a cutting edge to penetrate the soil and is inserted into the ground at the desired depth. It is connected to a control unit on the ground surface. After the penetration, pressure by a gas tank is applied to inflate the membrane. The pressure required to initiate the movement of the membrane against the soil is recorded and is called “A-pressure”. The inflation continues until the center of the membrane is moved 1.1 mm against the soil. The required pressure to achieve that is called “B-pressure”. If the required depth is below the water table, the membrane can be slowly deflated to record “C-pressure”, which represents the pore pressure acting on the membrane. The corrected DMT results are used to obtain information on soil stratigraphy, in situ state of stress, shear strength and deformation properties.

Top 10 Papers on the Flat Dilatometer

Suggested by Professor Marchetti S., Professor, Department of Civil Engineering, L' Aquila University, Italy. List compiled in January 2003.

Most of the following 10 papers (and of other relevant papers) are downloadable from the website: http://www.marchetti-dmt.it/

• Technical Committee TC16 (2001) "The DMT in Soil Investigations". A Report by ISSMGE's TC16, 41 pp.
• ASTM D6635-01 (2002) "Standard Test Method for Performing the Flat Plate Dilatometer". Book of Standards Vol. 04.09, 15 pp.
• Eurocode 7, (1997) "Geotechnical Design. Part 3: Design assisted by field tests, Flat Dilatometer Test (DMT)".
• Marchetti S. (2002) "The Flat dilatometer". Lecture at 3rd Croatian Conf. On Soil Mechanics and Geot. Engineering, Hvar, 36 pp.
• Marchetti, S. (1980) "In Situ Tests by Flat Dilatometer". Journal of the Geotechn. Engineering Division, ASCE, Vol. 106, No. GT3, Proc. Paper 15290, pp. 299-321.
• Totani, Calabrese, Monaco (1998)."In situ determination of Ch by Flat Dilatometer (DMT)". Proc. First Intnl Conf. on Site Characterization ISC '98, Atlanta, Georgia (USA), pp. 883-888.
• Robertson, P.K., Davies, M.P. & Campanella, R.G. (1987) "Design of Laterally Loaded Driven Piles Using the Flat Plate Dilatometer". Geotechn. Testing Jnl, Vol. 12, No. 1: pp. 30-38.
• Schmertmann, J.H.et al.(1986) "CPT/DMT Quality Control of Ground Modification at a Power Plant". Proc. In situ '86 ASCE Spec. Conf. Virginia Tech, Blacksburg, VA, pp. 985-1001.
• Reyna, F. & Chameau, J.L. (1991) "Dilatometer Based Liquefaction Potential of Sites in the Imperial Valley". 2nd Int. Conf. on Recent Advances in Geot. Earthquake Engrg. and Soil Dyn. St. Louis. May, 7 pp.
• Iwasaki K. et. al (1991) "Applicability of the Marchetti Dilatometer Test to Soft Ground in Japan". GEOCOAST '91, Sept. 1991, Yokohama 1/6, 4 pp.