m i l KHOA HOC - CONG NGH£
DANH GrA ANH HlTOlNG HIEU UING NHOM
DEN sure CHIU TAI NGANG TINH MONG COC CONG TRINH CAU
Tdm tat: Bii bio trinh bay kit qua nghien CLFU, danh gia si>c chju tai cua hi mdng cpc cdng trinh ciu chju tai trgng ngang tTnh bing phin mim SLF dung phuxyng phip PTHH (Plaxis 3D Foundation) cd xet tai h$ sd hiiu (mg nhom khi chiu tat trgng tmh.
Tir khoa: Hiiu ung nhdm; Plaxis 3D Foundation: phuong phap phan tLF huu h^n;
kit ciu; suv chiu tii.
Abstract: This paper presents results of research and analysis the load capacity of pile foundation in bridge structure under static lateral loading by using the finite element method (Plaxis 3D Foundation) taking into account the group efficiency factor under static load.
Keywords: Group effeciency; Plaxis 3D Foundation; finite element method, structure;
load capacity
I . D A T V A N D E
Khi xdy dyng cdng trinh cau tal nhung vj trf cd dja chat khdng dam bao de dgt mdng md vd t m trdn nen l y nhidn, thi mgt trong nhiing glai phap uu lien hang dau Id s d dung hd mdng cgc. Qua qua trtnh khai thac mdng cgc da cho thSy d u g c nhung u u diem va lgi the v u g t trdi trong vide Ihi cdng, khd ndng chju lyc cung nhu tmh kinhte.
Tuy nhidn, viec nghien cdu s y lam vide cila hg mdng cgc khi chju ldc dyng cua lai trgng theo phuong ngang (hg mdng cgc cua mo va tru cau t h u d n g xuydn cd lai trgng ngang tdc dyng len nhu dp lyc ngang dat sau mo; dp lyc do hoal tdi sau mo; lyc va xd cua tau Ihuy^n; lai trgng do ddng chdy...) khi xet ldi s y idm vigc dong Ihdi cua ca nhdm cgc cdn nhieu van de can nghien cCfu.
Cac nghien c u u thyc nghiem vd \'if thuyet cho I h i y s y lam vide cua cgc don vd cgc trong nhdm cgc khdc nhau rat nhi^u, doi vdi cgc ma sat thi cdng the hidn rd. Khi cdc cgc d u g c bd trf thdnh nhdm trong mdng cgc, tac ddng qua Igi cua he cgc - nen phu thudc vdo viec bd lr( cgc trong mdng va hinh Ihanh higu ung nhdm Irong mdng cgc. Anh h u d n g cCia hieu ung nhdm trong mdng cpc d i n den: 1) Lam Ihay doi (chu y^u la giam) sue chju tai ca nhdm so vdi tong sue ehju tai ede cgc thanh phan; 2) Hidu ung bd, lam tdng vung truyen ung suat. Hdu qua gay ra bien dgng cua dat theo phuong tal trgng trong nhdm cgc cao hon nhieu so vdi ege dan.
NCS. NGUYEN MANH H A NCS. PHAM T U A N THANH KS. L i DCrc LONG Hgc vign Ky thugt Quan su Tai Viet Nam, hign nay khi thl6t ke vigc tinh loan mdng cgc khi xdt tdi hieu ung nhdm d u d i tdc dyng eua tai trgng ngang chCi y^u v i n d y a trdn cdc khuyen eao theo Tleu chuan 22TCN 272-05 va TCVN 205- 1998 [5,6].
2. HIEU (TUG N H d M TRONG M 6 N G COC C 6 N G TRlNH CHIU T A I TRQNG NGANG T T N H Tidu e h u i n hidn nay djnh lugng anh hudng cua t u o n g tae giua cde cge trong nhdm cgc bdng hg so hieu l i n g nhdm T ] , d u g c djnh nghTa theo phuong trinh (1) id tJ sd giua ldi trgng gidi hgn cOa nhdm Q^^
vd'i tong tai trgng gid'l hgn eua n ege rieng re trong nhdm cgc Q,L-
2Q..
