• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
UNDISTURBED  SAMPLES
Figure 15-10.-Taking a chunk sample from a vertical face.

Engineering Aid 3 - Beginning Structural engineering guide book
Page Navigation
  492    493    494    495    496  497  498    499    500    501    502  
Figure 15-9.-Taking a chunk sample from a level surface. Figure  15-9  shows  the  process  of  taking a   chunk   sample   from   a   level   surface,   such as  a  subgrade  or  the  bottom  of  a  test  pit. After  smoothing  the  ground  surface  and  mark- ing  the  outline  of  the  chunk,  the  first  step is   to   excavate   a   trench   around   the   chunk. Then  deepen  the  excavation  and  trim  the  sides of  the  chunk  with  a  knife.  Finally,  using  a knife, trowel, or hacksaw blade, cut off the chunk at  the  bottom  and  carefully  remove  it  from  the hole. To  take  a  chunk.  from  the  vertical  face of   a   test   pit   or   trench,   as   shown   in   fig- ure  15-10,  smooth  the  surface  of  the  face and  mark  the  chunk  outline.  Then  excavate the   soil   from   the   top,   sides,   and   back   of the   chunk.   After   shaping   the   chunk   with a   knife,   cut   it   off   and   carefully   remove it. After  removing  the  chunk  sample  from the   hole,   you   need   to   seal   it.   One   method is   to   apply   three   coats   of   melted   paraffin, as   shown   in   figure   15-11.   Each   coat   is   al- lowed  to  cool  and  become  firm  before  the next   coat   is   applied.   This   gives   adequate protection  for  strong  samples  that  will  be used  within  a  few  days.  When  the  samples are   weak   or   may   not   be   used   within   a few   days,   wrap   them   with   cheesecloth   or other   soft   cloth   and   seal   them   with   paraf- fin   (fig.   15-12).   If   cloth   is   not   available, you   can   reinforce   the   sample   with   several loops  of  friction  tape  or  twine.  Then  apply three coats of paraffin. Take extra precaution in these  operations  so  that  the  sample  is  not damaged. Another  method  is  to  dip  the  entire  sam- ple  in  melted  paraffin  after  the  first  brush coat  is  applied  and  the  sample  is  wrapped (fig.   15-13).   This   requires   a   larger   container and  more  paraffin.  However;  this  method  pro- vides  a  more  uniform  coating  that,  by  repeated dippings,  can  be  built  up  to  1/8  in.  or  more  in thickness. When  samples  are  to  shipped,  as  from a  construction  battalion’s  remote  detail  site to   the   battalion’s   main   body   site,   additional protection   is   required.   This   can   be   accom- plished   by   applying   many   coats   of   paraf- fin   or   by   placing   the   chunk   in   a   small 15-12







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.