CA1177059A - Tool forming a hole in macroporous compressible soil and a method of forming a hole by the same tool - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A tool comprises a body having coaxial portions radially defined by soil compaction surfaces of step-down radii from the sizing portion to the tool tip. The soil-compaction surface of each portion is a cylindrical sur-face generated by a generatrix of a predetermined length extending parallel to the tool axis and bounded by two parallel helices of one and the same helix angle. These surfaces are successively conjugated by transition portions defined by cylindrical surface whose generatrix is parallel to the tool axis and uniformly approaches the same axis to thereby form a smooth transition from the surface of the body portion of a greater radius to that of an adjacent body portion of a smaller radius. A method of forming a hole by the same tool is also described. The invention is useful in making cast-in-place piles in the soft soil saturated with water.

Description

~,~,t7~0~

B~CEGROVN~ OF T~ N~TION
1. Field o~ the Inve~bion ~he pre~snt invention relates to a tool ~or ~ormin~;
a hole in macroporous compre sible ~oil and to a method l5i~ $~;~
o~ ~ormi~g a hole ~ ~ &~e tool.
:~ The invention may be utilized while forming holes in the soil s~eoi~ied ~or cast-in-place piles in i~dust-rial a~d civil e~gi~eering practice.
For the purposes o~ the present invention by "m~-croporous compressible soil" is meant loess, water-satur-ated sandy soil, so~t water-saturated cla~ soil with a consistency inde~ IL~ ~3 and other similar kiuds o~ 50il.
Such soil is known for its low structural streng~h, it easil~ collapses i~ contact witA water and under dy~a-mic load.
Conventional methods of forming holes i~ soil ~uch as percussio~ and rotary drilling, wa~hboring a~ well as tools ~or practicing such methods are practically of low e~iciency ~or the 50il speci~ied~ Thus, ~or e~ample, the percussion drilling d~st.roy9 the wall of a hole. ~ombined methods of percussio~ drilling and-vibratory actio~, apart irom the abovementioned disadva~tage 9 has an effect on ~e-arby buildi~gs and produces noise~ Si~ce the percussion tools operate by a sequenc~ of p~l89s th~ir e~icianc~ i8 limited. The method o~ rotary drilli~g doe~ not provide .
~or an ad~quate compactio~ of the wall o~ the hole. There-~ore such walls have an i~erior per~orma~se characteri~-tics, which i~ turn result~ i~ a iower car~ying cap~city .
. . . . --2--. .
' ' ''" ' ' ''' , ' ~

.

~IL77~

o~ !th~ pile. !rhe wash~ori~g o~ a hole' inithe 90il speci-~ied i~ inappropriate i~ general.
Furthermore9 ~o~ventio~al methods o~ ~ormi~g holes si~gly or in combinatiorl to a greater or lesser degree i~volve sQil excavatio~ but this i8 not know~ to be any help in compacti~g the wall o~ the hole.

2 . Descript~o~ o~ ~he Prior Art K~lo~n i~. the art are a tool a~d method of f orming a hole in macroporous compressible soil (US Patent ~o 4,193,461). The tool com~rises a body adaPted to be con-~ected to a borin~ rod and having a sizing part and co-axial body portions radially defi~ed b~ soil compactio~
~ur;~aces ~nd of step- down radii from the sizing part to the tool tip.
Eac~ body portio~ is constructed as a ram assemb~
comprising one or more r~m ~hoes radially mov-able ~rom a ret~acted position to a~ o~tendcd positio~. As the tool is driven in~o soil each body portion circum~erentiall~
compact~ the 50il to the ~adial extent which i~ equal to or slightly greater tha~ the radius of an adjacent bod~
portion in the directio~ ~rom the tool tip to the BiZi~g part ~he~ the ram shoe or shoe9 are in the retracted po~i-tionO In such a manner the hole i8 îormed simultaneous~y with the 80il compaction operatio~
- ~he prior art tool provides for 90il compactio~ by a discontinuous radial actio~ on the 80il with the ram-shoes i~ zones corresponding to tho bod~ portions.. ~Qere-.

.

t~,os~

~or~ a nonuniform compactio~ o~ th~ soil bo$h circum~e-rentially o~ the hole and along its length i9 the result which has an e~ect on the carr~ing capacity o~ the pile.
Such a disconti~uous actio~ on the soil, which ofXer5 an increased resistance to such action as it i9 compacted, is by the reciprocating ram shoes. Such a constructio~ o~ the tool as well as the method o~ acting on the 90il are limi~-ed as to e~icie~cy and are characterized by an increased consumption of power, since the ram shoes are to be retract-ed prior to e~fecting the next power stroke.
SUM~ARY OF TEE INVEN~ION
~ n object o~ the invention is to provide a more ef-ficient tool for ~orming a hole in macroporous compressible soil~
Another object o~ the invention is to provide a tool ~or ~orming a hole in macroporous compressible sQil - a tool of a lower power co~sumption tha~ the prior art tools.
A further object of the invention is to provide a tool ~or forming a hole in macroporous compressible æoil, which makes possible a u~if orm compac tion o~ the wall o~
~he hole both circum~erentiall~ and along the hole leng~.
A ~tlll ~urther object o~ the inventio~ is to pro-vide a method of for~ing a hole in macroporous compressible ~oil~ enabli~g a continuous and u~iform compactin~ o~ the wall of the hol~ with the tool o~ ~he inven~ion to improYe hole ~orming operatio~sO

., ' ' ', " ~ ' ~
.

O

~ ~t7~ ~ 5 ~

It is also an objecb o~ the i~ventio~ to provide a ~ool ~or and a method of ~ormi~g a hole, which make it possibie tG i~crease the carr~ing capacity o~ the cast-place piles.
Yet it is a 8~ill further o~ject o~ t~e inVentio~
to provide a method o~ formi~g a hole with the tool o~
the inventio~, which method a~d toGl make possible consoli-dati~g the wall of ~he hole with a ~uitable hardenable com-position.
Th~e a~d other objects o~ the i~ventio~ are attain-ed by that th~re is provided a tool ~or forming a hole in macroporous compressible soil, comprising a body adapt-ed to be connected to a boring rod and havin~ a sizing part and coa~ial body portions radially de~ined by soil compactio~ ~urfaces and o~ step-down radil ~rom the sizing part to the tool tip, whe.reinj according to ~he i~ventio~, the soil com~action sur~ace o~ each bod~ portion i9 a c~
lindrical sur~ace generated b~ a generatrix o~ a pr~deter-mined length ex~encli~K parallel to the tool a~is a~d bo-unded by two parallel helices o~ one a~d the same heli~
angle, these surfaces being successively conj~gated b~
transition portio~ de~î~ed by a cylindrical sur~ace whose ge~eratrix is parallel to the tool axis. a~d uni~oxmly a~
proaches this ~ame axis to thereby ~orm a smooth transi-tio~ ~rom the surface o~ the body portion of a greàter ra-dius to that of a~ adaace~t bod~ portion of a smaller ra-dius.
, ~ ~'7'7~ ~

