Cơ sở tính toán các thông số cơ bản của máy rung hạ cọc cừ

Nguyin Van Tinh Khoa Co khi Xay dt/ng Trudng Dai hgc XSy dung Tom tat BSi bSo dua m md hinh ca hgc, phuang trinh vi phSn vS Idi giSi cho vipc ha coc cu bing mSy mng.. Bdi bdo ndy trin

ca sd TiNH TOAN CAC THONG S6 CO BAN

CUA MAY RUNG HA COC CLf

PGS.TS Tran Van Tuan ThS Nguyin Van Tinh

Khoa Co khi Xay dt/ng Trudng Dai hgc XSy dung

Tom tat BSi bSo dua m md hinh ca hgc, phuang trinh vi phSn vS Idi giSi cho vipc

ha coc cu bing mSy mng Hudng din dch tinh chgn mdt sd thdng sd chinh cda mSy mng ha cgc cu DSc biet IS tinh do cimg cda Id xo - chi tidt dd hdng cin thay thi tmng quS trinh su dung

Summary: Ttie paper pmsents a mechanical model, drftemntial equations and

nsso/uf/o/JS for piling by vibmtory machines This paper also pmsents instmctions

on how to select a number of pammeters of the vibmtory piling machine and, especially, calculate the hardness of spring which is usually damaged during its use and needs to be mplaced

1 Oat vdn de

Md hinh co hpc md la qud trinh ha cpc

v i n cdn chua di den thda mdn su phu hprp

giira thue tiin vd ly thuyet [3] Bdi bdo ndy

trinh bdy ca sd tinh todn cdc thdng sd ca ban

cda mdy rung ha cpc cir; dde bipt trinh bdy

phuang phdp xdc djnh gid tri dd cd'ng cua d c

Id xo liPn ket ddi vdi loai mdy rung cd liPn k i t

mlm vdi d i u cpc

2 MP hinh c a hoc ha coc CUP

Mpt trong cae md hinh dpng lue hpe

dan gian, mp ta khd day dd d c dpc thu cda

qud trinh hg cpc bing rung dpng dupc trinh

bdy d hinh 1

Coi epc (1) Id tuyet ddi cd'ng vd bj kep

chpt bdi gudc ma sat (2) vd gude dupc gdn

vdi Id xo (3); giira cpc vd gudc ma sdt d lire

ma sdt khP tde dung, gid tri tuypt ddi cda luc

ma sdt dd bdng O^ luc ndy nhim md hinh

hod lire d n bPn d a thdn cpc; luc d n d i u

coc duoc mP hinh hda bdng Id xo (4) vd phao

(5), giOa phao vd ndn d l t tdn tai lire ma sPt d

gid tri tuypt ddi bing O' Hinh l b nhin Id IrPn

Hinh 1 a) Md hinh ddng luc ha cgc bSng mng ddng; b) Sad6 djch chuyin eua cgc dudi tSc dung cua It/c kich mng dtiu hoS F(t)

20 TAP CHf KHOA HOC C O N G N G H 6 XAY DUNG Sd06- 12/2009

xudng Id sa dd phd cda djeh ehuyin cpc dudi tac dung lue kich rung dieu hod F(t); dd thj d

giQ'a bilu diln su phu thupc giu'a luc d n Q° vd djch chuyen eua cpc (x); dd thj d cudi bieu

diln su phy thudc giQ'a luc d n Ql vd dich chuyen cua cpc (x)

Ld xo 4 chi chju ndn, cho nPn trPn cdc dd thj chi d djch ehuyen cua cpc d'ng vdi khoang

thdi gian t,-t2 vd XyU khi md lue d n d mui bdng 0

MP hinh trdn, tuy dd r l t dan gian song vipc giai nd lai rat phice tap; mdt khde vipc giai

gdp khd khdn cdn do tinh chit khdng ddng nhit cda nen dat Theo [3], de giai bdi todn xdc djnh

d c thdng sd ea ban cda mdy rung cd the sd' dyng phirang phdp tuyen tinh hda phuang trinh vi

phdn ehuyin dpng cda may cung cpc vd dp dyng gia thuyet eong suit Idn nhat khi hp epc

