B GIO DC V O TO

TRNG I HC M - A CHT

TRN NGC NG

NGHIN C C,

PHN TCH BIN DNG N

NH CAO TNG

Ngnh: K thut Trc a - Bn

M s: 62520503

TM TT LUN N TIN S K THUT

H Ni - 2014

Cng trnh c hon thnh ti: B mn Trc a cng trnh,

Khoa Trc a, Trng i hc M - a cht, H Ni

Ngi hng dn khoa hc: PGS.TS Trn Khnh

Trng i hc M - a cht

Phn bin 1: TS Dng Ch Cng

Vin Khoa hc o c v Bn

Phn bin 2: TS Nguyn Vn Vn

Hi Trc a Bn v Vin thm Vit Nam

Phn bin 3: TS V Vn ng

Cc Bn - B Tng tham mu

Lun n s c bo v trc Hi ng nh gi lun n cp

Trng, hp ti Trng i hc M - a cht vo hi ..gi ngy

thng nm

C th tm hiu lun n ti th vin: Th vin Quc Gia, H Ni hoc

Th vin Trng i hc M - a cht

1

M U 1. Tnh cp thit ca ti

Trong thi gian gn y, khi thi cng h o thi cng mng v tng hm nh cao tng khng t cng trnh ln cn h o thng xy ra s c nng n, gy nhiu tn tht v kinh t v gy ra bc xc trong x hi. Nhng tn ti phn ln l do khng kp thi theo di quan trc v phn tch nhng tc ng do qu trnh thi cng mng v tng hm c th gy ra.

Hin nay vn quan trc, phn tch bin dng nn mng v tng hm nh cao tng trong giai on thi cng xy dng tr nn cp thit. Tuy nhin, vn trn vn cha c ch trng thch ng, cha c nhng nghin cu thu o, hon chnh v mt gii php k thut no c xut. V vy, nghin cu phng php quan trc, phn tch bin dng nn mng v tng hm cng trnh nh cao tng trong giai on thi cng xy dng l rt cn thit. Gp phn khng ch nhm an ton cho ton nh cao tng m cn c cc cng trnh ln cn, con ngi v cc sinh hot bnh thng ca c dn. 2. Mc ch, i tng v phm vi nghin cu - Mc ch nghin cu ca lun n nhm gp phn pht trin v hon thin phng php quan trc, phn tch bin dng, nh gi v m hnh ha qu trnh chuyn dch ca nn mng v tng hm nh cao tng trong giai on thi cng xy dng. - i tng nghin cu l: phng php quan trc, phn tch bin dng nn mng v tng hm ca cc cng trnh nh cao tng Vit Nam. - Phm vi nghin cu ca lun n bao gm: Nghin cu phng php trc a, phng php s dng cm bin quan trc bin dng nn mng v tng vy nh cao tng; nghin cu kt hp phng php trc a v phng php s dng cm bin nhm nng cao cht lng v hiu qu quan trc bin dng nn mng v tng hm; phn tch, nh gi v m hnh ha qu trnh chuyn dch ca nn mng v tng vy nh cao tng trong giai on thi cng mng v tng hm. 3. Ni dung nghin cu 1- Nghin cu kt hp phng php trc a vi phng php s dng cm bin quan trc ln nn mng v chuyn dch ngang tng vy cng trnh nh cao tng trong giai on thi cng mng v tng hm. 2- Nghin cu ng dng h thng quan trc t ng quan trc lin tc chuyn dch ca tng vy. 3- Xy dng m hnh chuyn dch, phn tch, nh gi, d bo chuyn dch nn mng v tng vy nh cao tng. 4- Lp phn mm phn tch bin dng nn mng v tng hm nh cao tng. 4. Phng php nghin cu

Phng php thng k, phng php phn tch, phng php thc nghim, phng php so snh, phng php ng dng tin hc, phng php ton hc.

2

5. ngha khoa hc v thc tin ca lun n ngha khoa hc: Gp phn pht trin v hon thin phng php quan

trc, phn tch bin dng v m hnh ha qu trnh chuyn dch ca nn mng, tng hm nh cao tng trong giai on thi cng xy dng.

ngha thc tin: Cc kt qu nghin cu c th c ng dng quan trc, phn tch, nh gi v d bo bin dng nn mng v tng hm nh cao tng trong giai on thi cng xy dng thc t sn xut. Gp phn phng nga s c i vi cng trnh v cc cng trnh ln cn. 6. Cc lun im bo v - Lun im th nht: Gii php kt hp phng php trc a vi phng php s dng cm bin nh xut trong lun n cho php nng cao hiu qu cng tc quan trc bin dng nn mng v tng vy nh cao tng. - Lun im th hai: M hnh bin dng cng trnh thnh lp trn c s s liu quan trc cho php nh gi ln cng nh chuyn dch ngang nn mng, tng vy nh cao tng theo thi gian, trong khng gian v nh gi s ph thuc gia bin dng vi tc nhn gy ra bin dng . 7. Cc im mi ca lun n 1- xut gii php kt hp phng php trc a vi phng php s dng cm bin nng cao cht lng, hiu qu cng tc quan trc bin dng nn mng v tng vy nh cao tng. 2- xut thnh lp cc m hnh bin dng nn mng, tng vy nh cao tng theo thi gian, trong khng gian v nh gi s ph thuc gia bin dng vi cc tc nhn gy ra bin dng. 3- Thnh lp phn mm phn tch bin dng nn mng v tng hm cng trnh nh cao tng. 8. Cu trc v ni dung lun n

Ngoi phn m u, kt lun, lun n c trnh by trong 5 chng vi hn 130 trang thuyt minh, hnh v v bng biu. Chng 1. TNG QUAN V QUAN TRC BIN DNG NN MNG V TNG HM CNG TRNH NH CAO TNG TRONG GIAI ON THI CNG XY DNG 1.1. Tng quan cc cng trnh nghin cu ngoi nc 1- Quan trc chuyn dch nn mng nh cao tng trong giai on thi cng mng v tng hm. - Xc nh ni dung quan trc [82]. - Phng php quan trc: Phng php trc a v phng php s dng cm bin [46], [47], [48], [49], [52], [53], [54]. 2- Phn tch nh gi kt qu quan trc chuyn dch nn mng v tng hm nh cao tng [47], [50], [53], [60], [62]. 3- T ng ha qu trnh quan trc v x l s liu [51], [55], [57], [58], [61], [63].

1.2. Tng quan cc cng trnh nghin cu trong nc

3

1- Nghin cu v l thuyt - Nghin cu phng php v quy trnh quan trc bin dng cng trnh [3], [4], [5], [9], [13], [27], [28], [29].

- Nghin cu v thit k li v x l s liu quan trc bin dng cng trnh [2], [10], [15], [19], [[20], [32].

- Nghin cu ng dng cc thit b hin i trong quan trc bin dng cng trnh [3], [5], [32].

- Nghin cu phn tch bin dng cng trnh [18], [19], [29], [32]. - Nghin cu ng dng tin hc vo x l s liu quan trc bin dng cng trnh [8], [21], [29].

