Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
soil. investi.gati.on device~.
~ or executing soil investigation, a tube is driven sub-
stantially vertically into the soil, which tube, at or near i-ts
lower extremity, is constructed either as a sounding tube 7 in which
case i-t is provided with means for determinin~ the resistance
5 a~ainst dis~lacement, e.g. in the form of a so-called sounding cone
andjor sounding sleeve, or as a samp1ing tool by means of which a
sa~ple of the soil can be ta~en in order to be investigated in a
laboratory.
In order to press such a tube into -the soil, use is made
10 of a device, which is generally arranged in a vehicle, com~risin~
a yoke which is to be brou~ht into enga~elllent with the upper ex-
tremity of the tube~ which ~oke is cou~led with the pistons of the
two pressure meditun cy inders which are arranged at both sides of
the tube. ~s soon as the tube has been pressed downwards by means of
15 said yoke over the piston stroke, the yoke is moved upwards again,
and another tube is connected to the fornler tube by means of a
screw-thread connection, and then the tube is pressed further down-
wards. The force required therefor can be derived from the pressure
of the pressure medium (generally oil). In the case of a sounding
20 tube this force is generally determined by means of a transducer
provided between the sounding tube and the yolce, and, on the other
hand, force sensors are of-ten arran~ed in the lower end part~ which
are adap-ted to produce an elec-trical s:igna:!. which is a nleasure for
the resistanc~-~ met with, and which can be processed further at the
25 surfaceO
As soon as the tube has reached the desired or maximum
possible depth, a pulling head is mounted on the yoke, whlch is
adapted to enga~e the tube in such a manner that, by means of said
yoke, a pulling force can be exerted on the tube. Such a pulling
30 head can, for instance, comprise a conical inner wall and a plura-
lity o~ balls arranged in several layers within a cage, the di-
ameter of said balls in the different layers being such that, if
a tube is inserted through said cage with balls, the conical wall
surface uniformly presses said balls against the tube surface,
~5 so that the pulllng force will be transferred onto tne tube~
hn objection of such devices is tnat they are rather
bulky and henvy, ~nd mus-t, theret`o.re~ be arran~ed in or on a vehicle~
~`or measuremellts in di~icultl~ accessi.ble locations, in particular
in existing buiIdi.ngs, e.g. for determining the bearing capacity of
the foundatlon in view of reconstruction ~orks, or in dif~icultly
5 accesslble fielàs, these known devices are not suitable.
It is an object of the invention to provide a device .~or
the latter purposes which does not show these objections and is, in
particular but not exclusively, suitable for being constructed in a
transportable and, if required, portable manner.
To that end, the device according to the invention is
characterised in that the driving means ~or the tube ~rip around
said tube substantially coaxially.
In a first embodiment, said driving means comprise a
single cyllnder having a piston and associated piston rod which
15 are made hollow, and this in such a manner that the tube can be led
through the interiorthereof, snid piston rod bein connected to a
head by means of which -the pressing and pullin~ f`orces can be trans-
ferred on the tube. '~his unitnry construction without~ yokeprovidee
a substantial simplification in respect o~ the known constructions
20 with two cylinders, and,furthermore, lea~ to substantially smaller
dimensions, and, moreover, a pressure acting on the tube in an
accurately axial direction is ensured.
In a second embodiment of the invention, the drivins
means comprise at least one unit consisting of n pair of mutually
25 oppositely arranged driving wheels with a concave rim profile
adapted to the shape of the tube to be driven, at least one o~ said
wheels o such a unit being connected to a dri~ing motor, in par-
ticular a hydxaulic motor, and,in particular, several units can be
superposed along the tube, means being provided in each unit :Eor
30 dri~ing the wheels towards one another so as to increase the
clamping force.
With such a device the tube can be driven continuously
itself, ~u~ it is also possible to drive thereby an auxiliary tube
which is provided with means adapted to be brought into engagement
~5 with the tube to be driven into the soil, and corresponding to the
means used in -the first embodiment.
