about bimrocks

bimrocks are:

  • block-in-matrix rocks
  • mixtures of rocks composed of geotechnically significant blocks within a
    bonded matrix of finer texture
  • melanges, fault rocks, weathered rocks, etc.
  • geologically, spatially, and mechanically heterogeneous
  • trouble$ome to geotechnical engineers, geologists, contractors and owners
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The origin of "bimrocks": Bimrocks is a contraction
of  "
block-in-matrix rocks”, originally defined by Prof.
Loren Raymond to describe the chaotic fabric of
mélanges and olistostromes.

There are over a 1000 geological words and
expressions for fragmented and mixed rocks. The
geologically neutral word "bimrocks" is extended to
include, regardless of geological origin, those
geologically complex mixtures of hard blocks of rock
embedded in weaker rock which hamper accurate and
economic characterization, design and construction.

In bimrocks, blocks must have mechanical contrast  
with the matrix and there must be enough blocks of a
certain size range to contribute to the overall strength
at the scale of engineering interest. Accordingly, the
geotechnically significant in the above definition
of bimrocks imply criteria for scale, strength contrast,
proportion and size of blocks
(Medley, 1994).

bimrocks are not:
  • blocks in the bimrocks.
  • bimsteins  (pumices, or "air-in-matrix").
  • blokbims, (light weight building blocks made in
    Turkey, using pumice).
  • bimbo rock(s), which is a rock music label.  
    However, people who study bimrocks could be
    called bimbos (bimbeaux* et bimbelles, in
  • bumrocks, (a music play list) despite Google  
    suggesting otherwise.
  • bim on the rocks, a blog about 3D CAD in civil
    engineering (BIM is  Building Information

*For several years I proudly wore the PhD Graduation T-shirt
that Jim Falls, CEG gave me in 1994, emblazoned with his
bimbeau, a more elegant alternative to my "bimbo"
Prof. R. Ulusay and Dr.
Ed Medley near Ankara,
decomposed granite:  
highway cut near Tahoe,
Gwna Melange: blocks
in sheared matrix