VE MAT DAT NAM NGANG QUY \J6C

(1)

[iMm Bim^'bd

DlfeN B A N KHOfl HQC - C6Na NGH|:

::CACHQUYDOi

MAT DAT KHONG NAM NGANG

VE MAT DAT NAM NGANG QUY \J6C

KHI TINH COC CHIU LlJC NGANG

L Gidfl T H i l U CHUNG

1.1 Trong thtfc id thifi't kfi' ta ri't thtfdng gap mdng cpc cd cic cpc ddng qua mat dat khfing nim ngang.

Hinh vg 1 bidu didn mat cil didn hinh cua mdt mdng cpc gdm cic cpc ddng thing dtfng (a = 0) vi ddng xidn (a # 0) qua mat dit nSlm ngang (p = 0) vi nghifing (|3 # 0) ki hieu ABCDEF. Didm B vi D dtfdc gpi li didm chuydn dd'c diy cdn C vi E - didm chuydn dd'c dinh. Cpc Cl ddng qua mat da't n^m ngang AB, cich xa didm chuyen dd'c B, cd thd xem mat di't thtfc nim ngang hoin loan. Cpc C8 nim trfin doan nghifing P2. cich xa didm chuydn dfi'c D vi E, phai dtfdc xfit vdi mat da't thtfc nghifing ^2- Cic cpc C2 vi C6 ddng qua mat dit khdng nim ngang lai gin didm chuydn ddc diy B vi D; Itfdng ttf viy, cpc C5 vi C9 lin cin didm chuydn dd'c dinh C vi E cing khdng thd bd qua inh htfdng hinh dang nghifing cia mil di't thtfc.

Dd'i vdi cic cpc xifin: C4, CIO vi CU ta cung cd thd phin tich nhtf di lim vdi cic cpc ddng thing dffng.

* Ts. PHAN DUNG Trong khi dd cic phtfdng phip tinh toin cpc chiu life ngang kd ca TCXD 205: 1998 ddu dtfdc xiy dtfng dtfa trfin gia dinh mat da't hoin toin nam ngang. Vl viy, de cd thd ip dung cic cfing thffc tinh cpc chiu ltfc ngang, vific dlu lifin la cin phai lim ldi giai cua bai loin cpc chiu ltfc ngang trong didu kien mat di't khfing nim ngang.

1.2 Tdm lit mfit sd nfit ve hifin trang cich xfit mil dit khfing nim ngang khi tinh toin cpc chiu ltfc ngang.

Theo cic tai lifiu tham khao cd dffdc thi viec xfit inh htfdng cua mat dit khfing nSm ngang cd thd chia thinh 3 nhdm:

1- Nhdm thtf nhi't [4], [5] dffa trfin kinh nghiem, ngffdi la thay mat da't nghifing bing mfit mat di't nim ngang gia dinh cd vi tri d giffa khoing cich tff dtfdng chuIn de'n giao didm cua dtfdng lim cpc vdi mat nghieng (Hinh 2). Tifiu chuIn OCDl cua Nhil Ban tfng dung cich niy vio khuyfi'n nghi ding cho mat dat ddc vi B < 20m

2- Nhdm thtf hai: Ding hfi sfi' chidt giam sffc khing cua da't 1 de didu chinh stfc khing cua dit ndn xung quanh cpc chiu Iffc ngang.

sg 5*6 • NSm 2012

55

(2)

\Biin^b6

Dilm B A N KHOfl HQC - CdNG NGHt

Phlabe»(B) Mil dat tliuc

Cl C2 a C4 05 C6 07 08 09 OlO CII Hinh 1 : M?t cit ngang mdng cpc vdri m?t ddt khdng nim ngang

3 M a t dait thyc

M j t dSt quy d6i

0,5h3_ J

0^5 h3 Duong chu^ji

Hinh 2: Cich xac djnh nijt dat nim ngang quy ir6c theo OCDI-2000 a. Cdng thffc cia Reese (3) :

- Sd dd coc 1 vi cpc 3 hinh 2, khi Itfc ngang htfdng ra phia ntfdc, la cd:

Khi l\Sc ngang htfdng v i o phia bd : cos^

1 = ^= (2) V2cos(45°+^)

b. Cdng thiJc ciia Bowles [2]:

- Sd dd cpc 1 vi cpc 3 hinh 2, vdi di't rdi:

1 = ^ (3)

56

- Vdi di't dinh

(4) Trong cic cdng thffc niy:

X(,„ vi Xtp: cic hfi sd ip Ivfc bi ddng dit rdi khi mil dit nim ngang vi nghifing gdc P;

Eho vi Eb&: cic ip life bi dong cia dit dinh khi mil di't nim ngang vi nghifing gdc

p.

