The farmer and mechanic. [volume] (Raleigh, N.C.) 18??-19??, 1912-06-04

- So -
these slides move just like them. The
earth flows down the slopinE surface
q the bed rock. the lateral support
OF the masses having been removed
by the digging. II 5 jus- IS though
the earth made of molaSSes and
neld back By dams at the sides.
These dams were taken away BY the
diSglng of the canal.
Squeezing Old Mother Earth
IN addition TO these surface slides
or flows there is another class Of
earth motion whoich IS carrying great
masses Of rock into the canal. These
masses do not come from the TOP. Aut
from the strata Of which the canal
banks are made. SOMETIMES they
come from below the canal bed
ana force themselves up in humps
through II. oNerturring steam shovels
ana throwing down the railroad
racks.
During the walk through the cut
CnlS morning. at a point just oppoSlt.-
Gold Hill. saw a hump or great hill
which had risen up in the hed Of the
canal during the night. moving the
tour railroad tracks which ran paral-
lei across it. The rails were twisted
and torn and the ties We're pulled
out of the earth. Col. Gaillard and
myself stopped to watch the men
who wer: getting ready 10 repair the
tracks and were bringing up shovels 10
take out tn hump, when 10. right un /
er our eyes. We saw the earth rise ana
throw the railroad. ties and all, to
one side. | had my camera ready and
made photographs Of the ground
while it was moving. | had lust fin
lshed taking my last picture when one
Of the tracks fell clear over and rolled
down the side Of the hill. This humI
was right in the bed of the cut and
almost on the bottom of what viii be
the permanent bed Of the canal.
Where Rock Moves Like Water.
Shortly after this | went with Col
, Galllard to one side of the cana
where the rock was such tha tn,
strata could be plainly seen. TIL
walls Of the cut contained many diff
ferent layers of rock of varying de
+ grees of density, lying one upon tn
s other. Here was q stratum Of shale
\ there one Of lava, and above it on,
t OF limestone or a layer of volcano
dust hardened to stone. There wer
also strata of Ignite and other sof
rocks.
Now, before we began e~xcavatine
II as these strata lay one upon the other
g the weight of the mass was equal
distributed, bed upon bed, so that
. was not possible for any of the STRAIT
to move, no matter lay abov
them. Then the great ditch was CT
and the weight and pressure on thu
e side were taken away. This above
d the great weight above to exert i
" force on the weaker strata beneatl
n and it has squeezed some Of thel
o out into the canal. You may imagOT
h how this could be if you regard son
l. Of the weaker strata as like a THE
r. fluid, say mOlaSSes or the jelly IN
n layer cake. The layers above "
force the molasses out at the side
and if you pRss on the q k the jel
will ooze. Nav, the Ignite strata e.
n pecially are Of this nature. h
e give way to the weight above an
force themselves out into the can;
IF bed, or if the stratum is under II
l. bed Of the canal it is squeezed out
: that it humps up and throws the raj
road as l AVE described.
,p Slides Can Be Controlled.
&c Slides of strata such as | have d
If scribed are but the eng
~ reers know how to control the1
n They have occurred so often hat tn
Is are now taken as q matter Of cours
IN The hump | saw today will be all o
ID of the way before night. Four hu+
ne dred men are working at it and sen
n ing it down to Balboa.
m Col. Gaillard tells me that the
I'd has not been one week during Il
past three years when the bottom
the canal has not been heaNlng al
TO rising, but he adds that the heaVil
of grows less and less as the weight fro
al the slides OF the cut is removed al
IS. the upper banks properly slOped.
he present the only place where t
earth is 20 working is right und
Gold Hill. The trouble occurs with
al q length of perhaps 200 feet, Wher
Ike as it formerly extended over 20
he feet. The humps make it necess1
rs to rebuild a great deal of track, q
is on this account altogether more tn
II. 100 miles of track have already be
,es shifted. This is one Of the II
cessities Of the work, however, and
IN Will all be TeInedled Whe1 lhe cal
has been properly sloped and [
re earth is again in equilibrium.
rs The Rainfall.
ig. The surface slides will likewise st
a. as soon as the natural slope Of
O. earth has been reached, although
We. this account VIII nave 70 pt ldh