KHOA HQC - CONG NGHE
NGHIEN cufu VA DE XUAT CAC GIAI PHAP XUf LY NEN DAT YEU MOT SO TUYEN DlTfllNG THUOC TINH LONG AN
TS. LE VAN BACH Trudng D^i hac GTVT
Tdm tit: Hidn nay, cd nhieu giiiphip xdiy nen ddt ydu khi xay dtfng dUdng. Nham gdp phdn vio vide dinh gii thtfe te cic giii phip xd if nen dUdng dip trdn ddt ydu, gdp phan vio tiep e$n phit trien vi hoin thidn cic phuang phip tinh toin vi cdng nghd thi cdng xd /y nen dUdng dip tren dat yeu, cdn phii nghidn edu vi de xuat cic giii phip khi thi de xd ly nen ddt yeu khi xay dtfng mdtsd tuyen dUdng thude tinh Long An.
Abstract: Currently, many weak ground han- dling solutions road construction. To contribute to the assessment of practical solutions to handle em- bankment on soft soli, contribute to the develop- ment approach and complete the calculation methods and construction technology embank- ment on soft soil treatment, need to research and propose possible solutions to handle soft ground when building a number of roads in Long An province.
1. Gidi thidu chung
NhOng nSm g i n ddy, d l dap Ong nhu d u phat triln, lou thdng hang hda vdi eac tfnh lan can cung nho giOa cae trung tam kinh t l trge thupc tinh, tinti Lpng An da thgc hidn vide md rdng, lam mdi nhilu t u y l n dgdng nhd: QL1A, cao tdc Sal Gdn Trung Lgdng, tuydn N2 dogn Chdn Thdnh DOc Hda, doan M6 Vpt - Binh Hidp thupc tuydn N l , dUdng kdnh 79 ndi QL62 vdi thj trIn Tdn HOng...
Vide md rdng, lam mdi cdc tuydn dodng ndu tren khi qua khu voc ndn dd't ydu vdi dja chat phUe tap, tdy thude vdo logi dja chit, dja hinh, thdy vdn tgi chd cda tdng khu vgc, d n p h l i ed cac g i l l phap xd ly khae nhau dd d i m bdo v l an toan va dgt dgpc cae ydu e l u ky thuat trong giai dogn thi cdng cung nhu trong giai dogn khai thde.
Do do nhilu gidi phap xO ly da dupe ap dgng trong dd ed nhieu giai phap ddng, xCf ly n i n dat yeu hidu qud, phu hpp vdi cdng trinh, bao d i m dupe c h i t lopng va hg gid thanh cdng trinh. Tuy nhidn, mdt sd cdng trinh dp dgng gidi phap xd ly ehua hpp ly, gay lang phi va khdng dem lgi kdt qua nhu mong mudn.
NhIm gdp p h l n vao vide ddnh gid thgc td cae giai phdp xd ly ndn dUdng d i p trdn d l t ydu, gdp phan vdo tidp can phat tridn va hoan thIen cac phUdng phap tfnh toan va cdng nghd thi cdng xd ly ndn dUdng d i p trdn dd't y l u , d n p h l i nghldn eUu vd de x u l t cae g i l l phap k h i thi d l xd ly nen dat ydu khi xay dong mot sd tuydn dUdng thude tinh Long An.
2. Oleu kl#n dja chat cua mpt s d tuydn dUdng thuQC tinh Long An
Do didn tich tinh rdng Idn, dja chat phan bd phOc tgp, khong ddng ddu, do dd chi tap trung danh gia phan bd dia c h i t tgi mdt sd tuydn dodng chfnh quan
trpng da va dang trong qua trinh xay dOng:
+ Dodng Kenh 79 ndi huyen Tan Hong vdi QL62;
-I- Md rdng Qudc Id 1 dogn thupc dja phdn thanh phd Tan An;
+ Tuydn Nl dogn Md Vpt - Binh Hidp;
Dga vao hinh trg Id khoan tgi tuyen Nl dogn M6 Vet - Binh Hidp trong dg an lam mdi (qua 2 huy^n Ddc Hud - Mdc Hda), hinh trg l6 khoan dpc dUdng kenh 79 trong dg dn ndng cap md rdng (ndi huy§n Tdn Hgng vdi QL62) vd hinh trg Id khoan hal ben trfin Qudc Id 1 thupc dg an md rdng glal dogn 2012- 2020, trong pham vi dp sau khoang 30m trd lgi co the nhan xet mot sd Idp dja chat.
