Direct shear tests were run on a dry sand reinforced with different types of fibers. Both natural and synthetic fibers plus metal wires were tested. Experimental behavior was compared with theoretical predictions based on a force equilibrium model of a fiber reinforced sand. Test results showed that fiber reinforcement increased the peak shear strength and limited post peak reductions in shear resistance. The fiber reinforcement model correctly predicted the influence of various sand‐fiber parameters through shear strength increases that were: (1) Directly proportional to concentration or area ratio of fibers; (2) greatest for initial fiber orientations of 60° with respect to the shear surface; and (3) approximately the same for a reinforced sand tested in a loose and dense state, respectively. The findings of this study are relevant to such diverse problems as the contribution of roof reinforcement to the stability of sandy, coarse textured soils in granitic slopes, dune and beach stabilization by pionee...

Mechanics of Fiber Reinforcement in Sand

A review on the angle of repose of granular materials

This paper describes the results of numerical analysis of the effects of installing a driven pile. The geometry of the problem has been simplified by the assumption of plane strain conditions in addition to axial symmetry. Pile installation has been modelled as the undrained expansion of a cylindrical cavity. The excess pore pressures generated in this process have subsequently been assumed to dissipate by means of outward radial flow of pore water. The consolidation of the soil has been studied using a work-hardening elasto–plastic soil model which has the unique feature of allowing the strength of the soil to change as the water content changes. Thus it is possible to calculate the new intrinsic soil strength at any stage during consolidation. In particular the long-term shaft capacity of a driven pile may be estimated from the final effective stress state and intrinsic strength of the soil adjacent to the pile. A parametric study has been made of the effect of the past consolidation history of the soil...

Driven piles in clay - the effects of installation and subsequent consolidation

Influential factors of friction between steel and dry sands

Interfacial shear strength of fiber reinforced soil

Synopsis Until recently the values of skin friction used for design purposes were the average values obtained by field tests, with only qualitative reference to such factors influencing their magnitude as type of soil, type of construction material, and surface finish, moisture content of the soil, etc. The modern trend is to establish skin friction coefficients through laboratory experiments in which the factors influencing the results may be controlled quantitatively. Several hundred experiments were carried out by the Author to determine the magnitude of skin friction, in which the following variables were considered:— (1) Various construction materials: steel, wood, concrete. (2) For each material two surface conditions were used: smooth and rough; which are described in such a way that they may be reproduced by anyone with a reasonable degree ofaccuracy. (3) Various types of soil. (4) Strictly controlled moisture content. (5) Variation of the normal load between the friction surfaces. The test result...

J. G. Potyondy

Papers

Skin Friction between Various Soils and Construction Materials