(1)mm
S y lam vigc cua nhdm cgc d u d i tac dung c^a tdi trong ngang Id rat phuc tgp, da cd nhieu nghidn cuu cua cac nhd khoa hgc khac nhau chl ra didu dd. Vi du nhu: Thi nghiem kiem tra dd rung cua hg cgc trong cdi dudi lac dung cCia tai trgng ngang do cac vy nd Idn cua Salto et al. (2002); thi nghidm nhdm cgc chiu ldi trpng ngang Irong nen eat cOa Brown et al. (1988); thi nghidm SLT Idm vide cua he cgc va nen dudi lal trgng ngang cOa Suzuki et al. (2003); cde nghien cuu thyc nghiem ve ung x u cua cgc trong nhdm cgc dudi tac dyng cua tai trgng ngang cua Tominaga el al. (1988)... [2], Trdn I h ^ gidi den nay da cd nhieu nghien CLPU rieng ve he mdng cgc d u o i tac dyng eua tal trgng ngang ITnh. Cde nghien euu ndy thud'ng bao gdm hai nhom CO ban: 1) Nhdm cac nghien CLPU thyc nghiem (mo hinh t h y c vd mo hinh trong phdng thl nghidm); 2) Nhdm cae p h u o n g phdp xdc djnh Ihdng qua bdi loan trdn md hinh so [1].
Trong nhdm cgc chiu tde dung cua tai trgng ngang, khi cac cge d u g c xkp thang hang theo phuong cOa lyc ngang, cac vung ung suat ndn trong d^l cua hdng cgc phia t r u d c se chdng len vung ung sual nen Irong d i t do hang cgc phia sau gdy ra (hign tugng chong i>ng s u i t ) dan tdi lam giam sd-e ehju lai n^n dat cua cac hang cgc trifdc (Hinh 1). S y dnh hudng do hign t u g n g nay ggi la tuong tde cgc - d i l - coc hay cdn ggi Id t u o n g tac hidu ung nhdm. Cdc lac dgng do t u o n g tac hidu ting nhdm cang giam ktii khoang each giua cac cgc lang len [3].
S6 8 nam 2017 I
KHOA H Q C - C O N G NGHE # # # # # Tai bpng ngng
Apkdtbidfflg a) Sa do cgc chju tai trong ngang (Cubrinovski and
Ishihara - 2007) Tai trong Qgang
Vikg trang thai bi dpng
b) S o do twang tac coc - dat dwdi tac dung tai trong ngang
Khoang dat bet Vimg ch5ng ling suit
Cd mgt diem chung trong t i t cd ede ket qua thye nghiem la anh hudng hieu ung nhdm sd rat nhd khi khoang cdch giua lim cgc d i n tim cgc Irong nhdm ldn hon hoac bang 6D theo hudng song song vd'i tdi trgng hoge Idn hon hoge bang 3D theo phuong vudng gde vdi tai trgng. Cde ket qua ndy dd d u g c xdc nhan thdng qua cac kiem tra t h u nghigm eua Prakash (1967), Franke (1988), Lieng (1989) vd Rao e t a l . (1996) [7,8,12].
Mdt s o cac c h i d i n xac d|nh he s 6 hidu ij>ng n h o m c h o m o n g cgc c o n g t r i n h c h j u tai t r g n g n g a n g tTnh:
• Chi din xac dinh he so hi^u u-ng nhom theo cac Tieu chuan hien hanh cua Vi$t Nam:
Hidn nay t h u d n g d y a vao cdc eh? d i n trong cdc qui trinh, lieu e h u i n hidn hanh nhu TCXD 208:1998 vd 22 TCN 272-05 de tfnh toan va dua ra phuong an thiet kd khi xel eho hidu i^ng nhdm ege. Tuy nhidn Irong ca 2 tieu chuan chua cd cac chi ddn cy t h i xde djnh hg so hidu i>ng nhdm cho nhdm ege chju tdi trgng theo phuong ngang.
