N A N G CAO HIEU QUA
D A O H A M THUY DIEN TIET DIEN NHOVADAI
Dao Van Canh KS.LeVanLirong ThS. Ngd Van Djnh
ABSTRACT Comparing with short and large tunnels, long and small tunnels are more difficult and complicated to construct, not only in selecting construction machines, but also in arranging and executing all works
in cycle. As a result, the less of tunnel cross section area, the less of labor pro- ductivity and excavating speed. In order
to overcome these problems, based on actual performances at some tunneling
sites in Vietnam as hydro power plants Rao Quan, Ngoi Phat, Nam Toong, Nam Chim, Ho Bon, and Nam Ma, this paper presents some author's proposals of suit-
able excavating technologies for long and small tunnels.
TS. Dao Van Canh Tri/cmg Dai hoc Mo - Dja chat Dong Ngac - Tir Liem - Ha Npi
DD: 0982274636
KS.LeVanLiromg ThS. Ngo Van Djnh Tap doan Than va Khoang sin Viet Nam
1 . Nhufng van de chung Thiiy dien II ngudn nang lupng sach v l day tiem ning ciia nude ta.
Ben canh viec xly dung cle thiiy dien Idn tam qude gia: Thiiy dien Hda Binh (1920fVIW), Thiiy dien Yaly (729MW), Thiiy dien Son La (2400MW), rl't nhieu cac dU an thiiy dien vUa v l nhd d l v l dang dUpc xly dung tai nhieu dia phuang tren el nude.
Cac nha may thiiy dien nly phan Idn ed edng suit nhd hon lOOMW, chieu dai ham dan nUdc Idn v l cd tiet dien dIo nhd (S^<18m^) do nhieu don vj nhU cae cdng ty thude Tdng edng ty Sdng 0 1 , Tong cdng ty Xuat nhap khau Xay dung Viet Nam (Vinaconex), Cdng ty xly ddng Lung Ld,... thi edng (bang 1).
Khi thi cdng cle dudng ham ed tiet dien Idn, ta ed the bd tri cle thiet bj dao h i m tien tien, cd ning suit cao v l tde dp thi cdng nhanh (cae xe khoan tuhanh 2 den 3 can khoan vdi dau khoan thiiy ldc, may xuc tay vo hoac mIy xiie xuc gau cd dung ti'eh Idn, cle mIy l i p neo va van tai bang dtd cd trpng tai Idn). Tuy nhien, khi thi cdng cle h i m cd tiet dien nhd v l d i i phii sd dung cac thiet bj trong day ehuyen cdng nghe ed cdng suat nhd (xe khoan 1 can hole mIy khoan elm tay, mIy xiic tay vo loai nhd hoac xiie thii cdng, v|n t i i bing cdng ndng hole xe cli tien). Chinh vi vay dIo ham cIng nhd, cang dai
nang suit va tde dp d n g thap.
Oieu dang quan t l m la thdng gid khi dIo ham nhd va dai rat phdc tap.
Neu bd tri quat cd cdng suit Idn thi chiem het dien tich guong, neu bd tri quat gid cd dng gid phii hop vdi dien tich thi cdng thi cdng suit nhd, keo d i i thdi gian thdng gid sau nd min v l tao mdi trUdng dpe hai cho thp him.
Chinh vi vay viec nghien cUu de xuat edng nghe dao ham tiet dien nhd va d i i phu hpp trong xay dung ngam va xly dung md II van de cap thiet, cd tinh thdi su eao.
2. Giai phap nang cao hieu qui dao ham
2.1. Gidi phdp ve ky thuat, cdng nghe khoan nd min vd xuc bde
2.1.1. Ve hinh dang tiet dien dudnghdm
Phln Idn tiet dien ben trong (tiet dien sd dung) dudng ham dan nudc ciia cac cdng trinh thiiy dien cd dang hinh trdn. Oly la dang tiet dien cd nhieu uu diem ve thiiy nang.
Tuy nhien, ta quan t l m nhieu hon ve hinh ding tiet dien dao eua dUdng ham ( S /
Qua nhieu edng trinh nghien edu eho thay, dudng h i m cd hinh dang tiet dien dao hinh vdm tudng ddng la phii hop va tdi Uu ve ky thuat, cdng nghe va kinh te (hinh 1).