If the driving means operate in a discontinuous manner
and are to be reset when providing or taking away an extensior tube
section, preferably a special coupling element is used which is
3 -
nrranged in a horizontal sliding æuide connected to the driving
means, so as -to allo~ this el~ent to be slid away laterall~ for
clearing the passage for a tube, and this element can be con-
structed as a pressing or pulling head respectively, said guide
5 being adapted to allow the replacement of R pressing head by a
~ulling head and vice versa.
For application in the case of a sounding tube with an
inner rod which is connected to a measurins element, the pressure
head can be provided with a rotatable fitting with two bores of a
10 different die~eter, the narrower one forming an abutment shoulder
for the upper e~tremity of the upper tube section but allowing the
inner rod to pass so as to bring said inner rod into enæa~sment
with a superposed force meter, whereas the wider bore also passes
the sounding tube so that the latter itself will, then, engage said
15 force meter. In the latter case, for instance, -the lateral friction
in the soil a!ong the soundine tube can be measured.
~ or retracting the tube, preferclbly a special pulling head
is used comprisin~ a sleeve surroundinæ the tube in which a plurali-
ty of slightly upwardly inclined strips of ~etal or the like are
20 arranged having, at their free extremity, a concave rounding adapted
to the tube per phery. By means of such a head the friction force
required for the pulling force can be distributed lllore evenly over
the tube surface, so that the latter will not be damaged, this in
contrast to the above-mentioned pulling heads with balls which, in
25 a rather s1llall n~ ber, are being brought into enga~el~ent with the
tube wall.
I~hen using a sounding tube with an inner rod, the ex~
tension tube sections are preferably provided with inner rods
which are secured against falling out, this in contrast to the
30 known constructions.
T~ electrical force transducers or the like are provided
in the lower portion of the sounding tube, a pressing or pulling
head resp. is to be used whlch is provided with recesses for passing
a measuring cord~ ~urthermore it can be advisable to arrange the
35 current source for the measuring circuit in the lower par-t, and then,
in particular, the inner rods o the sounding tubes sections can be
used as a conductor for signal circuits, said inner rods being pro-
vided with coupling means adapted to interconnect adjacent rods
electrically; the contact resistance between the VariOUS inner r~d
_ ~L _
sections will, then, have no inrluence on tho si~nal availnble at
the transducersA The time-conswnln3 and troublesome strir.glng of`
the soundin~ tubes on an electric c~ble is, then, superfluous.
Instea~ of electrical signal transer, also modulated
5 radiation can be used, and then, in the lower portion o~ the
soundin~ tube, a raclia-tion source, in particular a laser diode, and
in the upper end portion o~ this tube a photo-diode or the lilce wlll
be arranged. The inner tube diameter is, preferably, chosen as lar~e
as is compati~le with -the strength of the tube so as to keep ~ree
10 a direct radiation path even in the case o bending of the tube.
~t is also possible to polish the inner wall so as to allow, if
necessary7 radiation transmission by re~lection, but then care
should be taken to avoid disturbing signal broadening by transit
time dif~erences, e.g. by a suitable choise o~ the modul~tion shape
15 or by screening off undesired radiation directions near the photo-
diode.
It can sometimes be ~avOurable to include in the lower
porti.on o~ the soundin~ tube a memory in which the Measurement
results can be stored, which can be read out la-ter a-ter retraction
20 o~ the soundin~ -tubes, and a ti~lng signal should, then,be recorded,
allowing to correlate the measure~ents with the insertion depths
recorded at the surface. ~s a memory, besides a usual electronic
memory, also a s~.all tape recorder with micro-cassettes can be used.
Such a tube can also be constructed E~S a soil sample
25 cutter, an improvelllent being obtained by accommodating the usual
hose,used or reducing the friction between the soil s~llple and the
tube wall, in a chamber surrounding the sample space o~ the tube,
said chamber being situated between the cutting mouth at t~Ae lower
extremity of the tube and the exit slot between said chamber and
30 the sample space, so that the hose provided in this cha~ber can be
pulled straishtly upwards through the slot, intrusion of soil
particles lnto said chamber being hampered, and damaging the hose
in the slot beinO avoided then, so that the use o a supporting
liquid,as is required in the current soil sample cutters in wnich
35 the hose is deflected by 180 in tne slot,will be super~luous.