3- Nhdm thff ba: Ding mat dit quy ddi dtfa trfin ly tbuyfi'l ip ltfc di't. Khoing cich ttt giao didm cia tim cpc tdi mil di't nghifing sg 5*6 • NSm 2012

(3)

Bien^bd

D I £ N B A N KHOfl HQC - CdNG NGH$

dfi'n vi tri mil di't nim ngang quy ddi dtfdc gpi li chidu cao quy ddi: hqd. Theo htfdng niy li nhffng cdng thffc nhtftrong22TCN 207-92 vi di dtfdc lim rd trong [8].

° Sd dd cpc 1 vi 3 hinh 2, khi ltfc ngang htfdng ra phia ntfdc:

° Khi ltfc ngang htfdng vio phia bd:

*..=*..!-

(5)

(6) Trong dd:

A„j: chidu siu ngim quy tfdc kd ttt mil di't quy ddi cd xfit inh htfdng cia gii tri ltfc ngang cua cpc trong didu kifin tdng quit: di't cd gdc ma sit trong vi ltfc dinh.

m^^Xte- X^f, (8) Xco vi Xc5 : cic hfi sd ip ltfc dat chu dfing

khi mat di't nim ngang vi nghifing gdc p.

1.2 Mfit sd nhin xfit

Phin tich cic cich xfit mat di't nghieng khi tinh cpc chju ltfc ngang nhtf trfin cd the nil ra mfit sd nfit sau:

1. Da cd nhidu cich khic nhau dd xfit mat dit nghifing khi tinh cpc chiu ltfc ngang nhtfng cd did quy vd hai htfdng:

- Htfdng kinh nghifim chi ydu xfit mfit cich kinh nghifim gdc nghifing cia mil dit mi cpc ddng qua.

- Htfdng dd ra cd cdng thtfc tinh toin chffa khdng chi gdc nghifing mat dat ma cfin chtfa ci tinh chit vit IS - cd hpc dat.

2. vd cich giii quyfi't cu thd bii tcin dtfdc dat ra ttt cic phtfdng phip da cd thi ta lai cd the quy vd hai bien phip:

- Bifin phip didu chinh sffc khing cua he cpc - dit bing hfi sd thtta sd T|. Nfi'u mil dit nghieng cd tic dung lim ling sffc khing cia hd thi 11 > 1; ngtfdc lai, lim giim sffc khing cia hfi thi 11 < 1.

sg 5*6 • NSm 2012

- Bifin phip didu chinh chidu dii tinh toin khi chiu ufi'n cia cpc bing cich quy ddi mat di'l nghifing vd mil dit nim ngang dtfdc gpi li mil di't quy ddi hay mil di't quy tfdc phu thufic vio chidu cao quy ddi: ftqd. Khi mat dit nghifing cd tic dung lim ling sffc khing cua hfi thi mil di'l quy ddi nim cao hdn mil di't nghifing tai vi tri tim cpc, ki hifiu /j^^ ; ngtfdc lai, lim giim stfc khing cia hd thi mil di't quy ddi nim thi'p hdn vi k! hieu li: A,j.

Khi mat di't nghifing cd tic dung lim ting stfc khing cda hfi thi chidu dii chiu ufi'n ciia coc (xic dinh nhd [6]) theo bifin phip ding r| ldn hdn bifin phip ddng /iqd. Nd'u mat di't nghifing cd tic dung lim giim stfc de khing c i a he thi nhin dtfdc kfi't qui ngtfdc lai. Tuy nhifin qua mdt so' vi du hing so' thi dfi chfinh cua chiing khfing ldn, khoing 1-f 5%.

- Cung phai thtta nhin ring bifin phap ding mat di't quy ddi vdi /iqd li Mdng minh vi ddn giin trong tinh toin coc chiu ltfc ngang.

3.Cic phtfdng phip hifin cd chi mdi giii quyfi't trtfdng hdp mat da't nghieng P, chtfa dip tfng dtfdc cic bii toin nfiu trfin hinh 1, li nhffng trtfdng hdp r^t thtfdng gap trong thtfc td thifi't kd.

4. Nhtf da nfiu trong [8], ban chd cua cac cfing thtfc (5) vi (6) cia 22TCN 207-92 li d chd chi ding khi gdc nghifing P nhfi hdn gdc ma sit trong cia dat. Didu niy cd the khfing phii hdp vdi di't dinh.

