KHOAHOC-CONGNGHE I I I I I
SUT DUNG DAT GIA CO HOA CHAT VA PHU GIA
LAM CAC LdP MONG DUdNG THAY THE MONG DA DAM CAP PHOI TRUYEN THONG TRONG KET CAU AO DUOING
KS. Hd HOANG TUNG ThS. DINH XUAN NGOC Sd Giao thdng Vgn tdi Thiia Thien Hul
TS. T R A N HO'U TUYEN
Khoa dja chdt, Dai hoc Khoa hoe Hul
Tom tit: Gia co dit bing phuong phap hda dipn: (Electro-Chemical) hay con ggi Id phuong phap lon
hda 6n djnh dit (Ionic Soil Stabilization - ISS) VOT tac nhan la eac chit ion hda la mpt trdng nhung bipn phap gia co lam tang sire ehju tai eOa dit; Cdng nghp ndy dugc cac nuoc tidn tiin nhu Dire. Mp, Thyy ST, Nam Phi ung dyng ipng rdi tCr nhQng nam 1950 trong nhieu linh vyc, dac bidt la trong xay dung du&ng giao thdng. Mac dii da dugc ap dung tir nhung nam chien tranh nhung cho den nay, vi nhiiu ly' do khae nhau ma edng nghp ndy vin chua dugc pho bien o Vipt Nam. Bai bdo nay la mgt phin kit qua di tai NCKH cip tinh & Thim Thidn Hui nham thir nghidm ung dyng edng nghp gia co dit tren dja bdn tinh.
Abstract: Reinforcement of land by electrochemical methods (Electro-Chemical), also known as the method of stabilizing soil lon (Ionic Soil Stabilization - ISS) with agent is ionized substances is a measure of trying to increase the load bearing capacity of the soil. This technology is the advanced countries such as Germany, Switzerland, South Africa, widely used since the 1950s in many areas, especially in the construction of roads. In Vietnam, this technology is not yet widespread although the US military has been used effectively since the war years. This paper is pari of the result Research topics in Thua Thien Hue province in order to test the application of soil reinforcement technology in the province.
I.DATVANOe
Hien tgi, dudng giao thdng d nudc ta khi thiet k l theo kit clu do dudng mem hlu hit dlu thilt k l theo md hinh "3 lap":
Ldp 1: Be tdng nhya (12~15cm) hoac lang nhya 2 din 3 Idp Ldp 2: Cap phoi da dam (Idp mdng fren CPDD loai 1 ddy 20-30cm, Idp mdng dudi CPDD Iogi2day25~30cm) Ldp 3: Dat dip chgn Igc dat K=98(ti>30~50cm) Tuy vdo moduyn dan hoi E^^ va E„ cua nen dudng d l tang giam chieu day Idp d p phoi dd dam va Idp d p phoi doi, co trudng hgp Idp CPDD day din 80cm mdi dam bdoE . Nlueiiphu thuOcvaomd hinh trin, vdi toe dO phat triln nhu hien nay thi khdng nhung cae mo
I So 9 nam 2015
da se ching mly choc cgn kiet ma nguIn dlt cap phdi doi cung ngdy cang khan hilm.
(y nudc ta, dlt rlt da dgng va phan hda ro ret tu dong blng din vung nui cao; Vide tim hieu, nghien ciiu thii nghipm d l iing dgng cdng nghe gia co dlt lam cac Idp mdng dudng thay cho mdng da dam truyln thong la giai phdp kha lhi eho nguon vat iieu xdy dyng dudng trong tuang lai.
2. CONG NGHE GIA C6 O A T Cae phuang phdp gia e l on djnh dat cd the phan loai nhu sau:
Phuxrng phap c<y ly: Dung cac thilt bj dim, nen Idm thay doi ly tfnh cua dlt;
Phuong phap cd" hat: Thay doi thdnh phin cd hat d l cai thipn chit lugng dat;
Phuong phap hda ly: Dung chit kit dinh hda hpc thay doi ly tinh cua dlt;
Phuong phap hda dien:
Dung hda chit cd tinh ion hda tdc ddng vao lien kit tmh dien eua dlt;
Phuong phap vi sinh hoc:
Dung eae chung vi sinh vat hoac enzymes iam tang kha nang kit dinh cua dlt set.