Such tool i~ simple in co~struction a~d reliable in operation ~i~ce there is ~o parts movable in respect to each other. A s~ooth transition Irom o~e body portion to another provides ~or a continuous radial action on the soil to increase e~ficie~cy i~ hole forming. The tool i~
noiseless in operatio~ and does.not produce any impact load on the soil an~, consequently, o~ the nearby buildings~
w~ich is an advantage when the tool is used i~ densely-populated areas. Si~ce there is no impact load on ths soil, the wall o~ the hole i~ compac~ed more uni~ormelyO
In the tool o~ the prese~t invention the adiacent transition portions are displaced in relation to each other.
alo~g the cylindrical helix by an a~gular value ~ot great-er than 720. Such a tool has no radial run-ou~, i.e~ the tool body is uni~ormly loaded.
It is advisable that the cylindrical sux~aces ad-jacent the steps provided between the body portions hav-ing step-down radii and the trans~tion portio~s have ridge members di~posed along the heli~, each ridge member havi~g a radial extent not exceeding t-hat o~ the ~tep of an ad-jacent body portion of a greater radius. ~hese ridge memb-ers additionally force the soil radially. Also, they sta-bilize axial movement of the tool in the soil.
It is iurther advisable that ~ach tra~sition portio~
be a roller rotatable about a~ axle disposed angularly to the tool aXi8, the angle o~ the roller disp~sitio~ being .
~ 6- .

: , , O

~ ~'7'7~ ~

equal to khe helix angle o~ the helices bou~ding the cy-lindrical surfaces of the adjaoe~t body portions so that each helix extends in the plane oX a cor~sponding end f ace of the roller~, Such a modified tool makes it possible to ~Qrm a hole having a compaote~ wall~ which improves load-carry-ing ca~acity of cast-in-plAce piles. ~he rollers take the function o~ radially compacting the soil to reduce ~ric-tion by 3 to 3.5 times, since sliding friction on metal is substituted ~or rolli~g frictio~.
It is ~urther advisable tha~ the bod~ has an axial cavity taperin~ towards the tip and a vibrator for caus-ing lateral vibratio~s, mou~ted i~ said cavity and includ-i~g a rotary drive, a ~ha~t connected to the drive and ex-tending substantially a~ially of the tool, and unbalanced mass member mounted on the shaft along it~ le~th and ha-ving di~erent mass value d~minis~ing in the direction o~
the taper of the cavity i~ the body.
. Such a tool enable~ ~ormi~g hole~ o~ a l~rg~ dia-meter (more than 0~8 m) due to an additional vibratory action on thc ~oil.
urth~r advisable that support members ~or the 9~a~t be provided be~wse~ the u~balanced mas~ members ~hereby ~ibratory action o~ each u~balanced ma99 member o~ the soil i9 localized.
It is ~urthsr advlsable that the tool body compr$s-e~ coaxial body portio~s o~ step-do~ radii from the siz .

, ' . ' , i;"7(~5~

in~S portio~ toward~ t~e locatlo~ o~ t~e borin~ rod attach-me~t, the ~tep-dow~ portio~ bei~g radially defined by c~ drical surra~e~, ge~erated by t~e generatrix of a predetermi~ed le~t~ e~tendin~ parallel to bhe tool axis and bounded by two parallel helices of one and the ~a~e helix angle and these surface bein~ successively con~u-gated by transition portio~a de~ined b~ a cyli~drical sux-~ace who3e generatrix ispaxallel to the tool axi~ and is uniformly approa~hing this same axis to thereby ~orm a smooth transition ~rom the ~ eace o~ the bod;y poxtio~
of a greater radius to that o~ an adjace~t body portion of a smaller radius.
~ he above modi~ication of the tool is use~ul ~or co~olidating the wall o~ a hole with various conaolidat-ing materials while driving the tool into 80il as well as withdrawing it there~rom a~d provides for a desired stre~OEth and thick~ess o~ the consolidated well area, and further makes possible a hig~er load-carrying capacity o~ cast-i~;placa piles a~d lower labor input.
Po~ible is ~uch a modi~ica~ion of the tool, wherein there is a ~urther body coaxial with the body a~d havin~
an axial bore ~or co~ducting a hardenable ~luid, a~ well as a ~izing part and coaxial portions bei~g radially de-fi~ed by cyli~drical sur~ace~ generated by generatri~ o~ ~
a predetermi~ed length extendi~g parallel to the tool axis and bounded by ~wo parallel helices of one and the same , ~-- .
, .

~ 7Q 5~3 helix angle and these ~ur~aces being succes~ivel~ con-jugated by transition portions de~ined by a cyli~drical surface whose generatri~ is parallel to the tool axis a~d is uniîormly approachi~l~ t~e same a~is to thereby ~orm a smooth transitio~ ~rom the surface o~ the body portion o~ a greater radius to that of an adjacent bod~ portisn o~ a smaller radius!, at on~ side the ~urther bod~ i8 ri-gidly connect~d b~ means o~ a hollow connector communicat-ing with the ~ial bore ~or conducting a hardenable ~luid a~d havi~g openi~s for the hardenable ~luid ~lowing into t~e hole, a~d at ~he other side the body has a por~io~ ~or a~taching t~e tubular borin~ rod through which the harden-able fluid may pass to the bore in the body and further on through the opening into the hole.
~ hiQ modification ia suitable for forming holes and solidiiying their walls simultaneously with drivi~g the tool in and withdrawing it from the soil, which make~
the labor i~put lower and ef~ioiencD higher. As a result, wall stabilitg i~ improved with a con~e~uent improvement i~ the load carryiag capacity o~ cast-in-place piles a~d i~ the reliability o~ development wells~ Furthermore, such arrangement pr~vides ior forcing a consolidati~g material into the wall of a hole to~form on~ or several l~yers o~
one or several various materials.
Possible is such a modification of th~ tool, wherein the body comprise~ at least t~o parts of which the ~i~st part is attacked with its side having a greater radiu~ to - . 9 lg~t7~ 3 t~e tubular bori~ rod and ~as a through a~ial bore w~
on the side ha~ing a smaller r~diu~ this parb has an end face similar to the step provided between adjacent body portions, and the second part is received in the axial bore ~or co~ducti~g a hardenable ~luid~ the ~irst part havi~g lo~gitudi~al grooves provided in the wall of th~
axial bore and the seco~d Part havi~ projections provid-ed on the outside thereo~ a~d re~eived i~ the lo~gitudi~al grooves ~or sliding therealong so that when the ~ool i9 bei~g driven into tha soil, the seco~d part retracts i~to the ~irst part, and the outlet openi~gs are closed with the ~irst part o~ the body, whereas the se~ond part extends ~rom the ~irst part when the tool is bei~g withdrawn ~rom the hole and the outlet openings become open, whereby the harden~ble fluid may ~low there~rom to form a pileO
~ his modi~icatio~ may be used ~or ~ormi~g a hole and co~creting a pile without ~ cha~ge of equipment a~d with-out a casi~g pipe to protect the hole made in ~o~t soil with a co~sequent iLprovement i~ labor produativity.
Possible ~s still another modi~iaation of the tool, wherein there i9 prov~ded a t~ird part ~ the body which is similar to the ~irst part but rever~ed, ~lipped over the tubular bori~g rod ~or sliding motion therealong and having a portion of a greater radius ~erving as the siæing part and provided with a skirt e~te~ding toward3 the ~lr~t part and having an end face similar to the ~bep betwee~
adaacent portions, ~here being a radial sur~ace haYi~ a~
en~aging means where the ~irst part is attached to the bor-_ 10-- - ~
.

