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BO CO A CHT CNG TRNH

Cng trnh: KHU PH THNG MI LIN K 25 CN.a im: ng 30 thng 4, th x Ty Ninh, Tnh Ty Ninh.

I- M UCng tc khoan kho st a cht phc v cho vic thit k xy dng Khu ph Thng Mi Lin k 25 cn ti ng 30 thng 4,Th x Ty Ninh,Tnh Ty Ninh thc hin t ngy 25.2.2002 n ngy 1.03.2002.Khi lng kho st gm 3 h khoan,mi h su 15.0m,mang k hiu HK1, HK2 ,HK3.Tng su khoan l 45mvi 22 mu t nguyn dng dng thm d a tng v th nghim xc ng tnh cht c l ca cc lp t.II-CU TO A CHTT mt t hin ha n su kho st l 15.0m,nn t ti y c cu to bi 5 lp t,th hin trn hnh tr h khoan theo th t t trn xung di nh sau:

Mt ct a cht :

1./Lp t s 1(ch c ti HK1)t st ln ct, mu nu ,dy 0.5m2./Lp t s 2St pha nhiu ct ,mu xm nht n xm trng m nu vng /nu , do trung bnh - trng thi do cng n na cng,gm 2 lp:* Lp 2a: Trng thi do cng :c b dy ti HK1=5.5m, HK2=5.3m,HK3=3.2m, vi cc tnh cht c l c trng nh sau:- m :W= 21.4%

- Dung trng t nhin : w=1.885 g/cm3- Sc chu nn n : Qu= 1.211 kG/cm2- Lc dnh n v : C= 0.151 kG/cm2- Gc ma st trong : = 14030* Lp 2b:Trng thi na cng , c b dy ti HK3=2.5m vi cc tnh cht c l c trng nh sau:- m :W= 20.1%

- Dung trng t nhin :w= 1.917 g/cm2- Lc dnh n v : C= 0.241 kG/cm2- Gc ma st trong : = 1703./Lp t s 3St pha ct ln si sn laterite, mu nu vn xm trng,m vng nu, do trung bnh- trng thi na cng; c b dy ti HK1=1.5m, HK2=1.9m, HK3=1.3m vi cc tnh cht c l c trng nh sau:- m :W= 20.1%

- Dung trng t nhin :w= 1.972 g/cm3

- Dung trng y ni : s=1.031 g/cm3- Lc dnh n v : C= 0.255 kG/cm2- Gc ma st trong : = 160134./Lp t s 4Ct mn ln bt , mu xm trng vn nu vng nht - trng thi bi ri; c b dy ti HK1=4.1m,HK2=4.3m, HK3=4.5m vi cc tnh cht c l c trng nh sau:- m : W= 25.7%


- Dung trng y ni :s=0.925 g/cm3- Lc dnh n v : C= 0.025 kG/cm2- Gc ma st trong : = 2705./ Lp t s 5St ln bt v t ct, mu xm trng/ nu nht n nu nht, do cao trng thi na cng : c b dy ti HK1=3.4m, HK2=3.5m, HK3=3.5m, vi cc tnh cht c l c trng nh sau:- m :W= 25.1%


- Dung trng y ni :s=0.995 g/cm3-Sc chu nn n : Qu= 2.060 kG/cm2- Lc dnh n v :C= 0.290 kG/cm2- Gc ma st trong := 150Trong phm vi kho st, a tng khu vc chm dt y.III- TNH CHT C L V A CHT THU VNTnh cht vt l v c hc ca cc lp tc xc nh theo tiu chun ca ASTM v phn loi theo h thng phn loi thng nht, c thng k trong Bng tnh cht c l ca cc lp t km theo bo co ny.Ti thi im kho st (thng 2/2002) mc nc ngm n nh c ghi nhn su -5.5m so vi mt t hin ha.IV- KT LUNCng tc kho st a cht cng trnh Khu ph thng mi Lin K 25 cn ti ng 30 Thng 4, Th x Ty Ninh, Tnh Ty Ninh ho thy nn t ti y c cu to a cht nh sau: Lp t s 1: t st ln ct,dy 0.5m(ch c ti HK1) Lp t s 2:St pha nhiu ct - trng thi do cng (lp 2a) n trng thi na cng (lp 2b) l cc lp t tt Lp t s 3:St pha ct ln si sn laterite - trng thi na cng cng l lp t tt. Lp t s 4:Ct mn - trng thi bi ri l lp t tng i. Lp t s 5:St - trng thi na cng l lp t tt. xy dng,ngi thit k cn kt hp ti trng ca cng trnh vi s liu a cht ca tng h khoan tnh ton kch thc v su t nn mng thch hp v an ton.Ngoi ra ,lp t s 2 cn rt d b thm nc b mt ,khi sc chu ti ca nn t s gim i.ngi thit k cn la n c tnh ny c h thng thot nc cho tt,trnh nc b mt thm vo chn mng gy nh hng n cng trnh.V- THNG K*Lp t s 1: Khng thng k.*Lp t s 2: Gm 2 lp.c im chung: st pha nhiu ct, mu xm nht n xm trng m mu nu vng/ nu , do trung bnh trng thi do cng.*Lp t s 2a su: HK1= 0.0 - 5.5m, HK2= 0.0 - 5.3m, HK3= 2.5 - 5.7m.c im: Trng thi do cng.Theo s liu thi nghim, co 6 mu lp t th nht (nghia la cac chi tiu co 6 tri s ring) ta tp hp lai va tinh tri s trung binh s hoc:Bang 10.3-1: Tp hp cac chi tiu c ly cua lp t 2a:

w d s W(%) WL(%) WP(%) IP(%) e

Theo TCVN 45-78 quy inh, tr , tt ca cac chi tiu khac co tri s tinh toan bng tri s tiu chun. Vy: W(%) WL(%) WP(%) IP(%) e

H s lun ai (cm2/kg) va modul tng bin dang Ei (kg/cm2):Bang 10.3-2:

Vy: ai = 0.135Ei = 41.520Vi , h s kd 1 nn ta tip tuc tinhTrng hp w: Bang 10.3-3:

Chon tri s thng k:

Tra bang 10.2, ta co = 2.07 (khi n = 6),

Vy khng co tri s nao bi loai bo khoi tp hp thng k.

Tinh toan theo trang thai gii han th nht, theo TCVN 45-78 ta chon = 0.95. Vi n-1 = 6-1 = 5 va = 0.95 tra bang 1-2, trang23 _Chu Ngc n- Nn Mng Cng Trnh ta co t = 2.01. Vy:

Tinh toan theo trang thai gii han th hai, theo TCVN 45-78 chon = 0.85. Vi n-1 = 6-1 =5 va =0.85 tra bang 1-2, trang23 _Chu Ngc n- Nn Mng Cng Trnh ta co t = 1.16. Vy:

Trng hp d: Bang 10.3-4:

Chon tri s thng k:

Tra bang 10.2, ta co = 2.07 (khi n = 6),

Vy khng co tri s nao bi loai bo khoi tp hp thng k.

Khi tinh toan theo trang thai gii han th nht, theo TCVN 45-78 ta chon = 0.95. Vi n-1 = 6-1 = 5 va = 0.95 tra bang 1-2, trang23 _Chu Ngc n- Nn Mng Cng Trnh ta co t = 2.01. Vy:

Khi tinh toan theo trang thai gii han th hai, theo TCVN 45-78 chon = 0.85. Vi n-1 = 6-1 =5 va =0.85 tra bang 1-2, trang23 _Chu Ngc n- Nn Mng Cng Trnh ta co t = 1.16. Vy:

Trng hp s:Bang 10.3-5:

Vy:

By gi ta tim tri s tiu chun, tri s tinh toan cua c va . xac inh ctt, tt ta co th thc hin nhanh chong nh sau:ng dung ham linest cua MS Excel trong thng k s liu ia cht (c, ):Ta ghi kt qua ng sut ct cc ai max vao ct 1.Ta ghi cac ng sut phap tng ng i vao ct 2.Chon mt bang gm 5 hang 2 ct, anh vao lnh:= linest (vi tri day s max vi tri day s i,1,1).Nhn cung luc Shift+Ctrl+Enter ta co c cac gia tri sau ( tri tiu chun): A (=tg), B (=c), C (=tg), D (=c).