Trong dd phuang phdp hda dipn va phuang phap vi sinh hge dugc xem la nhiing phuang phdp mdi so vdi cdc phuang phdp truyln thong khae vd vdn dang duge nghien ciiu phat then.
d day d l cgp din phuang phap
hda dien hay con gpi Id phuang
phap lon hda on djnh dlt.
' KHOA HOC - C 6 N G NGHE
2.1. Phuong phap lon hoa on djnh dat (Ionic Soil Stabilization -ISS):
Ld p h u a n g phap s u d g n g cae hda chat cd phan i i n g hda hpc v d i d l t de eai thien ede tinh c h i t c a ly cua d l t . Cdc c h i t ion hda on djnh d l t dang s i i dgng d cae n u d e d l u cd thdnh p h i n chinh la thdnh p h i n tan d u g c trong n u d c cua dau md da d u g c sulfon hda.
Chung co ehung mOt nguyen ly la pha v d hien t u a n g n u d c mang trong thdnh p h i n set c u a ddt, tao dieu kipn quyet djnh de k h u n u d e trong d l t [2,3,4]. D a cd n h i l u loai hda c h i t gia eo d l t d u g c gidi thieu vd t h i i nghipm d Viet Nam n h u : SA44/LS40 (Hoa Ky); RRP (CHLB D i i c ) ; Con-Aid (Nam Phi); C O N S O L I D (Thyy ST); D u s t e x ( O c ) . . .
C d nhung cdng ty nhu D u e T h u g n , RRP Vigt Nam, Cdng ty T N H H cdng nghe Hipn dgi the gidi dd nhgp hda c h i t , may mdc chuyen dung ve 6e thi cdng mOt s l nai d mien Bac vd mien Nam t i i nhung nam 2003. Nhung vi n h i l u ly do khac nhau, d i n nay cdng nghp gia cd d l t b l n g hda c h i t van ehua p h a t t r i l n d Viet Nam.
2.2. Cvs&ly thuyet chung cua phuxmg phap lon hda on djnh dit:
Cdc hda c h i t on djnh d l t theo p h u o n g phdp lon hda ndi chung deu d y a tren n h i i n g nguyen t i c CO ban nhu sau:
- Ld nhung c h i t co hogt tinh cao, phdn ly thdnh lon khi hoa vao n u d c
- DiJng lon Hydro (H*) trong phdn t u cua nd k i t hgp vdi cac nhdm Hydroxyt ( O H ) cua d l t va cac Hydroxyt kim logi tgo thanh n u d e thoat ra khdi d l t
- La cau noi g i n k i t cdc Cation Kim loai vd eac Anion ( S i O j ) cd mat trong d l t tao ndn mach khdng gian trung hda dipn tich d u d i
dgng mdt Polime m d i , ben v u n g , mdt tinh nhgy cam v d i cdc Cation, kim loai.
- Lam thay doi cae dae diem d u true tinh t h i cue khoang vat set, lam mdt di thugc tinh t r u a n g n d khi gap n u d c cua khoang vgt set nhom Montmorilonit [3,4].
- Khdi d l t da d u g c k h i i n u d e vmh v i l n n h d tac dung dam nen md ngdy cdng sit chat h a n , ngan chan s y mao dan cua n u d c n h d be gay cdc mao mach. D l t tang c u d n g dO theo thdi gian.
T i i d d , cdc hda c h i t d u g c san x u l t d y a vdo qua trinh Sunpho hda d l u khi, lay cac goc SOg^", 30^^" Idm g l e c a ban de ket h g p v d i cdc gde huu eo t h u d n g thuOc eac nhdm n h u Alkin, Caeboxyl, Amin hay goc Phenol trong cac h g p chat h i i u ea da c h i i c (tham) mgch vdng [5].
V i d u : Hoa c h i t SA44-LS40 cua My lay S O / " Idm goc, hda c h i t RRP-235-Spezial cua CHLB O i i c l l y SOj^-lam goc... [3,4]
Khi t u d i dung djeh hoa c h i t vao ddt thi cdc goc h i i u c a trong hda c h i t t h y e hien qua trinh c h u y i n hda lon, lien k i t cdc ion kim loai trong d l t va qua trinh trung hda tach nude.-,
L l y hda c h i t RRP lam vf dy, se cd cdc giai doan sau [4]:
S y phdn ly
(vdi Me la cac Cation kim loai Ca^*, Mg^% K \ Na*, Fe^*,AP*...)
