5/28/2018 Le Van Hung1.2011

1/7

NG DNG PHNG PHP O CAO HNH HC TRONG QUANTRC VNG CA H DM THP KHU LN

KS. NGUYN VN XUNThS. L VN HNGVin KHCN Xy dng

Tm tt: D n239/05 - B Cng an c xy dng trn din tch 5,8ha l t hp a chc nngvi tnh k thut, m thut rt cao, nh thit k a ra gii php thit k h dm thp vi khu

nhp l 43m,cao 8m v c lp t cao 31m so vi chn cng trnh. H dm gm 4 dmthp c t ln 4 vch b tng ct thp dy 1.4m. Do phi ti trng ca 10 tng nn h dmthp b vng, cc nh thit k tnh ton gi tr vng d kin ca h dm thp. theo di v

a ra gi tr vng thc t ca h dm thp trong qu trnh cht ti, Trung tm T vn Trc av Xy dng c giao nhim v quan trc vng ca h dm thp ny. Cn c vo nhngyu cu kht khe v k thut v trang thit b cng vi c im kt cu ca h dm thp, Trung

tm T vn Trc a v Xy dng la chn phng php o cao hnh hc quan trc vngh dm thp trn. Bi bo ny nu chi ti t phng php quan trc h dm thp bng phng phpo cao hnh hc.

1. M t kt cu

H dm thp c thit k nm trong h kt cu ca nh A thuc cng trnh tr s B Cng an.

H dm gm 4 dm thp c t ln 4 vch b tng ct thp dy 1.4m, mi dm c khu nhp l

43m, cao 8m v c lp t cao 31m so vi chn cng trnh, h dm phi ti trng ca 10

tng pha trn.

Hnh 1.H dm thp

Vi dng kt cu dm thp, vic xc nh gi tr vng ca dm c p dng theo tiu chunTCXDVN 338:2005 Kt cu thp Tiu chun thit k.

2. p dng phng php o cao hnh hc xc nh vng h dm thpkhu ln

2.1. Phng php o cao hnh hc

Phng php o chnh cao gia 2 im bng mt tia ngm nm ngang ca my thy chun. Gi

s c 2 im A, B trn thc a. t mia trn cc im A, B, ti v tr c th ngm ti 2 im A, B t

my thy chun. Hiu cao h = HA-HB l chnh cao ca im B so vi im A, l hiu cc s c

trn mia t ti A v ti B qua my thy chun. Nu 2 im A, B cch xa nhau , ti mt trm my

5/28/2018 Le Van Hung1.2011

2/7

khng thngm ti c 2 im A v B ta vn c th o c chnh cao gia 2 im ny bng cch

o chnh cao lin tip tng cp im gn nhau. im trc ca cp im ny l im sau ca cp

imni tip to thnh mt tuyn o lin tip. Khi h = HA- HB=S - Tr; S l tng cc s c mia

sau Tr l tng cc s c mia trc. o cao hnh hc c tin hnh theo tng tuyn. Nhiu tuyn

ni vi nhau to thnh mt li cao. Khi trong li ct nht 1 im bit cao, tin hnh tnh

ton bnh sai li cao o c s c cao ca cc im cn li trong li.

T mc 1 ta thy xc nh gi tr vng h dm thp ta cn xc nh gi tr cao ca 2im u dm v cc im cn xc nh gi tr vng trn dm thp. Khi ta cn o ni cc im

quan trc vng dm thnh cc vng cao khp kn v ni cc vng khp kn cao khp kn

ny vi cc mc cao c s.

2.2. La chn cp chnh xc o cao hnh hc v thit b s dng

a. La chn cp chnh xc o cao hnh hc

Theo tnh ton ca thit k gi tr bin dng vng nh nht ca h dm l 1.9mm, do vy sai s

quan trc ca kt cu khng vt qu 1 mm. Vi chnh xc nh vy chng ti la chn cp

o cao hnh hc c chnh xc tng ng li cao hng II.

b. Thit b s dng

Vic quan trc vng h dm thp c thc hin bng my thu b nh chnh xc cao NA2.

