Elastic friction mechanism between granular soils particles

Abstract

The laws and other experimental facts regarding friction between geologic materials are summarized. Some of the mechanisms proposed to explain these laws and facts are recalled. A friction mechanism is presented, in which the elastic deformation of the asperities of contact surfaces intervenes, on basis of a physical model in which the asperities consist of steelribbon arches. The following main conclusions were drawn: i) The deformation of a pair of asperities in contact undergoes three phases:  the first in which it stores elastic energy, the second, of instability, in which it undergoes wide elastic displacements with almost no apparent sliding of  the  bodies  in contact, and the  third  in  which  it  gives  up  part  of  this  elastic  energy,  forcing  the  sliding  instead  of opposing it; ii) static friction is stronger than kinematic  friction  because,  when  sliding  begins,  almost all the contacts of  the  asperities  are in  the first deformation  phase,  whereas,  after sliding  has set in, the number of contacts in the third phase is sufficient to reduce total resistance.