UNG DUNG PHU^ONG PHAP C Q T DAT

TAP CHl KHOA HQC CONG NGHE GIAO THIING VAN TAl, S 6 22-02/2017 7 1 UNG DUNG PHU^ONG PHAP C Q T DAT - XI MANG VA CAC NHAN

TO ANH HUOfNG DEN CHAT LU^ONG COT DAT - XI MANG 6 DUYEN HAI ^ TRA VINH

APPLICATION OF THE SOIL - CEMENT COLUMN METHOD AND FACTORS AFFECT TO THE QUALITY SOIL - CEMENT COLUMN IN DUYEN HAI - TRA

VINH

Nguyin Thdnh Dgt, Huynh NguySn Ngoc TiSn Dai hoc Giao thdng vdn tai Thdnh phd H6 Chi Minh Tom lat: Bdi viet trinh bay not dung ddnh gid kha ndng ung dung ciia cdng nghe iron xi mang duai sdu. Tir cdc thi nghiem trong phong vd tai hi?n truang vd^ diiu kien dia chdt khu vuc Diiyen Hai - Trd Vinh, chiing ta se lim ra cdc nhan i6 anh huang den chdt luang. do bin cua Irif xi mang dal Dong Ih&i, xdc dmh duac fj- le tdi uu vi hdm luang xi mang, nude sao cho mdu ddi sau khi duac gia CO ddp irng duoc cdc yeu cdu vekinh te-ky thudt. Cuoi ciing, tiin hanh phdn lich. lira chon du lieu thi nghiem phuc vu cho tinh todn bdng phucmg phdp gidi lich vd mo phong bdng phdn mim Plaxis 3D

Tu khoa: Coc hon hap xi mang - dat. cdc yen Id dnh huang din chdt luang coc xi mong -dal Abstract: The paper presents the content assessment of the application of deep cement mixing technology From tests in laboratory and in site with geological condUioin in Duyen Hai - Tra Vinh areas, we will find out Ihe factors that affect the quality and diirabdit)- of ihe soil cement column The same time, determine the optimal ratio about content of cement and walei for soil samples after being reinforced to meet the economic - technical requirements Finally, analysis of lest data to sei-ve calculations by analytics and Plaxis 3D simulation soflware.

Keywords: The sod - cement column method: the factors affect to the quality soil - cemnel Chis6phan hgi: 2.4

1. Gidi thieu

Vdi thdi ky hoi nhap kinh tS hien nay, d nude ta, nhu eau phat tnen co sd ha tang lai h^t sue can Ihiet Trong khi dd lai nhiJng do thj, trung tam thanh pho ciia cac tinh thudc chau thd Ddng bang sdng Cuu Long cd quy dai xay dimg khu cdng nghiep, nha may cd dien lich tuong doi Idn trd nen cang khan hidm va han hep. Nguoc lai vdi khu vuc ngoai thanh, ven song, ddng bang - noi cd dien lich xay dung rong Idn lai dii de phuc vu cho nhu c3u tren. Tuy nhien vdi nhiJng khu vuc vira de cap cd tien than la dat ndng nghifp, CO kk nhe, ngn dat thuong kha yeu ed kha nang chiu l^rc hiong ddi thap Vdi viec dat cdng trinh cd lai trong hrong ddi idn, irai dai tren dien lich rong thi cdng tac gia co nSn &k yfiu la hSt sire cSn thiet. Dc han che duoc nhihig nii ro, tidl k!?m chi phi dau lu va thdi gian ihi cong, hien nay cong nghe h-pn xi mang dudi sau trd nen kha ihi hon so voi cac phuong phap khae nhu. Cir tram, bac tham, coe BTCT, cir tre .. Nhung vdi dieu kien dia chat tai ven biln Ddng bang sdng Ciru Long ndi chung va d^i dien la khu vuc Tra Vinh

ndi rieng, viing dat cd phii sa bdi lap lau nam, l3ng dal yeu kha day li^u cd dap ung duoc kha nang chiu lai, kinh te cua cdng trinh dal len nd sau khi gia cd nen d^t bang cdng nghe trpn XI mang dudi sau hay khdng'' Van de nay se duoc chiing loi trinh bay chi tict trong bai nghien ciru nay.