~ uch a deYice for driving a tube into the soil should be
directed vertically as well as possibleA To that end, as usual,
hydraulically a~tuated ~acks can be used by means o- which the
carrier o~ the device, in particular a vehi.cle, can be supported.
Accordi.rlrr to -the invention, r~.re:rerMbly nn inc~ination sensor is
used then, cons.sting of a housin,r fil'ed with oil in w`nich an
elec'rica1ly conductive bocy is resi'ient'y supported, which body
will contac~ electrical contac~s prov:ided around the circumference
5 as soon as the housing .is not directed exact'y vertically, which
body and contacts are included in a cor~rol circuit for the pressure
mediun supply. Inc'ination .neters to be ~rovided in soundirg tubes
adapted to measure the inclination of the tube,so as to correlate
the inclination with -the depth measurement~are ~nown per se. For
10 directing a devi.ce of the present kind, however, inclination meters
have not yet been ùsed. The sensor according to -the invention allows
to direct -the device in a fast and ~reclse manner.
The invention will be elucidated in more detail below by
reference to a drawing, showing in:
Fig. 1 a lateral view, partly in section, of a first em-
bodiment of the invention;
~igs. ~ ~nd B a la-ter.1:' view, partly in section, of a
special pulling head for such a de~tice, and a top view of an e~ement
of thi.s pulling head resp.;
Fig. 3 a section of a specia' ~ressing~ head with a
measuring body for such a device;
Fig~ 4 a diagrammatlc to~ view o~ an other embodiment of
a device accord ng to the invention;
~igs. 5~, B and C highly s Illplified representations of
25 different means for transmltting signals n such a device;
l~ig~ 6 a sil~lpli.f:ied representation, partly i.n section, of
a cuttlng tube -to be used in sucll a devlce; and
Fig. 7 a diagrammatic cross-section of a si~.ple inclina-
tion sensor ~or such a device.
In Fig. 1 a flrst embodiment of the device according to
the invention is diagrammatically shown, which device is intended
for pressing a tube 1 into the soil and, respectively,pulling it
therefrom again, which tube is, in particular, a sounding tube.
This device co~prises an annular cy1inder space 2 defined
35 between an outer wall 3 and a coaxial inner wa'l 4 7 the inner wall
4 definingr L~ sp~ce 5 in which t~e tube 1 fits w th some play.
In the cylinder spa.ce 2 an annular piston 6 sealingly
contracting the walls 3 and 4 by meAns o~ sealing rings 7 is sli-
dable. This ~iston 6 is cornected to a tubular ~i.s-ton rod 8 ~uided
-- 6 ~
by n1onns of seal.5 9 in a cat? 10 c:'.osin~ the 5~ace 2. ~t the upper
end o~ the piston rocl S a f`lnnge 11 is mounted on which a horizontal
sliding Ouide 12 is provided in which a ri~ 1~ o~ a oressin~ head
14 to he described be_ow i.s horizontally sliciable, so tha-t, "hen
5 slid:ing away this head, the inner spnce 5 of the inner wall 4 be-
comes accessible from above so as to insert a tube 1 into it, which
tube can be an extension tube which can be scre-.~ed on another tube
section 1 alre2dy pressed downwards.
The piston 6 is shown in its lowest ~osition, and can be
10 moved upwards by supplying a pressure mediu~., e.~. oil, the stroXe
length corresponding to the len~th of the tube sections :Erom which
-the tube 1 is to be assembled. ~fter having slid away the head 14
in the highest ooslt~on~ another tube section can be introduced into
the space ~ and screwed on the precedin~ tube section, after which
15 the head 14 can be sl:;d bac'c so that lt can be brought into enga~e-
ment with the upper extremi-cy of the tube. Thereafter the pres~ure
medium will be supplied to the upper sidc of the piston 6 so as to
press the tube 1 further into the soil.
The cylinder wall 3 is mounted in a foot 15 which is im-
20 mobilised in respect of the soil in a mallner not shown. ~his footis1 for instance1 mounted on a suficiently heavy vehicle, but can
also be .i~ed by means of ~roun~ anchors or the like. The latter
will be the case if the clevice is constructed as a portable one
which is adapted for bein$ usecl in inacce6sible places (e~g. in a
25 basement or the like).