3 Phuvrng trinh vi phan vd Id'i gldl

Td' phuang phdp tuyen tinh hod phuang trinh vi phdn ehuyen ddng cda mdy eung epc,

theo [3] cd t h i vilt:

nix-i-bx-i-cx = mor(»^cos(Bt = F3COscot

trong dd: x Id tpa dp eua epe so vdi vj tri edn bing ddng khi ha cpc; m Id khdi lucng dao dpng

cda cpc vd cdc phin Id dao dpng kPm theo; t IP thdi gian; b Id giam chin quy ddi cua dat vd ca

hp mdy - cpc; e Id dp cirng quy ddi eua dat vd hp mdy - cpc duae xde djnh nhd g i i thuyet cdng

suit Idn nhit khi hg cpc; co Id t i n sd gde eua lye gPy rung; m^r Id mo men qudn tinh ITnh gdy

rung

Nghipm cua phuang trinh vi phdn (1) nhu sau:

X = XjCOsCco t - i p )

X = -coXjSin((nt-(p) ,„,

2hco , ,

trong dP: (p = arctg —z 5-; b = 2hm ;

co„ - c o

F, cos 9

(3)

sin cp = ; «„ = /— Id tan sd dao ddng riPng eua hp mdy - epe

J ( c o J - c o ^ ) ' + 4 h V ^ ' "

Cdng d n thilt de duy tri dao ddng trong mpt chu ky dupc xdc djnh nhu sau:

A = J F(t)xdt =-FJXJCO J cos CO t.sin(co t-cp)dt

0 0

A = 7iF,XjSin(p (4) Cdng suit trung binh do ddng ca eung d p cho he rung dupe tinh nhu sau:

N,b= —= A ; ^ = - F x , cosincp (5)

I itt I

trong dd: T = — Id ehu ky dao dpng Thay x Id' d n g Ihipc (3) vdo bieu thu'c (5) ta cd:

CO

TAP CHf KHOA HOC C O N G N G H E XAY DUNG Sd06 -12/2009 21

^ j ^ _ F.cDsin2(p (6) 4m(coJ-CB^)

Xet bieu thu'c (6) vd phai dat eye tri neu:

sin2cp = l khi cOo >co (7) hode: sin 2cp = - 1 khi cOo < co (8)

Trudng hpp (7) xay ra khi <p = 7r/4; trudng hp'p (8) xult hipn khi cp = 37:/4 Ca hai

trudng hpp gid tri ldn nhit cua cdng suit trung binh dupc xae djnh nhu sau:

N K = i - * r ( ^ '

4m|(Bo-co I

Ap dyng gia thuyet edng suit Idn nhit cda mdy khi hg cpc, thay bieu thu-c xdc djnh coj

vdo (9) d n g suit duge tinh theo bilu thu'c sau:

Jm^rfco' 4\c-mco

Ndn d l t ddng nhit, khi hg epe d dp sdu nhit se cd lyc can Idn nhit Idc dd dpng ca phdt

cdng suit Idn nhit tinh theo (10)

4 Tinh chpn cdc thdng sd chinh cua may rung h? cpc

Tu- ly thuyet vd qua thyc nghipm, tdc g i i [3] dd de xult cdch tinh ehpn sa bp ede thPng so

chinh cua mdy rung hg epc nhu sau:

-" Trudc hit ehpn sa bp: x,; co phu hpp ddi vdi tu'ng logi nen dat c i n hg epc, cy vd tinh

tdng khdi lypng mng bing khdi lypng cpc vd khdi lupng mdy rung (m = mc-*- mmr)

+ Tilp den tinh todn theo cdc cdng thdc sau:

- Md men qudn tinh tinh :

mor = l,06mx3 j.,.,j

- T i n sd rung: x , =coXj (12)

- Cdng suit rung tinh chpn sa bp theo ePng thu'c sau :

x '

N = 0,374.m— (13)

5 Tinh dp cu>ng Id xo lien k i t giira dpng c a vd cpc

Tordng hp'p dpng ea ndi cd'ng vdi gia trpng dau epc vP vdi cpc (hinh 2.a) thi cdc cdng

thuc tu (11) cho den (13) Id du de xdc djnh vd tinh todn cdc thPng sd ea ban eda mdy nhu: co,

Xa, m(,r, X,, N Cu t h i , ty khao sdt vd kinh nghipm thyc tiPn ddi vdi nen d l t cy the, chpn trydc

bipn dp rung nhd nhit cda epc Xa vd co, tiep den nhd cdng thufc (11) tinh m^r vd cdng thuc

(13) tinh edng suit ddng ea N

Trudng hpp dpng ca ndi mem vdi cpc (hinh 2b) thi vipc tinh todn thiet k l Id xo dya theo

md hinh nguypn ly vd gia thuyet cdng suit trung binh ldn nhat khi hg cpc dd trinh bdy cd Ihl

xdy dyng md hinh nguyPn ly eda mdy hg cpc nhu hinh 3

22 TAP CHf KHOA HOC CONG N G H $ XAY DUNG Sd06 -12/2009

Hinh 3 Id sa dd tinh Id xo mdy rung hg cpc Cpc vd cdc phin ty dao dpng cdng cd khdi lup'ng mi, bidn dp dao dpng x,; dp ctpng quy ddn cua cpc vd d l t c = c, dupc xde djnh theo ePng thu'c (10)