• Chi dan xac dfnh he so hieu ung nhom theo thu-c nghi&m:
Tren the gidi nghidn cisu t h y c nghigm ve hidu Cpng nhdm da cd ILF hon 60 nam trud'c, moi tdc gid t u eac thf nghiem deu dua ra mgt cdng Ihuc ridng xac djnh h# sd higu i>ng nhdm phu thudc vdo mdt sd di^u kien dnh hudng ey the. Cd the ke den mgt so ket qua thye nghigm da d u g c dua ra eiHa cdc tdc gia n h u : Prakash vd Saran (1967) dua ra ket qua thi nghigm khi lidn hanh vdi cac md hinh nhdm cgc khac nhau chju tal trgng ngang trong mdi trudng d i t set. Cde thi nghiem duge t h y c hien Iren cac nhdm cgc 2x2 vd 3x3; qua eac thi nghiem dua ra rang hidu O-ng nhdm gidm khi khodng each giua cac cgc lang len theo hudng cua tai trgng va bien mat khi khodng edeh ldn hon 6 l i n dudng kinh cge. Vdo ndm 1990, Prakash va Saran ldm l i t Igi ket qua nghidn CCPU hd so hieu ung nhdm t u bdi bdo nam 1967 va sua Igi cdc khuyen nghj. Nhu'ng ket qua nay d u g c the hidn Irong bang d u d i ddy [4]:
Bang 1. Hisd nhdm i] theo Prakash va Saran
c) Hien tupng chong wng suit trong nhom coc dLF&i tic dung tai trgng theo phuxyng ngang (Rolline et al.
1998 va Ashour et al. 2004) Hinh 1. Sa d6 tuang tic cgc - dit trong nhdm cgc
du^i tic dung tii trgng theo phwang ngang TSs6
S/D 3.0 3.5 4 0 4.5 50 6,0 8.0
Hf so hifu ijng nhdm trong m6ng cpc chju tdi trong ngang T|
Nhom coc 2x2 0.42 0.50 0.57 0.61 0 63
-
Nh6m coc 3x3 0.39 0.42 0 44 0.47 0.48
KhuySn nghi 0,40 0 45 0 50 0.55 0.55 0.65 1.00
Sl!JJ@l!«J@
aaaaa KHOA HOC - CONG NGHE
Broms et al. t u ede ket qua nghidn cuu thyc nghigm lau dai dd dua ra khuyen nghj xac djnh he s6 higu ung nhdm cho nhdm ege chju lai trgng ngang Iheo bdng d u d i ddy [7]:
Bang 2. Hi so nhdm r\ theo Broms Khoang each S (theo phuvng tai trgng)
T|
3D 0.4
4D 0.5
6D 0.8
80 1.0 Trong do:
S: khoang each giua cac tim ege D: dudng kfnh hodc ehieu rdng cua cgc Ta t h i y rd r i n g , s y lam vide cua cgc chju lai trgng ngang Id rat phipc tgp. Tuy nhien, hign nay cac lieu c h u i n Irong nude chua ed cac khuyen edo cho v i f c xde dinh hg so hidu ung nhdm khi linh loan nhdm cgc chju tai trong theo phuong ngang. Cdc cdng thuc thye nghidm cung da cd nhung viec si> dyng c i n phdi cd s y chgn Ige va k i i m chung cho dieu kidn dja c h i l , Ihi cdng t h y c te tai Viet Nam.
Cung vdi s y phdt Irien cua phuong phdp PTHH v d mdy tinh d i f n t u eho phdp I h y c hidn cac linh toan phuc tap vdi khoi lugng ldn, ILF nhung nam 70 cua the k f XX vigc phdn tich kel c i u ndi ridng va cdc bdi lodn dia ky Ihuat bdng PTHH dd phdt trien manh.
Oen nay da cd nhieu phan mem dja ky thugt chuydn dyng de phan tich l u o n g tde k i t cau - nen d i l nhu Plaxis. Geostudio, Ansys, Abaqus...
C o s d khoa hge cua phuong phap nay Id ly thuyet eo hgc mdi trudng iien tyc, ly Ihuyel ddn hdi deo d i xdy d y n g hg phuong trinh vi phdn dao ham ridng md ta dieu kidn cdn bdng, dieu kidn idn tyc cua hg kel cau nen d i t va trgng thai ung xi> cua vat lieu; s u dyng phuong phap PTHH d i rd-i rgc hda hd khao sdt va giai b i n g phuong phap s6.
Trdn c o s d nhung nghidn c u u , cac ket qua t h y c nghiem tren the gidi; ldc gia xay d y n g md hinh xac djnh he sd hi^u ung nhdm Irong mdng cge cdng Irinh chiu tai ngang tTnh vdi cac d i i u kien t h y c td tai Vigt Nam bdng phan mem PTHH 3D. Tii' k i t qua dd so sdnh vdi cdc edng Ihuc I h y c nghidm vd dua ra cde khuyen nghi.