Ta co th kim tra lai vi cach tinh bng cac cng thc nh sau: y ta co 3 mu, mi mu nen 3 cp ap lc; vy co tt ca 3.3 = 9 tri s thi nghim. Thc hin cac tinh toan phu:Chon tr s thng k:

Vi pi = 1.0 (kg/cm2):

Tra bang 10.2, ta co = 2.07 (khi n=6),

Vi pi = 2.0 (g/cm2):


Vi pi = 3.0 (g/cm2):


Vy khng co tri s i nao bi loai bo khoi tp hp thng k:

Bng 10.3-7:

Ta co:

Theo cac biu thc (1.7), (1.8), (1.9) ta tinh c:

xac inh ctt, tt ta cn tinh c lch cua chung. Tinh ai lng phu:

Bng 10.3-8

Vy: T o, theo biu thc (1.20) ta tinh c lch cua :

Vy, theo ( 1.18) va ( 1.19) lch cua c va la:

Khi tinh toan theo trang thai gii han th nht, theo TCVN 45-78 ta chon = 0.95. Vi n-2 = 18-2 = 16 va = 0. tra bang 1-2, trang23 _Chu Ngc n- Nn Mng Cng Trnh ta co t = 1.75. Vy:


Kt qua nh sauBang 10.3-9: Gia tri thng k tt, ctt, tgtt:

TT tinh toanwttdttsttctttgtt

TTGH I1.8761.9021.5311.5770.9500.1080.2340.2390.295

TTGH II1.8811.8971.5411.5670.9500.1320.2100.2500.284

*Lp t 2b su: HK1= 0.0m, HK2= 0.0m, HK3= 0.0 - 2.5m.c im: Trng thi do cng.Theo s liu thi nghim, co 1 mu lp t th nht (nghia la cac chi tiu co 1 tri s ring) ta tp hp lai va tinh tri s trung binh s hoc:Bang 10.3-1: Tp hp cac chi tiu c ly cua lp t 2a:

w d s W(%) WL(%) WP(%) IP(%) e

Theo TCVN 45-78 quy inh, tr , tt ca cac chi tiu khac co tri s tinh toan bng tri s tiu chun. Vy: W(%) WL(%) WP(%) IP(%) e

H s lun ai (cm2/kg) va modul tng bin dang Ei (kg/cm2):Bang 10.3-2:

Vy: ai = 0.120Ei = 45.330Vi , h s kd 1 nn ta tip tuc tinh:Trng hp w: Bang 10.3-3:

Vy:

Trng hp d:Bang 10.3-4:

Vy:

Trng hp s:Bang 10.3-5:

Vy:

By gi ta tim tri s tiu chun, tri s tinh toan cua c va . xac inh ctt, tt ta co th thc hin nhanh chong nh sau:ng dung ham linest cua MS Excel trong thng k s liu ia cht (c, ):Ta ghi kt qua ng sut ct cc ai max vao ct 1.Ta ghi cac ng sut phap tng ng i vao ct 2.Chon mt bang gm 5 hang 2 ct, anh vao lnh:= linest (vi tri day s max vi tri day s i,1,1).Nhn cung luc Shift+Ctrl+Enter ta co c cac gia tri sau ( tri tiu chun): A (=tg), B (=c), C (=tg), D (=c).

Ta co th kim tra lai vi cach tinh bng cac cng thc nh sau: y ta co 1 mu, mi mu nen 3 cp ap lc; vy co tt ca 1.3 = 3 tri s thi nghim. Thc hin cac tinh toan phu:Chon tr s thng k:

V lp 2b ch c 1 mu nn khng co tri s i nao bi loai bo khoi tp hp thng k.

Bng 10.3-7:

Theo cac biu thc (1.7), (1.8), (1.9) ta tinh c

xac inh ctt, tt ta cn tinh c lch cua chung. Tinh ai lng phu: Bng 10.3-8

Vy: T o, theo biu thc (1.20) ta tinh c lch cua :

Vy, theo ( 1.18) va ( 1.19) lch cua c va la:



Kt qua nh sau:

Bang 10.3-9: Gia tri thng k tt, ctt, tgtt:TT tinh toanwttdttsttctttgtt

TTGH I1.9171.5960.0000.2350.2470.3030.309

TTGH II1.9171.5960.0000.2380.2440.3050.307

Phn 2THIIT K MNG N, MNG BNG V MNG CC

MNG BNG TRN NN T NHIN

Bng 1.1. Ti trng tnh ton mng di ct. Ct4 - C4 - D4 - E

N (T)627085

M (T.m)6.18.16.5

Q (T)3.51.61.0

Ti trng tc dng ln mng bng (vi h s vt ti n = 1,15)Bng 1.2. Ti trng tiu chun

Ct4 - C4 - D4 - E

N (T)53.960.973.9

M (T.m)5.37.05.7

Q (T)3.01.40.9

I- CHN KCH THC S B :- Kch thc ct : bc x ac = 300 x 300- Ta c: Ntc =N = (53,9+60,9+73,9)= 188,7 T Tng chiu di mng bng L = 1+3+4+1,5 = 9,5mV mng phi t trn nn t tt nn da vo kt qu th nghim a cht ta chn t mng ti lp t 2 c Df = 2m

Lp t s 2 :Trng thi do cng :c b dy ti HK1=5.5m, HK2=5.3m,HK3=3.2m, vi cc tnh cht c l c trng nh sau:- m :W= 21.4%

- Dung trng t nhin : w=1.885 g/cm3- Sc chu nn n : Qu= 1.211 kG/cm2- Lc dnh n v : C= 0.151 kG/cm2- Gc ma st trong : = 14030Chn th mng c cnh b = 1m

Ta c:Theo QPXD 45 -70 sc chu ti ca t nn di y mng ( lp t th ba)

Vi m = 1 v ta c:

308,02180.30143014cot.25,02cot.25,0'0'0ggA

232,22180.30143014cot12cot1'0'0ggB766,42180.30143014cot3014cot.2cotcot.'0'0'0ggggD = 2.1 =2.1,885 = 3,77 (T/m2) Khi m b = 1m, hm= 2m ta c = 1.(0,308.1.1,885+2,232.3,77+4,766.1,51) = 16,2 T/m2 = 162 KN/m2

Khi :

Chn B=2 mVy kch thc mng:

M ta c:

Vy nn iu kin lm vic nh mt vt liu n hi.Theo h s a cht th t nn di mng bng l lp t st pha nhiu ct ,mu xm nht n xm trng m nu vng /nu , do trung bnh - trng thi do cng n na cng => Tra bng 3.1 ( H s tiu chun Terzaghi ) Trang 159 - Chu Ngc n Nn mng cng trnh ta c = 50 (MN/)= 5000 (T/m3).H s nn di mng vung cnh 2m:

Trn nn st: k2 x 2 = = 5000.=750 (T/m3) H s nn di cnh mng bng hnh ch nht cnh b=2,4m, L=17m,h s nn c chuyn i t mng bng vung c cng p lc tc ng l :

(T/m3)Khi h s nn di mng hnh bng cnh 2.4m l:k*=k.b=500.2=1000 (T/m2)c trng hnh hc ca tit din mng chn:-Xc nh tm mng:

FxFyiiic80.30.250.40=17,94 (cm)15.80.30.225.50.40.Momen qun tnh i vi tm mng: Jx = Jx1 + 2.Jx2

Jx = Jx1 + 2.Jx2 = 516353 + 2.200886 = 929723 (cm4)

Chn btng mc B25 c:Moun n hi ca btng: E = 3.105 (KG/cm2)= 2,65.106 (T/m2)Cng chu ko Rbt =1,05 (KG/cm) = 105 (T/m2)

Ta c : 0,319.9,5 = 3,03 > (/4 ) Do ta xem dm mng l di v hn.Do mng bng trong trng hp ny l mng mm nn ti trng t ti mi ct s nh hng n cc v tr ct khc do ngoi lc gy ra theo cc cng thc sau:Ta c ti mi ct ti trng cng trnh truyn xung mng bng trn nn Winklerc tnh theo cng thc sau:+ Khi ti l lc tp trung:q(x) =.A(x)y(x) = .A(x) M = .C(x) Q = D(x)+ Khi ti l moment tp trung:y = .B(x) q(x) = 2.Mo.B(x)M = .D(x) Q = (x) Cc h s:(x) = e-x.cos(x) + e-x.sin(x)B(x) = e-x.sin(x)C(x) = e-x.cos(x) e-x.sin(x)D(x) = e-x.cos(x)II - NI LC TRONG DM MNG, PHN LC T NN, VNG CA MNG DO TI TRNG CNG TRNH LN MNG :Do mng bng trong trng hp ny l mng mm nn ti trng t ti mi ct khng ch nh hng n v tr ca chnh n m cn nh hng n cc v tr khc. Nn ta tnh nh hng ca lc N, M ti mi ct, sau tng hp tt c cc nh hng ca cc ct ta s c biu vng, phn lc t nn, lc ct, moment. Vic tnh ton oc th hin thng qua cc bng tnh sau:IIi - NOI LC TRONG DAM MONG, PHAN LC AT NEN, O VONG CUA MONG DO TAI TRONG CONG TRNH LEN MONG :CT CP=62T

M=7.85T.m

iemXxCM (do P)DQ (do P)AM (do M)Q (do M)Bq(x)y(x)

