hd sử dụng slope

5/26/2018 HD S D ng Slope

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1. NG DNG CA SLOPE/WChng trnh SLOPE/W s dng l thuyt cn bng gii hn v lc v mmen xc

nh h s an ton chng li s ph hoi (trt). H s an ton (FS) l h s m bn chng ct cn phi gim i mt trt t n

trng thi cn bng gii hn.Trong phn tch ng sut c hiu, bn chng ct c nh ngha:

s = c' + ( n - u).tg '

Trong :s- bn chng ct; c- lc dnh c hiu; n- tng ng sut php; ( - gc ni ma stc

hiu; u- p lc nc l rng;Trong phn tch ng sut tng, cc thng s bn c nh ngha trong iu kin ng

sut tng v p lc nc l rng khng k n.Vic phn tch s n nh ca mi dc thc hin vi tng mt trt thng qua chia nh

khi trt thnh cc mnh nh theo phng ng. Mt trt c th l cung trn, mt trt hnhp (chng hn, mt trt l t hp ca cc phn cung trn v phn thng) hay c hnh dng

bt k bao gm nhiu phn thng c ch ra (nh mt trt ch nh y - mt trt gykhc).

Cc cng thc v cn bng gii hn c thit lp da trn 3 gi thit quan trng sau:- t c xem nh l vt liu tho mn iu kin Mor Coulomb;- i vi mi loi t, h s an ton ca thnh phn lc dnh v thnh phn ni ma st

c xem l bng nhau;- H s an ton c xem nh l bng nhau i vi mi mnh trt.Hnh 1 v 2 th hin lc tc dng ln cc cung trt trn v hn hp.

Hnh 1 - Lc tc dng ln mt mnh trt trong trng hp mt trt cung trn


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Hnh 2 - Lc tc dng ln mt mnh trt trong trng hp mt trt hn hp

*Gii thiu cch tnh h s an ton theo phng php Bishop

Xem cc hnh v trn ta thy rng trong mi trng hp tng m men ca tt c cc ctt i vi mt Im chung c th c vit nh sau:

1

. . 0 1

n

m ni iWx S R Nf kWe D d A a Q t

Du ngoc vung trong phng trnh (3) c ngha l cc lc ny c xem xt cho ctt c lc D tc dng vo n. Thay phng trnh 2(phng trnh gi tr ca lc ct huy ngc tho mn cc iu kin cn bng gii hn - sm) vo phng trnh 3 v gii, ta tmc h s an ton theo phng php cn bng moment.

1

' . ( ) . tan '2

. .m n

ni i

c R N u R g F

Wx Nf kWe D d A a Q t

Phng trnh (4) l phi tuyn bi v lc php tuyn N(ti y ct t) cng lhm sca h s an ton.

Trong :W :Trng lng ton b ct t c b rng b v chiu cao h

N :Lc php tuyn ton phn ti y ct tSm :Lc ct huy ng c ti y ct t.E :Lc php tuyn nm ngang ti mt tip xc gia cc ct t.KW:Lc ng t nm ngang t ti trng tm mi ct t.


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R :Bn knh i vi mt trt trn hay cnh tay n ca lc ct huy ng cSm i vi mt trt dng bt k.f : lch thng gc ca lc php tuyn tnh t tm xoay hoc tm moment.X : Khong cch nm ngang t tm ct t n tm xoay hay tm moment.E :Khong cch thng ng t tm ct t n tm xoay hay tm moment.D : Ngoi lc tp trung(nhng c dng phn b dc theo phng thng gc vi hnh

v)d : Khong cch thng gc t ti tp trung D n tm xoay hay tm moment.A : Hp lc ca p lc nc ngoi lc. Ch s L v R ch pha phi hay pha tri

ca mi dc.a : Khong cch thng gc t hp lc ca p lc nc ngoi lc n tm xoay hay

tm moment.

( : Gc hp bi phng ca ti tp trung vi phng nm ngang. Gc ny o theochiu kim ng h tnh t chiu dng ca trc X.

Qni : Lc neo th i ca thanh neo hay lc ko hiu dng ca vi a k thut i vict t ang xt.

ti : Khong cch t phng lc neo ti tm xoay hay tm moment.