Vdi dudng ham tiet dien nhd (S,
< 18m-) CO the chia ra 2 nhom:
iSini.lSIT . 7.2009 71
Bang 1: Cle edng trinh thiiy dien cd tiet dien nhd STT
1 2 3 4 5 6 7 8
Ten cdng trinh Thuy dien NI Loi Thuy dien Rao q u i n Thuy dien Ngdi Phlt Chu Linh -Coc San Thiiy dien Nam Todng Thiiy dien Nam Chim Thiiy dien Nam Ma Thiiy dien Hd Bdn
Oja diem Lai Chiu QuIngTrj Llo Cai LloCai Llo Cai San La HI Giang Yen Bii
Cdng suit (MW)
9,3 64 57 84 34 16 12 18
Chieu d i i ham (m) 1306 5600 7077 8081 5314,6
1245 1067 1800,5
Tiet dien ham (m^)
5,3 11,2
16 7 10,5
5,4 3,8 17,2 Bing 2: Cle d i e tinh co ban ciia xe khoan
STT 1 2 3
4
5
Oletinh kythuat Dien tich phii hpp (m^) Sd can khoan (cli) PhUdng tien di ehuyen Cle kich thude (mm) Oil
Rdng Cao
Trpng lupng (kg)
Loai xe khoan Boomer H-104
6 - 2 0 1 Binh Idp
7.700 1.220 1.900 7.000
TamroekRMJ1F/E50 4H-24
1 Tren ray
9.100 1.300 2.500 10.000
- Nhdm 1: h i m ed tiet dien d I o <
lOm^
- Nhdm 2: ham ed tiet dien dao >
lOm^
Viec bd tri trang thie't bj d nhdng dudng ham nly cd nhdng diem khIc nhau k h i rd ret.
2.1.2. Thiet bi dao ham
2.1.2.1. Co so viec lua thiet bi dao ham
Co sd viee lUa chpn thiet bj dao ham can cdvao:
-Tiet dien dudng ham can dIo.
- Cle tinh ehl't eo ly d l . -Tde dp dao ham can dat.
- Nang lue eua don vj thi edng.
- Thiet bj tham gia gid gin mdi trudng h i m .
2.1.2.2. Thiet bi khoan no min va vat lieu no
Trong ehu ky d I o ham, thdi gian khoan Id min tren guong thudng chiem 35 - 40% thdi gian ehu ky.
Chinh vi vay, viee sd dung thiet bi khoan gUOng cd edng suit eao hole nhieu thiet bj khoan ed edng suit nhd, nhung hoat ddng ddng thdi eung se l l m g i l m thdi gian khoan
guong. Hien nay khi d I o elc dUdng Id da tai cle md h i m Id thude Tap d o l n cdng nghiep than v l khoang sin Viet Nam hoac elc dUdng ham ed tiet dien nhd trong xay ddng thuy dien, thiiy Ipi ehu yeu sd dung bua khoan khi nen cam tay ed chin dd.
Bua khoan khi nen eua Lien Xd cu (Lien bang Nga) thudng ed trpng lupng t d 20 H- 30 kg; dUdng kinh Id khoan 35 -f 45 mm; chieu slu Id kho- an den 3m. Cle bua khoan nay ed lupng tieu hao khi nen 3,5mVphut va ap suit khi Sat nhu PR-24, PR-30, PR-63. Ngoli ra, cdn ed bua khoan khi nen eiia Trung Qude (YT-27), cua Thuy Sy (SIG). Cle bua khoan nly ed trpng lUpng td 25 -=- 30 kg va tieu hao khi nen 3,5mVphiit.
Nhin chung, cae bua khoan nay sddung khi dIo elc h i m cd tiet dien nhd hon 10m^ II rl't phu hpp, vdi tde dp khoan thuc te II 0,2m/phut.
Oe dao eac dudng ham ed tiet dien nhd vdi dien tich Idn hon 10m^
sd dung cle biia khoan khi nen cam tay van hieu q u i . Tuy nhien, neu sd dung d i n xe khoan tU h l n h
eua elc hIng TAMROCK (Phan Lan) hole ATLASCOPCO (Thuy Oien) vdi d l u khoan thuy lUe se gdp phan riit ngIn thdi gian khoan guong. Cae xe khoan nly ed the ed 1 can hole 2 can, di chuyen bang banh xich, Idp hole tren ray (tuy theo don dat hIng). Cae thie't bj khoan thuy luc nly cho phep dat tde dp khoan rat cao trong d l cdng vdng:
- Khi f = 7 ^ 10 tde dp khoan thUe te Im/phut
- Khi f = 10 ^ 15 tde dp khoan thucte0,8m/phut
Cle xe khoan 1 cIn dupe the hien d hinh 2 v l 3.