3. CTNG DUNG P H A N M E M PLAXIS 3D FOUNDATION N G H I E N CLFU T I N H T O A N H I E U U'NG N H 6 M T R O N G M 6 N G CQC C H m T A I TRQNG NGANG TINH
• Hieu chinh trong mo hinh bai toan tren Plaxis 3D Foundation tuvng u'ng voi kit qua thi nghiem nen ngang cgc tai hien truxmg
De hieu eh!nh SCPC ehju tdi eua cgc tren md hinh Irong Plaxis 3D Foundation, tde gia higu chinh thdng qua h§ so R,^^ trong khai bdo phan ILF Interface.
Ti> k i t qud s6 lieu thi nghiem ndn tTnh ege thyc t l (thi nghigm ege pha huy) d i l vd'i cgc P I 08 - ong kh6i vd thi nghidm cgc nen ngang vdi cgc P92 - ong khdi [10]; tdc gia xay d y n g mo hinh cge don Irdn Plaxis 3D Foundation vdi cOng ehieu ddi cge, cung so li^u dia c h i t sau dd lde gia ehay bdl todn cho 2 trudng hgp: 1) Khdng hidu chinh hg so R,^^^; 2) Cd tiidu chinh hg s i R^^^ cho tCrng lop dat theo nhu phan Iren. Gid tri hieu chJnh n h u trong Bdng 4 doi vot phin t u t i i p xiic eho tung loai d i l khae nhau.
Ket qud bdi toan cho d u d n g cong ndn - lun trong 3 trudng hgp: thf nghigm thye, ket qua md htnh khong d i i u chinh vd kdt qua md hinh sau d i i u chinh dugc the hien nhu tren Hinh 2.
Sau khi cd k i t qua tCf md hinh cgc don higu chinh, tac gid xdy d y n g md hinh bai todn cho mdng cgc trdn p h i n mem de xdt eac yeu t d dnh hudng d i n higu ung nhdm.
^Y^
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]=n a) Kit qua nen dgc^^S4>i^
. _ U . -
^ ^ J • — - n - p
-^tk qoiintMabclna m 1
XT-
VZL—
ttt^
?««*»iL
mm
b) KSt qua nen ngang
Hinh 2. Nen doc va ngang tnh cpc tfon thuc nghi0w.
md hinh Ithong dieu chinh vi md hinh co diiu chinh
sfi 8 nam 2017 I
K H O A H p c - C O N G N G H E # # # # #
• Xet anh / i u o n g cua tham so so Iwg'ng cgc m din st>c chfu tai cua nhom cgc
Xel cac bdi loan cd thdng sd d i u vao theo Bang 3, so l u g n g cge thay dol l u 1 cgc, 2 ege, 4 cgc, 6 cgc va 9 cge, ty so S/D khdng ddi b i n g 2,5. Dja e h i t d u d i mdng bao gdm 5 Id-p ed cae dgc trung eo ly n h u trong Bang 4.
Gidi hgn vung khdo sat Idn h o n 20D; D - d u d n g kfnh cge khao sal, phu thudc vdo l u n g bai toan.
Sang 3. S6 ligu kit cau diu vio bii toan
a) Mo hinh khdng gian
b) Md hinh chia lu^i 3D
c) Mit bing chia iLPdi mo hinh Hinh 3. Md hinh bai toin
STT 1 2 3 4 5 6
Kich thtpo'c b^ mong 12m X 12m 12m X 12m 12m X 12m 12m X 12m 12m x 12m 12m X 12m
So cpc 0 1 2 4 6 9
t 1 5m 1.5m 1.5m 1 5m 1.5m 1 5m
L„
18.36m 18.36m 18 36m 18.36m 18.36m 18.36m Trong d d :
P^ = P^n: SCPC ehju tai cua cge trong mdng;
P^. S u e ehju tai cua nhdm cge trong bd mdng n: Sd cgc trong bd mdng;
I: Chidu eao be mdng;
L : Chieu ddi ege
Khi be ehju tai trgng ngang P^ = lOOOkN (vdi sd-c chju tai cua cgc thiet k i D800 P„^ = 250kN), k i t qua c h u y i n vj tgi dinh hdng cge ngoai cung khi khdng ed cge, ed 1 cgc, 2 cgc, 4 cge, 6 cgc vd 9 cgc d u g c the hien Irong Bang 5, l u o n g Cpng vdi cde d u d n g do thi 2a, 2b, 2c, 2d, 2e, 2f trdn Hinh 4. Khi c h u y i n vj Idn nhat eCia bd mdng v u g t qud gia In 3,80cm (chuyen vi ngang Idn n h i l cho phdp be mdng cdng Irinh c i u BTCT), coi n h u be khdng cdn kha ndng chju l y c [5,6],
o i a n 4 m • s m ?