Tff nhffng nhin xfit nfiu trfin, muc tifiu ciia bii bio niy ii kifi'n nghi mfit cich xfit mil di't thffc td nghifing theo hffdng ding chidu cao quy ddi, Aqd d^ giai quyet ti't ca cic bii toin dat ra vdi dit rdi va di't cd ltfc dinh dtfa trfin phtfdng phip luin khoa hpc va chit che se dtfdc Irlnh biy tifi'p sau day.

n . Phtfdng phap luin

2.1 Dtfdng mat di't khfing nim ngang mi

57

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Bieit'bd

DI£N BAN KHOA HQC - C 6 N G NGHf cpc ddng qua cd ci'u hinh phffc lap dtfdc quy di't li dn dinh, khdng thay ddi trong sudt qui vd bifi'n dang cd bin: nim ngang, nghifing Irlnh cpc chju ltfc ngang.

(trfin, dtfdi), nffa nghifing (trfin, dtfdi) vi nffa 2.2 Cic bii loin dtfdc xfit ddi vdi cpc ngang (trfin, dtfdi) bidu thi trfin hinh 4 nhtf da ddng thing dtfng (o = 0) cdn mil dit nghifing nfiu trcng [7]. ^ ^^,1 phtfdng nim ngang (P # 0) vdi cic ci'ii

Hinh dang vi kich thtfdc cia dtfdng mil a> « = 0

j*»»*j*»»» p — U

&WWWMWW*:

a = O

p = 0

hinh khic nhau (nhtf 6 2.1) bidu thj trfin hinh 3:

p = 0

BT m BT_rv

a = 0 a = 0

= 0

BT_ V BT_ VI Hinh 3. Cac bii loan trong tnrdng hpp cpc dfing thing dung (a = 0)

58

sg 5*6 • NSm 2012

(5)

Bi^It:1ld

D i f o l B A N KHOfl HOC - C d N G N G H $ 1. B i i t o i n 1 (hinh 3a): a = P = 0 l i b i i

t o i n chu^n.

2. B i i t o i n II (hinh 3b): a = 0, p± i O l i b i i l o i n cd ban

3. Anh htfdng c i a didm chuydn dfi'c d i y A dfi'n sff l i m vific c i a cpc dffdc xfit bdi:

3a./ B i i t o i n III (hinh 3c): o = 0, m i l di't cd didm chuydn dfi'c d i y cdn cpc ddng phia trii A, trfin doan P = 0.

3b./ B i i t o i n IV (hinh 3d): a = 0, m i l di'l cd didm chuydn dd'c d i y cdn cpc ddng phia phai A, trdn doan P ^ 0.

4. Anh hffdng c i a didm chuydn dfi'c dinh A dfi'n sff l i m vific c i a cpc dffdc xfit bdi:

4a./ B i i l o i n V (hinh 3e): a = 0, m i t di't cd didm chuydn dfi'c dinh cdn cpc ddng phia trii A, trfin doan P i 0.

4b./ B i i t o i n VI (hinh 31): a = 0, mat da't cd didm chuydn dfi'c dinh cdn cpc ddng phia phai A, trfin doan P = 0.

2.3 Dd'i vdi cpc ddng xifin a * 0:

l.Vdi gdc nghifing a nhd cd thd xem nhff cpc ddng thing dtfng nfi'u chi'p n h i n l i p luin trong [6].

2. Vdi gdc nghifinga ldn, la chia thinh hai trffdng hdp:

2a./ Cpc ddng xifin a :* 0, P = 0, 2b./ Cpc ddng xifin a ^^ 0, P * 0, Sau dd cd the tfng dung c i c h g i i i quyfi't nhtf cpc ddng t h i n g dtfng nfiu cr muc 2.2.

2.4 Nhieu t i i lifiu chuyfin k h i o vd mdng cpc trfin thd gidi da thd'ng nha'l thtta nhan rang chi cd mpt idp da't n i o dd d phia trfin mat, nam xung quanh cpc, tham gia cd tinh chi't quydt dinh v i o stf l i m vific cua cpc chiu tec ngang. Chidu d i y Idp d i t nhtf thd dtfdc gpi l i chidu s i u anh htfdng. ky hifiu: h,t,. Dai Itfdng n i y da dtfdc ndi kT trong [9] cdn d day chi xin nfiu tdm l i t . Hai trong ba cfing thffc linh chidu sau i n h htfdng chi phu thufic v i o dtfdng kinh cpc, d(m)', dd l i :

Aah = 2(d+l) (9) Aah - 3,5d+ 1,5 (10) Cfing thffc thff ba vifi't theo thuit ngff cua

TCXD 205: 1998, phu thufic v i o hfi sd bifi'n dang a ( m - l ) , cd dang:

' . . = ^ (11) a

P h i n tich, so s i n h kfi't q u i tinh t o i n lheo ba cfing thtfc trfin cho t h i y :

* Trong c i n g mfit didu kifin, c i c cfing thffc (9), (10) v i (11) cho c i c kfi't q u i k h i c nhau nhtfng ri't "hfii tu", dfi chfinh k h i c giffa c h i n g ri't bfi.

