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Bi tp s10

HMNG SU(PHNG PHP TOP - DOWN)

(V/v: Xc nh ni lc, chuyn v, ng sut, bin dng)

Bc 1:Thit lp m hnh v gn cc iu kin binVo File General Settings. Khai bo cc dkin trong cc phn Project, Dimensions.

Dng biu tng LINEvmt ct a cht ca 1 hkhoan gm c 4 lp t, chiu caohkhoan 60m, chiu rng di t 40m.

Lp 1: St, do nho, dy 10m.Lp 2: Ct, cht va, dy 7m.Lp 3: Ct, cht dy 18m.Lp 4: St cng, dy 25m.

Cc c trng cl, chc cc lp t: xem THNG SPLAXIS 2D. Quy c: code 0.00 ti cao trnh mt t tnhin.

Dng phn tPlate Vtng trong t (tng vy; diaphragmwall) c tit din ngang b*h = 1m*0.6m(bi ton phng nn ly b = 1m, thc tb 2m, tit din ngang ca diaphragmwall

phthuc vo kch thc ca gu o tiu chun), L = 25m ktmt t tnhin.Ti nh tng trong t (c cc hct khung) sc cc ti N, V (snhp cc gitrcthtrong cc phases tnh ton).

Vsn tng trt tng hm 1 tng hm 2.Chiu dy sn tng trt : 300mm nm ti code 0.00Chiu dy sn tng hm 1: 300mm nm ti code -3mChiu dy sn tng hm 2: 500mm nm ti code -6mCc sn ny chnh l cc hthanh chng (anchors; shoring).

Hmng tit din hnh chnht c kch thc: 20m*6m. Ginh tng chiu cao 2tng hm, H = 2*3m = 6m.

Vphn ttip xc, chn biu tng, . Mc nc ngm nm ti code -1m so vi mt t tnhin. Vo Loads, chn Standard fixitiesgn cc iu kin bin.

Lu : Cn phi thit lp sn cc cao trnh dkin so t, hmc nc ngm, lpt cc thanh chng,v.v.Dkin mc nc ngm shxung cc cao trnh -5m v -12m so vi mt t tnhin.

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Bc 2:Khai bo cc thng scho m hnh t nn, tng trong t BTCT (MC350) v sn BTCT (MC 350)Chn biu tng Material Sets (hoc vo Material, chn Soil Intefaces).

Biu tng Material Sets : Chn NEW, khai bo cho lp t 1. ST DO NHO

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Chn Advancedthit lp cc thng snng cao.

Lu :Thng thng cc thng snng cao, chng trnh stng tnh. Nu cn thayi, tc gistgn li nu thy cn thit.

Tng t: khai bo cho lp t 2. CT CHT VA

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Tng t: khai bo cho lp t 3. CT CHT

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Chn Advancedkhai bo cc thng snng cao.

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Tng t: khai bo cho lp t 4. ST CNG

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Gn cc lp t bng cch: ko LP T vo MT CT A CHT ri th. Nu gn nhmth chn lp t mi ri gn li. c trng vt liu tng trong t

Moduyl n hi, E = 3*107kN/m2Tit din ngang, A = 1*0.6 = 0.6m2Moment qun tnh: I = 1*0.63/12 = 0.018m4

Vo Materials, chn Plate New

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Lu :

mmkNdw tbsoilsconcrete

//74.36.03

206.197.1625

c trng vt liu sn tng trt, t = 0.3mModuyl n hi, E = 3*107kN/m2Tit din ngang, A = 1*0.3 = 0.3m2Moment qun tnh: I = 1*0.33/12 = 2.25*10-3m4

mmkNdwsoilsconcrete

//17.43.01.1125

c trng vt liu sn tng hm 1, t = 0.3mModuyl n hi, E = 3*107kN/m2

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Tit din ngang, A = 1*0.3 = 0.3m2Moment qun tnh: I = 1*0.33/12 = 2.25*10-3m4

mmkNdwsoilsconcrete

//49.23.07.1625

c trng vt liu sn tng hm 2, t = 0.5mModuyl n hi, E = 3*107kN/m2Tit din ngang, A = 1*0.5 = 0.5m2Moment qun tnh: I = 1*0.53/12 = 0.0104m4

Lu : Gn phn ttip xc cho sn tng hm 2 (y sn tng hm tip xc vi t nn).