Hinh 4. Chuyen vi be mdng khi so lupng cgc thay ddi cung chiu tai P,„
iixi@
gaaaa KHOA HOC - CONG NGHE
Bing 4. D$c tnjng vit lieu
Thong so
Miu v$t lieu Loai v§t li^u
TL ri§ng dat tren myc nifac nglm TL rieng d^t dydi myc miac ngam Mo dun bien dgng
Hg so Poisson LLPC dinh don vi Goc ma sat trong Goc tnfong no Hs giam cuong do
Ky hieu
Model Type V™,
v„
E V X
*
^
f m .
L09i vat ii$u Lo-pl
M-C Drained
Ldp 2 M-C Drained
16,2 19,7 10700 0.3 11,2 18 0 0,75
Lop 3 M-C Drained
16.9 20,3 12600
0,3 16,4 18
0 0,80
L6'p4 M-C Drained
17,6 20,4 13800
0,3 21,5 21
0 0,80
LApS M-C Drained
18,2 20.8 22600
0.3 23,0 23
0 0.85
C9C BHTT Non-porous
24
29,2E6 0,3
Domvi
kN/m' kN/m"
kN/m!
kN/irf d«
as
Sang 5. Ket qua bai toan STT
1 2 3 4 5 6
Kich thu'oc mdng 12m X 12m 12m X 12m 12mX12m 12m X 12m 12mX12m 12mX12m
S6c9C 0 1 2 4 6 9
t 1 5m 1.5m 1.5m 1.5m 1.5m 1.5m
Lp 18.36m 18.36m 18.36m 18.36m 18.36m 18.36m
S/D
2,5 2,5 2,5 2,5 2,5
Pn (i<N)
352,1 205.8 181,5 170,2 165,9
He so hieu U'ng nh6m T]
1 0.5845 0,5156 0,4835 0,4714
So sanh ket qua chay tren mo hinh Plaxis 3D Foundation vd'i khuyen cao thirc nghidm Tdc gia so sanh vdi kit qua khuyin nghj Iheo Prakash va Saran (1967) va theo Broms et al.
Sang 6. So sanh kit qua bii toin vai tii nim ngang khi thay doi so lupng coc STT
1 2 3 4 6 6
Kich thuvc mdng 12m X 12m 12m X 12m 12m X 12m 12m X 12m 12m X 12m 12m X 12m
So C9c 0 1 2 4 6 9
L„
18.36m 18.36m 18.36m 18 36m 18.36m 18.36m
S/D
2.5 2.5 2,5 2,5 2,5
P. {KN)
352,1 205.8 181,5 170,2 165,9
Hf s6 hi#u ijng nh6m Theo PTHH
1 0,5845 0,5156 0.4835 0,4714
Broms et al.
1
< 0,400
< 0,400
< 0,400
< 0,400
Praltash va Saran
1
< 0.400
< 0,400
< 0,400
< 0,400
KHOA HOC - C O N G NGHE I I I U Bang 7. So sanh l<el qua bai toan vai tai nim ngang ithi thay doi ty so S/D
STT 1 2 3 4 5 6
Kich thu'd'c mdng 12mX12m 12m X 12m 12m X 12m 12m X 12m 12m X 12m 12m X 12m
So coc 9 9 9 9 9 9
Lp 18.36m 18.36m 18.36m 18.36m 18.36m 18.36m
S/D
2,0 2,5 3,0 4,0 6,0 6,5
P.(I>N) 124,1 144,6 158.9 201,9 283,9 310,7
Hf so hifu Crng nhom Theo PTHH
0,3523 0,4108 0,4512 0,5734 0,8064 0,8823
Broms et ai.