110.320.4622.460.69-21.400.922.71-1.1500.239.260.009

200148.591-31.0013.93-1.2509.890.010

31.50.480.2612.860.55-17.050.842.16-1.050.298.490.008

430.96-0.09-4.510.22-6.860.540.87-0.670.315.540.006

551.60-0.21-10.090.000.150.1979-0.02-0.2480.202.120.002

672.23-0.15-7.31-0.072.040.02-0.26-0.020.0850.250.000

78.52.71-0.09-4.28-0.061.87-0.03-0.240.040.03-0.300.000

CT DP=70T

M=8.9T.m


141.28-0.1860-10.200.08-2.840.350.36-0.490.083.960.004

230.96-0.09-5.090.22-7.740.540.98-0.760.226.180.006

31.50.480.2614.520.55-19.250.842.45-1.190.559.830.010

400154.861-3514.45-1.42112.070.012

520.640.116.020.42-14.850.741.89-1.050.428.640.009

641.28-0.19-10.200.08-2.840.350.36-0.490.083.960.004

75.51.75-0.20-11.06-0.031.110.14-0.14-0.20-0.031.520.002

CT EP=85T

M=7T.m


182.55-0.11-7.20-0.062.75-0.02-0.230.020.043-0.260.000

272.23-0.15-10.02-0.072.800.02-0.23-0.020.080.310.000

35.51.75-0.20-13.43-0.031.340.14-0.11-0.150.172.000.002

441.28-0.19-12.390.08-3.450.350.28-0.390.274.910.005

520.640.117.310.42-18.040.741.49-0.830.3110.240.010

600166.611-4313.50-1.12013.560.014

71.50.480.2617.640.55-23.380.841.93-0.930.2911.530.012

BNG TNG HP M DO N CA TT C CC CT TC DNG LN MNG

M (do P)ABCTNG

22.46-10.20-7.205.06

CT A48.59-5.09-10.0233.48

12.8614.52-13.4313.95

CT B-4.5154.86-12.3937.96

-10.096.027.313.24

CT C-7.31-10.2066.6149.10

-4.28-11.0617.642.29

BNG TNG HP M DO Moment CA TT C CC CT TC DNG LN MNG

M (do M)ABCTNG

-2.71-0.360.23-2.84

CT A-3.933.93-0.980.23-4.683.17

2.16-2.450.11-0.18

CT B0.87-4.454.45-0.28-3.875.03

-0.021.89-1.490.38

CT C-0.260.36-3.503.50-3.403.60

-0.24-0.141.931.55

BNG TNG HP LC CT Q DO Momnet CA TT C CC CT TC DNG LN MNG

Q (do M)ABCTNG

-1.15-0.490.02-1.62

CT A-1.25-0.76-0.02-2.03

-1.05-1.19-0.15-2.39

CT B-0.67-1.42-0.39-2.48

-0.248-1.05-0.83-2.12

CT C-0.02-0.49-1.12-1.63

0.04-0.20-0.93-1.09

BNG TNG HP LC CT Q DO N CA TT C CC CT TC DNG LN MNG

Q (do N)ABCTNG

21.402.84-2.7521.48

CT A31.0-31.07.74-2.8035.94-26.06

-17.0519.25-1.340.86

CT B-6.8635-353.4531.59-38.41

0.15-14.8518.043.34

CT C2.04-2.8443-4341.70-43.30

1.871.11-23.38-20.40

Tng M (do N v M)Tng Q (do N v M)

CTDo NDo MTngCTDo MDo NTng

5.06-2.842.21-1.6221.4819.86

C33.48-4.683.1728.8036.65C-2.0335.94-26.0633.91-28.09

13.95-0.1813.78-2.390.86-1.53

D37.96-3.875.0334.1043.00D-2.4831.59-38.4129.11-40.89

3.240.383.62-2.123.341.21

E49.10-3.403.6045.7052.70E-1.6341.70-43.3040.07-44.93

2.291.553.84-1.09-20.40-21.49

Tng phn lc t nn qTng vng ca mng y

CTABCTNGCTABCTNG

9.263.96-0.2612.960.00930.0040-0.00030.0130

C9.896.180.3116.38C0.00990.00620.00030.0164

8.499.832.0020.310.00850.00980.00200.0203

D5.5412.074.9122.52D0.00550.01210.00490.0225

2.128.6410.2421.000.00210.00860.01020.0210

E0.253.9613.5617.77E0.00030.00400.01360.0178

-0.301.5211.5312.75-0.00030.00150.01150.0127

III B TI TRNG :Sau khi tng hp ni lc tc dng ln mng do ti cng trnh tc dng ln mng bng thit k, ta thy hai u mt ca mng xut hin cc ni lc Mt , Qt v ti u mt phi ca dm mng tn ti gi tr Mph; Qph Do kh ni lc d ny, phi t h ti trng b , v , ti hai u mt ca dm mng. = 4.Mt ; = 4..Mt + 4.Qt = 4.Mph ; = 4..Mph 4.QphMomen M, lc ct Q, p lc t q(x) v vng y trong dm mng do h ti trng b t ti mt tri c tnh theo cng thc: = .D(x) + .C(x) = .D(x) .A(x)q(x) = .A(x) + .B(x)

y = .B(x) + .A(x)Momen M, lc ct Q, p lc t q(x) v vng y trong dm mng do h ti trng b t ti mt phi c tnh theo cng thc: = .D(x) + .C(x) = .D(x) .A(x)q(x) = .A(x) + .B(x)y = .B(x) + .A(x)

B tri ln 1

= 0.3191/m

Mt =2.21T.mMo(trai) = -133.38T.m

Qt =19.86TQo(trai) = 82.27T

imxxC(x)D(x)A(x)B(x)MQ q(x)y

1001111-2.21-19.86-0.450-0.014

210.320.460.690.920.69-16.23-8.862.681-0.009

32.50.80-0.010.310.640.31-21.480.614.088-0.004

441.28-0.190.080.350.08-17.404.073.469-0.001

561.91-0.19-0.050.09-0.05-8.853.941.8450.001

682.55-0.11-0.06-0.02-0.06-2.652.210.5980.001

79.53.03-0.0533-0.05-0.04-0.05-0.241.070.0920.001

Tng M sau khi b triTng Q sau khi b tri

CTMM bTngCTQQ bTng

2.21-2.21019.86-19.860

C28.8036.65-16.2312.5820.43C33.91-28.09-8.8625.05-36.95

13.78-21.48-7.70-1.530.61-0.92

D34.1043.00-17.4016.7025.60D29.11-40.894.0733.18-36.82

3.62-8.85-5.231.213.945.15

E45.7052.70-2.6543.0550.05E40.07-44.932.2142.28-42.72

3.84-0.243.60-21.491.07-20.42

B phi ln 1

= 0.3191/m

Mp =3.60T.mMo(phi) = 142.45T.m

Qp =-20.42TQo(phi) = 86.29T


19.53.03-0.053-0.05-0.040.005-0.19-1.10-0.51-0.001

28.52.71-0.09-0.06-0.030.03-1.66-1.86-0.050.000

372.23-0.15-0.070.020.08-5.48-3.271.480.001

45.51.75-0.20-0.030.140.17-11.39-4.514.370.004

53.51.12-0.150.140.440.29-20.41-3.7510.290.010

61.50.480.260.550.840.29-21.284.7515.630.016

7001110-3.6020.4213.760.014

Tng M sau khi b phiTng Q sau khi b phi

CTMM bTngCTQQ bTng

0-0.19-0.190-1.10-1.10

C12.5820.43-1.6610.9218.77C25.05-36.95-1.8623.19-38.81

-7.70-5.48-13.18-0.92-3.27-4.19

D16.7025.60-11.395.3114.21D33.18-36.82-4.5128.67-41.33

-5.23-20.41-25.645.15-3.751.40

E43.0550.05-21.2821.7728.77E42.28-42.724.7547.03-37.97

3.60-3.600-20.4220.420

B tri ln 2

= 0.3191/m

Mt =-0.19T.mMo(trai) = 7.66T.m

Qt =-1.10TQo(trai) = -4.65T


10011110.191.100.0390.000

210.320.460.690.920.690.960.48-0.1420.000

32.50.80-0.010.310.640.311.23-0.05-0.2270.000

441.28-0.190.080.350.080.99-0.24-0.1950.000

561.91-0.19-0.050.09-0.050.50-0.22-0.1050.000

682.55-0.11-0.06-0.02-0.060.15-0.12-0.0350.000

79.53.03-0.05-0.05-0.04-0.050.01-0.06-0.0060.000

Tng M sau khi b triTng Q sau khi b tri

CTMM bTngCTQQ bTng

-0.190.190-1.101.100

C10.9218.770.9611.8819.73C23.19-38.810.4823.67-38.33

-13.181.23-11.95-4.19-0.05-4.24

D5.3114.210.996.3015.20D28.67-41.33-0.2428.44-41.56

-25.640.50-25.141.40-0.221.18

E21.7728.770.1521.9228.92E47.03-37.97-0.1246.91-38.09

00.010.010.00-0.06-0.06

B phi ln 2

= 0.3191/m

Mp =0.01T.mMo(phii) = 0.41T.m

Qp =-0.06TQo(phi) = 0.25T


19.53.03-0.053-0.05-0.040.0050.000.000.000.000

28.52.71-0.09-0.06-0.030.030.00-0.010.000.000

372.23-0.15-0.070.020.08-0.02-0.010.000.000

45.51.75-0.20-0.030.140.17-0.03-0.010.010.000

53.51.12-0.150.140.440.29-0.06-0.010.030.000

61.50.480.260.550.840.29-0.060.010.050.000

7001110-0.010.060.040.000

Tng M sau khi b phiTng Q sau khi b phi

CTMM bTngCTQM bTng

0.00-0.0010.0000.000.00

C11.8819.73-0.00511.8819.73C23.67-38.33-0.0123.66-38.34

-11.95-0.016-11.97-4.24-0.01-4.25

D6.3015.20-0.036.2615.16D28.44-41.56-0.0128.42-41.58

-25.14-0.06-25.201.18-0.011.17

E21.9228.92-0.0621.8628.86E46.91-38.090.0146.92-38.08

0.01-0.010-0.060.060

Tng phn lc t nn q sau khi b

imCTq (x)B tri 1B phi 1B tri 2B phi 2q (T/m)