2. Muctieu, phirong ph^p nghien ciru Phuong phap thuc nghiem' Thuc hieti cac Ihi nghiem trong phong, hien Irudng de xac dmh eac linh ch4l dac Irung va nhan id anh hudng din dp ben, chat luong ciia tru dat xi mang

Phuong phap ly IhuySl. Tdng hop, lira chon sd liSu ihi nghiem dua tren md hinh hdi quy luyen linh

3. Tinh chdt cff ly ciia d^t nen va vat lieu lam thi nghi6in

Mau dat nfin phuc vu cho cdng tac thi nghiem duge \ky tai hien trudng thudc khu vuc Nha may Nhiet dien Duyen Hai - linh Tra Vmh ed dilm chung la bim set Irang thai deo mim mau xam nau [I] MSu dugc lay lai hien trudng va bao quan c^n than dam bao cac chi lieu lu nhicn dc thi nghiem.

Journal of Transportation Science and Technology, Vol 22, Feb 2017

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4. Thi nghiem n^n don true khong han che no' hong

4.L Ket qua thi nghiem cho mau tron sir dung nii'dc sinh hoat vdi ty I? nirdc/xi mang lan lirQt la: 1,4; 1; 0,8

4. Thi nghiem 1 W/C=l.4

7 14 IS 90

s u e K H A N O N E N BON QU (kPnl

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"Mi 925 1419,75?

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6S73t)9 106K 154 1339 902 1952 909

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2114 r.3l 0 7 ™

914135 1176 31 1779,457 252ft,202

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1206,737 1609,054 1060,446 1001 ,Sfi

Hinh 1. Duong sire klidng nen dan thi nghiem I Trong dd: Ham lugng xi mang Ml00 tuong duong 100 kg xi mang/m^ dal lu nhien va tuong lu cho cac ham lugng eon lai.

Nhan xet thi nghiem 1:

- Di,ra vao hinh I, la thay rSng gia tri qu (kPa) tir khi bat dau che bi den 90 ngay tudi tang luyen linh theo ham luong xi mang. 6 Ihoi dicm 28 va 90 ngay ludi gia Iri siic khang nen don (qL=l5kPa) ciia dSt ty nhien lang kha nhanh lan lugl khoang 89, 128 I5n sau khi dugc gia cd.

- Nhung khi ham lugng xi mang khoang rtr 14 - 20% thi cudng do tru ddi xi mang cd xu hudng tang cham lai va dn dinh theo thdi gian.

i- Thi nghiem 2: W/C = I (nude sinh s6

7 14 2S

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SLTCKKANGNENDONOUIKPa, MKUI

IHfl.UH 421 461 iM.m 7««J144

MI5D

SlWjW 957,023 l3ftS.OI3 l«li.7M

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9B2,3B8 1394,516 2076.721 2563.9IS

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Hinh 2. Dirang site khang nen dem thi nghiem 2 Nhan xet thi nghiem 2:

Vdi kel qua d hinh 2 chi ra rang gia tri qu (kPa) d thi nghi?m nay tang manh hon vol thi nghiem I cu the khi d 28, 90 ngay tudi gia tri sire khdng nen don qu (kPa) tang len lan lugt khoang 137, 169 lan sau khi dugc gia cd.

Nguyen nhan chii yeu la do anh thay ddi ham lugng nude khi Iron mau So vol thi nghiem I, tai thi nghiem nay, khi ham lugng nude giam 40% khi trdn d3n den gia trj qu (kPa) ciia mau se lang 55,24% d thdi diem 28 ngay ludi. Su phat tnen cudng dd qu (kPa) ciia mau den 90 ngay tudi cham hon so vdi thi nghiem 1

^ Thi nghiem 3 Nudc/Xi mang (W/C = 0,8)

Hinh 3. Ihrovg. ur, khdng nen dim fhi nghiem 3 Nhan xet thi nghiem 3:

Dua vao hinh 3, ndi rang gia In qu (kPa) cua mau dal xi mang d thi nghiem nay lang

_ TAP CHi KHOA HQC C O N G NGHE GIAO THONG

f'TAl, SO 22-02/2017 73 manh hon so vdi ihi nghiem I va 2 Gia In

sire khang nen don {qu=!5kPa) ciia dk tu nhien lang lan lugt khoang 21 ]. 265 Un- sau khi dugc gia ed d 28, 90 ngay tudi. Ciing nhu hai thi nghiem ban dIu khi ta thuc hien thi nghi?m thay ddi ty le nudc/xi mang khi chi bi mlu se lam thay ddi kha rd ret gia tri qu (kPa) eua tru dk xi mang.