+ K h i i nifim chidu sau i n h htfdng /igh v i g i i tri c i a nd thu dtfdc tff c i c cfing thffc trfin p h i n i n h d i n g b i n chi't v i t ly cua b i i toin cpc chiu ltfc ngang.

VI nhffng Ifi dd nfin d day, chidu s i u anh htfdng se dtfdc sff dung nhtf l i chidu cao cua

"ttfdng c h i n " cd mat di't n^m ngang quy ddi hay ndi mfit c i c h k h i c , /lah la chieu cao cd sd ciia "ttfdng c h i n " dd tifi'n hanh quy ddi.

2.5 Mfit vi'n de quan trpng nffa cung da dffdc c i c n h i dia ky thuat chi'p nhin l i khi cpc chiu ltfc ngang thi t o i n bp khfi'i Itfdng di't n i o dd tifi'p lien phia trtfdc v i phia sau tren m i l bfin cpc, cd chidu cac Agh sfi dat den trang t h i i can b i n g gidi ban chu v i bi dfing phu thufic htfdng c i a ltfc ngang Q t i c dung v i o cpc.

Ndu xem mfit p h l n cpc nhtf l i mfit ttfdng chin tuyfit dfi'i ctfng - t h i n g dffng, bd qua ma s i t ngoii thi g i i tri gdc p h i hoai c i a m i l tnldt chu dpng, 9c v i i p ltfc di'l chu dfing ttfdng ffng, Ec cung nhff gdc p h i hoai ciia mat trtfdt bi dfing, Ob v i i p Iffc di't hi dfing ttfdng tfng, Eb c i a di't dinh cung nhtf da't rdi co thd dtfdc tinh bdi c i c cfing thtfc g i i i tich ddn gian nfiu trong [10] va [7] dfi'i vdi c i c ci'u hinh mat da't k h i c nhau suy Iff hinh 3, dtfdc bidu d i l n d hinh 4.

So 5*6-NSm 2012

59

(6)

Bienibci

D I £ N B A N KHOA HQC - C 6 N G N G H ^

a- MJt dat nim ngang b- Mit dit nghifing tren c- Mat dit nghieng duoi d- MJt dit nira nghifing trdn e- Mil dat nira nghieng dtfdi f- Mil dat nira ngang tren g- Mit dit nira ngang dudi

Hinh 4; cic sa do tudng chin vdi d?ng mjt dit nghieng kliic nhau 2.6 Nhtf da phin tich d trfin, giii phip

dtfdc chpn ding li thay thd mil di't thtfc khdng nim ngang bing mdt mil di'l nim ngang quy tfdc cd vi tri dtfdc xic dinh bdi dai Itfdng dtfdc gpi li chidu cao quy ddi, /iqd. Gii tri cua chidu cao quy ddi dtfdc xic dinh dtfa trfin neuvfin ly ttfdng dtfdng sffc khing cia da't Ifin coc.

Chi'p nhin nhffng nfii dung cd ban nfiu trfin ta se xay dffng dtfdc ldi giii bii loin da dtfdc dit ra.

III. Cach quy dd'i m$t di't khfing n^m ngang vd m^t di't nhm ngang quy tfdc :

3.1 Xiy dtfng cfing thtfc tinh chidu cao quy ddi cho bii toin cd bin, BT - II:

1. Trtfdng hdp BT.II - N vi chidu siu quy ddi h'^:

Xfit mfit cpc chiu itfc ngang Q htfdng ra

phia ntfdc cd chidu cao ttf do L„, chidu siu chfin cpc L, mat di't nghifing dtfdi, P" khi linh i p ltfc hi ddng, v i nghifing Udn P' khi tinh i p ltfc chii ddng nhtf d hinh 5.

+ Stfc khing cda di't khi mat da't thffc nghifing:

- Chidu siu linh ip life di't:

l> = h^+h^=OC Ap ltfc di't bi dfing;

Hfi sfif ip Itfc di't hi dfing quy tfdc:

3 =

Ap lUc d^t chu dgng :

60

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Bieu:bd

Dli:N B A N KHOA HOC - CdNG NGH^

Mat dat nam ngang guy viae

JL

Nu(>c

Q_

Bo

Mat dat thuc nghieng

Hinh 5: Sd dd xic dinh chidu siu quy ddi A" trong BT.ii-N.