Dac diem chung dja c h i t tai 3 tuydn dUdng chfnh:
Ldp 1: Dat rupng la logi set mau xam den, xdm vang, trang thai ddo chay - chly. Ldp nay nim trfin mat den dd sau 2m. Day la logi dat phd bidn xuSt hien hau h i t tgi t u y l n dddng Idm mdi vd md rpng.
Ldp 2: Bijn set mau xdm den. Ldp nay nim fi dfl sau td 1,7m d i n 9,9m. B l day Idp la 8,2m. Ddy l i Idp d l t y l u , sOe chju t i i kem, tinh ndn lun manh xult hien khi khdo sat dpc tuyln Qudc Id 1, tgi vj trf dUdng cap kdnh 79 dogn dodng dau cau va dogn M6 V?t- Binh Hidp thude tuydn N l . Ld ldp dd't d n dope xii ly thich hdp tranh anii hUdng den chat lUdng cdng trinh khi xdy dgng tuydn dodng mdi di qua.
Ldp 3: Set l l n eat, mdu ndu hdng, nau vang, ndu do, xam tring, deo cOng. Ldp nay nam dUdi ldp 1 vd gap tgi dp sau 9,9m va 17,5m. B l day Idp la 7,6m.
Day la Idp dat tUdng ddi tdt xuat hidn d hau hdt cac tuydn dUdng.
Ldp 4: Set cat kep cat, mdu nau vdng, ndu d6, xam trIng, nda cdng. Ldp nay nam dUdi Idp 3 vd g^p tgi dp sau 17,5m va 23,4m. B l day Idp la 5,9m. Day la ldp dat tdt khdng d n p h l i e l l tgo.
Ldp 5: cat hat nhd ddn vOa, mau xam trIng, ndu vang, kdt d u chat vOa ddn chat. Ldp nay n i m dUdi Idp 3 be day den dp sau 30m. Day la Idp d l t tUdng ddi tdt xuat hidn d hau hdt cdc tuydn dUdng, cd thi dat mdng cdng trinh trdn Idp ndy.
cae chi tidu cd ban cda cdc Idp dja c h i t dUdc the hien chi t i d t d (bang 1).
Bing 1
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B 9 10 11 12
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KHOA HQC - C 6 N G NGHE Tap Chl GTVT 12/2012
11
Phan vdng dja c h i t d l t ydu cdng trinh:
Do chi xem xdt 3 tuydn dUdng chinh d cdc vj trf khae nhau trong tinh Long An ndn vide ddnh gia v l phdn bd dja c h i t trdn trong toan tinh khdng hodn toan chinh xdc ma chi cd gia trj tham khao d cac khu vgc lan can g i n vdi cac tuyen dUdng da dupc danh gia.
Nhdn xdt: C i t dpc dja c h i t dUpc thOc hien tO cae l6 khoan each nhau 200m - 500m. Dia c h i t mdi tuydn tuy khae nhau nhOng ddu cd net tOdng ddng Id cd Idp 1 vd Idp 2 la Idp dat ydu. C i n phdi ed bidn phdp xd ly phu hpp tdy theo chilu sau Idp dat y l u khi thilt kd tuyln di qua cac khu vgc trdn.
3. Dd xuift g i l l phdp x d ly dat yeu tai mdt s d tuydn dUdng chfnh thude tinh Long An
3.1 Kidm toin dn dlnh truat vi idn cua ndn dUdng khi ehua xd ly
Mge dfeh cda vi$e k i l m toan nhIm xac djnh vdi cac thdng sd chd ydu dope nghldn cOu thi khi khdng xd ly, c h i l u cao d i p tdl da cda ndn dUdng cd t h i dgt dope Id bao nhidu vd dd Idn cung nho hd sd dn djnh tOdng dng.
Kidm todn dn djnh trupt vd bidn dgng Idn cda nen dUdng vdi 3 tuydn dUdng nhu sau
3.1.1 Tuydn dUdng 1 (cdp Kenh 79):
Bd rdng ndn dUdng: 9m; Hasp = 3,4m - 4,2m; Hbun
= 24m - 33m.