4.2. Ket qua thi nghiem cho m3u tron su- dung nir^c tai vi tri liy m3u |2| vdi ty le nird'c/xi mang = 1

Bang 2. Chi lieu ca ly cua mrdc Im vi Iri Idy mdu diing eho che bi mau f2J

•i- Thi nghiem 4: W/C = l(nude vj tri I3y mlu)

NGA HO 7 14 28 90

S t r c K H A N O N E N D O N Q U (kPa) Te^'i'

I 5 9 . M 7 216,238 304.228 467,193

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^9%, 259.396 40(1,343 574 236 74S.258

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505,251 S71,621 127! 21 1612,S

HAZ 562,143 1059,04 161332 2026,15

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903,59 1645,S 2121 S 2675.9

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1091.K6 1 896.05 2432.66 31S6,ai

Hinh4.Dircnigiirc khdng nen don ihi nghiem 4.

Nhan xet thi nghiem 4.

- So vdi thi nghiem 1.2, 3 (W/C = 1.4. I, 0,8) thi thi nghiem 4 ihay riing gia Iri qu (kPa) d 28 va 90 ngay tudi cho ket qua kha thap. Dien

hinh d 28 ngay mdi giam khoang 36 79% so VOI Ihi nghiem 2 (W/C = 1), 57,82% so vdi Ihi nghiem 3 (W/C = 0,8) va kem ] ,83% so vdi thf nghiem 1 vdi ty le W/C=L4. Nguyen nhan chii yeu la do chat lugng nude khi trdn mlu cd ham lugng goc axil qua cao lao diSu kien cho qua tritih an mdn clorua va tSn cdng sunfale san pham, su hinh thanh ellrmgiie (sulfoaluminatehydrate:

3CaO.AJ203-3CaS04.32H:0) va thaeh eao (gypsum: CaS04 2H30) lam mim hda hd xi mSng, Ihay ddi vi eiu mic den lang do rdng va giam cudng dd ciia cgc dk xi mang,

4.3. So sanh ket qua thi nghiem

Hinh 5. Duang 9ih khang nen don Iheo thdi gian ciia fl4 llu nghiem irong phdng Vdi thi nghiem ciing loai nude va xi mang nhung vdi ty le pha trdn khae nhau cho ta thay cae kit qua kha chenh lech. S(r anh hudng Idn ciia chat lugng nude din do bin va chat luong ciia cgc dal - xi mang, vi ihl thuc hien gia cd nen dal yen bang cdng nghS h-dn khd d khu vuc nay la khdng kha ihi.

4.4. So sanh kit qua thirc nghidm Ta thay vol ly le W/C - 0,8'va ham lugng xi mang la 14% se la ham luong tdi uu cho viec thi cdng dai tra. De kiem chirng lai xem tinh kha thi ciia lua chon nay, chiing la lien hanh so sanh vdi kel qua hien Irudng nhu sau

i I ;

Hinh 6.Gid in q„ (kPa) 10 sanh llnrc nghiem Khi ham luong xi mang la 14%. xet ihay kel qua nen mlu hien trudng eho gia tri cao hon ban cac ihi nghiem trong phdng d ty le W/C=l,4 va W/C=l. Ung vdi ham lugng nay thi gia trj sue khang nen don qu (kPa) hien

ll of Transportation Science and Technology, Vol 22, Feb 2017

trudng cho kel qua kha cao nhung thip hon chinh xac ciia he thdng co gidi, dieu kien dja khoang 35,5% so vdi thi nghiem trong phdng chat khu vuc gia c6, ky thuat thi cdng. . nguyen nhan la do Dieu kien che bi mau

trong phdng gan nhu la iy tudng Kel qua nen hien trudng cdn phu thuoc vao Dd hie

Mr, A Y 0 7 14 2H 1)0

GOC N O I M A SAT Wgl

174 21,S4 20,51 17.13 16,1)8

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1,7';