112.96-0.45-0.510.04-0.00112.04

2C16.382.68-0.05-0.140.00018.87

320.314.091.48-0.230.00425.66

4D22.523.474.37-0.190.01330.18

521.001.8410.29-0.100.03033.06

6E17.770.6015.63-0.030.04534.01

712.750.0913.76-0.010.04026.64

TNG VNG y CA MNG SAU KHI B

imCTy B tri 1B phi 1B tri 2B phi 2y (mm)

10.013-0.014-0.0010.0000.000-0.001

2C0.016-0.0090.0000.0000.0000.007

30.020-0.0040.0010.0000.0000.017

4D0.023-0.0010.0040.0000.0000.026

50.0210.0010.0100.0000.0000.032

6E0.0180.0010.0160.0000.0000.034

70.0130.0010.0140.0000.0000.027

II KIM TRA SC CHU TI CA T NN :

Theo QPXD 45 -70 sc chu ti ca t nn di y mng Khi m b = 2,4 m, hm= 2 m ta c

Vi m = 1 v ta c: A=0,308; B=2,235; D= 4,766

(T/m2) t nn m bo lm vic bnh thng th :pmax 1,2.Rtcpmin > 0

Da vo biu phn lc nn ta c qmax = 34,01 (T/ m) v qmin = 12,04 (T/m)Khi phn lc nn ln nht theo tit din mng bng:

= = = 17,005(T/m2)

= = = 6,02 (T/m2)Ta thy = 17,005(T/m2) < 1,2.Rtc =1,2.16,77= 20,124 (T/m2) = 6,02 (T/m2) > 0 t nn m bo kh nng chu ti.

VI - KIM TRA KH NNG CHNG XUYN THNG CA MNG:

a - Theo phng ngang:- Kim tra ti v tr c phn lc nn ln nht v ti mng s nguy him nht d b thng nht.- T biu phn lc t nn ta c : qmax = 34,01(T/ m)

=> pmax = (T/m2) - Theo quy phm ta c: Trong mng ta c : Trong : B tng s dng l B25 c:Rbt = 10,5 kg/cm2=105 T/m2 Sc = b.h0 = 1.0,25 = 0,25m2ED=> 0,75.105.0,25 = 19,69 T

- Mt khc ta c : Qxt = p*.L = 17,005*0,5 = 8,5TTa thy Qxt = 8,5 T < [Q]= 19,69 T Kt lun : Vy theo phng ngang mng m bo kh nng chng xun thng.

b - Theo phng dc:Theo quy phm ta c: Trong mng ta c : Trong :- Sc =30*200+40*20 = 6800 cm2- B tng s dng l b tng B25 c: Rbt = 10,5 kg/cm2

=> (kg) = 53,5 (T)

Ta thy Qmax =46,92 (T) < T Nh vy theo phng dc dm mng m bo yu cu kh nng chng xuyn thng.

VII - KIM TRA LN CA NN:

Da vo biu vng ta thy ln ca cng trnh gy ra chnh l vng ln nht ca dm mng:Ta c: S = 0,034 mm = 0,34 ( cm ) < [S] = 8 cmVy mng thit k tho mn yu cu v ln cho php.

VIII - TNH TON CT THP TRONG MNG BNG:1 Tnh ton thit k ct thp theo phng dc mng (dm mng):S dng cc mt ct ti v tr c moment ln tnh ct thp.

- Chn Btng Mc B25 Rb= 145 kg/cm2; Rbt = 10,5 kg/cm2- Ct thp CII c Rs = 2800 kg/cm2- Ta xem nh lc tnh ton truyn ht ln dm mng do ta tnh thp theo tit din 40 x 80cm l tit din ca dm mng.- Ta tnh ton thit k ct thp nh dm ngc.- Vi b tng nng ta c: = 0,85 0,008.Rb = 0,85 0,008.14,5 = 0,734=> => R = R.(1 0,5. R) = 0,595.(1 0,5.0,595) = 0,418

a Tit din mt ct I - I:

- Ti tit din ny dm mng chu moment dng M = 19,73 T.m = 19,73.105 (kg.cm)- Chn a = 5cm => h0= 80 - 5 = 75 cm

Ta c = =< R = 0,418 .Tnh tn thit k ct thp theo bi tan ct n.185,0167,0.211211m- Khi din tch ct thp cn thit cho tit din l: cm217 ,24280045.40.145.185,0...sobsRhbRA - Kim tra hm lng thp:% tha yu cu05,0%96,0100.45.4017,24.minoshbA.

- Tra bng chn 322 + 220 vi Abtr =17,68 cm2 , v c t pha di ca dm mng nh hnh v ( thp k hiu 1,3,5 )- Chn abvcdai = 2,5 cm , dai = 8 mm =>abvcdoc = 2,5 + 0,8 = 3,3 cm (tha)- Khong h thng thy t:

(tha) - Kim tra li kh nng chu lc ca ct thp thit k

Chn a =6 cm => h0 = 50 6 = 44(cm)

Khi : < R = 0,595=> m = .(1 0,5. ) = 0,194.(1 0,5.0,194) = 0,175=> [M] = = 0,108.145.40.442 =1965040 Kg.cm = 19,65 T.mTa thy M = 19,65 T.m < [M] = 19,73T.m => Vy ct thp thit k m bo yu cu v cng .( vi sai lch M = 0,4 %)

b Tit din mt ct II II :

- Ti tit din ny dm mng chu moment m M = 11,96 T.m = 11,96.105 (kg.cm)- Chn a = 5cm => h0= 50 - 5 = 45 cm

Ta c = ==0,102< R = 0,418 . Tnh toan thit k ct thep theo bi ton ct n.

==0,108Khi din tch ct thp cn thit cho tit din l:

=10,03 (cm2)

Kim tra hm lng thp:.100% =0,56% >% tha mn yu cu

- Tra bng chn 322 vi Abtr = 11,4 cm2 , v c t pha trn ca dm mng nh hnh v ( thp k hiu 2,4) - Chn abvcdai = 2,5 cm , dai = 8 mm =>abvcdoc = 2,5 + 0,8 = 3,3 cm (tha)- Khong h thng thy t:

( tha ) -Kim tra li kh nng chu lc ca ct thp thit k

=> h0 = 50 4,4 = 45,6 cm

Khi : < R = 0,595 m = .(1 0,5. ) = 0,12.(1 0,5.0,12) = 0,11 [M] = = 0,11.145.40.45,62 = 1326631 Kg.cm = 13,2 T.mTa thy M = 11,96 T.m < [M] = 13,2 T.m => Vy ct thp thit k m bo yu cu v cng . ( vi sai lch M =9,4%)

c Tit din mt ct III III :


- Ta c : = ==0,129< R = 0,408 . Tnh ton thit k ct thp theo bi ton ct n.

==0,138

Khi din tch ct thp cn thit cho tit din l:

=12,92 (cm2) Kim tra hm lng thp:

.100% =0,72% >% tha mn yu cu.

- Tra bng chn 422 vi Abtr =15,2 cm2 , v c t pha di ca dm mng nh hnh v ( thp k hiu 1,3,5 )- Chn abvcdai = 2,5 cm , dai = 8 mm =>abvcdoc = 2,5 + 0,8 = 3,3 cm (tha)- Khong h thng thy t:

(tha) - Kim tra li kh nng chu lc ca ct thp thit k

Chn a = 4,4 cm => h0 = 50 4,4 = 45,6(cm)

Khi : < R = 0,595=> m = .(1 0,5. ) = 0,161.(1 0,5.0,161) = 0,148=> [M] = = 0,148.145.40.45,62 =1785399 Kg.cm = 17,8 T.mTa thy M = 15,17 T.m < [M] = 17,8 T.m => Vy ct thp thit k m bo yu cu v cng .( vi sai lch M = 14 %)

d Tit din mt ct IV IV :

- Ti tit din ny dm mng chu moment m M = 25,2 T.m = 25,2.105 (kg.cm)- Chn a = 5cm => h0= 50 - 5 = 45 cm =

- Ta c = ==0,214< R = 0,418 .Tnh toan thit k ct thep theo bi ton ct n.

==0,244- Khi din tch ct thp cn thit cho tit din l:

=22,78 (cm2)- Kim tra hm lng thp:

.100% =1,26% >% tha mn yu cu.

Tra bng chn 422 + 320 vi Abtr =24,62 cm2 , v c t pha trn ca dm mng nh hnh v (thp k hiu 2,4,8 )- Chn abvcdai = 2,5 cm , dai = 8 mm =>abvcdoc = 2,5 + 0,8 = 3,3 cm (tha)- Khong h thng thy t:

(tha )- Kim tra li kh nng chu lc ca ct thp thit k

9,5 (cm)

a = => h0 = 50 6,4= 43,6 cm

Khi : < R = 0,595=> m = .(1 0,5. ) = 0,273.(1 0,5.0,273) = 0,236=> [M] = = 0,236.145.40.43,62 = 2599117 Kg.cm = 25,9 T.mTa thy M = 25,2 T.m < [M] = 25,9 T.m => Vy ct thp thit k m bo yu cu v cng .( vi sai lch M = 2,7%)

e Tit din mt ct V V :


Ta c = ==0,246< R = 0,418 .Tnh tan thit k ct thp theo bi tan ct n.

==0,287 Khi din tch ct thp cn thit cho tit din l:

(cm2) Kim tra hm lng thp:

.100% =1,48% >% tha mn yu cu.