2- Trin khai cng tc quan trc nn mng nh trong thc t Cng tc quan trc nn mng nh cao tng c cc cng trnh nghin cu [1] v mt s cng trnh nghin cu tr thnh tiu chun Quc gia nh [34], [35], [37], [38]. - Xc nh ni dung quan trc [36]. - Phng php quan trc: Phng php trc a v phng php s dng cm bin. 1.3. nh gi chung v tnh hnh nghin cu 1- Trn th gii, nhn chung cc nghin cu v lnh vc ny c mt s im cha ph hp vi iu kin Vit Nam (t yu, xy chen, yu t xy dng, ...). 2- Vit Nam, ch yu s dng cc thit b cng ngh hin i nhp khu, cha c iu kin ch to cc thit b o chuyn dng cho cng tc quan trc bin dng cng trnh. 1.4. Vn tn ti v nh hng nghin cu trong lun n

Hin nay phng php trc a v phng php s dng cm bin quan trc bin dng nn mng v tng hm nh cao tng vn ang tch bit vi nhau. V vy, nghin cu s dng kt hp phng php trc a vi phng php s dng cm bin nhm nng cao cht lng v hiu qu cng tc quan trc bin dng nn mng nh cao tng l vic lm cn thit.

Nghin cu ng dng h thng quan trc t ng t ng quan trc lin tc chuyn dch ca tng vy cng trnh nh cao tng nhm gp phn phng nga s c c th xy ra trong qu trnh thi cng h o l cn thit.

Hin nay cc s liu quan trc trong giai on ny mi ch khu cung cp s liu ch vn cha c nhng phn tch nh gi c th nh hng ca qu trnh thi cng h o n cc cng trnh ln cn. Do cn tin hnh nghin cu, phn tch s liu quan trc, thnh lp m hnh chuyn dch nn mng v chuyn dch ca tng vy nhm kim sot s c c th xy ra i vi cng trnh.

Chng 2. QUAN TRC LN NN MNG V TNG HM CNG TRNH NH CAO TNG TRONG GIAI ON THI CNG XY DNG 2.1. Yu cu k thut quan trc ln trong qu trnh xy dng mng v tng hm nh cao tng 2.1.1. Nguyn nhn gy ra ln trong qu trnh thi cng mng v tng hm

4

Trong qu trnh thi cng h o thi cng mng v tng hm, khi ly i mt lng t no s lm thay i trng thi ng sut nn dn ti bin dng ca khi t quanh h o. t s chuyn dch v pha h o, ln ca chuyn dch ph thuc vo cht lng ca kt cu chng gi, loi t, khong cch cng nh v tr v ti trng ca cng trnh ln cn. Tng hp cc loi chuyn dch ny s lm mt t ln cn h o ln xung. Nu trong vng nh hng ny c cc cng trnh th chng s b bin dng. 2.1.2. Ni dung cng tc quan trc ln trong qu trnh thi cng mng v tng hm

- Quan trc ln b mt t, quan trc ln theo chiu su ca cc lp t xung quanh h o.

- Quan trc ln cc cng trnh ln cn. - Quan trc tri h mng (bng nn y h o). - Theo [35] vic o v xc nh ln ca cng trnh cn c tin hnh

ngay t khi xy xong phn mng. Do vy, khi thi cng xy dng tng hm, cng trnh c ti trng nn cn quan trc ln ca cng trnh ngay c trong giai on ny. 2.1.3. Xc nh vng quan trc ln trong qu trnh thi cng mng v tng hm

Trong trng hp thit k khng a ra vng cn quan trc ln th chng ta c th tnh vng nh hng ny theo cc cng thc c tnh ca l thuyt c hc t. Theo , phm vi nh hng ca t xung quanh h o c tnh theo cng thc [80]:

o

oB = H . tg(45 - / 2 ) (2.1)

Trong : Bo - Phm vi nh hng ln ca khi t (m); H - su ca kt cu tng chn (m); - Gc ma st trong ca t (o). 2.1.4. Yu cu chnh xc v chu k quan trc ln trong qu trnh thi cng mng v tng hm 2.1.4.1. Yu cu chnh xc quan trc ln

Cch 1: Da vo gi tr ln d bo (do n v thit k cung cp) xc nh yu cu chnh xc quan trc.

Cch 2: C th s dng cc cp hng o ln trong TCVN 9360:2012 [35] quan trc ln nn mng nh cao tng. Theo tiu chun ny vic o ln cng trnh c chia lm ba cp: cp I, cp II v cp III. 2.1.4.2. Chu k quan trc ln

Chu k quan trc ln trong qu trnh thi cng mng v tng hm ph thuc vo tc thi cng m xc nh. 2.2. Quan trc ln nn mng nh cao tng trong giai on thi cng mng v tng hm bng phng php trc a 2.2.1. Kt cu mc quan trc ln nn mng v tng hm nh cao tng 2.2.2. Thit k h thng li quan trc

5

H thng li cao quan quan trc ln cng trnh thng c thit k gm 2 bc li: li cao c s v li quan trc.

2.2.3. Quan trc ln nn t xung quanh h mng

cao ca im quan trc ln nn t xung quanh h mng nn o theo phng php o cao hnh hc vi chnh xc theo o ln cp III.

2.2.4. Quan trc ln cc cng trnh ln cn h o

chnh xc o ln cc cng trnh ln cn (nh dn, cng trnh b tng ct thp) cn o ln vi chnh xc o ln cp II.

2.2.5. Quan trc tri h mng

cao ca im quan trc bin dng tri h mng nn o theo phng php o cao hnh hc vi chnh xc theo o ln cp III.

2.2.6. Quan trc ln cng trnh chnh trong qu trnh thi cng tng hm

Quan trc ln cng trnh chnh thc cht l quan trc ln tng vy (tng tng hm) v cc phn bn trong tng vy (ct, vch, vch thang my, ). chnh xc o ln cho cng trnh chnh cn o ln vi chnh xc o ln cp II.

2.2.7. X l s liu quan trc ln nn mng nh cao tng trong giai on thi cng mng v tng hm

2.2.7.1. Phn tch n nh mc cao c s

Tiu chun n nh ca mc cao c s:

Si

2

m| S | t.

1 k (2.15)

Trong cng thc (2.15): Si - ln ca im cao c s chu k ang xt so vi chu k u; mS - yu cu chnh xc xc nh ln; t: l h s xc nh tiu chun sai s gii hn (t = 23); k - h s suy gim chnh xc gia cc bc li (k = 23).

2.2.7.2. Tnh ton bnh sai li cao quan trc ln

2.2.7.3. Tnh ton tham s ln cng trnh

2.2.8. Nhn xt v quan trc ln nn mng nh cao tng bng phng php trc a

Phng php trc a c u im l cho php t chnh xc cao, cho gi tr ln tuyt i. Nhc im ca phng php l quan trc ln cc lp t theo chiu su (quan trc ln cc tng t nn) i hi phi thi cng cc mc quan trc ring bit cho nn cng lp t ln, do ti mi v tr su cn quan trc phi thc hin mt h khoan ring bit lp t mc.

2.3. Quan trc ln nn mng nh cao tng trong giai on thi cng xy dng bng cm bin

2.3.1. Cu to h thng a t

a t l loi thit b chuyn dng quan trc ln theo nguyn l cm ng t. H thng thit b a t bao gm: ng dn hng, nam chm chun,

6

nam chm nhn, nam chm a, dy o v u d t.

Hnh 2.9. Quan trc ln bng a t [17]

P O O PH = H + L - L (2.18)

Trong : HP: cao im P; Ho: cao mc y ( cao mc chun); Lo: Khong cch gia nh ng v mc y; LP: Khong cch t nh ng n im quan trc P.