K..-

^yfc+A^y-l^

^(a)

- He sfi' ip ltfc dat chu dpng quy tfdc:

- Hieu hfi sfi' stfc khing quy tfdc khi mil di'l thffc nghifing:

- Stfc khing cua dat khi mil di't nghifing:

' 2

' Stfc khing cua di't khi quy ddi thinh mat di't nam ngang:

- Chidu siu linh ip ltfc di't:

fhh = OlC - Ap ltfc di't bi dfing:

- He sd ip ltfc di't chii ddng quy tfdc:

sg 5*6-NSm 2012

- Ap ltfc di't chu dpng :

£co = ficoClah)

- Hfi sfi' ip ltfc da't bi dfing quy tfdc:

- Hifiu hfi sfi' stfc khing quy tfdc khi mat dit ngang bing:

K ~ ^ ~ '^co

Stfc khing khi mat dit quy ddi ngang

E,'\M^^.

^(b)

+ Ap dung nguyfin ly ttfdng dtfdng sffc khing dd tim A'^ :

Ddng nhi't (a) vi (b) vi sau mfit sfi'bifi'n ddi ddn gian ta nhin dtfdc:

'''^=*-lJi:^'

⁽¹²⁾

61

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Bieitbd

D I £ N B A N KHOfl HQC - C 6 N G N G H $

2. Trtfdng hdp BT.II - B vi chidu siu quy ddi h j la nfiu c i c kfi't qui tdm tit sau

quy ddl h* diy:

Xfit mfit cpc chiu life ngang Q cd hffdng + Sffc khing cia dit khi mil dit Ihtfc ngtfdc lai, mil di't nghifing trfin p* khi tinh nghifing:

ip ltfc bi dfing vi nghifing dtfdi P" khi tinh i p „ _ J^ (. _ L . 1j

ltfc chddfing nhtf trdn hinh 6. E, - ^rV.-h,,)^, (c) Ttfdng ttf nhtf cich lim ddi vdi chidu siu

Q Nuoc Mat dat nam ngang quy «•(

A=*

Mat dat thuc nghi

K

jOi 0

^

eng

f

c

/>'•*•/

B6

>fp

_{y '}

Lo

L

k"

Hinh 6: Sd dd xic djnh chidu siu quy ddi h\

• Stfc khing cia dit khi mat di't quy ddi Vl cic cfing thffc (12) vi (13), d ci hai vd ngang bing: ddu chffa h^, nfin dd tim gii tri chidu siu quy 1 , J ^ ,., ddi la phii ddng bifin phip lap thep sd dd

khdi bidu didn trfin hinh 7.

Didu kifin dffng lip:

£, =-rhl,k.

Ddng nhit (c) vi (d) vi nhin dtfdc:

hl=h\\-\-^ (13)

3,2 Trinh WS tinh chidu siu quy ddi:

'— , , '100<£%

Trong dd:

e: sai sd' chip nhin (%) m: vdng l i p thtf m.

(14)

62

-Co ^j.fi _ WiTm 9/H2

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BBieui'bd

Dlf:N B A N KHOfl HOC - C 6 N G N G H £

2a) £bo(A.h)

3a) J bo

1,1 ^

4) ? - J. ,!

2") SccP'.h)

3b) I /I m

Hinh 7. So dd khoi xac dinh chidu cao quy ddi h^.

63

(10)

Bieit; bd

D I £ N B A N KHOfl HQC - C6WG WGH$

3.3 Xac djnh chidu siu quy doi co xfit inh htfdng cua diem chuyen ddc diy A den sir lim viec cua cpc chju lyc ngang: BT.IIl va BT.IV

1. Trudng hop BT.II! - B:

Q NuAc Mit dit nim nRaiifi quy uc

h c

Mat dSt thuc h

nghi

i—w

eng c

\9\

0

c

B*

1-0 A-jT Y

s

L

Hinh 8. BT. Ill - B Chieu cao

tudng h = h^-h;.

Kl,

Ap luc chu dpng vdi mit dit Nam ngang: £c„(/i) Nim ngang; E^^iKh)

Ap luc bj dpng vdi mit dit Nila ngang tren p*: E (A) Nam ngang: £,.,(/i„,,)

Hf so sire khing quy udc

h

\,

2. Jmang h(;rp B T . I I l - N :

Hinh 9. BT.IIl-N Chieu cao

tudng A = Aah + h-j

Aal,

Ap lyc bi d p n g vdi mat dat N i m n g a n g : Et„{h) Nim ngang: EUha,)

Ap lyc chil dgng vdi mit dat Nira ngang trdn yS*: E^^, (h) Nim ngang; £c„(/;ah)

H? s6 site khing quy tfdc

Ap

x„

64

sg 5*6-Nam 2012

(11)

Bi^itbd

DifeN B A H K H O A HQC - C d N G NGH$

3 . Tnxdrng h o p B T . I V - B :