Tra bng chn 822 vi Abtr = 30,41 (cm2), v c t pha di ca dm mng nh hnh v (thp k hiu 1)- Chn abvcdai = 2,5 cm , dai = 8 mm =>abvcdoc = 2,5 + 0,8 = 3,3 cm (tha)- Khong h thng thy t:

(tha)- Kim tra li kh nng chu lc ca ct thp thit k

9,6 (cm)

a = => h0 = 50 7 = 43 (cm)

Khi : < R = 0,595 => m = .(1 0,5. ) = 0,34(1 0,5.0,34) = 0,282=> [M] = = 0,282.145.40.432 = 3023796 Kg.cm = 30,23 T.mTa thy M = 28,86 Tm < [M] = 30,23 T.m => Vy ct thp thit k m bo yu cu v cng .( vi sai lch M = 4,5%)

2 - Tnh ton thp theo phng ngang: - Ct 1m chiu di mng ti v tr c phn lc nn ln nht tnh ton:- Xem mt bn dm nh l ngm:

- Ta c h = 30 cm , a = 5cm => ho = 25 cm - Momen ln nht ti ngm:

Mtc = = (T.m) - Din tch ct thp cn thit:

Fa1 = = (cm2)B tr 412, F = 4,52 (cm2), a200 (mm) cho 1m di mng bng3 - Tnh ton ct ai :a Tnh ton ct thp ai cho cnh mng :Ta c kh nng chng ct ca b tng theo phng dc mng l:Qxt = p*.L =17,005*0,5 = 8,503 T < [Q]= 19,69 TV th dc mng b tng m bo kh nng chng ct do ch t thp cu tao.Chn v b tr theo cu to : 10 12, = 11,311cm2 vi a= 200 mm (k hiu 13 )b Tnh ton ct thp ai cho dm mng:Ta c kh nng chng ct ca b tng theo phng dc dm mng l:

Qmax =76,38 (T) < Nn dm mng m bo kh nng chng ct, do ch t thp ai theo cu to:+ Trong on nhp ta b thp ai theo yu cu cu to m bo yu cu: => chn bc ai S = 100 cm+ Trong on gia nhp cn li ta b thp ai theo yu cu cu to m bo yu cu: => chn bc ai S = 20 cm Vy ct thp ai trong dm mng c b tr : on u ca nhp th s c b tr ai 8 vi bc ai l 100 , on gia nhp mng c b tr ai 8 vi bc ai l 200.

------ ------

Phng n 3 MNG CC P(THIT K MNG CC DI CT 2 F )Cng trnh : KHU CHUNG C 9 TNGa im : S 202 NG NG CH KHIM QUN 11-THNH PH H CH MINHA. BO CO A CHT CNG TRNHI - CU TO A CHT :Kho st n d su 50m, cu to a cht khu vc ny c th chia lm 7 lp t chnh th hin trn cc hnh tr a cht v mt ct a cht cng trnh. Kt qu c m t nh sau :Mt ct a cht :

Lp t s 1: Nn gch dy 0,2-0,5m Lp t p dy 1,3-1,8m:- Dung trng t nhin:w = 1.9 g/cm3- Lc dnh n v:c = 0.156 kg/cm2

- Gc ma st trong:= 13028Lp t s 2:Lp t s 2a: at set pha cat lan t soi san ,mau xam van vang ,o deo trung bnh , trang thai deo mem , tr so chuy tieu chuan N=5 en 8 .Lp co be day t 1,9m(HK2)en 2.1m(HK3) vi cac ac trng c ly nh sau :- Dung trng t nhin:w = 1.899g/cm3- Dung trng y ni:n = 0.926g/cm3- Lc dnh n v:c = 0.123 kg/cm2

- Gc ma st trong: = 110Lp t s 2b: Thuoc set pha cat lan soi san laterite ,mau o deo trung bnh trang thai deo cng en na cng ,tr o chuy tieu chuan N=16 en 19 HK1=1,6m; HK4 v HK5 = 1,5m- Dung trng t nhin:w = 2,003g/cm3- Dung trng y ni:n =1.041g/cm3- Lc dnh n v:c = 0.184 kg/cm2

- Gc ma st trong: = 15012Lp t s 3: at set lan bot cat mn mau trang xam o lt ,o deo trung bnh trang thai deo cng en na cng .Tr so chy tieu chuan N=14 en 17 .Be day tai HK3 = 1,6m;HK4,HK2,HK5=1,9m - Dung trng t nhin:w = 1.982g/cm3- Dung trng y ni:n = 1,004g/cm3- Lc dnh n v:c = 0.256 kg/cm2

- Gc ma st trong: =140 Lp t s 4: at set pha cat mau xam trang dom o lt ,o deo trung bnh trang thai deo cng .Tr so chuy tieu chan N=12 en 15 .Lp at so 4 co be day tai HK1 va HK4 =2,9m ,HK2 =2,2m HK3=3,6m va HK5=2,1m vi cac tnh chat c ly ac trng nh sau- Dung trng t nhin:w = 1.944g/cm3- Dung trng y ni:n = 0,980g/cm3- Lc dnh n v:c = 0.160 kg/cm2

- Gc ma st trong: =13007Lp t s 5: Cat pha set mau xam trang en vang om o , do deo thap ,trang thai deo .Tr so chuy tieu chuan N=10 en 15 .Lp co be day tai HK1=1,9m, HK2=3,2m ,HK3=2,4m va HK5=2,1m vi cac ac tnh c ly nh sau :- Dung trng t nhin:w = 1.939g/cm3- Dung trng y ni:n = 0,987g/cm3- Lc dnh n v:c = 0.0,075 kg/cm2

- Gc ma st trong: =13045Lp t s 6:Lp t s 6a: Cat mn lan bot ,mau vang ,trang thai bi ri tr so chuy tieu chuan N=5 en 10 .Be day tai HK1=3,2m ,HK2=5,8m,HK3=4,0m ,HK4=1.3m HK5=9m .Vi cac tnh chat c ly nh sau:- Dung trng t nhin:w = 1.843g/cm3- Dung trng y ni:n = 0.929g/cm3- Lc dnh n v:c = 0.030 Kg/cm2

- Gc ma st trong: = 26031Lp t s 6b: Cat va ti mn lan t bot va soi san nho ,mau vang en o lt .Trang thai chat va .Tr so chuy tieu chuan N=11 en 30 ,lp cat chat v 6b co be day tai HK1=26,6m ,HK2-22,3m, HK3=25,7m HK4=17,5m, HK5=20,2m- Dung trng t nhin:w = 1,918g/cm3- Dung trng y ni:n =0,988g/cm3- Lc dnh n v:c = 0.026 kg/cm2

- Gc ma st trong : = 290257. Lp t s 7 :T cc su -38,7m (HK2); -40,7m (HK3); -39,4m (HK5) dng a tng chuyn sang lp t st ln bt mu xm nu vng n nu do cao, trng thi na cng ti cng Tr s chy 2 tiu chun N = 35n 40, lp c b dy ti HK2 = 1,3m; HK5 = 0,6m; HK3 = 9,3m. Ti cc h khoan HK1, HK4 cha pht hin c lp ny. Tnh cht c l c trng ca lp :- m:W= 20,5%- Dung trng t nhin:= 2,022 g/cm3- Dung trng y ni:=1,052 g/cm3- Lc dnh n v:c= 0,374 kg/cm2- Gc ma st trong:= 16o10 Trong phm vi kho st, a tng khu vc chm dt y .II. TNH CHT C L V A CHT THY VN :Tnh cht vt l v c hc ca cc lp t c xc nh theo tiu chun ca ASTM v phn loi theo h thng phn loi thng nht v c thng k trong bng Tnh cht c l cc lp t km theo bo co ny .V mt a cht thy vn lp t ny c quan st t 4-1996 .Ti thi im kho st, mc nc n nh su t -0,8m (HK2), -1,2m (HK4), -1,6m (HK3) v -1,8m (HK1).cc mc nc s thay i theo ma .

III. KT LUN :V mt a cht cng trnh ti khu vc xy dng khu chung cu 9 tng s 202 DC/2 ng ng ch Khim, Qun 11 TP.H CH MINH pha trn mt c lp t ct p, b dy t 1,3m ti 1,8 m. Sau l lp hai thuc st pha ct,trng thi khng ng nht m thay i t trng thi do mm n trng thi cng. Ti HK2 v HK3 lp t s 2 c trng thi do mm, dy trung bnh 2m l lp t yu. Ti v tr HK1, HK4, HK5 lp ny c ln si sn laterite, trng thi do cng l lp t tt .Lp 3,4 v 5 l cc lp t tt sau cc lp ny l lp ct bi ri 6a l lp t yu, lp t 6b thuc ct cht va l lp t tt .n su khong 39m, a tng chuyn sang lp t st trng thi cng (lp 7) l lp t tt sc chu ti cao .Trng hp s dng cc b tng, ngi thit k nn cho mi vo lp ct cht va. Chiu di v kch thc cc cn kt hp vi ti trng cng trnh v d kin a cht ti tng v tr quyt nh . Thng 5.1996