, ~17~V~9 ing rod and the third parb ha~ an opposite sur~ace having a correspondin~ e~aging means~ where~y tur~iag of the third part with respect to the first part a~d the second part is prevented whe~ the tool i~ being withdrawn from the hole, th~ skirt su~ficiently extending in the asial directio~
so as to provide an enclo~ed ~luid disc~arge zo~e for the ~luid ~lowing from the outlet ope~ings i~ the seco~d part as the tool is being withd~aw~ ~rom ~e hole, while a stop is provided o~ the boring rod for limiting the motion o~
the third part alo~g the bori~g rod a~ the tool is being drive~ into the soil, thereby setting the end face o~ the skirt on a respective helix.
'~hen the tool according to the above modi.fi~ation i8 bei~g withdrawn ~rom the hole ~or~ed while a concrete mix-t-ure is being fed to ~orm a pile, the soil that may ~all is prevented from intermi~ing with the concrebe mixture.
~ he inventio~ also p~ovide~ a method of forming holes i~-mRcroporous compressible soil consisting in drivlng a tool into the ~oil~ consolidating the wall of the hole, and withdrawl~g the tool from the hole. According to the inven-tio~, the wail of the hole ls co~solidate~d, ~imulta~eously ~ e~ ;Q~with the step of drivi~g i~ the tool of ~ , by conti-nuously applyi~g radial forces per æone o~ co~tact of the tool with the soil continuously and circumferentiall~ o~
the hole being formed to widen the hole to a prede~ermined diameter and to compast the soil as .~t~B tool is bei~g driv e~ in.
~ modifi-catio~ of the method provides ~or a con-. , , --11-- . -. ~,.:. ~ '' , ~Lt~ S~

tinuous compactiOn O~ the soil as the tool is being dri~en in or or the hole formed, which rèsults in an improved com-pact wall of the hole.

It is preferable that at first a pilot hole of a diameter less than a predetermined one is formed with a con-ventional tool and by a conventional method and then this hole is filled with a consolidating material and a hole of a pre-determined diameter is formed with the tool of the present invention driven in along the axis of the pilot hole to press the consolidating material into the soil.

Such a modification of the method enables formation of a hole and simultaneous solidification of its wall with a hardenable material to improve the load-carrying capacity of the cast-in-place piles and to make development wells more reliable.

The pilot hole may be filled with a consolidating material up to the level of from 1 to 1.5 m below the mouth of the hole.

It is exped.ient that the ratio of the diameter of the pilot hole to the diameter of the hole to be formed is in the range of 0.4 to 0.8.

Such conditions make it possible to prevent forcing the harden.ing material from the mouth of -the hole as the tool is being driven into the pilot hole.
The method may be practiced by using a tool further comprising, apart from the main soil compaction part, an ~dditional soil compaction part including similar coaxial .l~t77~5~

portions of the radii diminishi~g in a steplike ~ashion ~rom the sizing part to the location where the borin~ ro~
is attached to th~ tool.
I~ accordance with this modification of the tool the met~od can be carried out in the follo~i~g manner:
first, the tool is driven into the soil to a predetermined depth, whereupo~ a consolidating material i9 ~ed into the obtai~ed hole and the tool is withdrawn from the hole to press the consolidati~g material into the wall o~ the hole.
~his modificat~on of the method makes it possible to con-solidate the wall o~ the hole both while drivi~g the tool into the soil and while withdrawin~ it there~rom.
. Depending o~ the material u~ed and the length of the hole the consolidating material may be fed batchwise~
~his makes it possible to sub~tantially decrease the cou-sumption of the consolidati~g material and to control a lo-ad upon the tool in a desirable manner.
While carrying out the method in accordanoe with the above modi~ication o~ the ~ool the latter can be driven into the ~oil with ~imultan~ous feeding of the co~solidat -i~g material and aft~r dri~ing the tool to a predetermined depth the tool is withdraw~ ~r~m the hole to pre~ the ~on-solidating material into ~he wall of the holeO
~ he method can b~ al80 C ried out with th~ aid o~
a ~ool comprisi~g two coa~ially mou~ted bodies simllar to that w~ic~ is u~ed ~hen ~arryi~g out t~e modi~ication o~

.

- , .
.

Lt~7~

th~ mebhod describe~ above. On~ of th~se bodie~ has a tip, a~d the other is connected to a hollow boring rod and has a throug~h a~ial bore. These bodie~ are connected by a hol-low connector commu~icatin.g with the axial bore and having openings for a conæolidating material to be ~ed into the hole. When carrying out the method according to this modi-~ication of the tool the latter is driven i~to the soil to a predetermined de~th with simultaneous ~esding o~ the consolidating material and with pressing this same material into the wall o~ the hole, whereupon the tool is withdrawn îrom the hole .
When carrying out such a modi~ic~tion of the mebhod it is possible to additionally feed a consolidating materi-al into the hole while the tool is bei~g withdrawn there-~rom with simultaneous pressing o~ this material into t~e wall of the hole to thereby ~orm a further consolidati~g layer~
The above-me~tioned a~d other objects and adva~t-ages o~ the invent~o~ will become apparent from the ~ollow-ing descriptio~ o~ the embodiments thereo~ with re~ere~ce to the accompany-ing drawings in which the same part~ are desi~natéd by the same re~ere~ce numerals a~d i~ wbich:
~ ig. 1 generally ~hows a tool according to tha in-ve~tio~ t Fig. ~ i~ a vie~, looking in the directi~n o~ ar-r~w A i~ Fig.~
. 3 is a geometrical constructio~ of ~he tool according to the i~ventio~;
- ' . -14 .

,7~

Fig. 4 is a modi~icatio~ o~ the tool accordi~g to th~ inve~tion;
~ i~. 5 is a ~urther modification of the tool ac-cording to the inve~tio~;
Fi~. 6 is a~ alternative-modifica~ion of the tool according to the invention;
Fig. 7 is a view in axial section of the tool o~
~ig. 6;
Fi~. 8 is a sectio~al view taken o~ line VIII-VIII
in ~i~. 7;
Fig. 9 is an enlarged detailed view of a transition portion of the ~ool constructed aocording to a modi~ied iorm shown in Figc 7 J
Fig. 10 is a sectional view taken on line X-X in Fig, 9;
~ ig. 11, a through e, is a d~a~rammatic repre~en-tatio~ of an alternatlve wag o~ pra¢ticing the mothod ac-cording to the invention;
Fig. 12 i8 an alternative consbruc tioa oï the tool accordi~g to the invention;
~ ig, 13 i~ a se¢tio~al view ta~en o~ llne XIII~
i~ Eig~ 12;
Fig. 14 is a modiI i~d ~orm of the tool o~ the in-ve~tD~on, the tool being providea with a reversed soil compaction part7 Fig. 15`~ 3 ~hrough d~ is a diagramma~ic representa-tion o~ a~ alternative way of prac~ici~g the method accord--15- ~
.. . . .