Gi tr ln ca im quan trc c xc nh bng cch so snh cao ca im 2 chu k o khc nhau.

2.3.4. chnh xc o ln bng phng php a t

Theo ti liu [14] th sai s trung phng ln xc nh theo cng ngh

a t t c (5 8) mm.

2.3.5. V d o ln nn cng trnh bng a t

2.3.6. Nhn xt quan trc ln nn mng nh cao tng bng cm bin

Phng php s dng cm bin (a t) c u im l ti mt l khoan c th b tr nhiu mc quan trc cho nhiu su khc nhau. Nhc im ca phng php l ly im y ng lm chun. V vy, i hi y ng dn hng cn c neo vo lp t n nh nm di su (khng b ln). Trong trng hp lp t ny nm qu su th kh lp t v khng hp l v kinh t khoan su. Mt khc, trong mi chu k quan trc khng th nh gi c n nh ca im tham chiu cho nn dn ti tnh trng nu im tham chiu b ln th gi tr ln thu c ti cc bn o ln s khng phn nh chnh xc ln ca cc lp t c quan trc.

2.4. Gii php kt hp phng php trc a v phng php s dng cm bin quan trc ln nn mng nh cao tng

khc phc nhc im ca phng php trc a v phng php s dng cm bin, trong lun n xut s dng kt hp hai phng php vi nhau quan trc ln cc lp t v tri h mng. Qu trnh kt hp c thc

2.3.2. Phng php lp t ng dn hng c chn

nhn t c lp t trong h khoan v b tr theo th t nh hnh 2.9. 2.3.3. Nguyn l o ln bng a t

Trong phng php a t ly im y ng lm chun v cao im quan trc c xc nh nh sau

(hnh 2.9).

. . . . . .

. .

. . . . . .

. . . .

. . . . . .

. . . . . .

. . . .

. . . . . .

. . . . . .

. . . .

. . . . . .

. . . . . .

. . . .

. . . . . .

. . . . . .

. . . .

. . . . . .

. . . . . .

. . . .

. . . . . .

u d

Nam chm a

Nam chm nhn

Nam chm chun

t p

gc

L0

L P

A

P1

O

Pn

Pi

Dy o

7

hin nh sau: 2.4.1. Trng hp y ng dn hng c neo vo lp t n nh

Sai s khp o ln bng a t ( ), c tnh theo cng thc sau:

T T = S - S (2.19)

Trong cng thc (2.19): ST - ln im nh ng (im A hnh 2.9) o bng a t; ST - ln im nh ng o bng trc a.

Phn phi sai s khp ( ) cho cc im o nm di su theo nguyn tc t l thun vi khong cch t y ng n im o s xc nh c cc gi tr ln ti cc bn o ln vi chnh xc c nng cao (cng thc 2.20).

i

i i

OPT

P P

OA

.LS = S -

L (2.20)

Trong : i

T

PS : ln ca im Pi o bng a t;

iOPL : khong cch t im

y ng n im quan trc Pi; OAL : khong cch t im y ng n im

quan trc A nh ng. 2.4.2. Trng hp y ng dn hng c neo vo lp t khng n nh

i vi trng hp ny gi tr tnh c theo cng thc (2.19) c th coi

l ln ca im tham chiu y ng, khi tin hnh hiu chnh gi tr cho cc im o nm di su theo cng thc sau:

i i

T

P PS = S - (2.21)

Cng trong trng hp ny, c th s dng im nh ng lm im tham chiu. cao ca im tham chiu c xc nh bng phng php trc a (thng l o thy chun hnh hc). 2.4.3. V d o ln nn cng trnh bng phng php trc a kt hp a t 2.4.3.1. V d trong trng hp y ng dn hng neo vo lp t n nh 2.4.3.2. V d trong trng hp y ng dn hng khng neo vo lp t n nh 2.4.4. Nhn xt quan trc ln nn mng nh cao tng bng phng php trc a kt hp vi phng php s dng cm bin

Gii php kt hp phng php trc a v phng php s dng cm bin (a t) quan trc ln nn mng nh cao tng c ngha nh sau:

- Nng cao chnh xc o ln ti cc bn quan trc ln (trong trng hp y ng dn hng c neo vo lp t n nh).

- Cho php ly im nh ng lm chun xc nh ln ti cc bn quan trc ln. Nh vy, trong trng hp ny th ng dn hng khng cn neo vo nn t n nh m ch cn lp t ng dn hng n su ca lp t cn quan trc ln, do s thun li cho vic thi cng lp t ng dn hng, cho php nng cao hiu qu cng tc quan trc ln nn mng cng trnh nh cao tng.

Chng 3. QUAN TRC CHUYN DCH NGANG TNG VY NH CAO TNG TRONG GIAI ON THI CNG MNG V TNG HM

8

3.1. Yu cu k thut quan trc chuyn dch ngang tng vy nh cao tng 3.1.1. Mt s khi nim chung v thi cng mng v tng hm nh cao tng 3.1.1.1. Cc bin php thi cng tng hm nh cao tng 3.1.1.2. Cc bin php chn t thi cng h o trong qu trnh thi cng mng v tng hm 3.1.1.3. Tng vy nh cao tng 3.1.2 Nguyn nhn gy ra chuyn dch bin dng ca tng vy

Trong qu trnh o t thi cng mng v tng hm cng trnh nh cao tng, khi ly i mt lng t no s lm thay i trng thi ng sut dn ti bin dng ca khi t quanh h o. t s chuyn dch v pha h o v lm cho tng vy c th b chuyn dch. 3.1.3. Mc ch quan trc chuyn dch ngang ca tng vy

Quan trc chuyn dch ngang tng vy nhm cc mc ch xc nh mc chuyn dch bin dng, nghin cu tm ra nguyn nhn chuyn dch bin dng ca tng vy v t c bin php x l, phng s c i vi cng trnh v cng trnh ln cn. 3.1.4. Yu cu chnh xc v chu k quan trc chuyn dch ngang tng vy 3.1.4.1. Yu cu chnh xc quan trc

Cch 1: Da vo gi tr chuyn dch ngang d bo (do n v thit k cung cp) xc nh yu cu chnh xc quan trc.

Cch 2: C th s dng cc cp o chuyn dch ngang trong TCVN 9399:2012 Nh v cng trnh xy dng - Xc nh chuyn dch ngang bng phng php trc a [38] quan trc chuyn dch ngang tng vy. 3.1.4.2. Chu k quan trc chuyn dch ngang tng vy

Chu k quan trc ph thuc vo tc thi cng h o. 3.2. Quan trc chuyn dch ngang tng vy bng phng php trc a 3.2.1. Thit k kt cu v phn b mc quan trc chuyn dch ngang tng vy 3.2.2. Thit k h thng li quan trc chuyn dch ngang tng vy

H thng li quan trc chuyn dch ngang tng vy thng c thit k gm 2 bc li l bc li khng ch c s v bc li quan trc.