Kidm todn dn djnh sd dgng phan m I m Geoslope (Hinh 3.1).
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Hinh 3.1: KiSm toin dn Hinh 3.2: KiSm toin dn dlnh truat khi dip trtfc tidp dinh truat khi dip trtfc tiep (Cdng trinh: Budng QL62- (Cdng trinh: Md rdng Tin Hung (Kdnh 79)) QL1A)
3.1.2 Tuydn dudng 2 (md rdng QL1A)
B l rdng n i n dudng: 9m; HdSp = 3,0m - 3,5m; Hbon
= 11m - 12m.
Kidm toan dn djnh sd dgng p h l n mdm Geoslope (Hinh 3.2).
3.1.3 Tuydn dUdng 3 (Tuydn Nl do^n Mo Vet - Binh Hidp)
Bd rdng ndn dUdng: 30m; Hasp = 4,0m - 5,5m; Hton
= 15m - 18m.
Kidm toan dn djnh sd dgng p h l n mdm Geoslope (Hinh 3.3).
B i n g 2, 3 vd 4 thdng kd h§ sd dn djnh vd dd Idn cda ba tuydn dudng trdn.
Nho v$y, thdng qua tlnh todn trdn ta nhan t h I y tai 3 tuydn dodng ndu trdn vide d i p trOe tidp trdn ndn d l t ydu la khdng d i m b i o . Do v^y, khi thidt kd ndn dodng d i p trdn ndn d l t ydu thi vi0e tinh toan, Iga
ehpn gidi phap xd ly la d n thiet.
3.2 Tinh toin vi so sinh hieu qui kinh te ky thudt cua cic giii phip
DUa vao d l xuat cae gidi phap xd ly dat y l u dUde ndu k i t luan d trdn, t i l n hanh tinh todn va so sdnh hidu qua kinh td ky thudt cda cdc giai phap nhIm dua ra dupc giai phap hdp ly xCf ly n i n dat y l u trong xay dgng dudng tgi 3 tuyln dUdng thupc tinh Long An vdi chilu cao dat d i p >3m, b l rpng n l n d u d n g ^ 9m, dudng d p IV trd Idn, chilu ddy d l t y l u thay ddi.
Tinh toan dga trdn phln m I m Plaxis V8.2 vd bang tfnh lap bang Excel, k i l m toan dn djnh trUdt cda n i n dudng bang Geoslope hoae Plaxis (Hd sd dn djnh sau khi xd ly phdi dgt Kmin ^ 1,2 trong giai dogn thi cdng vd Kmin ^ 1,4 khi cdng trinh dupe dua vdo xd dgng).
Sd lieu dia chat cua 3 tuyen dudng tren dupc thdng kd d bdng 5.
Hinh 3.3: Kiem toin dn djnh truat khi dip trtfc tiep (Cdng trinh: Tuyen Nl do^n Md Vet - Binh Hidp)
Bang 2
Chi^u saudit yeu 33,6 33,6 24,3
Hfso on dinh
1,216 1,218 1,224
Dp lun t6ng cpng
(cm) 95 104 125
Dp lun cdn lai sau 15 nam (cm)
84 95 101 Ban 2 3
Chieusiu ditylu
11 12
Hf sd on djnh
1,329 1,282
Dp lun tdng cdng
(cm) 77 78
Dp lun cdn lai sau 15 nam (cm)
51 50
Bane 4
Chi^sau dat yeu
15 18
H$s6 6ndinh
1,103 0,933
D§lun tdng cpng
(cm) 99 137
Dp lun cdn lai sau 15 nam (cm)
74
108
m KHQA HQC - CQNG NGHE
Bang 5
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3.2.1 De xuat giai phip xd I'/ vi tinh toin cho tuydn dudng 1 (cdp Kenh 79)
Gidi phdp xd ly: D a o bo Idp hOu cd, dap tra bang cat, d i p ddm eat hat trung, e l m b l e tham vd dap gia tai theo t d n g giai d o g n . Tinh toan vdi chieu cao dip 3,5m, chiSu siu dat yeu 33,6m, PVD cam vio ldp bun sit Ii 10m, khoing cich giOa cic bac tham 1m. Ket qud nhu sau:
- Dp lun tdng cpng cda ndn: 95cm.
- Dp lun cdn lgi khi xd ly bang PVD sau 10 thang gia tai la 31cm (dgt).