Mat dat nam n N'uo'c gang quy \xifc

, , iO,

K

M i t dit th Vi

h

vc ly

0 K ^

;hieng

" ^ V

c

B*

( ^ +

Lo

L

Hinh 10. B T . I V - B Chieu cao

tudng A = Aah - A*,

' ' a h

Ap lire chij ddng vdi mit dit Nira nghieng dudi: E^^(ii) Nim ngang: E^,ih^

Ap lire bi ddng vdi mat dat Nghieng tren: £ (/?) Nim ngang: EiJ,h^

He .so sue khang quy udc

\

x„

4. Trudng hop BT.IV - N:

Lo

L

,

Nirc^

^ ^ \

\ °'

_s

c

jf- \

P*

Q _ Bo-

l a dat thu-c nghiSng

h

Mat dat nSm nj?ang quy vcbz Hinh 11. B T . I V - N

Chieu cao tudnng li = hA+h;,

Kk

Ap lyc bj dpng vdi mit dat Nua nghieng dudi: EY^(h) Nam ngang: fboC'ah)

Ap luc chu ddng vdi mit dat Nghieng Ufin: £.^.(A) Nim ngang: £„(*„,,)

He sp site khang quy udc

h

65

(12)

Bieit^ bd

DI£N BAN KHOA HQC - CdNG NGH$

3.4 Xic djnh chieu sau quy doi co xdt inh hudng cua didm chuyen doc dinh A den SiT lim vi?c cua cpc chju lyc ngang: BT.V vi BT.VI.

1. TruoTighgrpBT.V-B:

Q Nir*

Mit dSt nim nxanK quy

Aa»

Mjt dit thsf A ; h

c u6c

i P"

c nghiSng Ol

0 s

c

B * A

r

>r

Lo

Hinh 12. B T . V - B Chieu cao

ttfdng h = h^- h^j

AaJi

Ap lire chu dgng voi mit dit Nghieng dudi: E^(h) Nim ngang: f^C/iah)

Ap luc bj dpng vdi mit dat Nira nghieng iren: £^^. (A) Nim ngang: £b„(/jai,)

He sd sue khing quy udc

h K<

2. Truong hop B T . V - N : Nudc

Mat dat thuc nghieng

M^t dat nam ngang quy troc

^

Hinh 13. B T . V - N Chifiu cao

tucmg h = h.^+h;,

Aah

Ap lire bi dgng vai m5t dit Nghieng duoi: Et^CQi) Nim ngang: fhoCAab)

Ap lire chu dgng vai mit dit Nira nghifing trfin: £.^, (A) Nim ngang; fcoCAah)

Hd so sire khing quy udc

h h

Sg 5*6-Nam 2012

(13)

Bieit-'bd

DifiN B A N KHOA HQC - CdNG NOHl!

3. Trudng hgp BT.VI - B:

Hinh 14. BT.VI-B Chieu cao

tuoiig h = h^- h*j

Aah

Ap lire chu ddng vdi mat dat Nira ngang dirdri: £c|i(A) Nam ngang: £(„(/!„!,)

Ap lire bj ddng vdi mil dit Nim ngang: £,,„(/)) Nam ngang: Ebc,(hah)

He so sue khang quy udc

h

u

4. Trudng hgp BTVI-N:

Lo Wtfoc

s shiSna ^ ^

T.

^

0 B*

0 ^_.. ^

oT^

TTT

c

,

_A^ ^A

MSt dit nim nsans quy u*c Hinh 15. BTVl-N

Chieu cao tuong h = h^+ h;j

Kh

Ap luc bj ddng voi mat dit NOa ngang dudi: £b|i'(A) Nim ngang: £bi,(Aah)

Ap lyc chu dgng vdi mit dit Nam ngang; EJ^h) Nim ngang: £,.„(/!,!,)

He so sire khang quy u6c

h

Xfl

sg 5*6 • NSm 2012

67

(14)

Henibd Ditn BAN KHOA HOC - CdNG NGH$

^1 =-12,688 W,=-11,8938

^3= 14,3076 Lip phffdng trinh

-12,6681Z" - 11,89387, + 14,3076 = 0 Giii vi chpn / = 0,692(M3

Tinh gii tri ip Iffc chi dfing cia dit dinh lheo cfing thffc (11):

Ec|).= -16,7.'i08T/m

Gii trj hd sd' i p ltfc chQ ddng quy tfdc:

)L.„. =-1,93672 4c. rim X5= 6,24979 4f. Tim A^-j lheo cdng thtfc (12) h\ = 0,314947 m

2- V6ng lap IhiJ 2 thu du'dc k^'l qu5 cu6'i cOng:

h- =0,32174 m

3-Tinh sai so' giffa hai vdng lip lheo (14):

Ah7r = 2,4';i Viy A^-j = 0,322 m.