(hnh 2: My thu chun LEICA NA2 do Thu S sn xut).

Hnh 2. My Thu chun LEICA NA2

Bng 1.Mt s tnh nng k thut ca my NA2

ng knhGi tr phn

khong bt thuTnmy

NcSX vhng

phng

i

Khongcch ngn

nht

Btthudi

Bt thutrn

SSTP ochnh cao

1km i v v(mm)

Ghi ch

NA2Thu s

Leica 40x 0.9 mT

ng8/2 mm

S dngMicrometer:

0.3

2.3. Gii php thit k mc cao c s v mc quan trc vng dm

a. B tr, khoan gn h thng mc cao c s

Hai u h dm thp khu ln c gi ln 4 vch b tng rng 1.4m trn tng 9 ca 2 khi

nh hai bn. c c s chuyn cao vo cc mc quan trc vng ca h dm chng ti xy

dng h thng 3 mc chun quan trc c khoan su xung tng cui si, 3 mc chun c gi

nh cao v o ni vi nhau to thnh vng khp kn. Ti 2 khi nh hai bn uh dm chng ti

5/28/2018 Le Van Hung1.2011

3/7

khoan gn h mc ln vo cc ct chu lc ti tng 1 v tng 9 (v tr cc mc ln ti tng 1 v tng 9

tng ng vi nhau theo tng ct). T cao ca cc h 3 mc chun quan trc chuyn cao v o

cc mc ln ti hai khi nh u dm tng 1 sau t cao ca cc mc ln tng 1 chuyn

cao ln cc im ln ti tng 9. Ti mi chu k o chn ra mc ln n nh nht. T mc ln n

nh nht chuyn cao vo cc im o vng ca h dm.

b. Gii php thit k mc quan trc vng dm thp khu ln

* c im:

H dm thp khu ln l kt cu dng c bit, dm c cu to t nhng tm thp kh ln,

c lin kt vi nhau bi cc mi hn c bit. Khi thi cng xong dm c a ln trn cao

31m, sau sn chng g v sn chng chy. Khng ging nh cc cng trnh khc l c th t

trc tip mia ln cc i tng quan trc. H dm thp thi cng xong s khng t mia c ti v tr

cn quan trc. V vy ti cc v tr gn mc quan trc vng trn dm thp phi l loi mc c sn

mia trn . y l loi mc rt c bit, t trc n nay cha tng c cng trnh no s dng v

khng c bn trn th trng.

* Yu cu ca mc:

- Thp ch to mc c tnh cht ging thp ca dm;

- Sau khi hn gn mc vo dm thp, cc mi hnv sn chng g v sn chng chy;

-Thc chia vch ca mc khng c co dn theo thi gian;

- Cc k hiu trn mia phi r;

- Theo tnh ton ca thit k ti cc im y ca h dm u c gi tr v ng c th, v th

theo di gi tr vng ti cc v tr ny cn gn cc mc quan trc vng ti khi thp y h dm

theo ng v tr thit k (hnh 4).

* Thit k, ch to mc:

T nhng c im v yu cu ca mc. Cc cn b k thut ca Trung tm T vn trc a v

xy dng tm hiu, nghin cu v ch to ra loi mc p ng c cc yu cu kht khe k trn(hnh 3b).

a. Cu to mc chun quan trc b. Cu to mc gn trn h dm thpHnh 3. Cu to mc quan trc

Dm thp

V tr mi hn

Dy mia inva

Cht nh vmia

Thp gc

302

304

306

308

310

312

1

3

5

7

9

B tng

5/28/2018 Le Van Hung1.2011

4/7

Hnh 4. S b tr mc quan trc vng theo yu cu ca thit k

2.4. Phng php quan trc

Phng php o c s dng xc nh vng ca cng trnh l phng php o cao hnh

hc cp II.

Vic o vng c thc hin qua hai bc:

Bc 1.o li chun

Li chun l li gi nh cao ca mt mc chun v o ni cc mc chun vi nhau. Mc

ch ca vic o li chun l kim tra n nh ca cc mc chun. Vic o li chun c o

bng phng php o cao hnh hc chnh xc to thnh cc vng khp kn.