< 0.400
< 0,400 0,400 0,500 0,800 0,850
Prakash v i Saran
< 0,400
< 0,400 0,400 0,500 0,650 0,738
Nhan xet k i t q u a bdi t o a n :
Qua ket qua bdl todn cho Ihay khi vd'i cung kich t h u d c bg mdng, eCing dieu kign dja e h i t , chieu ddi cgc n h u nhau vd ti s6 S/D = 2,5 thi khi bg mdng cang nhieu cge thi s u e chju tai cua l u n g cgc ridng re trong bg cang giam. Ddi vd'i mdng cgc chju ldi n i m ngang cho thay higu u n g nhdm the hidn r i i rd, s u e chju tdi cua nhdm cge giam di r i t n h i i u khi so i u g n g cgc cdng tang Idn; so sdnh v d i gid tri k h u y i n nghj cua Prakash vd Saran (1967) vd Broms et a l . cho thay khi so l u g n g cgc cdng tang thi he so hidu Cpng nhdm cung d i n tigm cgn d i n gid tri TI <0,40.
Tuy nhidn qua k i t qua bdi loan cho thay, khi linh theo phuong phdp PTHH, gid Irj hg s6 higu ung nhdm Idn hon so vol cdc khuyen cao thye nghiem;
cd trudng hgp Id-n hon tdi 4 5 % . B i i u ndy cho t h i y cdc k h u y i n eao t h y c nghiem mang linh an loan qud eao, t h y c l i xdy d y n g gdy iang phi vdl ligu, lang ehi phi xdy dung khi cdng trinh cd khoi iugng mdng cge ehiem ty'trgng ldn.
• Xet anh huvmg cOa tham so S/D den S(K chju tai cOa nhom cgc
Xdt cac bdi lodn cho bd mdng cgc khoan nh6i D800 kieh thud-c 12mx12m s6 iugng cgc co djnh Id 9 cgc cd ty s6 S/D thay d i i ICf 2,0; 2,5; 4,0; 6,0 den 6,5 (Bang 3). Cae s i ligu ve dja chat vd so ligu cge nhu bdl lodn 1.
Khi bd ehju tdi trgng nam ngang P,^ = lOOOkN ( v d i SU'C chju ldi eua cgc t h i i t k i D800 P,^
2 5 0 k N ) , k i t qua ehuyen vj lgi dinh hdng cgc ngodi cCing khi ly so S/D thay doi l u 2,0; 2,5;...
den 6,5 6uf<yc t h i hidn trong Bang 7. Khi chuyen vj Idn n h i t cua bd mdng v u g t qud gid trj 3,80cm ( c h u y i n vj ngang Idn nhat cho phdp bd mdng cdng trinh eau BTCT theo dieu 10.7.2.2, T C V N 2 2 - T C N 272-05), coi n h u be khdng cdn kha nang chju l y c [5,6].
Hinh 5. Chuyin vi cua bi mdng khi ty so S/D thay doi cung chiu tai P,„
r # # # # KHOA HOC - CONG NGHE
So sanh k i t qua chay t r d n m o h i n h Plaxis 3D Foundation vd'i c d n g t h i r c t h i r e n g h i g m va t h e o Tieu chuan Viet Nam
Tac gia so sanh vdi k i t qua khuyen nghi theo Prakash vd Saran (1967) va theo Broms et al.
Nhdn xet k i t qua bai t o a n :
Qua k i t qua bdi todn cho t h i y khi vdi cung kich thudc bg mdng, cung d i i u kign dja chat, ehidu ddi cgc nhu nhau va so lugng cge trong mdng id n h u nhau thi sue chju tdi cua tCrng cge ridng re trong bg cdng giam khi tJ sd S/D cang gidm. Khi ty sd S/D
= 2,5 thi hg sd higu ung nhdm T) = 0,4512 vdi ndn ngang; khi ty so S/D = 6,0 thi hd sd hidu Cpng nhdm T)
= 0,8064 vdi nen ngang. So sanh vdi cac gid tri trong Bang 7 eho thiy, k h u y i n cao cua Prakash vd Saran cho hg so an loan qud eao, cao hon cCia Broms et al. khi khoang cdch giua cdc ege eang tang. Cdc k i t qua theo bai lodn phuong phap PTHH doi vdi tai trgng ndm ngang thi gia trj so vdi khuyen nghj Broms el al. dan Hem can, tuy nhien gid tri k h u y i n cao cua Broms et al. v i n thien ve an toan hon, lang phi vdt Iidu hon khi t h i i i ke [11].