4.5 Vi du 5

N, vdi sd' lieu vidl) 3, hi = 0,5 m

Giii

l.Vfing lip thff nhi't:

la. Gia dinh mfit gii tri: h'^ = 0,3 m lb. Tinh cic tham s6':

h = 3,lm Theo cic cfing thffc (16):/l=8,649T/m (40): A, = 0,225 T/m

h2 = 2,6 m (40): Aj = 6,084 T/m (16): B= 12,710 T/m (49): BJ = 10,66 T/m I c T l m V [7]:

Tinh cic hfi sd'theo cdng thtfc (43):

02=1,51674 D, = 6,40217 D„= 1,27628

Tinh cic hfi sfi'theo cfing thtfc (53):

D*n= 12,1767 /J*", = 6,40217 /J*„= 11,9362 Lip phtfdng trinh :

2,51674Z=- 1,254857,-3,87229 = 0 Giii vi chpn 7,= 1,51451

Tinh gii tri ip ltfc difl dinh theo cfing thffc (51):

£" =39,1734 T/m

bp

Gii trj he sfi' i p ltfc hi dgng quy tfdc:

Xt3- = 4,52924 Id.-HmX^j. [10]:

Tinh cic he sfi'theo cfing thtfe (12):

W, = -12,00 /V,=-11,8938 NI = 14,3076 Lip phtfdng trinh:

-12,688Z= -11,89387, -I- 14,3076 = 0 Giai vi chpn Z = 0,692043

Tinh gii trj ip ltfc chii dfing cua dat dinh theo cfing thffc (11):

£ „ , = -16,7508 T/m

Gii trj hd sd ip life chi dpng quy tfdc : X,|„=-1,93672

le. Tim X5= 6,46596

if. •nm A^ theo cong thtfc (12):

A, = 0,262435 m 2. Vdng lap thtf hai Sff dung kfi't qua cua btfdc If:

A,j= 0,262435 (m) lim so' lidu xua't phit ta thu dtfdc;

A;, = 0,24742 l ( m ) 3. Vdng lap thtf ba

Sff dung A,,, = 0,262435 (m) d vdng lip thtf hai ta tim dtfoc:

A,„ = 0,241388 (m)

4. Tinh sai s5' gitta hai v6ng lip Ah% = 2,5%

70

RA' Ai.fi - NUm M12

(15)

Bi^u^d

Difcw B A N KHOA H O C - C 6 N G NGHf:

Viy ta c6 the chi'p nhin A;^ = 0,241 (m) V. Kfi't l u i n

5.1 Chidu siu quy ddi mat da't nghifing vdi cic dang khic nhau vd mat nim ngang khi linh cpc chju ltfc ngang dtfdc linh thep cic cfing thffc (12) vi (13).

So vdi cic cfing thffc (5) vi (6) cia [1 ] vi hinh thffc thi ehung cing mfit dang, nhtfng khic biet ding kd d nhffng diem sau :

1-Chidu siu quy ddi dffdc tinh lheo chifiu siu inh hffdng ciia cic Idp di't trfin mat khi cpc chju life ngang. Didu dd phi hdp vdi nguyfin ly quy ddi khi xiy dtfng cic cfing thtfc (12) va (13) vi tao nfin mfit quan didm thfi'ng nhi't trong viec tinh cpc chju ltfc ngang khi xem di'l l i moi trtfdng bifi'n dang din hdi cue bp nhtf tifiu chuan thidt kfi' mdng coc hifin hinh: TCXD 205:1998.

2-Sff dung cic hfi sfi' ap life chii dpng, bi

dfing quy tfdc ciia di't rdi cung nhtf da't dinh khi xic djnh chieu sau quy ddi theo phin Itfdng cia chidu siu anh htfdng cho phfip xet cic hinh dang mat di't khic nhau vi do dd giai dtfdc ta't ci cic bii tcin da dat ra.

5.2 Cd hai cich sff dung cic cdng thffc (12) vi (13) dd xic dinh gii tri chidu siu quy ddi:

1- Cich thff nhi't: Sff dung sffc khing cuS'i ciing cua di'l d mil irtfdc vdi mat sau cpc nhtf la hifiu sfi' giffa ip life bj dpng vi chu dfing cia di't; nghia li trong cdng thffc (12) vi (13) ta ding Xo vi \^

2 - Cich thff hai: nhff Bowles [8] da kifi'n nghi, bd qua ip ltfc chu dfing, chi xfit ap ltfc bi dpng. Khi do, trong cic cfing thtfc (12) vi (13) ta ding Xbo vi X^^ thay vi l^viX^. Bang 1 ghi gii trj chidu siu quy dd^i Aqd tinh theo hai cich nfiu trfin vdi cic sfi' lieu trong muc vi du Bing 1. Chifiu sau quy doi

SIT 1 2 3 4 5 6

Bii loan BT.m-B BT.II-B BT.Il-N BT.IV-N BT.V-B BT.V-N

Gii tri Aqd (m) Dal

Cich thir 1 0,239 0,430 0,602 0,467 0,430 0,431

rdi Cach thii 2

0,221 0,365 0,439 0,346 0,358 0,278

Dit dinh Cich thir 1

0,256 0,327 0,322 0,241 0,282 0,308

Cich thii 2 0,259 0,437 0,529 0,396 0,402 0,359

Ghi chii A*qd A*,d A",d A'qd A*,d fl'ai Ro r^ng la vdi ciing mpt coc thi h lam

cho chilu d^i chiu u6'n ci3a coc ng^n lai n6n de thien vi an toan ta chpn h\ = min.