Lc php tuyn ln mi ct t c xc nh t hnh chiu ln phng ng ca tngcc lc tc dng ln mi ct t. Kt qu c l:

( ) cos sin [ sin ] 0 3L R mW X X N S D

Thay Sm vo phng trnh (7) v gii tm lc php tuyn N ta c:' sin sin tan '

( ) [ sin ]

4sin tan '

cos

R L

c uW X X D

FN

F

Phng php Bishop n gin ho a gi thit: X=0 v E=0(tc khng xt n cc lcct ti mt tip gip gia cc ct t). Khi phng trnh (8) tr thnh:

' sin sin tan '[ sin ]

5sin tan '

cos

c uW D

FN

F

Thay phng trnh (5) vo phng trnh (2) v gii lp , ta c h s an ton F theophng php Bishop.


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2. HNG DN SDNG CHNG TRNH SLOPE/W

Phn ny hng dn vi ngi sdng thng qua trnh ttnh ton phn tch n nh midc ca mt bi ton n gin.

Mi dc c hsmi m = 2 ct ngang qua 2 lp t. Lp trn dy 5m v chiu cao tngcng ca mi dc l 10m. nn nm thp hn chn mi dc 4m. iu kin p lc nc lrng c m tbng ng bo ha. Cc thng slp t c thhin nh trn hnh.

Mc tiu bi ton l tm hsan ton nhnht v xc nh vtr ca mt trt nguy himnht.

Trnh tgii 1 bi ton tnh n nh bng SLOPE/W c thc hin nh sau:

Bedrock

5m

5m

4m

3m

1

2

= 15kN/m3

c = 5kN/m2

= 200

= 18kN/m3

c = 10kN/m2

= 250


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I. Thit lp vng lm vic

1. Xc nh phm vi vng lm vic

Vng lm vic l ni sdng cho vic nh ngha bi ton, c thnhhn, bng hocln hn trang giy in. Nu vng lm vic ln hn trang giy in, bi ton sc in trn nhiu

trang khi hskhuch i bng hoc ln hn 1.Vng lm vic nn c thit lp ngi sdng c thlm vic vi mt tlthun tin. i vi bi v dny, din tch vng lm victhch hp l chiu rng bng 260mm v chiu cao bng 200mm.gn kch thc vng lm vic:

- Chn SetPagemhp thoi Page.

- Chn mm trong Units; nhp 260 cho Widthv 200 cho Heighttrong Working Area

- OK

2. Xc nh tlKch thc bi ton c xc nh theo n vmt. Chn tl1:200 ph hp vi ni

dung trang giy- Chn SetScalemhp thoi Scale.


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- Nhp 200 cho Horz 1 v 200 cho Vert 1 trong Scale- Chn meters trong Engineeri ng Uni ts; trongProblem Extends nhp -4 cho Minimum x , -4cho Minimum y. Maximum x stchuyn thnh 48 v Maximum y schuyn thnh 36- OK

(Do bi ton xc nh theo mt v kN nn trng lng ring ca nc phi l 9.807 kN/m3.y l gi trmc nh)

3. Xc nh khong cch li vMc ch to iu kin thun li vbi ton theo ta mong mun thng qua chbtim ( i vi cc bi ton khc c thkhng cn thit lp). Trong bi ton ny khong cch

cc li c chn l 1m

- Chn SetGridmhp thoi Grid.

- Nhp 1 cho X v 1 cho Y trong Grid Spacing.- nh du chn Display Grid v Snap to Grid chn chhin thli v chbtim.- OK


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4. Lu dliu bi ton: Chn Fi le Savelu bi ton

II. Pht ha bi ton1. Vpht ha bi ton- Trong thanh cng cZoom, chn Zoom Page. Khi ton bdin tch lm vic shin thtrong ca DEFINE.- Chn Sketch Lines. Khi con trdng mi tn schuyn sang dng chthp. Tin hnh

pht ha bi ton (bm phi chut kt thc lnh v).- Sau khi pht ha xong bi ton, trong thanh cng cZoom, chn Zoom Objects phng lnhnh va vchim y ca DEFINE.

2. Xc nh phng php phn tchChn KeyIn Analysis Settingsmhp thoi Analysis SettingsTrong hp thoi Analysis Settingsngi sdng c cc la chn c mc nh nh sau:

- Tp Method(phng php phn tch): thng thng chn only Bi shop, Ordinary and Janbu- Tp PWP (Pore-Water Pressure): chn Piezometr ic lines with Ru/B-barv chn Ru trong

Choose parameter: dng tnh p lc nc lrng.