N l u ky hipu g i c RSO^H n h u sau R SO • H
Trung hda dipn tieh
Trang thai binh thu&ng
Thi qua trinh tren d u g c md ta n h u Bit diu ed tae dpng eua hda chat
sau: RRP
®i»m
KHOA HOC - C O N G NGHE MM tti
0 © ,
Cau triic on dinh sau khi hodn thanh tic ddng cua RRP
© ©
ciu true da dugc on dinh sau khi dim ndn
N h u vgy, cd the thay r i n g thdnh phan khodng vat set trong d l t va ham l u g n g , logi Cation trong dat Id cdc y l u to q u y l t djnh hipu q u a eua viec gia c l .
3. Thi NGHIEM T R O N G PHONG Nhdm nghien c i i u d T h u a Thien H u l da t i l n hdnh t h i nghipm v d i 10 logi dat ddc trung tren dja ban tinh vd v d i 4 loai hda c h i t d a c d mgt tai Vidt Nam; Hda chdt VISS sdn x u l t tai Viet Nam; Hda c h i t SA44-LS40 cua My; Hda c h i t Consolid - Solidry cue T h y y ST;
Hda c h i t RRP cua COng hda lien bang D i i c . D y a tren k i t q u a mOt s6 cdng trinh t h i i nghipm t h y c t l da Idm d Vipt Nam, nhom nghien Cliu cung da t h i i nghipm k i t h g p hda c h i t vd vdi v d i l i i u l u g n g 2 - 4 % khoi l u g n g d l t .
Cdc chi tieu c a ly cue mau d u g c xdc djnh:
- Modun dan hoi cua t i i n g to h g p mau theo 7 ngdy. 14 ngay va 28
ngdy tuoi va d 2 8 ngay tuoi trong dieu kipn ngam bao hda n u d e . - C u d n g do nen dgc tryc cua t o h g p mau d 7, 14 va 28 ngdy tudi va d 28 ngdy tuoi trong d i l u kien ngdm bao hda n u d c .
- DO ben ep che eua to h g p m l u d 7 , 1 4 va 28 ngay tuoi va d 28 ngdy tuoi trong d i l u kien ngdm bao hda n u d e
- He s l tham cua t o h g p mdu d 14 va 28 ngay tuoi.
Qua k i t qua thi nghipm cua mdt so l u a n g Idn cdc to h g p m l u rut ra n h u n g nhan xet n h u sau:
* Cae loai hda chat ndi tren d l u phat huy tdc dgng t i t khi gia co v d i dat c d thanh p h i n hgt set mjn <= 0,06mm toi t h i l u la 1 5 % . Cae chi tieu c a ly cua d l t gia co (OGC) n h u Eg^, R^, R^^^ d l u tang theo tuoi gia co va cao h a n nhieu so v d i mau O G C c a hgc: Modun b i l n dang d a n hoi E^^ tang len 1,5 - 5 l l n , c u d n g d p chju nen R^
tang 2 - 4 l l n , d p b i n ep che R^^^
tang 1,5 - 3 l l n . D a c bipt khi s i i dung hda c h i t kem 4 % vdi l h i cdc chi tieu tren deu tang 1 0 - 4 0 % tuy thude t u n g loai d l t , rieng he so t h i m K^ giam ve gan m i i e 2,5x10"^ t i i c Id gan n h u khdng t h i m n u d c .
Tong h g p ede chi tieu e a ly eua cac to h g p m l u d 28 ngay tuoi n h u sau:
* D p on djnh doi vdi n u d c eua vat lieu D G C hoa c h i t doi vdi n u d e khdng I d n . Cdc chi tidu cua vdt lieu O G C hda c h i t d trang thai ngam bao hda n u d e tang r l t it vd h l u h i t cdc mdu d l u bj phd hogi sau 4 8 h . Vi vdy OGC v d i hda c h i t ehl thfeh h g p v d i vijng cao, kha nang lieu thodt n u d c tot ma khdng dp dung d u g c eho vung hay bi nggp n u d c .