Bc 2. Dn cao t cc mc chun vo cc mc o ln

Mc ch ca vic dn cao vo cc mc o ln l xc nh cao thc t ca cc mc trong

chu k hin ti. Vic dn cao vo cc mc o ln c thc hin bng phng php o cao h nh

hc chnh xc theo mt hng. Khi ophi to thnh cc vng khp kn v tun th cc hn sai theo

quy phm hin hnh.

2.5. X l kt qu o

Sau khi o, kt qu c x l tnh ton bng cc phn mm chuyn dng trn my tnh. Li

cao o vng c bnh sai cht ch theo phng php s bnh phng nh nht. Trong li

chun c bnh sai ring chn ra mc chun n nh nht v da vo bnh sai tip li o

ln cng trnh. c kt qu l cao ca cc im mc quan trc vng dm p dng theo tiu

chun TCXDVN 338:2005 tnh vng ca h dm thp.

3. Kt qu o c tnh ton thc nghim

5/28/2018 Le Van Hung1.2011

5/7

Hin ti, Trung tm T vn trc a v Xy dng - Vin KHCN Xy dng quan trc vng

ca h dm thp khu ln c 11 chu k. Di y l kt qu tnh ton bnh sai ca chu k 1 v

chu k 11.

Kt qu tnh ton vng

Chu K1 (ngy 10/1/2010)

STT Tnim

Khong cchti u dm

phi(m)

Dm cao(m) Chnh cao TBso vi 2 imu dm (m)

vng sovi chu ktrc(mm)

vng sovi chu kgc (mm)

a b c d e f g h

1 D 1 38.34540

2 D 2 4.55 38.25443 -0.10897

3 D 3 12.95 38.24457 -0.15205

4 D 4 21.35 38.24904 -0.18081

5 D 5 29.75 38.21354 -0.24953

6 D 6 38.15 38.22548 -0.27081

7 D 7

Dmthp1

38.51429

8 D 14 38.58544

9 D 13 4.55 38.24372 -0.33898

10 D 12 12.95 38.24225 -0.33538

11 D 11 21.35 38.24287 -0.32969

12 D 10 29.75 38.21307 -0.35442

13 D 9 38.15 38.21637 -0.34605

14 D 8

Dmthp2

38.55968

15 D 15 38.58520

16 D 16 4.55 38.26148 -0.31185

17 D 17 12.95 38.25901 -0.29242

18 D 18 21.35 38.26460 -0.26492

19 D 19 29.75 38.25053 -0.25709

20 D 20 38.15 38.25099 -0.23473

21 D 21

Dmthp

3

38.4738522 D 28 38.32510

23 D 27 4.55 38.26302 -0.07897

24 D 26 12.95 38.25791 -0.11525

25 D 25 21.35 38.25032 -0.15401

26 D 24 29.75 38.24791 -0.18759

27 D 23 38.15 38.25133 -0.21534

28 D 22

Dmthp4

38.48356

Chu K 11(ngy 07/09/2010 )

STTTnim

Khong cchti u dm

phi (m)Dm cao(m)

Chnh cao TBso vi 2 imu dm (m)

vng sovi chu ktrc (mm)

vng sovi chu kgc (mm)