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-Tp Sli p Sur face:Chn phng di chuyn ca mt trt (Di rection of movement): ttri sang phiChn mt trt (chn Grid and Radiustrong nhm Slip Sur face Option): xc nh mttrt bng cch nh ngha mt li tm cung trt v bn knh cung trt)Chn No tension crack cho nhm Tension Crack Option: khng xt n khe nt cngtrn bmt mi dc


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- Chn OK

3. nh ngha cc tnh cht ca tTin hnh gn cc tnh cht cho cc lp vt liu theo cc bc sau:

- Chn KeyIn Materi al Properti esmhp thoi KeyIn Materi al Proper tiesQu trnh nhp c tin hnh cho tng lp vt liu, bao gm cc thng s: sthtlp vtliu ( Matl), m hnh tnh ton ( Strength Model), m tlp vt liu ( Description) v muthhin lp vt liu ( Color). Cthnh sau:

Nhp 1vo MatlChn Mohr-Coulombtrong Strength Model tnh cng chng ct

Nhp Upper Soil Layervo DescriptionNhp 15cho Uni t Weight(trng lng n vkN/m3), nhp 5cho Cohesion(lc dnhn vkN/m2), nhp 20cho Phi(gc ni ma st)Chn Copy, cc gi trva nhp sc sao chp vo hp lit k bn trn

- Thc hin tng tcho cc lp vt liu cn li- Chn OK


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4. Xc nh min tnh tonThnh vphc ha bi ton chng ta stin hnh vmin tnh ton- Chn DrawRegions, con trchut schuyn sang hnh chthp- Di chuyn con trn cc im v nhp tri chut ti mi im theo th t: (0,14) (10,14)(20,9) (0,9) v trli im (0,14). Khi sxut hin hp thoi Region Proper ties:

Chn 1 ti Materi al Type (khi khai bo vt liu chng ta chn 1 cho lpUpper SoilLayer).

- Chn Closekt thc vic xc nh min tnh ton lp t 1- Tip tc vcho cc min cn li. Kt qucui cng c thhin trong hnh sau:


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5. Vng phn bp lc lrngCc iu kin p lc nc lrng trong lp t 1 v 2 trong trng hp bi ton ny c

xc nh bi Piezometr ic Lines(ng bo ha).- Chn DrawPore-Water Pressure: hp thoi Draw Piezometr ic Linessxut hin

- Chn lp t 1 v 2. Chn Drawcon trchut schuyn sang dng chthp- Di chuyn con trn cc im v nhp tri chut ti mi im theo th t: (0,11) (15,8)(30,3) (40,3). Bm phi chut v chn Done trong hp thoi Draw Piezometri c L inesktthc vic vng bo ha. Khi mn hnh sc dng sau:


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6. Vcc ng tnh ton bn knh cung trt- Chn Draw Sli p Sur face Radius: con tr schuyn dng chthp.- Di chuyn con trn cc im v nhp tri chut timi im theo tht: (15,4) (29,4) (15,2) (29,2). Mincha cc ng tip tuyn vi cung trt c vpht

ha v xut hin hp thoi Draw Sli p Sur face Radius- Chp nhn gi tr mc nh 2 cho # of RadiusI ncrements

- Chn OKpht sinh 3 ng tip tuyn trong caDEFINE. Module SLOVE ca SLOPE/W sdng cc dng tip tuyn ny tnh ton cc

bn knh cung trt.- Sau khi hon thnh cc bc trn, mn hnh sc dng sau:

7. Vli tm cung trtMt li tm cung trt phi c xc nh kim sot

vtr cc mt trt. vli cung trt:- Chn Draw Sli p Sur face Grid: con tr s chuyn

dng chthp.- Di chuyn con trn cc im v nhp tri chut ti miim theo tht: (23,25) (22,19) (26,19). Khi 1 hnh bnhhnh sc vt3 im ny. Min cha cc tm cung trtc vpht ha v hp thoi Draw Sli p Sur face Gri dxut hin. Gi trtrong gia sbiudin sphn chia theo phng ngang v phng ng to nn li tm cung trt.- Nhp 2 vo # of X I ncrement v 3 vo # of Y I ncrement.


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- Chn OKhoc Applypht sinh li tm trt. Mt li bao gm 12 tm shin thtrong ca DEFINE. Module SOLVE ca SLOPE/W sxc nh cc cung trt bng cch dng cctm ny.