Nhu" vay each tinh h^^ nen chpn nhu" d bang 2:

Chidu sau quy ddi

K,

A;

Bang 2: Khuydn nghi cich tinh fi^i Dat rdi

Cach thir 1 X

Cach thii 2 X

Dat dinh Cach thiif 1

X

Cach thir 2 X

71

(16)

B i e i i ? b d BI£N BAN KHOA HQC - CANG NGH^

5.3 Ltfc dinh, nhtf da dtfpc nhi'n manh hfi sfi' ip ltfc bj dfing bing nhau khi mil dit ttf trong [7], [10], ri't inh htfdng dfi'n kfi't qui nhifin vi mil dit quy ddi ddu nim ngang.

cufi'i cing, nfin cin dtfpc lffa chpn gii Uj linh Didu dd din dfi'n stf chfinh Ifich giffa Xp vi X<, mfit cich thin trpng.

5.4 Tinh toin cho thi'y, d cic bii toin BT.Ill-N, BT.Vl-B trong trffdng hdp dit rdi.

mfit cich thin trpng. ^^^ „^5 ^^ ^g-^ j ,j j ^ ^^• ^^ ^j-j |,g 5.4 Tinh toin cho thiy, 3 cic bii toin " • ,i

TAI LIPU THAM KHAO

II]. Tifiu chu^n nginh:

Cfing trinh bfi'n cing bidn - Tifiu chu^n thidl kd22 TCN207-92. Bfi Giao thfing vin tii.

Hi Nfii, 1992.

[2]. Bowles J.E:

Foundation Analysis and Desing. Fifth Edition, Mc.Graw - Hill, 1994.

[3]. Lymon C.Reese, William F.Van Impe:

Single P:les and Pile Groups under Lateral. Loading.

AA Balkema/Rotterdam/BrookfiledaOOl.

[4]. OCDI:

Technical Standard and Commentaries for Port and Habour Facilities in Japan, 2002.

[5]. Budin A.J A, Demina F.A:

Cdng trinh bfi'n lidn bd, sd lay chuyfin khio. Nhi xuit bin Xiy Dtfng, Moscow, 1970 ( Tifi'ng Nga).

[6]. K.X.Zavriev, G.X.Shpiro:

Tinh toin mdng siu tru ciu.

Nhi xuat ban Vin tii, Moscow, 1970 (Tifi'ng Nga).

[7). Phan Dung:

"Cic cdng thtfc giii tich dd tinh i p ltfc dit bj dfing Ifin ttfdng chin cd xfit hinh dang khfing nim ngang cia mil dif'.Tap chi Bidn va bd. No. 2012, Hfii Cang - Dtfdng thiy - Thdm luc dja Viet Nam, VAPO, Ha Nfii.

[8]. Phan Dung;

"Lam ro mfit sd vin dd cd bin vd bii toin cpc chju ltfc ngang trpng TCN 207 - 92". Tap ehl Bidn vi bd, No.7-f8/2012, Hdi Cing - Dtfdng thiy - Thdm luc dia Vifit Nam, VAPO, Hi Nfii,tr.l6-27.

[9). Phan Dung:

"Mdt sd vin dd cin hidu ding dd tinh ddng cpc chju lite ngang theo TCXD 205: 1998".

Tap chi Bidn vi bd, No.3-f4/2012, Hfii Cing - Dtfdng thiy - Thdm luc dia Vifit Nam, VAPO, Hi Nfii, tr.44 - 58.

[10]. Phan Dung:

"Mfit cich tinh i p ltfc chi dfing cia dit". Tap chi Thfing tin Khoa hgc vi Ky thuit, No.2/2003.Trtfdng Dai hpc Giao thfing Van tai, TpHCM,tt.l5-21.

[II]. Phan Dung;

"Cich xfit mat di't khdng nim ngang khi tinh cpc chju ltfc ngang"Ky ydu Hfii nghi Khpa hpc vi Cfing nghfi lin thff 10, Trtfdng Dai hpc Bich Khoa tp.HCM, tr.330 - 337.

72 <ig.^*K . UiSm miP