, i~g to t~e inven~ion;
Fig. 1~ is yet anobher modiried iorm o~ the t~ol ha~ing two coaxial bodies;
~ ig. 17-is=a-sectional view i~ line XVII-XVII
i~ ~ig. 16;
~ i~;. 18, a and b, i~ a diagrammatic representa-tion o~ an alternative wa~ o~ practici~g the method ac-cording to the invention, ~ ?ig. 19 i5 a view in a~ial ~ection o~ a modified form of t~e tool of the inve~tion, the tool parts bein~
shown i~ the position, which they assume ~he~ t~e tool iS driYen ill;
Fig. ~O is a sectional view on line XX-~X in ~ig. 19;
~ ig. 21 is a sectional view on li~e XXI XXI in .
~lg~ 19;
~ ig. 22 is a view in a~ial ~ectio~ o~ the tool show~ in ~i~. 19, the tool part~ being shown in the po-sition, which they as9ume w~en the tool is withdrawn;
Fi~. 2~ is a se¢tional view o~ e XXIII-~XIII
in Fi~o 22;
~ igo 24, a and b, is a diagrammatic repre~nta-tion o~ operation o~ the tool shown in two positionæ in Figs 19 and 22~
~SCRIP~IO~ O~ ~EB PR~F~RR~D EMBODIM~NTS
0~ ~Hæ INVE~TION
ReIerring to ~ig. ~1s a tool ~or forming a hole com-' ' ' ~ ~7'7V 59 prises a bod~ 1 adapted to ba ~o~nected to a borin~ rod 2. The bod~ 1 has a 8~ zing part 3 and coa~ial body por~ions 4 ~orming soil compactin~ part of the tool.
Each body portisn 4 is o~ its proper radius r and all the body portions are such t~at the radius o~ an adiacent body portion in the directio~ ~rom the 8iZi~g part 3 to the tip 5 is shorter than that o~ the previous body portio~.
Also, each body portion 4 i~ radially defined by a soil compacting sur~ace. ~his su~aoe is a cylindrical surface (~ig. 3) generated by a generatri~ 1 o~ a predeterminad length, parallel to the tool a~is i and bounded by two pa-rallel helices a a~d b of the same helix angle J\ so that the soil compaction Part of the body 1 ~as a cone-like form composed of the body portion9 4 radially defined by cylindrical surfaces o~ step-down radii ~rom the 9izing part 3 to t~e tool tip 5. Since the a~ially arranged body portions 4 have unequal radii, a step 6 i9 provided between them or t~eir cylindrical sur~aces~ which ~tep i9 show~, ror the sake o~ ~3mp~icity, as a shoulder (Fig. 1) though u 1~ e . it may have ~Y~h~r o~ corner~ as can be seen in Fig. 5.
Cyli~drical sur~aces o~ the a~ial body portio~ 4 are 9UC-~essively conaugated by tra~sitio~ portions 7 (Figs 1 a~d 2~ de~ined by a cylindrical ~ur~ace whose generatrix ~as a length equal to that o~ the generatrig 1, i9 p~rall~l to the tool axi3 i and ~e~hN~o~ approaches thi~ same axi8 -to ther~by ~orm a ~mooth tra~sition ~rom the cylindrical sur~ace o~ the body portion 4 of a greater radius to that ' .:

'7(~5~

o~ th~ ad~a¢e~t bod;sr portion 4 o~ a smaller r~diu~.
99 ~a~ be ~een ~rom Fig~ 1 and particularly ~ig. 2, each adjacent tran~itio~ portio~ 7 is displaced in rela-tion to each other alo~g the cylindrical helix b~ an an-gular ~alue not greater than 720C, i.e. the angular dis-placement ~ OI the transition portio~s 7 or the le ngth OI the coaxial portion 4 alo~g a heli~, suc~ as the helix a ~hould not exceed 720, becaus~ iI it does; the portion 4 will become a cylindrical body worL~ as a sizing part wh}ch does not participate either in widelling the hole to a predetermi~ed diameter or in compactio~ OI soil 9 which will become apparent Irom the description of the operatio~ .
o~ the tool accordi~g to the i~vention.
~ s can be seeu from Fi~;. 4, t~e c;srli~drioal sur-~aces o~ the portions 4 adjacent the steps 6 as well a.s the transitio~ portions 7 are provided with ridge members 8 disposed along the helix, each ridge member 8 having a ra-dial extent not e~ceedin~ thst o~ the step 6 O:e an adja-ce~t body portiob 4 of a greater radius. Such radial sizes oî the ridge members are selected to prevent the wall o~
the hole ~rom collapse in the cour~e o~ the ~ormatio~ there-o~ . , As can be 3een from the a compa~ ; drawisgs, the tool according t~ the inve~tio~ ha~ an axial bore 9 and la-.. . .
terals lO connected with a source of liquid~ such a~ water .

O

~ ~7 7~ ~

(~ot shQw~. Through the axial bore 9 and the laterals 10, a liquid may be supplied i~ nece~sary (for ins~ance9 the soil i9 very de~se) in an amou~t su~ficient to reduce load upon the tool wit~out 80il destructio~.
The tool according to the invention was described abov~ in such a way as to make those skilled in the art understa~d it. Speci~ic constructio~ charactexi~tics such as sizes9 can be readily impleme~ted b~ employing conven-tional materials and conventîonal methods of co~struction, taking into accountspeci~ic conditions and the purpose o~ the tool.
Given below are but ~everal hxamples o~ determina-tion ~ sizes o~ the tool according to the i~ve ntion. ~-perimental check o~ the tool o~ the inventio~ has show~
that the too} taper should be withi~ the range o~ 15 to ~0, the most e~ ienb ran~e being ~rom 20 bo 30. T~e number of portio~s 4 is ~ithi~ the ran~e of 5 to 20, the most advisable ~umber being ~rom 10 to 15.
- ~xample 1 With the diameter oî the hole being D = 600 mm, taper ~ - 2~ a~d angular displac0me~-t ~ = 450 it i9 ~ecessary to de l;ermine:
- ~alue of the step, t, - minimum size alo~g t~e axis o~ the portio~ of o~e rz~
- radius o~ eac~ coaxial portio~ o~ the body from - the sizi~g part ~o the tip; rl, r2.. ~r~. :
- Asswme that ~=10, R = 12 ~
.
. .

'7~59 ~hen: t = _ = _q~ 30 mm;

1 = 360 R = 360 300 = 109 ~n;
n0~gd~2 10 450 0 22 r1 = R-t = 300-30 =270 mm;
r2 = R-2t - 300 - 60 = 240 mm and SD UnD
~he len~th ~f the tool Dr the ~oil compaction por-tion thexeo~ can be determined by the fsllowiL~ fDrmula:
Q i=n L = l1 1 + l2 2 ~ n n ~ ll ~l) where ll, l2..~ ln is a pitch Df a cylindrical belix or the minimum axial size, this same is a len~th Df ~he generatrix of the cyli~drical sur~ace of axi~l pDrtion~
Df the body ~r~m l ~D n, ~ ~ ~2 ... en is an~ular dis-placement D~ transition portions frDm i to n, ~ i5 ~- ~0 the number Df tur~s, N, Df tbe helix within the range D~
Dne portion Df the body.
If ~ 2 = ln = const., and ~l - e2 = ~- ~n =
= c~nst., i~e. i-f the values l and 0 are equal for all the portions, bhe lengbh o~ the tool may b~ d~t~rmined by the following formula:
L = ~l = nlN, (2) ~here ~ is the number ~f the coaxial bDdy portio~s.
Note: the angular displacement o~ tbe tran~ition pDrtions iæ determined ~r~m the middle portio~ D~ one transitiD~
portiDn to tbe middle pDrtion D~ the next tran3ition p,or-.