I S LIU TNH TON :1 - Ti trng truyn xung mng:Ti trng tnh ton :Ntt = 85 TMtt = 6,5T.mHtt = 1 TTi trng tiu chun:Ntc = 85:1,15 = 73,9 TMtc = 6,5:1,15 = 5,65 T.mHtc = 1:1,15 = 0,87 T2 Kch thc ct :- Chn btng lm ct B25 c Rn = 14,5MPa = 145 kg/cm2 - Thp s dng lm ct l thp AII c : Rs = 280MPa = 2800 kg/cm2 Es = 21.104MPa = 2,1.106 kg/cm2Khi kch thc ct c xc nh nh sau:=> Gi s thit k ct vung, v s dng 418 (As = 10,18 cm2) lm thp chu lc cho ct:

Khi cm2

=> cmChn ct c kch thc 30 x 30 cmII CHN SU T I MNG :-V mng cc ta thit k l mng di cng trnh nh gm rt nhiu mng , n c ging v lin kt vi cc mng khc bng h thng king . Do mng cc ta thit k khng ch chu p lc ngang 1 mnh m l c h thng mng v king cng chu . V vy su chn i mng ta la chn sao cho va che lp i mng l va , khng cn xt ti iu kin p lc ngang .-Chn chiu su t i mng l Df = 1,5 mIII CHN V B TR CC :1 Chn loi cc :a cc s liu :Dng loi cc c tit din 30 x 30cm, c chiu di 16m ( trong 0,5m ngm vo i cn 15,5m )Vy ta chn chiu di mi cc l 8m. ni thnh cc 16m.S dng btng B25, tra ph lc 3, trang 364_Gs,Ts Nguyn nh Cng_Kt Cu BTng Ct Thp ( Phn Cu Kin C Bn) ta c Rn = 14,5 MPa = 145 kg/cm2 Rk = 1,05 Mpa = 10,5 kg/cm2 Eb = 30.103 MPa = 3,0.105 kg/cm2Thp s dng lm cc l thp CII, , tra ph lc 4, trang 365_Gs,Ts Nguyn nh Cng_Kt Cu BTng Ct Thp (Phn Cu Kin C Bn) ta c : Rs = 280 MPa = 2800 kg/cm2 Es = 21.104MPa = 2,1.106 kg/cm2- Ta c trng lng ct n v :(cn k n h s ng n = 1,2 2)q = n.Fc.bt = 2.0,3.0,3.2,5 = 0,45 (T/m)b chn thp cho cc :Chn ct thp trong cc theo iu kin cu cc v dng cc :

* Theo iu kin cu cc :V tr mc cu cch chn cc mt khong : 0,207L (Vi L l chiu di cc ) th khi cu s gy ra moment : Mnhp = Mgi = 0,0214qL2Khi Mmax1 = Mnhp = Mgi = 0,0214.q.L2 = 0,0214.0,45.82 = 0,6163 T.m

Hnh 3.1 S cu cc

* Theo iu kin dng cc :Khi dng cc, cc mt u ta vo t mt u mc vo dy cu.

Hnh 3.2 S dng cc

- Khi ta c Mmax2 = 0.068.q.L2 = 0.068.0,45.82 = 1,9584 T.m chnh xc thit k ct thp cho cc ta chn M = max(Mmax1, Mmax2) = Mmax2 = 1,9584 (T.m)Chn lp bo v a = 3 cm => h0 = 30 3 = 27 cm

Ta c :

==0,064

= 2,68 cm2Kim tra hm lng ct thp

Tha mn yu cuChn 412 c As = 4,52 cm2 ( b tr theo 4 gc ca ai)Ghi ch: Theo iu kin an ton chn momen ln trong hai trng hp cu cc v dng lp ct tnh ct thp chu lc cho ct.

2 Sc chu ti ca cc :Ta c sc chu ti ca cc QTK = min (Qvl ,Qn )a sc chu ti ca cc theo vt liu lm cc :Qvl = .( Rb.Ap + Rs.As )Trong :Rb : Cng chu nn ca btng lm cc Rb = 145 kg/cm2Rs : Cng chu ko ca thp dc trong cc Rs = 2800 kg/cm2Ap : Din tch tit din ngang cc Ap =30.30 -4,52 = 895,48 cm2As : Din tch ct thp dc trong cc As = 4,52 cm2 : H s nh hng n mnh ca cc c xc nh :Ta c chiu di tnh ton ca cc :(Xem nh cc mt u ngm mt u khp ,mt u ngm vo i mt u vo lp t 6b) => = 0,7)Khi o l0 = .L = 0,7.15,5 = 10,85 mnh d = > 4 nn phi k n un dc Tra bng 2.2 sch phn tch v tnh ton mng cc ,ta c = 0.895 Do cc s dng c ni t 2 on cc , nn an ton ly = 0,7-Khi : Qvl = .( Rb.Ap + Rs.As ) = 0,7.(145.895,48 + 2800.4,52) = 99750kg-Ly Qvl = 99,8 (T)b Sc chu ti ca cc theo ch tiu cng t nn :Vic xc dnh ch sc chu ti theo ch tiu c l ca nn t c tham kho trong ph lc A quyn tuyn tp TCVN 205-1998Theo muc A3 ph lc A TCVN ch sc chu ti tiu chun ca cc thi cng bng phng php ng cc c b rng tit din t 250 n 800 chu ti trng nn c xc nh theo cng thc Qtc=m ( mRqpAP + u)Trong + m H s iu kin lm vic ca cc trong t, i vi tit din vung : m = 1+ mR, mf : H s iu kin lm vic ca t mi,mt bn cc. Xc nh theo bng A3 Vi phng php thi cng cc p vo lp ct ht va nn mR = 1,2 ; mf = 1+ Xc nh qp: Cng tnh ton ca t di mi cc (Bng A.1). Vi mi cc cm vo trong t su 15,5 +1,5=17m, cm vo ct va n mn ln bt v t si sn nh, mu vng n lt, Trng thi cht va. T su mi cc v loi t mi cc tra bng A1 ni suy ta c qp=308T/m.+ Ap = 0.09 m2 l din tch cc+ li: chiu dy lp t th i cc i qua+ u = 4x0.3=1,2 m l chu vi tit din ngang thn cc.+ fsi: ma st bn ti su trung bnh lp t th i m cc i qua c ly theo bng A.2, cc lp c chia l ng nht v c chiu dy khng qu 2 m.Chn h khoan s 3 t cc. Da vo mt ct a cht ta bit c cc lp t m cc i qua (nh hnh v).

Chia cc lp t nh hnh v, ta c bng tnh ma st thnh cc nh sau:Ta c bng tnh sau:Lpli(m)z(m)ILg (T/m3)fsifsi.li

2a1.92.450.500.9261.873.55

31.64.200.231.0045.078.11

426.000.300.984,208,4

1.67.800.390.983,235,17

529.600.760.9870.881,76

0.410.800.760.9870.880.35

6a212.00/0.9294.909.8

214.00/0.9294,79,4

6b216.00/0.9887.7615,52

SUM62,06

Qtc= m ( mRqpAP + u) = 1.(1,2.308.0,3.0,3 + 1.62,06) = 95,3 (T) Sc chu ti cho php ca cc n theo ch tiu c l:

(2)ktc: h s an tn ly ktc = 1,75 ( theo TCXD 205:1998).c sc chu ti ca cc theo ch tiu cng t nn :Theo TCXDVN 205 1998 sc chu ti ca t nn c xc dnh theo cng thc sau:Qn = + Qp = + Ap.qp Trong :+ c xc nh :Vi u l chu vi ca tit din cc : u = 0,3.4 = 1,2 m2li l b dy lp t th ifs = ca + .tga = ca +Ks..tga V cc s dng l cc BTCT nn theo TCXD 205 -1998 : - lc bm dnh gia cc v t nn ca = c- gc ma st gia thn cc v t nn a =Theo TCXD 205 -1998 : h s p lc ngang Ks = 1,4.(1 - sin )

Ta c bng tnh sau:

Lp t su su gia lpli(m)(T/m3)Ca(T/m2) ja ()tg(ja)'v(T/m2)

Ksifsifsi.li

Lp 2a(-1,9 : -3,4)-2,451,90,9261,23110,1942,2691,1331,7293,285

Lp 3(-3,4 : -5,0)-4,21,61,0042,56140,2494,2171,0613,6745,879

Lp 4(-5,0 : -8,6)-6,83,60,981,613,120,2336,6641,0823,28011,808

Lp 5(-8,6 : -11,0)-9,82,40,9870,7513,750,2459,6731,0673,2797,869

Lp 6a(-11,0 : -15,0)-1340,9290,326,520,49912,080,7754,97019,882

Lp 6b(-15,0 : -17,0)-1620,9880,2629,420,56415,810,7126,60813,216

61,938

=> = 1.1,2.61,938 = 74,33 (T)

+ Qp = Ap.qpVi Ap : Din tch tit din ngang mi cc Ap = 0,32 =0,09 m2qp : Cng chu ti ca t di mi cc c tnh theo cng thc : qp = 1,3.c.Nc + .Nq + . .dp.Nlp t (6b) t mi cc c : = 29025= 29,42 tra bng v kt hp ni suy ta c c = 0,026 kg/cm2 =0,26T/m2 = 0,988 g/cm3=0,988T/m3 dp : ng knh tit din mi cc dp = 0,3 m:ng sut hu hiu theo phng thng ng ti su mi cc do trng lng bn thn t := 1,5.1,9 + 1,9. 0,926+ 1,6.1,004 + 2,0.0,980 + 1,6.0,980 + 2,0.0,987 + 0,4.0,987 + 2,0.0,929 + 2,0.0,929 + 2.0,988 = 17,805 (T/m2)

qp = 1,3.c.Nc + .Nq +. .dp.N =1,3.0,26.35,685 + 17,805.21,21 + 0,4.0.988.0,3.18,5 = 391,9Ap = 0,3.0,3 = 0,09 (m2) Qp = Ap.qp = 0,09.391,9 = 35,27 (T)Khi sc chu ti ca cc theo ch tiu cng t nn l: : h s an tn cho thnh phn ma st bn, ly bng 2.: h s an tn cho sc chng di mi cc, ly bng 3.