Cle die tinh ky thuat cua cae xe khoan dugc the hien d bang 2.
Viee sd dung cle loai thude nd hpp ly trong d I o ham se dUa lai hieu qua sd dung Id min cao hon, day nhanh tde dp d I o ham. Hien nay, trong nglnh than thudng sd dung thude no nhu tuong P-113 de dao Id da. Trong nglnh xly dung thuy dien, thiiy lpi, ngoli thude nd P-113 cdn sd dung thude no Powergen- 3151 cua Australia. Tuy thude nd Power- 7 2 O 0 n i l i 1 B l . 7.2009
gen- 3151 cd g i i thanh eao, nhung hieu q u i nd min t i n g len vi cd sde cdng p h i Idn (380 em^), tao ra it khdi, d i m bao mdi trudng khdng gian trong ham tdt hon.
2.1.2.3 Thiet bixuc boe vd van tai Vdi nhdng dddng ham ed tiet dien nhd thi cdng doan bde xuc d I t da v l van t i i II edng doan k h i vat v l v l chiem thdi gian k h i Idn tU 30- 35% thdi gian chu ky. Hien nay, khi dIo h i m thiiy dien, thuy Ipi cd tiet dien nhd thudng sd dung mIy xuc gau ket hpp xe d td cd kich thude nhd hole edng ndng. SU bd tri thiet bj xuc t i i nhu vay d l dan tdi ning suit xuc bde v l keo theo tde dp dao him rat thap, mdi trudng h i m d nhiem nang do khdi t h i i . Oe nang cao tde dp thi edng ham tiet dien nhd nen sd dung thiet bj xuc gau dd t i i len bang t i i tren t h i n mIy v l ehuyen t i i vIo godng. Oly II hlnh thde xuc t i i ed ning suit cao, khdng phlt sinh khi t h i i ddc hai v l da dugc thd nghiem thi edng tai eac dUdng Id da thude Tap doan edng nghiep than v l khoing sin Viet Nam.
2.2. Gidi phdp ve to chde thi cdng
Ve td ehdc thi edng eIn chii y:
- Md cae h i m phu thi cdng.
Ngoai t i c dung tao dieu kien cho thdng gid, cung cap khi nen tdt hon, cle h i m phu tao ra nhieu guong thi edng ddng thdi n h i m rut ngIn thdi gian thi edng tuyen dudng ham chinh. Kinh nghiem dao ham eho t h i y khoing each gida hai ham phu lien ke khdng nen vUOt q u i 2000m.
- Odi thp thi edng h i m tiet dien nhd nen II dpi thp t o l n ning (cd khi ning khoan nd, xuc bde, chdng tam) de chu ddng trong thi cdng.
- Vl ham d i i nen td chde cho thp ham lam theo kip (6gid), ngly l l m 4 kip de dam b i o sue khde cho dpi thp h i m v l phii giao ca tai gUong him.
3. Ket luan
Oao h i m tiet dien nhd v l d i i la nhiem vu khd khIn nang ne ma nhung ngudi xay dung phii ddi mat
HIrndlrrtiacWft
Hlnh 1. Hlnh dang tiet dien j_ dudng ham
trong hien tai v l trong thdi gian tdi.
Vi vay can cd nhdng giai phlp cdng nghe cd tinh khoa hoc v l tinh thUc tien cao.
Oe thuin loi cho edng tie thiet ke v l thi cdng ham d l den luc can mddun hda cle tiet dien mat elt ham tiet dien nhd de giam chi phi
thiet ke va thi cdng, day nhanh tde
dp thi cdng him. •
TAILIEUTHAMKHAO
[1|. N.M Pocrovxki, Cong nghe va co gioi hoa xay dung cong tnnh ngam va mo (ban tieng Nga), NXB Long dat, Moscov, 1997.
raXITlSiT . 7.2009 73