Such a device reauires lit-tle s~ce, slnce only one
cylinder without a bridge piece is used. Only the æuide 12 is
laterally protrudin~, but can be relatively short. The pressure
medium source can be mounted seoarately from the device, and can be
30 coupled thereto by !neans o. ~ressure hoses.
In order to retract a tube 1 pressed into the soil, the
rim 16 of a pu'ling head 17 accordin6 to ~ig. 2 can be slid into
the ~uide 12. Instead of the usual pu'.lin~ heads with balls bearing
on a wedse-shaped surface and adapted to contact the ou-ter side of
35 the tube 1, which may locally indent the tubes, use has now been
made of a plurallty of lip~ 13 made of hard steel or the like which
are fixed at a sli6ht upward inclination in the wal:L of the head 17,
and are provided, at their free extremi.ty, with a recess with a
rounded boundary ed~e having a curvature which corresponds to that
-- 7 --
o:E the extern-~:l surF.~ce o:E a tube 1. r"ne n-l!nber of lips 18 deperlds
on the w.Ath tlereor, t.he depth o t~e .recess, anc`~ the r~c~ui-ed
hs soor ~s a tl~be 1 arrives into the space between the
5 lips 1S from be ow, the rims oF the recesses 19 come intc contact
with the tube ~.~all. ihen retracting the head 15, the tube 1 is
ærinped fir~ly between the lips 18. Since the c'~ing Eorce has,
now, been distributed over a mucn larger surface portioll OI the
tube walI than in the case o F cl c~nping balls, -the tube wa'l will
10 not be damaged. On pressing downwards the head 17, the lips 18 will
be released automatically, and the head can be removed Erom the
tube.
In Fig. 3 a cross-section oE a special embodiment of the
pressure head 14 is shown, which serves, nt the s.~ne ti~ne, as a
15 Eorce meter. In this c~se the tube 1 compr-.;ses an inner rod 20 which
is ~uided slidab1y in thc tube 1, and is, at the lower end, con-
nected to a mcnsuring cone or the lilce for determini~s the soil
resistallce. Jach extension tube section is providecl with such a rod
20, and the end Eaces of ad~acent rods 20 can contac-t each other.
20 In order to avoid that the rods 20 fall out of the corresponding
tube sections, each rod is provided with one or more rings 21 which
can abut against a corresponding shoulder 22 in the tube section 1
in question so as to prevent falling out.
In the head 14 a piston 23 is situated, a~ainst which the
25 rod 20 of the uppermost tube section w:ill bear when the head is
pressed on the tube section. The s~nce 24 above the piston 23 conl-
municates, by means o:E a ~`itti.n~ 25, with a pressure meter or force
transducer,not shown,for mea6urinS the force acting on the rod 20.
The end face of the tube 1 bears on a shoulder 26 which is
30 in a fixed position in respect of the head. This shoulder forms a
part of a rotatable insert 27, and is defined by a through bore 28
in said insert throu~h which the rod 20 extends upwards. Trans
~ersely to the bore 28 a second wider bore 24 is ormed in the in-
sert~ If the in.sert 27 ls turned 90 by means of a ha~dle 30, the
35 wider borc 29 is positioned in alignment with the tube 1~ This bore
is ~ider than the tube 1 so -that, then, the end face of the tube 1
will bear against the piston 23. This position wi'l. be used if1 for
instance, the adhesion force exerted on the tube 1 by the .soil is to
be measured~
:~';t~
~ ir~ r shows an other e?nbodi?1lent of the device of the in-
venti0n for ?ressing a tube into t`ae soil. r~his device eomprises
~t least one unit 31, but, if ref~uired, a plurality thereof can be
su~erposed. ~ach unit conmprises a pair of wheels 32 and 3~ witn an
5 outer riTn of subst2~ntiRlly semicircu1ar cross-sec-tion, which wheels
thus define & subs-tantially circ-nlar cavity 34 in which a tube to
be driven will fi-t. The ~/`neel rinls can be roughened or can be ~ro-
vided with a rr;ction covering n order to increase the grip on such
l tube. r~he wheel 33 is contained in a yoke 35 coupled to a ~ressure
10 mediwn cy inder 36 by means of which this yo`~e car be pressed
against the other wheel 32 so as to improve the grip on the inter-
posed tube sti.ll more.