a b c d e f g h

1 D 1 38.34459

2 D 2 4.55 38.24783 -0.11480 -0.69 -5.84

3 D 3 12.95 38.23267 -0.16327 -1.19 -11.22

4 D 4 21.35

Dmthp1

38.23636 -0.19289 -1.49 -12.08

5/28/2018 Le Van Hung1.2011

6/7

5 D 5 29.75 38.20302 -0.25954 -0.97 -10.01

6 D 6 38.15 38.22068 -0.27519 -0.13 -4.37

7 D 7 38.51391

8 D 14 38.58350

9 D 13 4.55 38.23570 -0.34515 0.14 -6.17

10 D 12 12.95 38.22673 -0.34922 -0.63 -13.85

11 D 11 21.35 38.22525 -0.34581 -1.21 -16.1212 D 10 29.75 38.20152 -0.36465 -1.17 -10.22

13 D 9 38.15 38.20953 -0.35174 -0.38 -5.69

14 D 8

Dmthp2

38.55862

15 D 15 38.58350

16 D 16 4.55 38.25337 -0.31841 -0.56 -6.55

17 D 17 12.95 38.24384 -0.30630 -1.29 -13.88

18 D 18 21.35 38.24696 -0.28153 -1.78 -16.61

19 D 19 29.75 38.23544 -0.27141 -1.36 -14.32

20 D 20 38.15 38.24474 -0.24047 -0.60 -5.75

21 D 21

Dmthp3

38.47349

22 D 28 38.32339

23 D 27 4.55 38.25595 -0.08446 -0.83 -5.50

24 D 26 12.95 38.24415 -0.12769 -1.97 -12.45

25 D 25 21.35 38.23586 -0.16741 -2.21 -13.40

26 D 24 29.75 38.23314 -0.20157 -2.27 -13.97

27 D 23 38.15 38.24447 -0.22167 -1.13 -6.32

28 D 22

Dmthp4

38.48316

Biu vng ca dm thp s 3:

5/28/2018 Le Van Hung1.2011

7/7

BIU VNG DM S 3

-20

-15

-10

-5

0

5

TN IM QUAN TRC VNG

CK1

CK2

CK3

CK4

CK5

CK6

CK7

CK8

CK9

CK10

CK11

CK1 0 0 0 0 0 0 0

CK2 0.01 -1.28 -1.34 -2.05 -1.96 -0.42 0.45

CK3 0.27 -0.85 -1.12 -1.73 -2.03 -0.52 0.07

CK4 1.28 -0.86 -2.78 -4.05 -3.22 0.14 2.49

CK5 0.53 -2.98 -6.08 -7.78 -7.04 -1.76 1.88

CK6 0.98 -2.61 -6.25 -7.77 -6.53 -1.04 2.20

CK7 0.43 -3.68 -7.86 -9.84 -8.99 -2.61 1.63

CK8 -0.52 -5.68 -10.56 -12.49 -9.78 -2.27 2.08

CK9 0.15 -4.32 -10.26 -12.67 -10.81 -3.97 0.74

CK10 -0.21 -6.23 -12.86 -15.15 -13.32 -5.54 -0.42

CK11 -1.70 -8.11 -15.17 -17.64 -15.09 -6.25 -0.36

D15 D16 D17 D18 D19 D20 D21

c

3. Kt lun- Quan trc vng ca h dm thc cht l quan trc cao ca cc im u h dm v cc

im cn quantrc vng ca h dm;- Do c cu to v v tr c bit nn cc mc quan trc vng dm cn c thit k c bit

nhnu trn;- T nhng s liu quan trc v kt qu tnh ton cho thy: gi tr vng ca h dm thp th

hin ng quy lut bin dng vng ca h dm thp v u nm trong gii hn tnh ton ca thit k;- Nh vy phng php o cao hnh hc chnh xc cao hon ton p ng c cng tc

quan trc vng ca h dm v cc yu cu v chnh xc ca thit k;- C th s dng phng php o cao hnh hc chnh xc cao quan trc v ng ca cc

(hng mc) cng trnh tng t.TI LIU THAM KHO

1. NGUYN TRNG SAN, O QUANG HIU, INH CNG HA, Trc a c s - tp 1,2. PHM VN HI, NGUYN QUANG VIN, Kt cu thp - Cng trnh dn dng v cng nghip.

3. B Xy dng, TCXDVN 338:2005 Kt cu thp - Tiu chun thit k.4. B Xy dng, TCXDVN 271:2002 Quan trc ln cc cng trnh dn dng v cng nghip bng

phng php thu chun hnh hc.5. B Xy dng, TCXDVN 309:2004 Cng tc trc a trong xy dng - Yu cu chung.6. Trung tm T vn Trc a v Xy dng VinKHCN Xy dng, cng Quan trc chuyn v

v bin dng h dm thp khu ln.