* Oe d p dyng cho vung hay nggp n u d e thi phai s t i d y n g hda chat kem vdi vdi hoge xi mang tuy loai hda c h i t vd vdi ty le thich hgp. Quan diem khi s i i dung kem vdl hodc xi mang vdi d l t Id: Hda chat chi x i i ly phan set vd hu-u c a trong d l t , vdi hoac xi mang x u ly p h i n bCin, cat [1]; Ham lugng vdi, xi mang chi dung tdi da Id 4 % vdi hoac 3% xi mang de giam he so t h i m ; N l u dung n h i l u han se b i l n khoi d l t thanh dgng be tdng ngheo, mat tac dung lang c u d n g dp theo thdi gian cua hoa chat vd khdng phil hgp vdi do d u d n g mem,
* Cae ehl tieu ca ly cua DGC hoa c h i t tang ro ret khi tang gia co ca hgc.
* Mdi logi hda c h i t se cho hipu qua eao khi s u dyng v d i logi d l t phu h g p vdi nd. D y a tren ban c h i t eua chat gia co (nguyen ly hoat dOng, phan u n g hoa h p c . ) va thdnh p h i n dat, tren c a s d cac t h u nghiem trong phdng se l y a chgn loai hda c h i t , ham l u a n g phu h g p eho vat lieu OGC.
4. T H U NGHIEM HIEN TRU-ONG 4.1. Hda chat thir nghiem Hda c h i t chpn t h i i nghiem la RRP-
Mau gia c6 Chi tieu Modun dan hoi E (kg/cm^)
Cudng do khang nen R„ (kg/cm^)
DO ben ep che R ^ (kg/cm^)
H? so tham K,^
Dat gia c6 ca hoc 384-850
3,4-8.5
1,1-1,7
9,78-6,5x10-6
Oat gia co hoa chat 650-4800
7,2-19,5
1,7-2,45
4,2-1,5x10^
Dat gia c6 hoa chit +4%v6i
800-6400
8,5-25,4
1.84-3,21
9,5-2,5x10''
I So 9 nam 2015
mm
# # # * # KHOA H O C - C O N G NGHE
235 Spezial eua hang RRP GmbH International CHLB O i i e . T u n h i i n g nam 70 cua thap ky 20, RRP da d u g c s i i dung tai Oiic va cac n u d e Chau Au; RRP da d u a c d u a vao M i l n Nam Viet Nam t i i t r u d c 1975 xay dyng d u d n g . san bay, khu don fru cua quan ddi Hoa Ky.
Thang 9.2003 Trung tam K H C N - KTQS Bg tong Tham m u u md t r y c t i l p la Vien cdng trinh da thi cdng thi diem doan d u d n g lien huyen thupc xa An Khanh - Ha Npi. O l tai da d u g c HOKH cdp Bg danh gid loai kha va co cong van d l ngh|
Bd tong Tham m u u eho i i n g dung m d rOng. Cho d i n nay da cd n h i l u t u y i n dudng quoc phdng khu v y e phia b i c ap dung cdng nghe nay.
4.2. Tuyen duong thu nghiem T u y i n t h u nghiem la dogn d u d n g cdu L u a n g Vien thudc Xa Vinh Hung - Huypn Phu Lpc - TT H u l . Ddy la doan t u y i n thupc d u d n g tfnh 21 n i i vdo Qudc Id 49B. cd mgt dp giao thdng t u a n g d l i Idn, du cdc logi tai trpng xe luu lhdng.
Chieu dai doan tuyen 620m d u g c t h i l t k l vdi quy md d u d n g d p VI dong b l n g (mat rpng 3,5m vd nen rpng 6,5m); Mong d u d n g b l n g d l t gia CO hoa chdt RRP+4%v6i tren n i n d u d n g cu c6 E^ = 850daN/
em^ tren mat phu Idp be tdng nhua nong day Scm.
O l t l l y t i i md d l t Km 17+500 d u d n g tranh phia Tay TP. H u l , thudc loai ddt set pha cd thanh p h i n hat set mjn <= 0,06mm Id 27%. Due mau thi nghiem v d i loai d l t ndy cho lhay E , cua OGC dat 4520~4540kg/cm^'
V d i E^^ l l y b l n g E,,^ cua doan t u y i n Quoc 16 49 B dang thi cong tai vj tri giao cat la 145 Mpa, l l y E^i = 4530kg/cm^ tinh d u g c c h i l u day cCia Idp dat gia co Id 18.5cm;
Chgn ehieu day t h i l t k l cua Idp d l t gia co la 20cm.
Hipn d Viet Nam da co nhieu loai may phay chuyendgng nhu Bomag.