;o,22 17,34 14,63 13.18

12%

1.7:

11.73 14,76 12,34 10,12

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I.7-:

H.Ul 12,98 S f i l 8,95

17%

1 74 1444 12.05 7,21 8,22

2n%

1 74 15.63 10,86 11,oy 6,40

5. Thi nghi§m cat trirc tiep Sir dung ham luong tdi uu xac dinh hai dac trung co ban cua sire chdng c5t nhu sau:

M , V-i II 7 14 Jh '10

LL'H D I M l t (V.l'.il 6",,

" 4 wdf.

t|-i2IS 116 89 l l i l 352

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1-:.

7 4 75,145 154 435 208 979 205 3615

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P'-o 7 4 228 M 267 50(

316 207 331 134

14"., - 4 2!9 4 l 2<r h-Js 44X 162 464 928

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20%

267 05 ) 399^24

> 457 11.7 503,6:1 K

Hinh 7. Kel qua tlii ngh tii'p vd bieu do quan he ™ (dd). C (kPa) theo ihdi gi

Dua vao hinh 7 chi ra rang: 6 ihdi diem 28, 90 ngay tudi thi gia tri lyc dinh eiia mlu o ty le 6 - 12% cd su rdi rac tuong ddi nhd nhung ddi voi ty le 14 - 20% Ihi gia tri gin nhu hdi tu khdng chenh lech nhieu, trung binh d^l khoang 451,89 (kPa). Dieu nay cung mdt lan nua khang dinh ham luong tdi uu d3 chgn cho thi eong dai tra la hgp ly, dap img yeu eau kmh te - ky thuat khi dau lu cdng trinh

6. Phan tich dir lieu thi nghiem, lira chon ket qua theo md hinh hoi quy tuyen tinh

Tir dir lieu thi nghiem nen don true d 28 ngay tudi la dugc phuong trinh hdi quy nhu sau. Y(X) = q„, (kPa) = -{34.346 X|) - (3550,21

\ . ) + (116,92 X3} - (526,02 X.) + (5531,98 X5) - (188,01 Xi) + (325201,76 X7I + (237,94 X,) - (181,IS X,) - (32,86 X,n) + (1,14 Xii)+ (0.6 X13) + 58687,13

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sau- V(X) = T,(kPa) = - (85,94 X,) + (0 Xi) + (0 Xj) + (0 X4) + (5190,39 X5} - (48.42 Xt) - (17,95 X7) + (0,5 Xs) + (6,77 Xg) + 12,84

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Tir dir lieu Ihi nghiem cat true lilp a 28 ngay ludi ta dugc phuong trinh hdi quy nhu

Gia tri qu (kPa) tim dugc sau khi Ihong qua phuong trinh hdi quy luyen tinh la 3491,90 (kPa). Voi R= 0,99998 Gdc ndi ma sal ^(do) va lyc dinh C (kPa) lim dugc sau khi thdng qua phuong trinh hdi quy myen linh lan lugt cd gia trj nhu sau: ^ = 8,33 (do) va C= 444,124 (kPa), Vdi R-0,999915, Khi phan tich, lua chon sd heu bang mo hinh hdi quy tuyen tfnh tira cho ta cac gi^ Iri dac trung ciia tru dat xi mang thap hon khi trung binh cdng khoang 0,9%, ddng thdi gia tri he sd luong i^uan R rlt cao xap xi = I. Tir dd cho thay mdi hen quan giira cdc dai lugng den ket qua cudi cdng la rat chat che, sai sdl trong qua trinh thi nghiem la thap.

