Determination of Rock Mass Modulus for Foundation Design

Weathering or the variation in frequency and tightness of joints may result in an increase in mass modulus with depth for some rocks. This increase in modulus will continue until a depth is reached at which the rock behaves as a sound intact unit and the modulus will be relatively constant with depth below this point. In this paper, elastic solutions are presented for the deformation of such a rock mass due to a uniform or approximately rigid circular loading.Two procedures are described for determining the rock mass modulus profile from plate load test results. The first procedure uses the results from three plate tests to infer the variation in modulus with depth. The second procedure uses the measured variation in displacement with depth below a single plate to infer the mass modulus variation. The application of the two procedures is illustrated by a worked example and by consideration of a field case where the inferred modulus is shown to be in good agreement with alternative modulus variation data.

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Determination of rock mass modulus

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/0148-9062(86)91017-x ◽

1986 ◽

Vol 23 (3) ◽

pp. 82

Keyword(s):

Rock Mass ◽

Rock Mass Modulus

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In situ determination of a rock mass modulus using a high resolution tiltmeter

Canadian Geotechnical Journal ◽

10.1139/t96-012 ◽

1996 ◽

Vol 33 (2) ◽

pp. 350-355 ◽

Cited By ~ 2

Author(s):

Bassam Saleh ◽

Abdallah I Husein Malkawi ◽

Pierre A Blum

Keyword(s):

Rock Mass ◽

High Resolution ◽

Boussinesq Model ◽

New Approach ◽

Structural Work ◽

Rock Mass Modulus ◽

Elastic Rock ◽

The Impact

A very high resolution tiltmeter (108 rad, 0.002 s) developed by P.A. Blum, in 1957 was used to establish a new approach to directly evaluate the in situ average elastic rock-mass modulus. Five tiltmeters were installed on the facades of the Louvre museum to study the deformations induced by internal structural work and by the impact of the Paris metro traffic movement. The measured data from the tiltmeter were used to determine the elastic rock modulus of the museum's foundation using the Boussinesq model. The results obtained by the developed approach are consistent with the typical elastic rock-mass modulus for the rock found in the museum's foundations. Key words: rock-mass modulus, tiltmeter, deformation, Boussinesq model.

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