K i t qud k i l m tra dn dinh trupt dupe the hien 6 hinh 3.4.
3.2.2 Dd xudt S = £ S ^ - . = r ; — ~ giii phip xd iy
vi tinh toin eho tuydn dudng 2 (md rdng 0L1A) GIdl phdp xd ly: Thay mot p h l n d l t yeu k i t hpp vdi vdi dja ky thuat ngan each.
Hinh 3.4: Kiem toin on djnh truat sau khi xd ly bang bdc tham Tinh toin vdi chiSu cao dap 3m, chieu sau dat yeu 12m. Dio bd Idp ddt ydu vdi chieu diy 2,5m, dap tra bing cit dip nin dUdng, trii 02 Idp vii dia ky thuat ngin cich cd cudng do 12kN/m.
K i t qud nhu sau:
- Dd lun tdng cpng cda ndn: 77cm
- Dp lun cdn lgi cda n i n sau 15 nam: 40 em K i t qua k i l m tra dn dinh trupt dUpc the hien 6 hinh 3.5.
3.2.3 De xudt giai phip xd ly va tinh toin cho tuydn dudng 3 (Tuydn Nl do$n Mo V^t - Binh
Hidp) P ^ -
Giai phap xd ly:
sd dgng g i l n g cat.
D a o bd Idp hOu cd, d i p trd b i n g eat, d i p d^m cat hgt trung, thi cdng gidng cat. gia tai theo tOng giai dogn. Dudng kinh gidng cat la D = 40cm, khoang cich
J A
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Hinh 3.5: Kiem toin dn dinh truat sau khi thay mQt phan dat yeu ket hQp vdi vai dia ky thuat ngin cich
cua gidng la 1,5m (tim den tim). Chieu siu gidng cat thay ddi dd dim bio ydu cdu ky thuat va tinh kmh te
Tinhi toan voi chieu cao dap 4m. chieu sau dat yet 15m. chieu dai gieng cat 11m
Ket qua nhu sau.
- Dp lun t6ng cong c u a n e n : 57cm
- Dp lun c o n lai khi xu ly bang gieng cat sau kh gia tai 10 thang la 14cm
Ket qua kiem tra on dinh trugt duoc the hien o hinh 3.6.
4. Ket luan
Tai 3 VI tri khae nhau c u a 3 tuyen duong tren co chieu sau phan bo khae nhau: Tuyen 1 co chieu sau dat yeu tu 24 - 3 4 m . tuyen 2 co chieu sau dat yeu tu 10 - 12m, tuyen 3 co chieu s a u dat yeu 20 - 25m, vdi cac chl tieu co ly cua cac lop dat yeu 3 tuyen duong cung khae nhau
- Ket qua c u a cac giai phap xu ly dat yeu cua 3 t u y e n d u o n g tren
duoc tdng h d p nhu bang 6.
- Hieu qua kinh te va thbi gian thi cong c u a 3 t u y e n d u o n g tren d u o c tdng h o p nhu bang 7,
Bang 6
Hinh 3.6: Md hinh tint) toan gieng cat
Bang 7
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Ket qua nghien cuu tren da tao cd sd cho cong tac danh gia quy mo xac dinh pham vi phan bo cua cac loai dia chat dat y e u , ddng thdi se la can ci) de de ra cac giai phap co b a n ve xuf ly nen d i p va quy hoach do cao xay dung ung vdi tCfng khu viic cho phu hop 6 giai doan nghien c u u sau
Ket qua nghien c u u cung se tao di6u kien thuar loi cho viec trien khai cac cong trinh ha tang gSn v6 p h a m VI n g h i e n c u u , g o p p h a n lua chon cac gia phap xu ly nhanh c h o n g va thuan lgi 3
Tai lieu tham khao
[1 ]. Ho so khao sat dia chat dudng Kenh 79.
[2]. Ho so khao sat dia chat mo rang Ouoc Lo ' doan Khanh Hau TP Tan An.
[3] Ho sd lieu khao sat dia chat duong N1 doar Mo Vet - Binh Hiep.
[4). Quy trinh khao sat thtet ke nen duong 6 lc dip tren nen dat yeu 22TCN - 262 - 2000
[5]. Thiet ke va thi cong nen dip tren dat yeu N g u y e n Quang Chieu N X B X a y dung