O . ~ . .
. , . ' ~t7~ 51t3 tion.
Example 2 T~e soil compaction por~ion, ~ to be deter-mi~ed if n - 10, 1 ~ 70 mm; ~ = 450.
Use is made o~ the ~ormula (2) wherefrom ~ =
= lQæ70~ ~ = 875 mmO
~ ample 3 The ~oil compaction portion9 L~ is to be determin-~d ii n = 12J 1 = 80 mm,o 0 = 420.
Use ~ made o~ the ~ormula (.2~ where~rom ~ _ _ lax~Ox ~ p mm.
The taol accordi~g to the i~vention operates i~
the ~ollowing manner ~.
On the sur~ace o~ soil there is installed a ce~ter-ing tip 5 at a point wh~xa a hole is to be made, and thro-ugh the bori~g rod 2 t~e to~ rotated irom ~ dri~e (~ot s~own). ~imulta~eou~ly therewit~ an axial pres~ure i8 ap~
plied to the tool utlder bhe actio~ OI the ma~s o:~ th~ tool, boring rod, drive, additional load (or pressure ~eed), As a result o~ rotation and axial pressure the ~ool i~ driven in the soil is continuously compacted ~rom the circumRerence o~ the hole being made by the transitio~ portions 7. ~he cy-lindrical sur~aoes o~ the port1ons 4 do ~ot participate in the soil compaction9which is carried out ~tep by step, first by the portion~ disposed near t~e ~ip 5, i.e. b~y tho~e sur:eace~ which are closer in radial direotion to the loll~;itu-.
dinal a~i~ of the *ool~ A~ the tool tur~s b~ t~e a~gular va . ~21-~ ~ 7 ~ S~

lue of ~, which i~ equal to the length o~ the cyli~dric-al portion along the heli~, the ~oil i9 compacted b~ the ~e~t transition sectio~ di~po~ed one s~ep hi~her ~rom the tip 5 and eo: on. When the sizi~g p~t pa~ses through soil, thexe is ~ormed a hole of a re~uired diamet~r.
~ he ridgs members ~ act as screw blades a~d aid in the progressive movement o~ the tool into the 90il a ~ sta-bilize thi~ movement. When drivin~ the tool i~to highly compresæible soiIs, such as clay soil9 havi~g a consistenc~
inde~ of IL~ 0.6 the ridge members 8 are as a rule not re-quired~ The 90il'is ~ot excavated as the hole i5 fOrmea~
it i9 gradually pressed i~to the wall o~ the hole. ~hus a zone of compacted soil is ~ormed around the hole. Due to compaction o~ ~oil around the hole the load carrying capa-city o~ the cast-in place piles increases and subsidence of soil is elimi~ated.
~ he tool acoordi~g to the inve~tion ca~ be used ~or ¢arr~ing out the method of ~orming a hole to be filled with a co~solidati~g material. As can be s~ fro~ Fig~ 11, _ throu~h e, at ~ir~t a pilot hole o~ a diameter le~s than a predetermi~ed one is ~ormed with a co~ve~tional .tool, such as drill bit a~d the~ this hole is ~illed with a co~solidating material (Fig. llb). The~ alo~g the axi~
of the pilot hole the hole o a predetermined diameter i8 made by the tool according to the i~vention (Fig~ 11 c and d) by pressiDg the consolidati~g material i~tv khe ~oil.
~he readg ~ole is illustrated ia Fig. lleO
, ~ 22_ ' . , , ' 7~5~ -Ver~y ~uitab~:~ in operatio~ i9 a mod:i~ioation ~
t~e tool~ ~how~ in Figs 6 to lû o~ the drawi~gs~ Accord-iog to this modi~ication each said transition portio~ 7 (Fig. 6 an~ 7) i5 formed by the roller 12 ~Fig~ 6 and 7) mounted ~or rotation around its a~le 13. ~he axle 13 o~ t~e roller 12 (~ig. 7) is disposed at an angle to the a~is of the tool, is e~ual to the angle o~ the helice~ defi~i~g the cylindrical 8UrIaCe8 OI coaxial portio~s 4 of the bod;y 1. Each heli~ i9 disp~sed i~ t~e plane of a correspo~ding end ~ace of the roller 12, às shown in dotted lines in ~ig. 70 ~ he roller~ are displaced in the cross-sectio~al plane of tb:e tool (Figs. 7 and 8~ with respect to o~e a~o-ther, in particular through 90, and are mou~ted in the body 1 o~ brackets 14 (~ig~ 8). Such bei~g the case 7 the body 1 has ops~ings, and the rollers are disposed in the~e openings ~o that there is formed a smooth transition from the cylind-rical surface o~ greater diamete~ ko the cylindrical sur-~ace of a smaller ~i~meter as is best seen in ~ig. 10 The diamet0r o~ each o~ the rollers 12 ~hould not e~ceed 0.5- o:~ the diameter oï the body 1 in the cross-sec-tion where a given roller i8 i~stalled, and t~e len~:th o~
the roller ~hould correspond to the dîsta~ce between hell ces of a given portion OI the bod~ ach roller 12 ~Figo9 and 10) is providea ~ith a ridge member 8 at~;he ~ide of the lower (in the drawings) end ~aceO This ~ member i~

- ~
' ' J . ' .

'7~

intended to ensure ~moot~ conjunctisQ of the ¢~lindrical sur~ace~ o~ the roller~ 12 and the portions 4 o~ the body 1. ~he above-described roll~rs aid in reduci~g ~riction when the tool is drive~ into soil, si~ce these rollers, tur~i~g to~ether with the bod~ 1 and ensurin~ radial com-paction of the soil, at the same time roll on the hole wall bei~g ~ormed, a~d thus the sliding ~riction whic~ took p~ace in previously described modi~icatio~ is substituted ~Y
rolling ~rictio~.
It is to be noted that the rollers described herein may be variously constructed. In particular. they may be mou~ted on rolling bearings 15 between which the~e is dis~
posed a sleeve 16 as shown in Figs 9 and 10. But it will be understood that there may also be used sliding bearin~s and othe like parts.
It is also to be ~oted tnat the reductio~ in fric-tion between the tool and soil due to t~e use o~r~llers aids in lowering power consumption and in enhancing the e~-fi6iency in operation~
Due to the rollers 12 the wall vf the hole being form-ed become~ more compact, which upgrades the carr~ing capa-city of the cast~ place pile produce~ later o~.
Where the e~icie~cy of the tool i~ to be increased, aQ ~or ihstance in ma~ing holes of a large diameter (above 0.8 m), particularly i~ soil containi~g ~ard inclusions, it is expadient to use the modification illustrated i~
Fig. 12. I~ accordance with this modi~ication, the body 1 . -24- .
.
.