- Sau khi hon thnh cc bc trn, mn hnh sc dng sau:

8. Cc u tin vhin thhnh nhKhi thc hin ti bc ny chng ta khng cncn xem cc im hoc chsnhn dng cc im

trong ca DEFINE. khng hin thcc imv chssny:- Chn ViewPreferencesxut hin hthoiPreferences- Khng nh du cc la chn trong nhmGeometry Information

- Chn OK. Mn hnh khi strthnh nh sau:


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9. Phc ha htrc ta Vic phc ha h trc ta vi mc ch to iu kin

thun li cho vic xem hnh vv gii thch cho hnh vsaukhi in.

- Chn SetAxesmhp thoi Axes- nh du Left Axis, Bottom Axi sv Axi s Numberstrongmc Display. Nhp tn cho cc trc ta trong mc AxisTitles.

- Chn OK. Khi sxut hin thm 1 hp thoi Axis Size.Tin hnh nhp cc thng strong mc X-Axisv Y-Axisnhhnh minh ha.

- Sau khi hon thnh cc bc trn, mn hnh sc dng nh sau:


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10. Ghi nhn tn cho cc lp vt liuTrong bi ton ny chng ta ghi nhn tn cho

cc lp vt liu nhm mc ch nhn dng tngloi vt liu.- Chn SketchText: khi xut hin hp thoiSketch Text- Tin hnh nhp tn cho lp vt liu tng ng (cthchn mc Fonthiu chnh kch thc hoc

dng ch). Con tr s chuyn sang dng chthp. Di chuyn con tr vo v tr mun ghi nhnv nhn tri chut.- hon tt vic ghi nhn, nhn Done trong hpthoi Sketch Text hoc nhp phi chut ktthc.

- Kt qutrn mn hnh sau khi kt thc cc bc trn


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11. Hin thc tnh ca cc lp vt liuMc ch kim tra li tnh cht cc lp vt liu m bo chng c xc nh mt

cch ng n.- Chn ViewMateri al Properti es: xut hin hp thoi View Material Properties- Nhn All Matlshin thtnh cht ca tt ccc lp vt liu.


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III. Phn tch bi ton

1. Kim tra li bi tonVic nh ngha bi ton nh trn cn phi c SLOPE/W kim tra chc chn rng cc dliu c xc nh mt cch ng n.kim tra bi ton:- Chn ToolsVerify mhp thoi Veri fy Data

- Chn Verify. SLOPE/W skim tra cc dliu ca bi ton, khi tm thy li cc cnh bo lishin thtrong hp thoi. Tng sli shin thdng cui cng.

- Khi hon tt vic xem thng tin trong hp thoi Ver if y Data, chn Done

2. Lu dliu bi ton nhpVic nh ngha bi ton hon tt. Chn Fi le Savelu bi ton vi dng * .gsz


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3. Gii bi ton- Chn ToolsSOLVE, xut hin hp thoi sau:

- Chn Start bt u gii tm hsan ton. Trong khi tnh ton, SOLVE hin thhsanton nhnht v smt trt c phn tch (36 mt trt i vi v dny)

SOLVE ghi kt quphn tch vo mt chui cc file. Mun CONTOUR c cc file ny hin thkt qu.


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4.Xem kt quKt qutnh ton c thc xem di dng ththng qua mun CONTOUR. khi

ng CONTOUR: chn WindowCONTOUR

Hnh vhin thtrong ca CONTOUR sc vng vi ty chn u tin hin th(ViewPreferences).

5. Phng php xem kt qu

Trong mun DEFINE, ta chn phng php Bishopkhi tnh ton hsan ton. Theomc nh, CONTOUR shin thhsan ton theo phng php Bishop. Chng ta cng cthxem kt quhsan ton theo cc phng php khc nh Ordinaryv Janbu.- Chn ViewMethodKhi xut hin hp thoi:

- Bm vo mi tn hng xung trong Method hin thcc phng php c sn xem.


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6.Xem lc tc dng ln ct tLc tnh ton i vi mt trt nguy him nht c thc thnh mt s vt thtdo

v a gic lc ca bt kct t no. xem cc lc tc dng ln 1 ct t:- Chn ViewSlice Information: Hp thoi Free Body Diagram & Polygonxut hin. Dichuyn con trvo ct t bt kv nhp tri chut vlc tc dng ln ct t .

7. Vcc ng ng hsan tonHsan ton nhnht ti mi tm cung trt c thc vdng ng ng gi tr.

Chn Draw Contourskhi xut hin hp thoi:


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Chn cc thng snh hnh chng ta sc kt qunh sau:

hd sử dụng slope

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