The shaft 37 o~ the wheel 32 is coupled to a hydraulic
motor 38 adapted to drive the w`neel 3v. If a larger driving force
15 is desired, also the shaFt 39 of the wheel ~3 enn be eoupled to a
motor 40. '~he dr Villg force can be increased sti'l further by ln-
ereasin~ the number of units 31.
Such a unit ean, For instanee, be used to drive a tube 1
directly so as -to obtain a substantia'ly continuous drive~ Coupling
20 extension tube seetions can ake plase during drivins. It is, how-
ever, also ~ossible to use such a unit for driving a tube eorres
pondinO to t~e piston rod 6 0 r ~i g ~ 1~ adapted to connect thereto
a pressin~ head 14 and/or a pullin~ head 17.
Instead of a pressure head 14 with a foree meter aeeor-
25 ding to ~ , other force measurin~g apparatuses can be used, inparticular measurinO cones or the lil;e with electrieal force trans-
ducers. In thnt CaSf' a simple pressing head witllout measuring bodies
can be used, but, then, said head should be provided with a recess
for passing the measurin6 cord. `~or the l~easuring cord is to be
~0 stringed through all tne tube sections to be used sinee the use of
extension cords with contact nlugs and soc~ets would lead to too
hi~h contaet resistances. 0f eourse ~ressing heads constructed in a
different manne- can be used instead which, if desi-~ed, can be con-
structed as a pulling head too. Such measurlng cords are, by -their
~5 nature, troublesome. r''he inven-tion provides a nunnber of possibili-
ties allowing to work w:thout such .measuring cords.
~ s shown in ~ig~ 5~, R central rod 20 can be used ins-tead
of a measurin~ cord, h~hich rod needs not to be slidablel and can be
provided~ Rt an extref~-ity, with a fitting Lr1 in which ~he e~trenmity
of` the rod 20' ol` an adjoining ~ube section ~li'l fit more or less
tightly so ~ls to obtclin an e'.ec-trica1 cor!nection, and the tube
sections 1 theD1se~ves serve as a return conductor. It can7 t~.en,
be advisable to arrange the current source ~2 for the measuring
5 circuit near the transducer 43 in the lower par-t of the -tube 1, so
as to ensure a su~ficient Yoltage reclr the transducer 43 independent
of the contact resistance in the couplings between the rods 20'.
"he transducer 43 can be provided with a circuit ~hich is adapted
to transI`orm the measuremert results lnto suita~le measurernellt
10 signals, e.~. in digital form.
I'nstead thereof lt i6 also possible to us~, for the signal
transfer, modulated radiation, and then, as shown in Fi~. 53, the
transducer 4~ can be connected to a radiation souxce 41~, e.~. a
laser diode, whlch can sen~i directed radiation through the interior
15 of the tube, and at the upper extremity of the tube 1 a radiation
receiver, e.~ a photo~diode, will be arranged. The tube 1 is,
preferably, mnde as wide as is compatlble wi-th the strength of the
tube, so as to maintain an unim~eded passaS~e for the radiation even
in the case of ber~ding ot` the tube. It is also possible to polish
20 the inner wall ot` the tube 1 in such a ~anner tha-t the radiation
will be trHnsferred by successive reflectiors, and, then, care
should be taken -that only radiation with a giveIl pa-th len~th can
reach the receiver, and radiation ~l~ith a di~f:ereI~t path len~th is
screened there so as -to avoid uns}larpness in the signal transmlsslon
25 caused by path 'en~th differences.
~ . 5C show~q still another solution ln which the trans-
ducer 43 is coupled to a memory 45 in ~-~hich the measurement results
can be stored. A~ter the tube is retracted again, the measurement
results can be read out fro~n said menory~ ~imirg signals should be
30 recorded then at the s~u1le time so as to allow to relate ~he measure-
ments to the insertion depth which is continuously recorde~d above
ground, this also with the associated timing siænals, Such a memory
can, for instance, be formed by a small tape recorder with micro-
cassettes.