7. Tinh toan theo phiroTig ph^p giai tich

Tien hanh phan tich va danh gia quan diem linh loan theo cac quy Irinh dang duoc

TAP CHl KHOA HQC CONG NGHE GIAO THONG VAN TAl, SO 22-02/2017 75 sii dimg ph6 bi4n hiSn nay. thdng qua do dS Mo hinh 2 la- L - 21m S - 1 6m n , t m ,a cuan diem tinh toan to, au va dam bao 0,9m cho do lun it hon mo hinh \'L - dia chat tai khu vuc dat yeu ciin g,a co la hj d„™g g,97% nguyen nhan chi y6„ 7 2 Uiong cong xa nuoc lam mat thuoc nha may tr,ng luong ban than aia khSi g,a c6 nho la, Nh,et d^eiDuyejiHa^-- Tra VjnJ^ _ lam g,Sm do lin cua toSn kh3.

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0 1391 Hbili S. Kel qua linli todn Iheo ba quan diim Muon linh loan dn dinh nen dua theo quy trinh Thuy Diln la kha thi, an loan nhit.

Bdi siic chju tai theo vat lieu cua iru don bdi quy trinh Thuy Diln thSp hon lan krgt la 11,12% va 16,38% so voi khi linh loan theo quan diem ciia Nhal Ban va Trung Qudc.

Cdn khi xet den bien dang ciia tru dat - xi m5ng nen sit dung quy trinh tinh toan ciia Trung Quoc vi viec tinh loan do lun theo quy trinh nay cao hon quy trinh Thuy Dien va NhatBan la 21,16%.

8. Tmh toan mo phong b^ng Plaxis 3D Thirc hien md phdng tinh loan bang phan mem Plaxis 3D cho hai md hinh tru dal xi mang vdi rad hinh 1 (thuc te); L = 18,9m, S

= 1,6m, D = Im va md hinh 2 (md hinh tdi uu tir giai lich) la- L = 21m, S = 1,6m, D = 0,9m de so sanh ddi chieu kel qua

Hinh 9. Dd lim V\

Hinh 10. Bieu dd so sdnh kil qud Imh lim U(yl iheo giai lich va Plaxis 3D Khi thuc hien linh loan bSng ph4n mim Plaxis 3D cho dg lun nho hon so vdi thuc hien tinh loan bang phuong phap giai lich I5n lucrt cho ca hai md hinh I: L = 18,9m, S = 1,6m, D = Im va md hinh 2 la- L = 21m, S = i ,6m, D = 0,9m la 31,72% va 43,08%

9. Ket luan v^ khuyen nghj Khi gia cd nen dat yeu khu vuc ven biln Tay Nam Bd ndi chung [3] va vimg Duyen Hai - Tra Vmh ndi neng bang cdng nghe Iron XI mang dudi sau nen chgn ty le W/C = 0,6 - 0,8, ham lugng xi mang tii 14% den

! 6% (250 - 270 kg XM/m^ dai tu nhien) Khdng nen sii dyng cong nghS Iron khd cho khu tren vi anh hudng ciia chat luong nude tai vi tri viing dal ven bien cd ham luong gdc axit qua cao va tSn cdng sunfale.

Xet ve hai mat thi khi tinh loan dn dmh va bien dang nen dua Iheo quy trinh Thuy Dien la kha Ihi va an loan hon.

Thuc hien tinh loan bang Plaxis 3D cho do lun chinh xac, nhd hon so voi giai lich cho ca hai md hinh i: L = 18,9m, S - 1,6m, D = I m v a m o h i n h 2 la L = 21m, S = 1,6m, D = 0,9m la 31,72% va 43,08%Q

Tai lieu tham khao

[!] n e sa khoan did chal cua Nha may nhi?! dien Duyen Hai - Tra Vinh

[2]. U€n doan QH&DT Tai nguyen nirae Mi In Nam [3] Nghien cuu lira chpn ham luong xi mang va ty le

ntroc-xi mang hpp ly cho gia co dal yeu viing ven biln DSng bang Song Ciiu Long

N g ^ y n h a n fo^i: 13/12/2016 N g ^ y c h u y e n p h a n b i | n : 16/12/2016 Ngiiy h o a n t h ^ n h s u a b a i : 06/01/2017 N g a y c h i p n h a n d d n g : 13/01/2017