Bc 3:Gn ti trng tc dng

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Vo Loads, chn Distributed load static load system Ahoc dng biu tng, . Kchchut vo 2 vtr trn bmt mt t gn ti.Ti trng tri cch bin tng trong t 2m, gi trq = 10kN/m2trn din b = 5m.Ti trng phi cch bin tng trong t 2m, gi trq = 12kN/m2trn din b = 6m.Kch double vo phn tcha ti thay i gi trti trng.Ti trng N, V tc dng ti nh tng trong t (ti loi B).

Bc 4:Chia li phn t(medium)Vo Mesh, chn General.

Chn Update.Bc 5:Khai bo iu kin ban u(vcao trnh mc nc ngm)Vo Initial, chn initial conditions.

Dng biu tng, vmc nc ngm ti code -1m.

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Chn Generate, Water pressure. Chn Phreatic level, OK.

Chn Update.

Chn Initial pore pressure(biu tng xanh m bn phi).

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Chn Generate initial stress,

Chp nhn cc gi trK0, chng trnh ttnh, OK. Lc ny sxut hin bng cnh bo. yl mt cnh bo NG.

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Chng trnh sttnh cc gi trng sut hu hiu trong nn.

Chn Update.Chn Calculate. Chn Yes.

Bc 6:Tnh tonThi gian cho mi cng tc l thi gian dkin, thc tcn phi cn cvo nh mc vtin thi cng.

Phase 1: Tc dng ti trng bmt (ti trng ca cc thit b, dng cthi cng, vtliu xy dng,v.v), t = 4 days

Chn Update.Chn Next.

Phase 2. Thi cng tng trong t mt module (khoan to l, thi ra lkhoan, hlng thp, b tng), t =12 days

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Phase 3. Hmc nc ngm xung code -5m so vi mt t tnhin, t =2 daysCn thit phi hmc nc ngm trc khi o t trnh st lhmng khi thi cngo t.

Chn Define. Chn nt BN TRI, .

Hmc nc ngm nm xung code -5m tta (0, 59) (10, 55) (30, 55) (40, 59)

Vo Generate, chn Water pressure groundwater calculation, OK.

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Chn Update.Chn Update.Chn next.

Phase 4.o t n code -2m, t = 4 days

Chn Update. Phase 5. Thi cng sn tng trt ti code 0.00 v thi cng tng 1, t = 8 days

N = 1000kN/m; V = 300kN/m

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Phase 7. Thi cng sn tng hm 1 ti code -3m v thi cng tng 2, t = 7 daysN = 2000kN/m; V = 600kN/m

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Phase 8. Hmc nc ngm xung code -12m so vi mt t tnhin v thi cngcy chng coffage sn tng 3, t = 4 days

N = 2200kN/m; V = 640kN/m(Trong thnh phn N, V kti trng ca sn tng 1, 2).Hmc nc ngm nm xung code -12m tta (0, 59) (10, 48) (30, 48) (40, 59)

Vo Generate, chn Water pressure groundwater calculation, OK.

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Chn Update.

Phase 9.o t n code -6m v thi cng tng 3, 4, cy chng coffage sn tng 5,t = 18 days

N = 4200kN/m; V = 940kN/m

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Phase 10. Thi cng sn tng hm 2 ti code -6m, t = 2 days

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Phase 11. Ckt, t = 9 days

Chn im trong nn dkin sxut cc biu quan h(nu thy cn thit).Chn Update. Chn Calcutate gii.

Mun xem kt qu trng hp no th VT SNG ti ri nhn Output. V dchnPhase 11 (CKT)

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Bin dng tng thkhu vc xy dng

Chuyn vngang tng trong t

CHUYN VNGANG CHO PHP

Theo Peck, M

(1/200 1/500)H

Vit Nam (Hin nay cha thng nht)

H/200

Hn Quc

(1/150 1/300)H

Trong : H l chiu su ho (hmng)

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Chuyn vng tng trong t

Biu bao moment dc theo thn tng trong t Trscc i sc dng kim tra li lng ct thp chn Ti vtr moment gim, nn gim (ct) thp tit kim vt liu

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Biu bao lc ct dc theo thn tng trong t (dng trcc i c lng ct ai)

Chuyn vng sn tng trt

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Chuyn vng sn tng hm 1

Chuyn vng sn tng hm 2

Chuyn vng ti mt phng y hmng

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Chuyn vng ti bmt mt t(Nhn xt: ti vtr cht ti trng bmt t nn bln st)

Biu quan hgia thi gian v chuyn vng ti mt vtr trong nn

Giai on t ln n dnh

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Biu quan hgia ng sut v bin dng ti mt vtr trong nn