=42,73 T * Kt lun :T (1), (2) v (3) ta c : QTK = min (Qvl ,Qn, Qtc ) = Qn = 42,73 T .Vy sc chu ti tnh ton ca cc l QTK = 42,73 T.IV Xc nh kch thc s b y i cc v b tr cc :a Kch thc i cc :- Khong cch gia cc tim cc nhm m bo cc cc t nh hng n nhau, khi p cc lm cho cc cc c p khng b chi ln, v trnh hin tng nn cht t cc cc m bo p xung ng su thit k.Khi chn khong cch gia 2 cc l 3d th ng sut trung bnh di y i cc l:

TB = = (T/m2) Din tch s b y i cc:

T TB = => Fm = = (m2) Chn B x B = 1,8 x 1,8 = 3,24 (m2) b Xc nh s lng cc :Trng lng tnh ton s b ca i v t trn nn t :

Tng lc dc tnh ton s b tc dng ln i

N= = 85+10,692 = 95,692(T)Chn s b s lng cc theo cng thc :

nc = . = 1,4. = 3,2 (cc) (Vi l h s xt n nh hng ca mment tc dng ln mng cc, ly t 1,1 1,5 tu theo gi tr moment)Chn nc = 4 ccc B tr cc :B tr cc nh hnh v

V Kim tra lc tc dng ln cc :Ta c trng lng ring trung bnh ca lp t trn i v ca i cc : TB = 0,5(t p +bt)= 0,5.(1,9 + 2,5) = 2,2 (T/m3) Trng lng tnh ton ca i cc v lp t trn i cc: = n.F.hm.TB = 1,15.1,8.1,8.1,5.2,2 = 12,296 (T)

Ti trng tnh ton tc dng ln i:Ntt = Ntt + = 85 + 12,296= 97,296 (T) Momen tnh ton tc dng ln i:Mtt = Mtt + Htt.h = 6,5 + 1.0,7 = 7,2 (T.m) Ti trng trung bnh tc dng ln mi cc: P = Ta c = 2.(-0,6)2 + 2.(0,6)2 = 1,44 m2 * Khi ti trng tnh ton tc dng ln cc 3 v 4 l nh nhau :y3 = y4 = 0,6 m P3 = P4 = =T* Ti trng tnh ton tc dng ln cc 1 v 2 l nh nhau :y1 = y2 = - 0,6 m P1 = P2 = =TKim tra iu kin an ton cho cc cc trong mng cc :Ta thy :Pmin = P1 = P2 = 20,04 T > 0Pmax = P3 = P4 = 28,6 T < QTK = 42,73 TVy cc m bo kh nng chu lc v m bo khng b nh di tc ng ca cng trnh.VI TNH TON I CC :- B tng s dng lm i cc l b tng B25 c: Rb =14,5 MPa = 145 kg/cm2Rbt = 1,05 MPa = 10,5 kg/cm2- Thp s dng l thp CII c : Rs = 280 Mpa = 2800 kg/cm21 Kim tra xuyn thng :Chn lp bo v a = 5cm => h0 = 60 - 5 = 55 cma Kim tra xuyn thng ct vi i:T ct ta v thp xuyn thng hp vi mt phng mt ct mt gc 450 , ta c thp xuyn thng, ta thy thp xuyn thng bao tt c cc cc khng c cc no nm ngoi thp xuyn thng. Nn Qxt = 0

b Kim tra xuyn thng cc vi i: - Lc gy xuyn thng: Qxt = Pmax = 28,6 (T) - Lc chong xuyen: Qcx = 0,75.Rbt.SxtTrong o :Theo hnh ve ta co Sxt =S1+ S2 =2S1=2.0,2925 =0,585 m2Be tong s dung lam ai coc la B25 co Rbt = 1,05 MPa = 105 T/m2=> Qcx = 0,75.Rk.Sxt = 0,75.85.0.585= 37,29 (T) Ta thay Qcx > Qxt ai mong am bao ieu kien xuyen thung cua coc.

2 Thit k ct thp cho i :a - Thit k ct thp cho i cc theo phng y :- Theo phng ny ta xt mt ngm i qua chn ct ( nh hnh v), moment do cc cc nm bn phi mt ngm l do phn lc ti cc cc 3 v 4:Ta c P3 = P4 = Pmax = 28,6T M = 2.Pmax.0,45 = 2.28,6.0,45 = 25,74 T.m- Khi thp theo phng y c xc nh :( Chn lp bo v a = 10cm => h0 = 70 10 = 60cm)

cm2Chn 1016 (As = 20,11 cm2 ) a = 160

b - Thit k ct thp cho i cc theo phng x:- Theo phng ny ta xt mt ngm i qua chn ct ( nh hnh v),moment do cc cc nm bn trn mt ngm l do phn lc ti cc cc 1 v 3:

Ta cM= = 0.45(20,04 + 20,04) = 18,04 T.m- Khi thp theo phng x c xc nh :( Chn lp bo v a = 10cm => h0 = 70 10 = 60cm)

cm2- an ton ta chn 1016 (As = 22,11 cm2 ) a = 160

VII TNH TON V NN :1 Kim tra p lc y mng khi quy c :Mng khi quy c c xc nh bng cch v mt ng thng t mp ngoi ca cc ngoi cng, hp vi mt thn cc mt gc nh hng vi: Trong : = =

Hnh 3.3 Mng khi quy c

- Xc nh kch thc mng khi quy cTa c chiu di lm vic thc ca cc l Lp = 15,5 m- B rng mng khi quy c:

Bq = b + 2 x + 2 x L x tg = 1,2 + 2 . + 2 x 15,5 x tg4039 = 4,02 m2- Chiu di mng khi quy

Lq = b + 2 x + 2 x L x tg = 1,2 + 2 . + 2 x 15,5 x tg4039 = 4,02 m2 Din tch mng khi quy c :Fq = Lq x Bq = 4,02 x 4,02 = 16,16 m2Trng lng mng khi quy c:Q = Q1+ Q2 + Q3Trong :Q1 : Trong lng cua ai: Q1=1,82.0,6.2,5=4,86 TQ2 : Trng lng ca lp t t y i n y mng khi quy c :Vi :tb= =0,965T/m3Q2 = V. =(Fq -Fcc).L.tb = (16,97 4.0,3.0,3).15,5.0,965 = 248,44 TQ3 : Trng lng cc Q3 = nc.Fcc.L.bt = 4.0,3.0,3.16.2,5 = 14,4 T=> Q = 5,67 +248,44 + 14,4 =268,5 TKhi ta c tng trng ti y mng:N = Ntt + Q = 85 + 268,5 = 353,5 TKhi chuyn t hp lc v y mng khi quy c ta khng chuyn lc ngang Htt v, m lc ny b trit tiu bi lc chu ti ngang ca cc u cc.Nn ti y mng khi quy c Mtt = Mtt + Htt.h = 6,5 + 1.0,7 = 7,2 (T.m)

Vy ti y mng khi quy c ta c cp lc :

Moment chng un ca khi mng qui c :

- Ta c phn lc di mng khi quy c :

Pmax = = ( T/m2 )

Pmin = = = 21,16 ( T/m2 )

Mt khc ta c kh nng chu ti ca t ti lp t ngay mi cc l:RTC = m.(A.Bm. + B.h.TB + D.c)Trong : m = 1 = 0,988 (g/cm3)c = 0,026 (kg/cm2) = 0,26 (T/m2) = 29o25 A = 1,097 B = 5,388 D = 7,784

Dung trng trung bnh t y mng tr ln

RTC = 1.(1,097.4,07.0,988 + 5,388.17.1,05 + 7,784.0,26) = 102,61 (T/m2)Ta thy pmax = 22,54 T/m2 < RTC = 102,61 T/m2 pmin = 21,16 T/m2 > 0=> Kt lun: Vy t nn di y mng khi quy c m bo kh nng chu lc.