Yu cu sai s xc nh chuyn dch i vi cc cp li c xc nh theo cc cng thc sau:

- i vi li c s:

CS

q

q2

mm =

1 k (3.3)

- i vi li quan trc:

QT

q

q2

k.mm =

1 k (3.4)

Trong cc cng thc (3.3) v (3.4): mq - chnh xc yu cu quan trc chuyn

9

dch ngang; k l h s gim chnh xc gia 2 cp li (thng thng k = 23). 3.2.3. Quan trc chuyn dch ngang tng vy bng li o gc - cnh 3.2.3.1. Phng php tam gic 3.2.3.2. Phng php a gic 3.2.3.3. Phng php giao hi 3.2.4. Quan trc chuyn dch ngang tng vy bng phng php hng chun 3.2.5. Quan trc chuyn dch ngang tng vy bng h thng quan trc t ng 3.2.5.1. Gii thiu h thng quan trc t ng 3.2.5.2. Quan trc t ng chuyn dch tng vy bng my ton c in t 3.2.5.3. Phn mm x l s liu quan trc t ng 3.2.6. X l s liu quan trc chuyn dch ngang tng vy 3.2.6.1. Phn tch nh gi n nh cc mc c s trong quan trc chuyn dch ngang tng vy

Cng ging nh trong quan trc ln tiu chun n nh ca im khng ch c s l:

q

i2

mq t.

1 k (3.7)

Trong cng thc (3.7): qi - chuyn dch ngang ca im khng ch c s chu k ang xt so vi chu k u; mq - yu cu chnh xc xc nh chuyn dch ngang; t: l h s xc nh tiu chun sai s gii hn (t = 23); k - h s suy gim chnh xc gia cc bc li (k = 23). 3.2.6.2. Bnh sai li quan trc 3.2.7. Tnh ton tham s chuyn dch ngang ca tng vy 3.2.7.1. Tnh ton cc tham s chuyn dch cc b 3.2.7.2. Th hin ha chuyn dch ngang tng vy 3.2.8. xut x l s liu h thng quan trc t ng khi quan trc nhiu hn mt trm my

Phng php quan trc t ng bng my ton c in t t mt trm my thc cht l phng php o ta cc v khng c tr o tha do tin cy khng cao v c th dn ti sai lm. tng thm tr o tha ca tr o cn p dng phng php quan trc t hai hay nhiu trm my cng mt thi im.

Hnh 3.20. hnh quan trc t ng nhiu hn 1 trm my

xc nh ta tin cy nht ca im quan trc th cn tin hnh bnh sai

A

3

y O

x

B

P

S1 1 S2 2

1 2

C S3 3

10

ta ca im quan trc. Qu trnh tnh ton x l s liu c thc hin nh sau: T hnh 3.20, ta ca im quan trc c xc nh theo cng thc:

G 0 G

G 0 G

x x S.cos( ) x S.cos

y y S.sin( ) y S.sin (3.14)

Trin khai tuyn tnh biu thc (3.14) vi ta gn ng ca im quan trc x

(0), y

(0) thu c:

(0)

G

(0)

G

x -xx cos -S.sin dSx

y sin S.cos d y - y (3.16)

Trong (3.14) v (3.16): xG, yG - ta im trm my; dS, d - s hiu chnh i vi cc tr o S v . K hiu: Kxy l ma trn tng quan ca ta im quan trc (x, y) v KS l ma trn tng quan ca cnh o (S, ). Khi :

XY S

cos S.sin cos sinK .K .

sin S.cos S.sin S.cos (3.17)

Vi

2

S

S 2

m 0K

0 m

Ma trn trng s ca tr o (x, y) l:

2 1

xy xyP .K

(3.19)

Phng trnh s hiu chnh ta im quan trc:

i i

i i

x x

y y

v l1 0 xx

v 0 1 y l (i=1n) (3.21)

Trn c s cng thc (3.21), p dng nguyn l s bnh phng nh nht lp v gii h phng trnh chun xc nh s hiu chnh ta i vi im quan trc v tnh ta sau bnh sai theo cng thc:

(0)

(0)

x = x + x

y = y + y (3.27)

3.2.9. Nhn xt chung v quan trc chuyn dch ngang tng vy bng phng php trc a

Phng php trc a c u im l cho php t chnh xc cao v xc nh c gi tr chuyn dch tuyt i, tuy nhin nhc im c bn ca phng php l ch thun tin quan trc chuyn dch ca cc im phn b nh tng vy. Trong khi , khi thi cng mng v tng hm cng trnh nh cao tng yu cu phi quan trc tng vy theo chiu su trong sut qu trnh thi cng mng v tng hm.

3.3. Quan trc chuyn dch ngang tng vy bng cm bin Inclinometer 3.3.1. Cu to Inclinometer

11

Inclinometer l thit b chuyn dng quan trc chuyn dch ngang theo chiu su. Cu to ca thit b ny gm 4 b phn chnh gm: ng dn hng, u o, cp tn hiu v thit b c s. 3.3.2. Nguyn l o chuyn dch ngang bng Inclinometer

o chuyn dch bng cm bin Inclinometer l o gin tip chuyn dch ca i tng cn quan trc thng qua chuyn dch ca ng dn hng (hnh 3.22, 3.23).

Hnh 3.22. Cc hng quy c trong quan trc bng Inclinometer

Hnh 3.23. S tnh ton trong o chuyn dch bng Inclinometer

Phng php tnh ton trong vic quan trc chuyn dch ngang bng Inclinometer l ly y ca ng o lm c s xc nh cc chuyn dch ti cc v tr o pha trn, do vy y ca ng o phi m bo iu kin khng c chuyn dch.

Trn hnh 3.23, lch ngang cho tng v tr o theo mt trc c xc nh theo cng thc:

i id L.sin (3.28)

Trong : di - lch ngang gia hai im o lin nhau theo mt trc; L - khong cch o gia hai im lin nhau; i -l gc nghing so vi phng thng

ng im o th i.

Gi tr lch ngang ca mt im bt k theo mt trc l tng gi tr o t y ng n im y (hnh 3.23), n c gi l gi tr tch ly (d) v c

12

tnh theo cng thc sau:

d = d1 + d2 + d3 ++ dn (3.32)

Trong : d - l lch ngang ca im n k t y ng (theo 1 trc); di - lch ngang ca tng im theo 1 hng trc (i = 1 n).

S thay i lch ngang ti mi khong cch o cc chu k quan trc cho thy ng dn hng c s chuyn dch. Chuyn dch c tnh bng cch ly lch ngang hin ti tr i lch ngang ban u.

3.3.3. chnh xc o chuyn dch ngang bng Inclinometer

Cn c vo l lch ca thit b o nh sn xut cung cp, u c s ca Inclinometer hin nay cho php c s vi gi tr hin th trn mn hnh ti 0.01mm, mi ln u o di chuyn 0.5m trong ng dn hng th s c s vi sai s mc phi l 0.25mm v khi chiu di ca ng dn hng l 25m th sai s tch ly l 6mm [16], [86].

3.3.4. Quan trc chuyn dch ngang tng vy bng Inclinometer

3.3.4.1. Lp t ng dn hng

3.3.4.2. Trnh t quan trc

3.3.4.3. X l s liu v lp bo co kt qu quan trc

3.3.5. Nhn xt chung v quan trc chuyn dch ngang tng vy bng cm bin Inclinometer

Phng php s dng cm bin Inclinometer quan trc theo chiu su ca tng vy c u i n ra cc chuyn dch theo chiu su. Tuy nhin phng php ny cng c nhc im l ch xc nh c chuyn dch tng i ca tng vy cc su khc nhau so vi mt im nm di su (y ca tng vy). Trong trng hp im nm di su khng n nh th gi tr quan trc thu c khng phn nh ng mc chuyn dch tuyt i ca tng vy.

