American Society of Civil Engineers

Theory of Brittle Fracture Applied to Soil Cement

by Kalankamary P. George, M.ASCE, (Prof. of Civ. Engrg., Univ. of Mississippi, University, MI)

Journal of the Soil Mechanics and Foundations Division
, Vol. 96, No. 3, May/June 1970, pp. 991-1010

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Document type: Journal Paper
Discussion: by C. V. S. Kameswara Rao and et al.    (See full record)
Closure:(See full record)
Abstract: The cracking in a soil-cement base is examined using Griffith’s theory of brittle fracture. Flexural tests are performed on soil-cement beams with crack-simulating notches to determine the critical strain energy-release-rate, Gc, associated with the rapid extension of the crack. Model studies are made to evaluate the crack propagation in a soil-cement pavement base. The variations of critical strain energy release-rate according to soil texture, clay mineral present, and the time rate of loading, as well as its independence of the notch geometry indicate that Gc is a physical property of the cement-treated soil. Fracture toughnes, Kc, a function of the stress intensity factor K and the crack extension force G, in accord with fracture mechanics concepts, exhibits an inverse relation with the rate of crack propagation. In addition, the crack patterns observed in the model slabs are in keeping with the fundamental postulate of Griffith. In simple and symmetrical cases, the cement base upon cracking tends to form a pattern of hexagons; but when the material is more brittle, the cracks form rather poorly defined “irregular random orthogonal polygons”, with the various cracks meeting primarily in three-way nodes.

ASCE Subject Headings:
Base course
Brittle failures
Model tests
Soil cement
Soil mechanics
Stress concentration
Temperature effects