~ uch a tube 1 can also be cons-tructed as a sample cutter
for taking soil samples. It is usual to counteract disturbation
o~ the soil sannples by wall friction by enclosinO the sa~ple by a
hose~ '~'his hose is provided, in the Xno~n sar~lplers, in an annular
chan~er surrounding the tube cavi-ty into which t e s,~mple is insertec~
-- 10 ~
and t.herl the hose cnn entc!r thc! cent.r.ll bore at thc lower end of
this chamber -';hrou6!l an annula.r slot, and the hose i.~ elosec there
50 t`nat a pene-tratin~s sa~mple pulls the hose alons. Bendinc~ the hose
around -the ec~e of this slo-t, however, can lead to damage, and also
5 soil partie es can penetrate into thls chamber~ I'herefore someti.nes
a so-ealled sv.pportingg licuid will be usec. which is supplied to the
hose char.ber and faeili-tates pullirg the hose througn the slot and,
moreover, kee s soil partieles out of this ehamber. ~`urthermore this
1iquid aets as a lubrieart ~or the hose.
According~ to the invention sueh a eutting tube ean be
made in a sinple marner as shown in ~ig. 6, ir whieh the hose
ehamber ~6 is situAtecl between the eutting mouth 47 at the extretnity
of -the tube 1 ancl an exit s'ot 4~ for the hose 49, so that the hose
ean be pu led substantially linear'y from the ehamber l~6O Damagi~t.
15 the hose in the slot 48 is prevented then, an~l, moreover, penetra-
tion of soil par-lieles is prevented. ~ sut.tporting licl~uld ean, tllen,
be omitted, which eonsiderably simplifies -the eonstruetion o.. the
over-a'l deviee.
In orc~er to clrive the tube 1 correetly vertica1ly into
20 the soil, 'he deviee should be directed vertlea'ly as well as
possible. In the ease of a device mounted on a vehie~e, g~enera'ly
jaek eylinders will be used having piston rods ~rovided with foot
plntes which can be driven ouiwards by a pressu.re rleclium sueh as
oil for relievin~D; the spr.ings o~ tlle veh:ie e, and~by a separate
25 pressure mecliw!l supply towarc`s thc clif:Perent eylin&ers~the floor of
the vehlele ean be hori~on-tnll.y adjus-ted.
'l'.he invention provides means for eonsiderably aceelerating
these operations and ma`;ing t.hem inclerendent o~ hwnan intervertion
anci, thus, of e.rrors. To that end a speeial sensor shown in ~i~. 7
30 is prefernbly used~ 'rhis sensor eomprises a substant~ally eylinciri-
eal housing 50 .rilleci with oi.l, in whien a float 51 o ir.sul~.ting
materia' is prov~de& whieh, ~y means oP a spr-ing 52, -is ~er,t in the
eentre when the housirg 50 is direeted ~ertieally~ Tn the inner wall
o~P the housing eleetrica1 eortaets 5~ are provided adapted to eon
35 taet the P~oat 51 as soon as t`^e housir-,g 50 has been removed sorne-
whnt from the vertieal orientation "he spring 52 is, wi-th these
eleetrical eon-tacts, ineludecl in a eontxol eireuit by means oP
whieh, in eorrespondenee ,rith the orien~ation of the float~ the
pressure mec?.ium sup~'y towc:rcls the cli..r:Pexe.nt ~ne~s ean be recu].ated4
~ st, automcltic ~nd accure~te orientation of the device c~n be
obtained thereby.
The device according to the invention can al~o be used
for driving a drainage tape into the ground by means of a protecting
5 tube which iB flnally retracted again, leavlng a a wedge-shaped driving
end piece -to which the tape is attached iD the soil,
~ he embodiments allowing a cont~nuous dri~ing force to be
exerted are particularly ~uitable for sounding purpo~es, as an inter-
rupted movement of a ~ounding tube may influence the measurement re-
~0 BUl't~;.
In the embodiment of ig. 4 the drlvlng motora 38 and 40can, of course also be electric motors.
Many other modiflcatione are possible wlthin the ~cope of
the lnvention ae defined in the appended callm~.