3.4. Gii php quan trc chuyn dch ngang tng vy bng phng php trc a kt hp vi phng php s dng cm bin

Nh trnh by trn, phng php trc a c u im l cung cp chnh xc cao v cho gi tr chuyn dch tuyt i, tuy nhin nhc im c bn ca phng php l ch cho php quan trc chuyn dch ca cc im phn b nh tng vy.

Phng php s dng cm bin Inclinometer c u i n ra cc chuyn dch theo chiu su. Tuy nhin nhc im ca phng php l ch xc nh c chuyn dch tng i ca tng vy cc su khc nhau so vi mt im nm di su (y ca tng vy). Trong trng hp im nm di su khng n nh th gi tr quan trc thu c khng phn nh ng mc chuyn dch tuyt i ca tng vy.

Nhm khc phc cc nhc im trn xc nh chuyn dch tuyt i cc v tr su ca tng vy. Trong lun n xut s dng kt hp hai phng php vi nhau quan trc chuyn dch ngang ca tng vy. Qu trnh kt hp

13

thc hin nh sau: 3.4.1. Trng hp y ng dn hng c gn vo lp t n nh

Trong trng hp ny qu trnh quan trc c thc hin nh sau: Trong mi chu k ngoi vic o chuyn dch ngang theo chiu su bng Inclinometer th tm ming ng dn hng cn c xc nh chuyn dch bng phng php trc a. T hnh (3.27) xc nh c cng thc chuyn i gia hai h ta (t

Hnh 3.27. H ta o chuyn dch h ta trc a v h ta Inclinometer) i vi im tm ming ng dn hng theo cng thc (hnh 3.27):

T ICL T T

T ICL T T

(o) (o) (o)

X X Y

(o) (o) (o)

Y X Y

q q .cos - q .sin

q q .sin q .cos (3.33)

Trong : T

(o)

Xq ,

T

(o)

Yq - chuyn dch im tm ming ng (im O) o bng trc

a trong h ta trc a; T-ICL

(o)

Xq ,

T-ICL

(o)

Yq - chuyn dch im tm ming ng

o bng trc a trong h ta Inclinometer; l gc xoay gia 2 h trc ta Inclinometer v trc a (hnh 3.27) c th c xc nh bng phng php trc a hoc xc nh trn bn v.

Gi tr lch ca cc trc ta c tnh theo cng thc:

ICL T-ICL

ICL T-ICL

(o) (o) (o)

X X X

(o) (o) (o)

Y Y Y

q - q

q - q (3.34)

Trong cng thc (3.34): ICL

(o)

Xq ,

ICL

(o)

Yq - chuyn dch im tm ming ng o

bng Inclinometer trong h ta Inclinometer. Phn phi sai s khp cho cc im o theo t l thun vi cao im

quan trc s xc nh c tr bnh sai ca cc gi tr chuyn dch o bng Inclinometer:

X X XICL-T ICL

Y YICL-T ICL

(i) (i) (o)i

(i) (i) (o)iY

Hq q -

H

Hq q -

H

(3.35)

Trong : XICL

(i)q , YICL

(i)q l chuyn dch ca im i o bng Inclinometer ti cao

Hi; XICL-T

(i)q , XICL-T

(i)q l chuyn dch im i o bng Inclinometer c hiu

chnh sai s; Hi, H tng ng l cao ca im quan trc i v cao ca im

XICL

YT

XT

TXq

ICLYq

ICLXq

YICL q

TYq

O

14

nh ng so vi im y ng. 3.4.2. Trng hp y ng dn hng c gn vo lp t khng n nh

Nh trn cp, nguyn l o Inclinnometer l s liu chuyn dch c so snh vi im tham chiu y ng dn hng nn khi im ny khng n nh th chuyn dch xc nh c s khng chnh xc. Do vy cn chn im tham chiu trong o Inclinometer l im c kh nng xc nh c v tr bng phng php trc a - l tm cc ming ng dn hng Inclinometer trn mt t. iu thun li l phn mm x l s liu o ca Inclinometer do nh sn xut cung cp km theo thit b cho php xc nh chuyn dch ca cc im o Inclinometer theo im tham chiu l ming ng dn hng. V vy, trong qu trnh tnh ton bng phn mm cn t li im tham chiu ca gi tr o Inclinometer l im trn ming ng dn hng, kt

qu thu c cc i lng chuyn dch ICL

(i)

Xq ,

ICL

(i)

Yq o trong lng tng vy.

Tuy cc im ming ng dn hng khng phi l cc im n nh, nhng chuyn dch ca n c th xc nh c bng phng php trc a. Nh vy, trong mi chu k quan trc, tm ca ming ng dn hng Inclinometer cn phi nh v chnh xc trong h ta trc a v chnh lch ta gia cc

chu k chnh l gi tr chuyn dch T

(o)

Xq ,

T

(o)

Yq ca tm ming ng dn hng

trn mt t. Tnh chuyn gi tr chuyn dch ca ming ng dn hng o bng trc

a v ta Inclinometer theo cng thc (3.33) c chuyn dch ca

ming ng T-ICL

(o)

Xq ,

T-ICL

(o)

Yq .

Xc nh ta theo phng php trc a c chnh xc cao nn chuyn dch xc nh bng phng php trc a c tin cy cao hn hn so vi xc nh chuyn dch bng Inclinometer. Nh vy c th s dng gi tr chuyn dch o bng trc a ci chnh cho kt qu chuyn dch o bng

Inclinometer. K hiu T-ICL

(o)

Xq x ,

T-ICL

(o)

Yq y , s dng gi tr ny ci

chnh cho tng tr o Inclinometer ICL

(i)

Xq ,

ICL

(i)

Yq trong ng dn hng

Inclinometer tng ng theo cng thc sau:

X XICL-T ICL

Y YICL-T ICL

(i) (i)

(i) (i)

q q x

q q y (3.36)

3.4.3. Nhn xt phng php quan trc chuyn dch ngang tng vy bng phng php trc a kt hp phng php s dng cm bin

Gii php kt hp phng php trc a vi phng php s dng cm bin nu trn cho php xc nh chuyn dch tuyt i ca cc im quan trc cc su khc nhau ca tng vy. Trong gii php kt hp ny y ng dn hng o bng Inclinometer cng khng cn neo vo lp t n nh. Tuy nhin i vi quan trc tng vy th ng dn hng cn c lp t bng chiu su ca

15

tng vy c s liu quan trc t y ln n nh ca tng vy.

Chng 4. PHN TCH BIN DNG NN MNG V TNG HM CNG TRNH NH CAO TNG TRONG GIAI ON THI CNG XY DNG 4.1. Nguyn tc thnh lp m hnh chuyn dch cng trnh theo s liu quan trc

Khi tng hp chuyn dch cng trnh nhiu chu k cn phn tch cc vn sau: 1- Xu hng chuyn dch chung ca cng trnh trong khng gian. 2- Xu hng chuyn dch chung ca cng trnh theo thi gian. 3- nh gi mc ph thuc chuyn dch cng trnh vo mt s yu t ngoi cnh (chuyn dch cng trnh c ph thuc vo mt s yu t no khng? nu c ph thuc th xc nh biu thc ton hc).

gii quyt cc vn nu trn cn phi xy dng m hnh chuyn dch ca cng trnh m thc cht l m t qu trnh chuyn dch cng trnh bng mt s hm ton hc no . V nguyn tc m hnh chuyn dch cng trnh c th hin thng qua hm s [17]:

= F1(x) + F2(u) + F3(z) + w] (4.1) Trong : F1(x)-thnh phn nh hng ca mt nhm yu t ch o gy nn chuyn dch cng trnh. Thng thng ch cn xy dng m hnh vi cc yu t ch o l . 4.2. M hnh ln nn mng v chuyn dch tng vy trong khng gian 4.2.1. M hnh ln nn mng cng trnh nh cao tng trong giai on thi cng mng v tng hm 4.2.1.1. M hnh ln ca kt cu mng cng

i vi kt cu mng cng, khi cc im quan trc phn b trn mt din rng, s dng phng trnh mt phng xy dng m hnh ln. Phng trnh mt phng ln c dng [17]:

i i iS a.x b.y c (4.2)

Trong : xi, yi, Si l ta theo trc OX, OY v gi tr ln ca im quan trc i; a, b, c: tham s ca mt phng ln (cc tham s cho php xc nh hng v gc nghing ln nht ca cng trnh).