~lt7~35~, has a~ a~ial ca~it~ 17 taperi~g towards the tip 5. ~he tool i~ provided with a vibrator 18 ~or causing lateral vibratioDs, mounted i~ ~aid ca~ity 17.
~ he above vibrator 18 includes a rotary drive 19 mounted ill the upper (i~ the drawing) por-tioa OI the body 1, a shaft 20 co~nected with thi~ drive and e~te~di~g sub-stautiall~ a~ially of the tool 7 and unbalanced mass memb-ers 21. These un~alanced mass members are mou~ted on the sha~t along its length and have dif~erent mass value dimi-nishing in the direction o~ the taper of the cavi~y 17 in t~e bod~ lc Su¢h dis~ribution o~ the mass value of t~e u~-balanced mass members 21 is due to the ~act that with an increase o~ the cross-section o~ the hole the resi.stance o~
the 90il to the tool bei~g d~ive~ creases~ which re-quires large ~orces to overcome this resista~ce.
In operatio~, the rotatlon of the sha~t 20 with unba~anced mass members 21 causes transverse vibrations o~
the body 1 and thereby the tool screws into æoil. In 90 do-ing, the resistance o~ the 80il i9 substantiall~ reduced and the co~pa¢tion of the latter improve~. In additio~, such way o~ driving t~e tool i~to soil pr~cludes the effect o~ va-cuum suctio~ usual in such cases~ which decrea~es the ~orce and time required ~or withdrawing the tool ~rom the hole~
With the above modi~icatio~, it is adYisabla that the tool have several support members 22 ~or the sha~t 20, provided between the u~baIancêd ma~s members 21 a~ show~

.' '.
- - . - .
o ~ ~7 ~ 5~

in Figs 12 a~d 13. Such support members 22 not onl~ take ralial load~ and reduce the wobble of the shaft ~0 bu~
also localize the vibratory a¢tion o~ each o~ the u~ba-lanced mass members 21 upon t~e soil. It is sui~able to use this construction when the structure and the de~sity OI s oil vary in depth.
The tool o~ the invention may also be constructed as shovln in Fig. 14 of the accompanyi~g drawi~gs,.
In accordance with this modification the body 1 com-prises a sizing part 3- and two soil compacting part~, name-ly the ~ront one desig~ated la (from the sizing part 3 to the tool tip 5) and the back one designated lb (from the sizing part 3 to the boring rod 2).
The soil compaction parts la and lb of the body 1 aresubstantially similar and have much in common with the soil compaction part hereinbefvre discussed in detail in con-nection with the firs~ tool $orm (~i~. 1). The present modificatio~ also has coa~ial body portion~ de~ined by cylindrical suI~aces and of step-down radil - of the front part la those are body portions 4a having radii diminish-i~g toward the tool tip 5 while those o~ the back part lb designated. 4b h~vi~ radii diminishing toward the boring rod 2~ Both the ~ront la and the back lb parts have tran-sition portions 7a and 7b as well as the ridge members 8a and Bb respectively. ~ .
Apart ~rom the ~ront part laS the back part lb enabl-es the tool of the present m~dification to ~e used in prac . ' . ' .
. .

s~

tic~ng Yariousl~ modi~ied ~ersions o~ the method accord-in~ to the inve~tio~.
~ hus, accordine: to o~e oî the modi~ications of the method, the tool is drive~ i~to soil to a predetermined depth (Fig. 15a~ to thereafter suppl~ a consolidati~g ma-terial 23 (Figo 15b~ through the mouth and into the hole formed and the~ the tool is withdrawn (Fig. 15c). As the tool is withdrawn ~Pi~. 15c) the back part lb ~orces the consolidating material 25 into t~e wall of the ~ole to ~orm a consolidati~g ca~ 24 circumferentially o~ the hole. The co~solidating material 23 keeps the wall of the hole ~rom ~allin~ down as the hole is being ~ormed and con-siderably improves the load-carr~ing capacity of the cast-place pile that is to be formed there.
As ca~ be seen in Figo 15 d the hole that has been formed has a consolidati~g casing 24. ~his hole may be used not only ~or forming a cast-in-place pile but for other pur-poses too, ~ or e~ample it may bé used as a well of various applications. ~he oonsolidating material may comprise con-crete mixture, sand, slag, sand-and-cement slurry, organic a~tringent Pastes~ soil mi~tures and other materi~
It is to be appreci~ted that the wall o~ a hole may be consolidated both alo~g the le~gth and at an~ location as desired. Thus, accordi~g to a modified method 7 the con-solidating materlal i9 supplied batchwise to fill a l~ngth of th~ hole, eO~. ~rom 2 to 3 m. ~rhé batch-wise suppl~ of, th~ consolidating material is essentially useful in decreas .
. -27- . .

O

;1t7 ing the material co~umption~ Al~o, the bat¢hwise ~uppl~
may be used ~or controlli~g the load on the tool both in dri~ing in a~d withdrawing it ~rom~he ~oil.
Accordi~g to an alternative mode o~ practicing the method a consolidating material may be supplied simultane-ously with dri~ing t~e tool i~to soil and then be pressed into ~he wall of t~e hole in the ma~ner previously disclos-ed as the tool is withdrawn ~ollowi~g the hole ~ormatio~.
~ he choice o~ the method vaxiatio~ depends on the conditions o~ the pile ~ormatio~, the desir~d labor e~ici-e~¢y, on th~ hole dimensions, the compositio~ o~ t~e conso-lidating material and ~ome other ~actors.
'~he tool of the inve~tio~ ~ay be constructed as shown in Figs 16 and 17. According to the instant modi~ica-tion .(Fig. 16) the tool co~prises, apart ~rom the main body 1 of a similar construction as that shown in ~ig. 1, sub-stantially the æame additional body 25 arranged coa~ially with the ~ormer and connected therewith by a hollow connect-or 26~
This additional body 25 has an axial bore 27 commu-nicating with the hollow con~ector 26 and a portion 28 for connecting a tubular bori~g rod 2. In such a connector like the present o~e designated 26 there are lateral openi~gs 29 ~ig~ 17). Due to such a syætem of commu~icating passageæ
the hole béing ~ormed may be supplied with a hardenable ~lu-id such a~ the consolidating material speci~i^ed aboveO
~ his tool is driven i~to soil ~ig. 18a) i~ the same wa~ as ha~ been disclosed ~or the ~iFst tool conætruction . -28 O