2 Kim tra ln ca mng cc :Sau khi kim tra s lm vic ca t theo trng thi gii hn th nht ( Trng thi gii hn v cng ), tho iu kin ta tin hnh kim tra s lm vic ca t theo trng thi gii hn th hai ( Trng thi gii hn v ln )Ta thy ln ca mng cc chnh l ln ca mng khi quy c.- Ta tin hnh tnh ln di mng khi quy c bng phng php lp phn t- ng sut ti y khi mng quy c do ti trng ngoi v ti trng bn thn khi mng gy ra:

- ng sut gy ln ti y khi mng quy c :

M = 0,926.1,9+1,004.1,6+0,98.3,6+0,987.2,4+0,929.4+2.0,988 = 14,95 T/m2

=6,93 T/m2- Chia t di y mng khi quy c thnh cc lp phn t, mi lp phn t dy:

hi = m chn hi = 0,5 mXc nh p lc bn thn ca t: (KN/m2)Xc nh ng sut gy ln: (KN/m2)- T th nghim nn c kt mu nguyn dng ca h s a cht c cung cp ta c bng sau:

Ap lc p (T/m2)02550100200400

H s rng e0.7630.7490.7260.6900.6570.619

Xc nh gi tr Xc nh gi tr

T gi tr P1i -> e1iT gi tr P2i -> e2i

Xc nh gi tr ca ln: B = 4,02

BNG TNH LN THEO PHNG PHP TNG PHN T

Lph su (m)P1il/b zz/bkoP2ie 1ie 2iSi (m)

Lp 6b0,51716,8017,04100,0016,9323,8870,7540,7490,0014

17,517,2910,50,120,9766,764

0,517,517,2917,5410,50,1224,1090,7540,7490,0014

1817,78110,250,9206,375

0,51817,7818,03110,2524,0730,7540,7490,0014

18,518,2811,50,370,8245,71

0,518,518,2818,5311,50,3723,8550,7530,7500,0008

1918,77120,490,7134,941

0,51918,7719,02120,4923,5620,7530,7500,0008

19,519,2712,50,610,5984,144

0,519,519,2719,5112,50,6123,3010,7520,7500,0006

2019,76130,740,4963,437

0,0064

Ta thy S < S = 8cm . Kt lun : Vy mng cc thit k m bo yu cu v ln cho php------ ------

SVTH: NGUYN KIM TIN MSSV: X074974Page 2Sheet1S hiu muChiu su ly mu (m)Dung trong g (g/cm3)T trng mGii hn chy do (Atterberg Limits)H s rng rnggwgdgsrW (%)WL (%)WP (%)IP (%)enHK 3-11.5-2.01.9171.5960.0002.67620.127.918.49.50.67840.400Tng1.9171.5960.0002.67620.127.918.49.50.678Trung bnh1.9171.5960.0002.67620.127.918.49.50.678

Sheet1S hiu muChiu su ly mu (m)Dung trong g (g/cm3)T trng mGii hn chy do (Atterberg Limits)H s rng rnggwgdgsrW (%)WL (%)WP (%)IP (%)enHK 3-11.5-2.01.9171.5960.0002.67620.127.918.49.50.67840.400Tng1.9171.5960.0002.67620.127.918.49.50.678Trung bnh1.9171.5960.0002.67620.127.918.49.50.678



Sheet1nai (cm2/kg)pi (kg/cm2)Ei (kg/cm2)pi (kg/cm2)10.4380.253.0600.2520.1460.509.0800.5030.0731.0017.9641.0040.0372.0035.4242.0050.0184.0069.9224.0060.0098.00136.5308.00SUM0.72115.75271.98015.75Trung bnh0.12045.330

Sheet1Th t mugigitcgitc-gi(gitc-gi)2HK 3-11.9171.9170.0000.00000Tng0.0000.00000

Sheet1Th t mugigitcgitc-gi(gitc-gi)2HK 3-11.5961.5960.0000.00000Tng0.0000.00000

Sheet1Th t mugigitcgitc-gi(gitc-gi)2HK 3-10.0000.0000.0000.00000

Sheet1tmax (kg/cm2)si (kg/cm2)Kt qu c v j1.1443ABCD

Sheet1tmax (kg/cm2)si (kg/cm2)Kt qu c v j0.5471.00.305500.241330.8522.00.000290.000621.1583.01.000000.000411119963.000001.000000.186660.00000

Sheet1npi = 1.0 (kg/cm2)pi = 2.0 (g/cm2)pi = 3.0 (g/cm2)tititb-ti( titb-ti)2tititb-ti( titb-ti)2tititb-ti( titb-ti)210.5470.0000.0000.8520.0000.0001.1580.0000.000SUM0.5470.0000.8520.0001.1580.000Trung bnh0.5470.8521.158

Sheet1ntipipi2ti .pi10.5471.01.000.54720.8522.04.001.70431.1583.09.003.474SUM2.5576.014.005.725

Sheet1ntipipi.tgjtc + ctc(pi.tgjtc + ctc)- ti[(pi.tgjtc + ctc)- ti]210.5471.00.5470.000020.8522.00.8530.0010.00000131.1583.01.1590.0010.000001Tng0.000002

Sheet1S hiu muChiu su ly mu (m)Dung trong g (g/cm3)T trng mGii hn chy do (Atterberg Limits)H s rng rnggwgdgsrW (%)WL (%)WP (%)IP (%)enHK 1-11.5-2.01.9011.5780.0002.67520.526.618.38.30.69541.000HK 1-33.5-4.01.8691.5280.0002.67622.328.218.49.80.75142.900HK 1-55.5-6.01.8771.5170.9502.67623.729.618.611.00.76443.300HK 2-11.5-2.01.8951.5700.0002.67520.727.018.38.70.70441.300HK 2-33.5-4.01.8791.5430.0002.67621.827.718.49.30.73342.300HK 3-33.5-4.01.9101.5850.0002.67620.526.818.38.50.68940.800Tng11.3319.3210.95016.054129.5165.9110.355.64.336Trung bnh1.8891.5540.1582.67621.627.718.49.30.723




Sheet1nai (cm2/kg)pi (kg/cm2)Ei (kg/cm2)pi (kg/cm2)10.4630.252.9300.2520.1540.508.6860.5030.0771.0017.2051.0040.0392.0033.9122.0050.0194.0066.6634.0060.0108.00130.4238.0070.5190.252.7220.2580.1730.508.0810.5090.0861.0015.9691.00100.0432.0031.4742.00110.0224.0061.8384.00120.0118.00120.9358.00130.4980.252.7880.25140.1660.508.2710.50150.0831.0016.3491.00160.0412.0032.2162.00170.0214.0063.1974.00180.0108.00123.6948.00SUM2.43547.25747.35347.25Trung bnh0.13541.520

Sheet1Th t mugigitcgitc-gi(gitc-gi)2HK 1-11.9011.889-0.0130.00016HK 1-31.8690.0190.00038HK 1-51.8770.0110.00013HK 2-11.895-0.0070.00004HK 2-31.8790.0090.00009HK 3-31.910-0.0220.00046Tng-0.0000.00126

Sheet1Th t mugigitcgitc-gi(gitc-gi)2HK 1-11.5781.554-0.0250.00060HK 1-31.5280.0250.00065HK 1-51.5170.0370.00133HK 2-11.570-0.0170.00027HK 2-31.5430.0110.00011HK 3-31.585-0.0320.00099Tng-0.0000.00396

Sheet1Th t mugigitcgitc-gi(gitc-gi)2HK 1-50.9500.9500.0000.00000

Sheet1tmax (kg/cm2)si (kg/cm2)Kt qu c v j0.4661.00.267250.170610.7442.00.016480.035611.0213.00.942630.057100.3961.0262.8999616.000000.6502.00.857070.052160.9043.00.3941.00.6442.00.8933.00.4711.00.7492.01.0263.00.4101.00.6682.00.9273.00.4901.00.7762.01.0633.0

Sheet1tmax (kg/cm2)si (kg/cm2)Kt qu c v j0.4661.00.267250.170610.7442.00.016480.035611.0213.00.942630.057100.3961.0262.8999616.000000.6502.00.857070.052160.9043.00.3941.00.6442.00.8933.00.4711.00.7492.01.0263.00.4101.00.6682.00.9273.00.4901.00.7762.01.0633.0

Sheet1npi = 1.0 (kg/cm2)pi = 2.0 (g/cm2)pi = 3.0 (g/cm2)tititb-ti( titb-ti)2tititb-ti( titb-ti)2tititb-ti( titb-ti)210.466-0.0280.0010.744-0.0390.0021.021-0.0490.00220.3960.0420.0020.6500.0550.0030.9040.0680.00530.3940.0440.0020.6440.0610.0040.8930.0790.00640.471-0.0330.0010.749-0.0440.0021.026-0.0540.00350.4100.0280.0010.6680.0370.0010.9270.0450.00260.490-0.0520.0030.776-0.0710.0051.063-0.0910.008SUM2.6270.0094.2310.0175.8340.026Trung bnh0.4380.7050.972

Sheet1ntipipi2ti .pi10.4661.01.000.46620.7442.04.001.48831.0213.09.003.06340.3961.01.000.39650.6502.04.001.30060.9043.09.002.71270.3941.01.000.39480.6442.04.001.28890.8933.09.002.679100.4711.01.000.471110.7492.04.001.498121.0263.09.003.078130.4101.01.000.410140.6682.04.001.336150.9273.09.002.781160.4901.01.000.490170.7762.04.001.552181.0633.09.003.189SUM12.69236.084.0028.591

Sheet1ntipipi.tgjtc + ctc(pi.tgjtc + ctc)- ti[(pi.tgjtc + ctc)- ti]210.4661.00.438-0.0280.00078420.7442.00.705-0.0390.00152131.0213.00.972-0.0490.00240140.3961.00.4380.0420.00176450.6502.00.7050.0550.00302560.9043.00.9720.0680.00462470.3941.00.4380.0440.00193680.6442.00.7050.0610.00372190.8933.00.9720.0790.006241100.4711.00.438-0.0330.001089110.7492.00.705-0.0440.001936121.0263.00.972-0.0540.002916130.4101.00.4380.0280.000784140.6682.00.7050.0370.001369150.9273.00.9720.0450.002025160.4901.00.438-0.0520.002704170.7762.00.705-0.0710.005041181.0633.00.972-0.0910.008281Tng0.052