4. K£T LUAN
Qua ket qua chay m o hinh cac bai toan c h o m g t so ket luan s a u :
Khi linh lodn bai toan tren md hinh so, cdc gid tri k i t qua tfnh cho thay hign t u o n g hieu ung nhdm anh hudng Idn nhdm cge khi chju tai Irgng ngang Idn hon nhieu so vdi khi chju lai trgng dung. Cdc k i t qua tinh Iheo md hinh phuong phdp PTHH phdn dnh dung theo qui ludt eac ket qua t h y c nghidm k h u y i n nghj.
Tuy nhidn ket qua tinh theo md hinh sd thidn ve tan dung vgl lieu lot hon; khi s i lugng cge il, dud'ng kinh coc thay d i i vide dp dung theo cdng thue I h y c nghi#m edn ban c h i .
Khi cd k i l qua Ihi nghiem nen ngang cgc t h y c t i ngoai hign trudng chung la hoan toan cd the xay dyng md hinh cge don thi nghiem dd tren phan mem Plaxis 3D Foundation sao cho bieu do lye - do lun l u o n g dong bang cdch dieu ehlnh cac he sd do d i i u kien Hep xuc t h y c te giu'a cgc va n i n ; he s i t r i i t gidm cudng do eua vgt ligu R,„^,... t u do xay d y n g md hinh ca be cgc de xae djnh sue ehju tal I h y c te cua nhdm cge trong mdng; danh gid sal t h y c l i nhat kha nang chiu tai trgng ngang eua hg mdng m6 vd try trong cdng Irinh cau.
Qua dd trong giai dogn thiet ke co s d , d y a tren cdc k h u y i n nghj thye nghiem chung la cd the t h i i t k i
d y bao khd nang ehju lai trgng ngang tTnh cua h?
mdng mo try cau. Khi cd k i t qua cgc thi nghidm nen ngang tTnh chung ta xay d y n g md hinh nhdm cgc trong mdng day dO de ddnh gia d u g c chinh xac sijc chju tai ngang cua mdng edng trinh trong dieu kign t h y c l i •
TAI LIEU THAM K H A O ^ [1]. Anil Ercan. Behaviour of pile groups u n d e r ^
lateral loads .08/2010. pp.5. % [2]. H. Kashlwa et al. Influence of NonlinearM
Behavior of Pile-Soil Structure on D i s p l a c e m e n t Amplitude Dependence for Efficiency of P l t ^ Group Based on Cyclic Lateral Loading Tests Subjected to Large Displacement Amplitude.
2008.pp.1-2. . [3]. Jasim M Abbas et al. Influence of Group a
Configuration on the Lateral Pile Group Response Subjected to Lateral Load, pp.761-
. ' ' ' • i
[4], Kyle Rollins, Ph.D. et al. Response, Analysis, and Design of pile groups subjected to static & dynamic lateral loads. 5-2013. pp.2- -<
• 15;2-16.
' [5]. TiSu chuan thiet l<ecJu. TCN 22 TCN 272- 05. Bo Giao th&ng vSn tai, 2009.
' [6]. Tieu c h u i n thi^t k i - Mong cpc. TCVN 206- II 1998. BS Giao thSng van t i i , 1998.
;! [7]. R. L. Moitwa - Mechanics of pile cap and pile group behavior, pp.15-22.
j [8]. A. Fadeev 1995; L. Delattre 2004; N.T. Lai 2010; T. Schweckendiek 2006.
[9]. Vu c a n g NgO, Nguyen Thai (2006). Mong cpc - Phan tich v4 thiet ke. Nha xuat ban Khoa hpc ky t h u i t - HS Npi. tr.29.
[10]. Bap cap thi nghipm nen tinh cpc va thi nghlpm cpc b i n g tai trpng tinh nam ngang dg" An "Nha may nhi?t dipn Vung Ang 1 ' . tr.215-225.
[11]. Nguyen M^inh H4. Nghien CLPU tinh toin hieu l i n g nh6m trong m6ng cpc cpng trinh chju t i i trpng tTnh. Hpc vipn Ky t h u j t Quan sif.
2016tr.91-92.
[12]. R.B.J. Brinkgreve & W.Brpere (2006).
Plaxis 3D Fpundatipn Version 1.5. Delft University of Technology & PLAXIS bv, The Neltherlands.