Trong trng hp c bit cc im quan trc phn b trn mt ng thng (hoc khi cn xy dng m hnh ln theo trc), khi biu din ln thng qua phng trnh ng thng. Phng trnh ng thng c dng tng qut sau:

i iS a.x b (4.10)

Trong : Si - ln ca im i (i=1n); xi - l ta theo hng ngang ca im quan trc (i=1n); a, b tham s ca ng thng. 4.2.1.2. M hnh ln nn t ln cn h mng

Theo l thuyt c hc t, ln ca nn t xung quanh cng trnh

16

thng xy ra khng u v hnh thnh phu ln. th hin ln tng qut ca phu ln c th s dng hm parabol (v d nh parabol bc 2).

M hnh ln nn t mi thi im (chu k) c dng hm parabol bc 2 tng qut:

2 2

i 0 1 i 2 i 3 i 4 i i 5 iS a a x a y a x b x y a y (4.11)

xc nh tham s ca m hnh ln theo (4.2), (4.10) v (4.11), da trn s liu quan trc (khi s lng im quan trc ln hn s lng tham s) trong lun n xut quy trnh v h thng cng thc xc nh cc tham s theo nguyn l s bnh phng nh nht. 4.2.2. M hnh chuyn dch ngang ca tng vy 4.2.2.1. M hnh chuyn dch tng vy trong mt phng ngang

Chuyn dch tng th ca tng vy c th c biu din thng qua 4 thng s l: chuyn dch tnh tin ti im trng tm ca cng trnh (ax,

ay), gc xoay ( ) v h s bin dng chiu di (m) - hnh (4.4). Bn tham s chuyn dch trn c xc nh trn c s cng thc chuyn i ta (4.13):

Hnh 4.4. Chuyn dch gia hai h ta

X

Y

X' a X.m.cos( ) - Y.m.sin( )

Y' a Y.m.cos( ) X.m.sin( ) (4.13)

K hiu vector tham s chuyn dch l Z; Z= (ax ay m)T. rng gc xoay c

gi tr nh ( 0), h s bin dng m 1, ly z(0) = (0 0 0 1)T, da trn s liu quan trc lp c h phng trnh s hiu chnh cho mi im o dng sau:

i i

i i

x

x xyi i

y i i y

a

v qa1 0 -y x= -

v 0 1 x y q

m

; (i=1n)

Khi s im quan trc ln hn 2, p dng nguyn l s bnh phng nh

nht s xc nh c vector n s TX Y

z (a , a , , m) v t xc nh c

cc tham s chuyn dch:

Z = Z(0)

+ Z 4.2.2.2. M hnh chuyn dch tng vy trong mt phng ng

i vi tng vy c quan trc theo chiu su, cc im quan trc c phn b gn trong mt mt phng thng ng. Khi c th xy dng m hnh chuyn dch tng vy trong mt phng ng. Phng trnh mt phng chuyn

Y'

aY

O

P2 ax

X X

O

P1

Y

17

dch trong trng hp ny c dng [27]:

i i iq aX bH c (4.25)

Trong : Xi, Hi, qi l ta theo trc OX, cao v gi tr chuyn dch ca im quan trc i; a, b, c: tham s ca mt phng. Khi s im quan trc ln hn 3, cc tham s ca m hnh c xc nh theo nguyn l s bnh phng nh nht. 4.2.3. ng dng phn tch phng sai nh gi bin dng cng trnh

M hnh ln (4.2), (4.10) hoc m hnh chuyn dch (4.13), (4.25) c xy dng trn cc gi thit l cng trnh tuyt i cng (c bin dng khng ng k). Sai s m hnh ny c tnh theo cng thc:

2

MH

[V ]m

n k

Trong : n s lng gi tr chuyn dch; k- s lng tham s m hnh. Da vo gi tr sai s m hnh c th nh gi c mc bin ca cng

trnh. thc hin iu ny c th s dng phn tch phng sai theo tiu chun kim nh Fisher, bng cch lp t s:

MH

0

2

2

mF

m (4.30)

vi bc t do bng (n-k) v (n), trong : n l s tr o, k l s lng tham s ca m hnh. Trong cng thc (4.30): mMH - sai s m hnh; m0 - sai s trung phng trung bnh chuyn dch ca cc im quan trc.

So snh, Nu ghF F (Fgh- tra bng) th cng trnh khng b bin dng. Nu

ghF F th chng t rng cng trnh c bin dng.

4.3. M hnh ln v chuyn dch nn mng nh cao tng theo thi gian 4.3.1. C s l thuyt d bo chuyn dch cng trnh theo s liu quan trc

Gi s m hnh chuyn dch cng trnh theo thi gian c th hin thng qua hm s dng tng qut:

q f(t) (4.31)

Trin khai tuyn tnh biu thc (4.31) theo cc bin zi vi vector tham s

gn ng 0 0 0 T0 1 2 k

Z (z , z ,..., z ) , xc nh c: 0

i i1 1 i2 2 ik k iq a dz a dz ... a dz q ; (i=1n) (4.33)

vi cc h s aij (j=1k) l hm ca thi gian quan trc. 0 0 0 0

i 1 1 2 2 k kq a z a z ... a z (4.34)

Hm s (4.31) vi cc tham s tnh c l biu thc th hin m hnh chuyn dch theo thi gian. Cc tham s ca m hnh c xc nh da trn s liu quan trc v nguyn l s bnh phng nh nht. 4.3.2. ng dng phn tch phng sai nh gi mc tin cy ca m hnh

18

Trong trng hp xy dng m hnh chuyn dch theo thi gian, m hnh la chn l m hnh d on, chng ta cha bit trc c thc t m hnh nh th no. Do vy, trong trng hp ny c th s dng phn tch phng sai nh gi mc tin cy ca m hnh theo tiu chun kim nh Fisher, bng cch lp t s:

MH

0

2

2

mF

m (4.40)

vi bc t do l (n-k) v (n). Trong : n l s chu k quan trc (khng k chu k quan trc u tin); k l s lng tham s ca m hnh. Nu F Fgh th m hnh la chn l ph hp. 4.3.3. Mt s m hnh ln v chuyn dch nn mng nh cao tng theo thi gian 4.3.3.1. M hnh hm s m 4.3.3.2. M hnh hm a thc 4.4. nh gi nh hng ca cc yu t gy nn chuyn dch bin dng cng trnh

nh gi nh hng ca cc yu t gy nn chuyn dch bin dng cng trnh c th p dng phng php phn tch tng quan tuyn tnh n. Qu trnh c thc hin nh sau [17]: 4.4.1. Xc nh h s tng quan

Xi, Yi i=1,n

XYr

:

i

XY2 22 2 2 2

i i

(Xi - X)(Yi - Y)

XY - X Ynr(Xi - X) (Yi - Y) X -(X) Y -(Y)

n n

(4.43)

:

i

Xi

X = n

; iYi

Y = n

; iXiYi

XY = n

(4.44)

2

2i

Xi

X = n

;

2

2i

Yi

Y = n

(4.45)

nh gi tin cy ca h s tng quan tu thuc vo s ln quan trc m s dng cc cng thc sau: - (n 50)

Tnh lch chun ca h s tng q :

19

2

r

1- r

n (4.46)

:

rr 3 (4.47)

2- Khi n < 50

Khi n < 50 s dng hm c bit phn b theo quy lut chun, c gi l tiu chun Fisher.