Stehr, Hamm, Dutzi, Wirtgen cua Diic; Sakai Nhat ban; CAT My,
v.v... Tuy nhien do cdng trinh t h u nghiem nho nen chpn chi dijng cac loai may san co d l thi cdng.
Phuong phdp thi cdng: Trgn d l t + Vdi tai md d l t b l n g may xuc vd may dao gau n g i i a , sau do van chuyen v l edng trinh rai len n i n d u d n g , T u d i n u d c pha RRP dam bao dO am toi u u , dung may muc dao d l u rdi t i l n hanh lu len. T r u d c tien s i i dung lu 8 t i n lu 3 l u g t / diem, sau dd dung lu rung 25 t i n lu 5 l u g t / d i l m . Ngdy hdm sau t i l n hang t u d i n h y a dinh bam va lham be tdng n h y a .
Trong qua trinh thi edng nhan thay rang n i n d l t dat dp chat yeu d u r l t nhanh chi sau vai lugt lu; D i l u ndy chung td cdng lu len gidm ddng ke.
* Ket qua thir nghiem:
- Modun dan hdi chung tren mat d u d n g tai 3 d i l m tren t u y i n do d u g c dat la va 1723,4daN/cm^;
1656,5daN/em2 va 1679,2daN/
em^; T h d i d i l m do la 28 ngay sau khi thi cdng. Sau 6 thang, gia do d u g c tai 3 vj tren l l n l u g t Id 1867,9daN/em^; 1764,1daN/cm2 v a 1 7 6 4 , 1 d a N / c m ^
- Sau 1 nam thi cdng, Toan bp mat d u d n g hoan toan on djnh, P h i n d l t gia c l c h i t l u g n g ddng d l u c h i i n g td qua trinh phdi trgn dat yeu c l u , tuy nhien phdn nhan cdng vd xe may phuc vu cong tdc p h l i trOn tang nhieu so vdi djnh m i i c . Phan l l d u d n g b l n g dat gia cd khdng co hien t u g n g lun nut, l l y hoac bong bat.
5. K^T LUAN
Cdc loai d l t set n l u chpn d u g c bien phap gia co phu hap theo cdng nghe tren co cdc ehl tieu c a ly phu hgp de dung lam mdng d u d n g giao thdng, ke ca d u d n g d p cao. Tat ca cac chi tieu cd ly cija ddt gia co d l u cao hon n h i l u so vdi mong d u d n g d l t d p p h l i hoac da dam d p phoi. chju n u d c tot h a n . C u d n g do tang d i n theo l h d i gian. Se r l t kinh t l n l u cd the tan dung ngay d l t tgi cho.
S i i dgng cdng nghp tren giam chi phi bao d u d n g do vgt liOu DGC ehju n u d c tot; Giam nhu d u khai thac loai vgt lieu von s i p cgn ki§tla da xay; Han che vide van chuyin vat lieu gay qud tai eho he thong giao thdng, d nhiem mdi trudng.
Cae v a n d l tidn q u y l t c i n luu y:
B i t bupc phai t h y c hien thi nghiem trong phdng vdl loai dat vd hda chat se s i i dyng de dam bao hieu qua cua cdng nghp.
- S i i dung may phay chuyen dyng trong cdng tac phdi trOn ma t i l nhit la loai mpt hanh lrinh (ttiyc hl?n ca 2 cdng doan la rudi hda chit + phay trdn) d l dam bao hda chat va phg gia d u g c Iron d l u vdo dlt.
- Nen s i i dung cac loai hoa chat co dai ly chinh t h i i c tai ViOt Nam, co s y hd t r g ve mat ky thudt vd hudng ddn c h u y i n giao cdng nghe •
- I
TAI LIEU T H A M K H A O [1]. James E. Mark , Harry R. Allcock, Robert West.
Inorganic Polymers, April 2 1 , 2 0 0 5 ;
[2]. Dallas Roadway Products.
Chemical Agent for Highway Construction Materials Stabilization. Technical Data Report, Dallas, Texas, 1994.
[3]. Con-Aid (Ply) Ltd.
Economical Road Maintenance, Pamphlet, Florida, RSA, 1998.
[4]. CH Non-Food Import- Export Corp. Reynold's Road Packer R R P 235 Special.
[5]. Yohannes Argu, Stabilization of Light grey and Red clay subgare soil using SA-44/LS-40 chemical and Lime, Masters dissertation. University of Addis A b a b a , 2008.