(~ig. 1). As the tool is driven in, a consolidati~g mate-rial 23 is supplied into the hole bei~g formed through the bori~g rod 2~ the bore 27 and ~e openings 29 in the con-nector 26 to fill the space between the main body 1 and the additional body 25. During the hole ~ormation the consoli-dati~g material 23 is pressed into the wall o~ the hole by t~e ~ront soil compacting Part 25a of the additional body 25 to produce a consolidati~g ca~ing 24 inside the hole~
After t~e tool ~as been driven into 90il to a desir-ed depbh a withdrawal operation begins ~Fi~. 18b~. Now the consolidating material 2~ is pressed into the wall of the hole by the back soil compactio~ part lb of bhe main body 1 and the casing 24 grows thicker.
To sum up, the prese~t modi~ication o~ the tool is used to simultaneously compact and solid~y soil both in dr~vi~g the tool in a~d withdrawing it from bhe soilO ~his helps bo increa~e labor productivi~y~
It is to the skill o~ the man o~ art that the tool of the invention may be constructed to have more than twn bodies. ~his being the case, a sin~le-layer casing as well as a multi-lager casin~ a dissimilar materials can be pro-duced. For the latter case it is imperative that one co~-solidating material be supplied when the hole is formed and a di~ferent material when the tool is withdrawn.
~ he tool may have more than one axiaL~bore, each con-ducting a di~erent consolidating material.
In order to cast piles in the holes formed by the . 2g- ' :

. : ., -~7t7()S~

met~od o~ the i~ventio~ the most suitable tool ig th~t shown in Fi~;s 1~ ough 24. Accord.in~; to thi~ modif ica-tion (F~g., 19) the body 1 o~ the tool comprise~ two par~s 30 and 31 in one arrangeme~t and a f ~ ther part 32 i~ ano-ther, thi~ latter arrangement being shown in the drawings as more versatile~
Each o~ the bod~ parts comprises body portions 4 having step-down radii hereinbe~ore discussed in more de-tail7 ~he ~irst Part ~0 i~ attached to a tubular boring rod 2 at the larger side thereo~ ~uppermost in the drawing) and has a through a~ial bore 3~, and at the smaller side (low-ermost in the drawing) it has an end ~ace similar to the step 6 provided between the adjacen~ body portions 4 o~
the second Part 31 o~ the body lo The second Part 31 has a tool tip 5 and i8 received in the bore 33 of the first part for axial movement there-along. Also, this part has an axial bore 34 with la~eral ope~ings 35 ~or admitting a hardenable ~luid9 ~or e~ample a concrete mi~ture, through the tool and inbo the hole.
In the walls of the axial bore 33 o~ the ~lrst part 30 are provided longitudinal ~rooves 36 and o~ the outside portion o~ the second part ~1 there are p~jections 37 re-cei~ed in the grooves for movement therein. Such arrange-ment makes pos~ible a simultaneous rotatisn of the ~irst 30 and the s~cond 31 parts on the boring-rod 2 as the lat-ter rotates in normal operation;
The third part 32 ~f the bod~ 1 i8 ~imilar to the : . 3 ~ ~t7~7~ ~ ~

rirs~ part 30 bu~ tur~ed with its portio~s 4 back~
its tapering is in ~he directio~ o~ withdrawal o~ the tool ~rom the soil. '~his part ~2 is slipped over the tubular boring rod 2 ~or sliding motion therealong and has a part~
q~re~e~
of a ~ radius 9 ervi~g as a sizing part and provided with a skirt 38 extsnding toward~ the ~irst part 30 of the body 1. This being the case, a stop 39 is provided on the boring rod 2 ~ or limiti~g the motion of the third part 32 of the body 1 along the boring rod 2 as the ~ool is being driven into soil. '~he skirt 38 has an end ~ace which is congruent with the step 6 between the coaxial portions 4 of the first part 30 of the body 1.
At the place where the first part 30 of the body 1 is attached to the boxin~ rod 2 the latter has a radial sur~ace 40 (see ~ig. 21) which in t~is case is made on the ~lange 41 (Fi~. 19) o~ boring rod 2 and ha~ an engaging mea~s ~ormed~ in particulari by projectio~s 42~ '~he third part has an oppo~ite sux~ace 43 ha~ng a corresponding en-gaging means 44. Such a construotion e~sures the en~age-ment between the projeotions 42 and the projections 4~ (see ~ig. 22) and thereby preclude ~urnl~ o~ the third part ~2 o~ the body 1 with re~pect to the ~irst 30 a~d the se-cond 31 parts, which prevents loozening o~ the hole wall being compacted. It is to be noted that the skirt 38 i9 SU~
cientl~ extendi~g i~ the axial direction so as to provide a~ enclosed fluid discharge æo~e for t~e ~luid ~lowing ~rom t~e outle~ openings 35 in the second part ~1 o~ the bo~y 1~
.
~ . -31 ~ ~

~t77~3 as shown in ~igs 22 and 23.
~ akin~ a oast-in place pile with the aid o~ the above modi~ication o~ the tool is done in the following marlner. ~irst, the tool i5 driven into soil as described above to ma~e a hole 45 (see Fi~. 24a). ~he arrangement of the elements o~ the tool at this stage is show~ i~
Fig. 19: the second part 31 of the body 1 bears against the ~lan~e 41 of the bori~g rod 2, t~e third part against the stop 39, and the end ~ace of the skirt 38 is disposed on a correspo~ding heli~ of the first part 30~ Suc~ being the case, the openings 35 o~ the second part 31 are over-lapped by the ~irst part 30 o~ the body l.
T~en (~ee ~ig. 24 b) tbrough the boring rod 2, a~i-al bore 34 and openin~ 35 o~ the second part 31 o~ the bo-dy 1, a concrete mi~tuxe 46 is ~ed into the hole 45 and simulta~eously therewith the tool i9 bein~ withdrawn ~rom the hole 45 which in the upper zone ~ay that time ~et fill-ed wit~ mud. Under the pressure o~ the concrete mixture 46 a~d by gravity the second part 31 o~ the ~ody 1 moves with respect to the ~irst part 30 into the po~ition shown in Fig. 22 with the result that the ope~ings get open and the concrete mixture 46 flows into the hole 45 thus formin~ the cast-in place pile 47. Since the skirt 38 b~ that time cir-cumferentiall~ provents the concrete mi~ture from ~lowing out, no particles of $10wing soll get thereinto, which sub-sta~tially up-grade~ the quality o~ the pile produced accord-.

ing to tk0 invention. In addition, the pres~ure of t~
~lowing 50il UpOIl the third part 32 of the body 1 pro-vides .~or a reliable engageme~t o~ the projeations ~2 and the projection~ 44 and thus prevents tnis part from b~i~g turned about with respect to the rod 2~
~ hus, this modi~ication o~ the tool makes it pos-sible to make the hole and to ~ill it wi~ co~crete wit~-out replacing the equipme~t and without emplo~ing casi~gs ~or rein~orcement of the hole in unstable grou~d. ~his con-siderably enhances the ef~iciency of ~he pile production process .

.

.
.

Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A tool for forming a hole in macroporous compressible soil, comprising: a body having a sizing part, said body adapted for connection to a boring rod and having a tool tip, coaxial body portions radially defined by soil compaction surfaces having radii decreasing stepwise from the sizing part to the tool tip so that a step is formed between adjacent portions, the soil compacting sur-face of each body portion being a cylindrical surface defined by a generatrix of a predetermined length extending parallel to the axis of the tool and confined by two paral-lel helical lines having an identical helix angle and transition portions, said transition portions being radial-ly defined by a cylindrical surface conjugating the surfaces of axially adjacent body portions, the generatrix of the surface of the transition portions having a length equal to the length of the generatrix of the cylindrical surface of said coaxial body portions to provide a smooth transition from the surface of the body portion of a larger radius to the surface of an adjacent portion of a smaller radius.