1 1+rZ = ln

2 1-r (4.48)

:

Z

1

n-3 (4.49)

Trong trng hp ny mi quan h tng quan gia X v Y cng c thit lp vi iu kin ging nh cng thc (4.47). 4.4.2. Xy dng hm hi quy

Khi quan h tng quan gia 2 i lng X v Y c xc lp, s s dng hm hi quy tuyn tnh n m t mi quan h , hm hi quy c dng.

Y a.X b (4.50) Cc tham s a, b ca hm hi quy c xc nh da trn nguyn l s

bnh phng nh nht hoc c th c xc nh nh sau: 2 2

XY2 2

X - (X)a r .

Y - (Y)

b Y - a.X

(4.53)

n dch cc cng trnh ln cn trong qu trnh thi cng mng v tng hm 4.5.1. Mt s tiu ch dng nh gi h hi s c cng trnh ln cn

Bin dng gc c dng nh gi s h hi ca cng trnh hin hu gn h o:

L

(4.59)

Trong : - l chnh ln ti 2 im cch nhau L. 4.5.2. nh gi mc h hi cng trnh ln cn

Da trn kt qu kho st, quan trc h o v cng trnh ln cn h o xp loi h hi cng trnh theo bin dng, t s a ra cc bin php (thit k v thi cng) nhm qun l ri ro trong xy dng mng v tng hm cng trnh nh cao tng. 4.5.3. Kim sot ri ro v s c cng trnh ln cn h o

20

h kt cu chng gi h o cng nh cng trnh ln cn n khng xy ra s c th phi khng ch chuyn dch ca cng trnh h o thng qua tnh ton v quan trc. 4.6. Thnh lp phn mm phn tch bin dng nn mng v tng hm 4.6.1. Ngn ng lp trnh

Ngn ng s dng lp trnh l ngn ng Visual Basic.NET (VB.NET). Phn mm c thnh lp mang tn ADFB c giao din gip cho ngi s dng d dng thao tc, kh nng tnh ton nhanh v cho kt qu ng tin cy. 4.6.2. Thit k tng quan phn mm Phn mm c thit k c cc tnh nng nh bng 4.3.

Bng 4.3. Tnh nng ca phn mm ADFB

Tp Tnh ton

chuyn dch M hnh

chuyn dch

Phn tch

v d bo chuyn dch

Tr gip

To tp

ln -Tham s ln -Th hin ha ln

M hnh ln -Tnh theo mt phng -Tnh theo parabol

-Tnh theo ng thng

-Phn tch tng quan tuyn tnh n -D bo chuyn dch theo hm a thc

HDSD

M tp

Chuyn dch ngang

-Tham s CDN - th CDN -Mt ct CDN

M hnh chuyn dch ngang

-Trong mt phng ngang -Trong mt phng ng -Tnh theo ng thng

Ghi

tp Ghi

tn

mi Thot

Chng 5. THC NGHIM 5.1. Thc nghim quan trc chuyn dch ngang tng vy nh cao tng trong giai on thi cng mng v tng hm

n d ng h thng quan trc t ng

Qu trnh thc nghim c thc hin i vi tng vy ca mt cng trnh nh cao tng qun Ba nh - TP. H N

,

chng thnh h o l tng vy c neo trong t.

H thng s dng quan trc chuyn dch lin tc ca tng vy l my TT Leica viva TS15PR1000 v phn mm quan tr

.

21

H thng quan trc t u u im ni tri hn so vi cng ngh truyn thng, l: chnh xc cao, thi gian cung cp kt qu nhanh nht, cung cp c nhiu thng tin nht, gim ti a cc ngun sai s o v tnh ton do yu t ch quan ca con ngi.

5.1.2. Thc nghim quan trc chuyn dch ngang tng vy cng trnh Cc tn s v tuyn in bng phng php trc a kt hp vi Inclinometer

kim chng l thuyt trn, tin hnh thc nghim i vi 5 v tr quan trc (ICL1, ICL2, ICL3, ICL4 v ICL5) ca tng vy cng trnh Cc tn s v tuyn in, s 115 Trn Duy Hng, H Ni. Ti mi v tr quan trc chuyn dch ngang bng Inclinometer tin hnh xc nh chuyn dch tm ming ng dn hng bng trc a.

Sau khi tnh ton xc nh c lch tm ming ng dn hng gia hai phng php, trong trng hp ny coi y ng dn hng l n nh nn lch ny chnh l sai s khp ca hai phng php, tin hnh phn phi sai s ny cho cc im o trong lng ng dn hng theo cng thc (3.35) s xc nh c gi tr chuyn dch vi chnh xc nng cao.

5.2. Thc nghim thnh lp m hnh ln nn mng cng trnh nh cao tng trong giai on thi cng mng v tng hm

5.2.1. Thc nghim thnh lp m hnh ln i vi mng cng trnh Nh Vn phng s 22-24-26 Mc Th Bi, TP. HCM

Trn c s s liu quan trc ln (ta , ln v sai s trung phng ln) ca 14 mc o ln [40]. Tin hnh s dng 11 mc o ln xy dng m hnh v 3 mc cn li so snh vi ln ni suy t m hnh. S dng phn mm ADFB xy dng m hnh, kt qu thu c:

Phng trnh mt phng ln:

S = -0.0000001x + 0.0000056y -0.00792 (m) vi sai s m hnh: 0.13mm.

nh gi bin dng mng cng trnh:

T sai s trung phng ln ca 11 mc quan trc tham gia xy dng m hnh tnh c m0 = 0.44mm. Khi :

2

2

0.13F 0.09

0.44; Fgh = F =0.05 (8,11) = 2.948

ghF F , iu chng t mng cng trnh khng b bin dng.

T kt qu xy dng m hnh v kt qu so snh ln o thc t vi ln ni suy c t m hnh, cho thy trong trng hp ny xy dng m hnh ln theo phng php mt phng l ph hp. Khi xy dng m hnh, p dng phn tch phng sai s cho php nh gi xem mng cng trnh c b bin dng hay khng.