Hinh 2 Sa di du tao mSy mng ha cgc

a MSy mng nii cUng; b MSy mng nii mim 1: KhPi Ipch tSm; 2: Ding ca; 3: Bp truyin xich; 4: Kgp cu; 5: Di mSy; 6: Ld;

y//^////^^////////////////////^

^ W ^ m

Hinh 3 Sa di tinh Id xo mSy mng ha cgc

C i n xdc djnh dp cd'ng vd dp ben cda IP xo liPn k i t giu-a khdi luang m2 (khdi lupng cdg dpng ca, bp dd ddng ca vd cdc ehi tilt ldp kdm theo) vdi m,; giim chin b, cug Id xo Id nhd cho ndn cd t h i bd qua bi= 0; giam chin cda hp quy d i n cpc vd dat b2 lay gid In b2 = 0 vl khi tinh todn hp Idm vipc ngodi vdng cdng hydng nPn vai trP cua giam chin trong sa do chi mang y nghla vpt ly - hp se dao ddng t i t d i n Khi bd qua b, phuang trinh vi phdn chuyen dpng eda sa

dd hinh 3 dup'c vilt nhu sgu:

m|X, -(-(c, -i-c,)X| - c , x , =m5rco*coscot

Nghidm cda (14) dupc tim dudi dgng:

TAP CHf KHOA HOC C O N G N G H $ XAY DUNG Sd06-12/2009 23

X| = A, coscot

X, =A2 coscot Liy dgo hdm cdg (15) the vdo (14), bien ddi tg d :

(c, -m,co ) 2 »

X, = ^ —^m^rco coscot

X, =-^mnrco^cosfot

- A

A = (c, -I- c, - m,co-Xc, - m^co-)-Cj Cdng suit mng dupe ehpn sa bp theo (13) Id N= 0,374.m, — = 0,374 m,.co'.x;

Cdng suit dpng ca lya chpn Id: Nac= k.N

O l dam blo dd d n g suit k 2 1 Thay (19) vdo (10) ta d :

(m(,r.co)^ , 4k.(0,374.m,.xJ)

Tilp tyc thay (11) vdo (20) ta cd:

, 2

c, = a.m CO

trong dd: a = I -i-0,75

Tif (16) vd (18) la xdc djnh dupe Ca nhy sau :

_ - , , 2

-.mj.co -c,m,co" -i-m,m2C0

C2 =

(15)

(16)

(17) (18)

(19)

(20)

(21)

(22) m„r.co

-c, -i-m,co" -t-m,co"

, , B.m.m, Thay (21), (11) vdo (22) roi rut gpn ta cd: c, = _ " ca' pm, -i-m

trong dd: p = 2 , 0 6 - a = 1.06—-—

k

T h i bilu thd'c xdc dinh c, vd C2 vdo (18):

l,06.m.m? 4

A = •—^co

(23)

(24)

Pm, -(-m2 Thay (23) vd (24) vdo bieu thd'c xdc djnh biPn dp dao dpng cua dpng ea A,^ c,

—=^m|,rco"

t g d g i d t r i : A , = M l _ 0 : Z O i

Nhy vpy, de giam biPn dp dao dpng cda dpng ea ta ed hai d c h :

Thu nhit: Dya vdo bieu thy (19) vd (25) de ehpn hp sd k vd d n g g i n gid tri 0,709 thi bidn dp dao dPng cda dpng ca d n g nhd;

Thir hai; Tdng khdi lucyng phin bp dd dpng ca

24 TAP CHf KHOA HOC C O N G N G H E XAY DUNG Sd06-12/2009

6 Vi dg tinh todn

Dya vdo dpc tinh k<j thuPt cda mdy mng Bnn-2A do Nga ehe tgo, tinh dp cd'ng IP xo Id chi tilt d l hdng d n thay the khi hg cu' logi W500A - 1000 d khdi luang 8200 kg

Thdng sd eho trydc Id:

Khdi lyp'ng dpng ca vd d l m2 = 250 kg; m ,= m^ -i-1500 = 8200 -i-1500 = 9700kg, trong dd

1500 kg Id khdi lup'ng gdn chpt trPn dau cpc; m^r = lOkg.m

Tinh todn ea ban:

Bidn dp dgo ddng Idn nhit cug cu' theo d n g thd'c (11) Id:

X, = X = - 10

1,06m, 1,06x9700 Cdng suit c i n thiet, tinh theo (13) Id:

« 0,00097m

N = 0 , 3 7 4 m , ^ = 0,374m,.co'x,'N= 0,374.9700.(152)^.0,00097'«ll987w

Chpn dpng ca cd cdng suit 13 KW; tdc dp n =1450 v/ph; Khi dd k = 13

11,987

1,085 Suy rg a = 1,69 ; P = 0,37

-TA A A t n 3,14.1450 , , , ^,

T i n s d g d c : co = — = -^ = 152rad/s

30 30 Thgy cdc gid In cdg co vd a vdo (21) tg tinh duce dp cu-ng quy d i n c, = 380.10^N/m Tuang t y nhu vpy, thgy cdc gid In cdg m,, mj, co, k, mor vd p vdo (23), (24) vd (25):

A = - 8 , 9 1 0 ' ^

C 2 = 5 , 4 1 0 ' N / m

A 2 = 0,014 m

MPI sd dd thj khio sdt ddi vdi C2 vd A2

30

2S

20 ( 1 1 5 )

11.6

' A2(mzti)

/1.13 I S 2 2 S 3 3 S

lc

4

Hinh 4 Dp thj cda hSm Az=f(k) Nhpn xit: H$ sd k d n g Idn tuang d-ng vdi dpng ca d d n g suit cdng Idn fhl biPn dp dao dpng

cua dpng ca vd d l cdng Idn

TAP CHf KHOA HOC C O N G NGHg XAY DUNG SO 06-12/2009 25

ID

5

t o o 1000

Hinh 5 Dd thj cua hSm A2 = f(m2) NhSn xdt BiPn dp dao dpng cda de vd dpng ca giam nhanh khi tdng khdi lup-ng m2 (tu 14mm a

250kg xudng edn 7mm d 500kg)

5.S AO

i.*S AO

(1;S.4 >10

S.35 ld.0

c2(Nfm)

k

4

Hinh 6 Dd thj cda hSm C2 = f(k) NhSn xdt: C2 khdng phy thupc nhilu vPo k

J

2)4.o'

l S J i o '

iAo'

5>10*

2 6 ) 1 0 '

• c2(N/m)

n (v/ph)

——^— >

1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0

Hinh 7 Dd thj cda hSm C2 = f(n) NhSn xit: Tdc dp quay cda dpng ca edng Idn thi dp cd'ng cua Id xo d n g Idn Do dd khPng nPn

chpn n qud Idn

26 TAP CHf KHOA HOC C O N G N G H 6 XAY DUNG sd06 -12/2009

1 8 > 1 0

1 6 > 1 0

1 4 > 1 0

1 2 > 1 0

L>i.O

S>10 6>i0

4 4>10 rn2(kg)

200 4 0 0 £ 0 0 8 0 0 1 0 0 0

Hinh 8 Dp thj eda hSm Cz = ftm^) NhPn xit: C2 g i n nhu ty ip thupn vdi m2 do dd khdng nPn tdng mjquP ldn

7 K i t luan

Bdi bdo dd dua ra md hinh ea hpc, phyang trinh vi phdn vd ldi giai eho viPe hg epe cd" bdng mdy rung

Hudng d i n edeh finh chpn mpt sd thPng sd ehinh eua mdy rung hg cpc ed' Ope bipt Id tinh dp cd'ng cua Id xo - ehi l i l t de hdng d n thay the trong qud trinh sd- dung

Bdi bdo Id tdi lipu tham khao r l t bd Ich cho vipe khai thdc, su- dyng, Hnh todn, thilt k l vd

e h l tgo mdy rung hg cpc cd

Tdi li^u tham khdo

1 T r i n Vdn Tuin, Luu Od-c Thgch, Phan Vdn Thio Ca sd ly thuyit tinh toSn cdng suit cho cSc ea ciu gSy rung Tuyin tPp cdng trinh khoa hpc Sd 2-1995, trang 230 -238

2 T r i n Vdn Tuin Ca sd ky thuSt rung trong xSy dung vS sSn xuit vpt li$u xSy di/ng Nhd xult

ban Xdy dyng - 2005

3 BaywaH B A., 1/1.H BbixoBCKnii Bu6pau,uoHHbie uaiuuHbi u npou,eccbi a empoumenbcmee

MocKBa, 1977

4 M.M CwopoflMHOBa Cneu,uanbHbie uawuHbi u ododypoeanusi dnn ycmpoucmea ocHoeanuu (pynbdai^eHmoe MoeKBa,1972

TAP CHf KHOA HOC C O N G N G H E X A Y DUNG Sd06-12/2009 27