2. A tool for forming a hole in macroporous com-pressible soil, comprising: a body having a sizing part, said body adapted for connection to a boring rod and having a tool tip, coaxial body portions radially defined by cyl-indrical compacting surfaces having radii decreasing step-wise from the sizing part to the tool tip so that a step is formed between adjacent portions, the cylindrical surfaces adjacent the steps being provided with ridge members disposed along the helical line, the radial extent of the ridge members not exceeding the radial extent of the step of an adjacent body portion having a larger radius, the soil compacting surface of each body portion being a cyl-indrical surface defined by a generatrix of a predetermined length extending parallel to the axis of the tool and con-fined by two parallel helical lines having an identical helix angle and transition portions, said transition portions being radially defined by a cylindrical surface conjugating the surfaces of axially adjacent body portions, the genera-trix of the surface of the transition portions having a length equal to the length. of the generatrix of the cyl-indrical surface of said coaxial body portions and being parallel to the axis of the tool and uniformly approaching said axis to provide a smooth transition from the surface of a body portion of a larger radius to the surface of an adjacent portion of a smaller radius.

3. A tool for forming a hole in macroporous compressible soil, comprising: a body having a sizing part, said body adapted for connection to a boring rod and having a tool tip, coaxial body portions radially defined by cylindrical compacting surfaces having radii decreasing stepwise from the sizing part to the tool tip so that a step is formed between adjacent portions, the soil com-pacting surface of each body portion being a cylindrical surface defined by a generatrix of a predetermined length extending parallel to the axis of the tool and confined by two parallel helical lines having an identical helix angle and transition portions, said transition portions being a roller having end faces and being rotatable about an axis disposed at an angle to the tool axis, said angle being equal to the helix angle of the helical lines confining the cylindrical surfaces of adjacent body portions so that each helical line extends in the plane of a respective end face roller to provide a smooth transition from the surface of a body portion of a larger radius to the surface of an adjacent body portion of a smaller radius.

4. A tool as claimed in claim 1 having an axial cavity tapering toward the tip and a vibrator having a rotary drive, said vibrator arranged in said cavity to cause lateral vibration, a shaft coupled with the drive and extending substantially coaxially with the axis of the tool, unbalanced members mounted on the shaft along the length thereof, said unbalanced members having different weights decreasing in the direction of the taper of the cavity in the body, supports for the shaft being provided between the unbalanced members, whereby the vibratory effect of each of the unbalanced members on the soil is localized.

5. A tool for forming a hole in macroporous compressible soil, comprising: a body having a sizing part, said body adapted for connection to a boring rod and having a tool tip, first coaxial body portions having radii decreasing stepwise from the sizing part to the tip and second coaxial body portions having radii decreasing stepwise from the sizing part to the point for attachment of the boring rod, the portions having stepwise decreasing radii being radially confined by cylindrical surfaces defined by a generatrix of a predetermined length extending parallel to the axis of the tool and confined by two parallel helical lines having an identical helix angle, said surfaces being successively conjugated with one another by transition portions having a cylindrical surface whose generatrix is parallel to the axis of the tool and uniformly approaches said axis to provide a smooth transi-tion from the surface of the body portion of a larger radius to the surface of an adjacent portion of a smaller radius.

6. A tool as claimed in claim 5, comprising:
a further body coaxial with said body, said further body having an axial bore for passage of a hardenable medium, a sizing part and coaxial body portions having radii decreasing stepwise from the sizing part, the coaxial body portions being radially defined by cylindrical surfaces defined by a genertrix of a predetermined length extending parallel to the axis of the tool and confined by two heli-cal lines having an identical helix angle, said surfaces being successively conjugated with one another by transi-tion portions having a cylindrical surface whose genera-trix is parallel to the axis of the tool and uniformly approaches said axis to provide a smooth transition from the surface of a portion of a larger radius to the surface of an adjacent portion of a smaller radius, said further body being rigidly coupled at one end with said body of the tool by a hollow reducing member having openings which communicate with the hole for the passage of a hardenable fluid into the hole, and having at the other end a means for connection to a tubular boring rod through which the hardenable fluid flows into the hollow reducing member and further through the openings in the reducing member into the hole.

7. A tool for forming a pile in macroporous compressible soil, comprising: a body having a sizing part, said body adapted for connection to a boring rod and having a tool tip, said body comprising at least two separate coaxial body portions wherein at least one of said coaxial body portions is radially defined by soil compacting sur-faces having radii decreasing stepwise from said sizing part to the tool tip, a first of said at least two portions having an axial bore and being attached at the end having a larger radius, an end face of the shape of a step between adjacent body portions and a second of at least two coaxial body portions carrying the tip and being adapted for axial movement into the axial bore of a coaxial body portion, said second of at least two coaxial body portions having an axial bore and openings whereby a hardenable fluid supplied through said tubular boring rod can be discharged in a hole formed by the tool to form a pile, the walls of the axial bore of said first body portion having axial grooves and said second body portion haying projections on the outside thereof which are received in said axial grooves of said first body portion, said projections slide along said grooves so that when said tool is driven into the ground the second body portion is moved into the first body portion and the openings are closed by a part of the first body portion and when the tool is extracted from the hole, the second body portion extends from the first body portion and the openings are uncovered/ whereby the hardenable fluid can flow therefrom to form a molded in-place pile.

8. A tool as claimed in claim 7, comprising a third body portion slidably fitted on the tubular boring rod having a cylindrical surface which serves as a sizing part, said third body portion being provided with a skirt extending toward the first body portion and having an end face identical in shape to the step between the adjacent portions, a radial surface with engaging means being provided at the point where the first part of the body is attached to the boring rod, and the third part of the body being provided with an opposite surface having a corresponding engaging means, whereby the turning of the first and second body portions relative to the third body portion is prevented when the tool is extracted from the hole, the skirt having an axial length sufficient to restrict the discharge zone of the hardenable fluid flowing out of the discharge openings in the second part of the body when the tool is removed from the hole, and the boring rod being provided with a stop to limit the travel of the third part of the body along the boring rod when the tool is driven into the ground, thereby setting the end face of the skirt on a respective helical line.

9. A tool as set forth in claim 1, wherein the adjacent transition portions are displaced in relating to each other along the cylindrical, helix by an angular value not greater than 720°.

10. A method of forming holes in macroporous compressible soil, comprising the steps of driving a tool to the required depth into the soil, supplying a consoli-dating material into the resulting hole and removing the tool and simultaneously pressing the consolidating material into the hole walls.

11. A method as claimed in claim 10, wherein the tool is driven to the required depth into the ground and simultaneously a consolidating material is supplied and pressed into the walls of the resulting hole, whereupon the tool is removed from the hole.

12. A method as claimed in claim 11, wherein the consolidating material is additionally supplied into the hole interior as the tool is removed from the hole, said consolidating material being simultaneously pressed into the hole walls to produce a second consolidating layer on the walls of the hole.