5.2.2. Thc nghim xy dng m hnh ln nn cng trnh Trung tm giao

dch v Tng i Nam H Ni

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T s liu quan trc ln (ta , ln v sai s trung phng ln) ca 10 mc o ln [41]. Tin hnh s dng 08 mc o ln xy dng m hnh v 2 mc cn li so snh vi ln ni suy t m hnh. S dng phn mm ADFB xy dng m hnh, kt qu thu c:

M hnh ln nn dng parabol: S = -0.02773 + 0.0001905x + 0.0012355y -0.0000134x

2 + 0.0000004xy +

0.0000492y2

(m) vi sai s m hnh l: 0.76 mm Da vo kt qu xy dng m hnh v kt qu so snh ln o thc t

vi ln ni suy c t m hnh, cho thy trong trng hp ny s dng hm Parabol xy dng m hnh ln nn l ph hp. 5.3. Thc nghim xy dng m hnh chuyn dch ngang tng vy 5.3.1. Thc nghim xy dng m hnh chuyn dch ngang tng vy cng trnh Golden Palace, H Ni trong mt phng ngang

T s liu quan trc chuyn dch ngang (ta , gi tr chuyn dch ngang v sai s trung phng chuyn dch ngang) ca 15 mc quan trc, s dng 10 mc quan trc xy dng m hnh v 5 mc cn li so snh vi gi tr chuyn dch ni suy t m hnh. S dng phn mm ADFB xy dng m hnh, kt qu thu c: M hnh chuyn dch tng vy trong mt phng ngang:

qx = -0.0009800 - 0.0000318Y + 0.0000095X (m)

qy = 0.0012200 + 0.0000318X + 0.0000095Y (m)

Vi sai s m hnh : 2.49 mm nh gi bin dng ca tng vy:

T sai s trung phng chuyn dch ngang ca 10 mc quan trc tham gia xy dng m hnh tnh c m0 = 1.72 mm v tnh c:

2

2

2.49F 2.096

1.72; Fgh = F =0.05 (16,20) = 2.20

ghF F , iu chng t tng vy cng trnh khng b bin dng.

Da vo kt qu xy dng m hnh v kt qu so snh chuyn dch o thc t vi chuyn dch ni suy c t m hnh, cho thy trong trng hp ny xy dng m hnh chuyn dch tng vy trong mt phng ngang l ph hp. Phn tch phng sai cho php nh gi tng vy cng trnh c b bin dng hay khng. 5.3.2. Thc nghim xy dng m hnh chuyn dch ngang tng vy cng trnh trong mt phng ng

Trn c s s liu quan trc chuyn dch ngang (ta x, cao H, gi tr chuyn dch ngang theo hng vung gc vi tng vy v sai s trung phng chuyn dch ngang) ca 7 mc quan trc [42], s dng 5 mc quan trc xy dng m hnh v 2 mc cn li so snh vi gi tr chuyn dch ni suy t m hnh. S dng phn mm ADFB xy dng m hnh, kt qu thu c: Phng trnh mt phng chuyn dch:

23

q = -0.0000444x -0.0003826y -0.00024 (m) vi sai s m hnh: 2.95mm nh gi bin dng ca tng vy:

T sai s trung phng chuyn dch ngang ca 5 mc quan trc tnh c m0 = 1.29 mm v tnh c:

2

2

2.95F 5.229

1.29; Fgh = F =0.05 (2,5) = 5.786

ghF F iu chng t tng vy khng b bin dng.

Da vo kt qu xy dng m hnh v kt qu so snh chuyn dch o thc t vi chuyn dch ni suy c t m hnh, cho thy trong trng hp ny xy dng m hnh chuyn dch tng vy trong mt phng ng l ph hp. Trong qu trnh xy dng m hnh, p dng phn tch phng sai cho php nh gi bin dng ca tng vy. 5.4. Thc nghim phn tch tng quan tuyn tnh n gia mc nc ngm v ln nn nh cao tng

Trong phn thc nghi

ngoi sn xu : thi gian quan tr 15. p dng phn mm ADFB tnh ton v kt qu cui cng thu c nh sau:

1. H s tng quan: xyr 0.68

2. Hm Fisher: Z = -0.83

3. Phng sai ca i lng Z: Z 0.17

4. Phng trnh hi quy S = -0.03546H -0.34475 (m) Qua kt qu phn tch tng quan trn cho thy: ln nn t cng

trnh v mc nc ngm c mi quan h tng quan va. Trn c s kt qu thc nghim nhn thy phng php phn tch tng

quan tuyn tnh n dng nh gi mc ph thuc ca chuyn dch vi mt nhn t c th nh hng n chuyn dch l hon ton thch hp. Phng php ny gip chng ta bit c nhn t m chng ta nghi ng l c th nh hng n chuyn dch cng trnh thc ra n c nh hng hay khng v khi c nh hng th mc ph thuc ca nhn t ny n chuyn dch cng trnh nh th no. 5.5. Thc nghim d bo ln nn cng trnh theo hm a thc

Qu trnh thc nghim c thc hin i vi 1 mc (mc NT11) o ln nn t nguyn th ca cng trnh Trung tm giao dch v Tng i Nam H Ni, ti s 811 ng Gii Phng, H Ni [41], c o 11 chu k (khng bao gm chu k quan trc u tin), s liu quan trc gm thi gian, ln v sai s trung phng ln. S dng s liu 07 chu k (chu k 1 n chu k 7) lp m hnh, s liu chu k 8 n 11 c dng lm kt qu nh gi mc ph hp ca phn tch l thuyt v thc t. Ln lt xy dng m hnh t bc 0

24

n bc 5 v tin hnh nh gi mc tin cy ca m hnh bng phn tch phng sai. Kt qu cho thy a thc t bc 1 n bc 5 u c F

DANH MC CC CNG TRNH KHOA HC CA TC GI

CNG B LIN QUAN N NI DUNG LUN N

1. Trn Ngc ng (2009), Phn tch nh gi kt qu quan trc ln

cng trnh, Tp ch KHCN Xy dng s 1/2009, ISSN 1859-1566,

H Ni.

2. Trn Ngc ng (2011), Tnh ton v phn tch nh gi thng s

chuyn dch ngang cng trnh, Tp ch KHCN Xy dng s 2/2011,

ISSN 1859-1566, H Ni.

3. Trn Ngc ng (2011), nh gi mc ph thuc chuyn dch

cng trnh vo mt s yu t ngoi cnh bng phng php phn

tch tng quan tuyn tnh n, Tp ch KHCN Xy dng s

4/2011, ISSN 1859-1566, H Ni.

4. Trn Ngc ng, Dim Cng Huy (2012), ng dng my Ton c

in t Leica Viva TS15 v phn mm GOCA t ng quan trc

bin dng tng vy nh cao tng, Tp ch KHCN Xy dng s

3/2012, ISSN 1859-1566, H Ni.

5. Trn Ngc ng, on c Nhun (2012), Nghin cu s dng kt

hp ton c in t v Inclinometer quan trc chuyn dch

ngang tng vy cng trnh nh cao tng, Tuyn tp bo co Hi

ngh Khoa hc cn b tr - Vin KHCN Xy dng - Ln th 12, H

Ni 11/2012.

6. Trn Ngc ng, Trn Mnh Nht (2013), Nghin cu ng dng

ngi my trc a v phn mm GOCA quan trc chuyn dch

cng trnh Vit Nam, Tuyn tp bo co Hi ngh Khoa hc k

nim 50 nm ngy thnh lp Vin KHCN Xy dng (Phn 1: a

k thut Trc a cng trnh), ISBN 978-604-82-0021-3. Nh

xut bn Xy dng, H Ni 11-2013.

7. Trn Ngc ng, Nguyn H (2014), Phng php kim tra sai s

vt gii hn trong cc tr o quan trc ln cng trnh, Tp ch

KHCN Xy dng s 1/2014, ISSN 1859-1566, H Ni.