TrUdng bien dang xung quanh dUdng ham ddn trong nen dat yeu d Thanh pho Ho Chi Minh
Deformation fields around single tunnel in soft ground at Ho Chl Minh City
Ngay nhan bai: 16/01/2017 Ngay su^a bai: 10/02/2017 Ngay chap nhan dang: 3/03/2017
Tran Quy Du'c, Le Dinh Tan Than Van Van, Le Bao Quoc
T O M T A T :
Kghien cilu nay danh gia cac yeu to anh hiidng den bien dang cua nen d^t xung quanh dilcjng ham dan trong dieu kien dat yeu cf TP. HCM. Tac gia da phan tich va t6ng hc?p cac tinh chat ct* ly ciia nen dat cua tuyen diltfng ham. Chiing toi mo phong cac kich ban vdi v6i 7 dp sau dat hjim khac nhau, 7 kich thddc ban kinh dttcing ham khac nhau. Chieu sau dat ham do sau dat ham cang Icin thi do liin d be mat cang be. V6i do sau dat ham 16n hdn 3 lan dUcing kinh ham thi bien dang be mat do sif co mat ciia ham co gia tri kh6ng dang ke. Gia trj chuyen vi theo phUOng ngang tai vi tri be mat dat giam nhanh hcfn theo chieu sau dat ham so vdi chuyen vi diing va co the coi la khong dang ke khi 6 chi^u sau dat ham Idn han 20m. Vdi ban kinh anh hudng R ldn han 6 lan difdng kinh ham thi nen dat v^ cong trinh xay dUng ngoai pham vi ban kinh anh hildng khong tac dong den sU lam vi?c ciia ham. Do dd cac cong trinh xay diJng trong pham vi 6 lan dUdng kinh ham td tim ham sang hai ben se anh hifdng den dieu kien lam viec ciia ham va ngUac lai.
Tii klida: Lun be mat do dao ham, nen dat yeu, TBM, EPB.
ABSTRACT:
The main aim of this study was to evaluate the factors that affect the deformation of soil surrounding a single tunnel in soft ground in Ho Chi Mmh City. The authors analyze and synthesize the main physical mechanical properties of soil. We simulate the scenarios with 7 different tunneling depths and 7 different tunnel diameters. The greater the depth of the tunnel, the smaller the ground surface setdement. If the tunnel depth is more than three limes the tunnel diameter, the ground surface setdement due to tunnelling is negligible.
With the increasing of tunnel depth, the horizontal displacement was reduced more quickly than the ground surlace setdement. The vertical displacement can be considered negligible when the tunnel depth is greater than 20m When a radius of influence is more than six times the tunnel diameter, the ground and buildings beyond the radius of influence do not affect ihe tunnel. Therefore, when the horizontal distance between the building and the tunnel centerlines is less LX times the tunnel diamctei, the biiildinj' will affect the working conditions of the tunnel and vice versa
Keytvords: Ground settlement due to tunneling, soft ground, TBM, EPB NCS Iran Quy Diic, TS Le Dinh Tan
Binh chiing Cong bmh TS. Than \'an \ ' a n - Dai hoc Thiiv lai TS. Le Bao Quoc - Dai hoc xa\' dUng Mien Tay
I . O a t v ^ n d e
De g'dp phan giSi quyet t i n h trang un tic giao t h o n g ngay cang gia t a n g , can phai phat trien he thong giao t h o n g van t^i hanh khach cong cong n h u tau dien ngam. Trong xay dung d u d n g ham ben dudi khu do thj, cac ky sU phai doi mat vdi van de ky thuat khi dao fiam trong 3at yeu bang phUong phap khien dao nhU; on d m h chu vi ham va gUong ham; on d m h va bien dang cua nen dat yeu xung quanh ham Cd rat nhieu yeu t d anh hudng den qua trinh bien dang cua khdi dat, trong do cac yeu to lien quan den cong n g h e x a y d U n g , dieu kien dia CO hoc cua khoi dat (do ben. dp ciing, t i n h tham), dieu kien Sia chat thuy van (cao do miJc nUdc ngam) va dac diem ket cau cua ham (dudng kinh dudng ham, do sau dat d u d n g ham)giLfvitri quan t r p n g . Liin be mat t h u d n g duoc mieu ta dudi dang mang lun (pheu lun] tren be mat khi dao d u d n g ham don trong dat [5].
0 6 lun be mat theo tinh toan ly thuyet, t h u d n g dUoc gia d m h c6 dang ham sal sd Gauss hay ductng cong phan phoi chuan [2],[
4].
2. PhUcJng p h a p n g h i e n cifu Dac diem cua Ung suat - bien dang ciia nen xung quanh dUOng ham phu thuoc vao p h u o n g phap va cong nghe thi cong Lua chon gi^i phap thi cong d u o n g ham ph^i dam bao han che tdi da tac dong den cac cong trinh hien hCfu; dam bio on dmh moi trudng dat da xung quanh va phfa tren cong trinh ngam; d i m bao dieu kien ve smh moi truang. han che toi da gay 6 nhiem moi truong dia chat, ddng thoi can luu y den viec han che cua mat bang thi conq
1.2. Mat c M n g a n g h a m Nghien cUu nay xem xet mat Cdl h^m co dang tron (Hinh 1) co d u a n g kinh h.im 0 = 7,8m, day d = 0,6m, day ham dat t,ii Oo •„iu 22,250m
2 2 0 ^ S n * » S * 03.2017
Hinh 1. Mat c3t ngang ham drni.
2 . 1 . Lifa chpn p h i i C n g p h a p t h i cdng
Tren the gldi c6 nhieu nUdc ap dung cong nghe TBM (Tunnel Bonng Machine) T a t c a c a c c o n g t r i n h t a u d i e n n g a m tren the gicfi deu ap dung cdng ngheTBM thanh cdng. CJ Viet Nam, khi thi cdng tau dien ngam thi TBM hau nhu la cong nghe duy nhat duoc sU dung.
Dua vao kinh nghiem thi cdng ham va cac cdng trinh ngam ciia cac nUdc tren the gldi, vdi dieu kien ciia TP HCM cd the vin dung cdng nghe dao ham bSng TBM. TBM cd the thi cong tren moi loai dia chat t d da Cling den dat yeu, dat set, dat bdi hay dat cat duoi mUc nUdc ngam, di xuyen niii hay dudi long bien. So sanh vdi cac phuong phap dao ham khac thi day la phuong phap dao ham an toan nhat, khdng ton dien tich phuc vu thi cdng va hau n h u khdng lam anh hudng den cac cong trinh xay dung tren mat dat, thi cdng nhanh. it lam 6 nhiem moi trudng; hieu qua kinh te cao.
2 2. Lua chon thiet bi dao ngam TBM
2.2,1. Pham vi dp dung ciia cac loai thiet bj dao hdm TBM CO nhCrng loai chinh la TBM khoan da, TBM EPB (ho tro can bang ap luc dat) va TBM Slurry (chdng do mat gUong bSng chat Idng] (Hinh 2).
Thiel bl dao ngam (TBM) I
THIST BI OAO (TVM)
Khong cliong do mat gii-ong
(SM-V1) Chong do rnal gi/ong blng co hoc [SM-V2) Chong ffo mai goong bang khi nen ISM-V3]
Chong do mat gifong bang chat
longiSI.I-V4|
Chong do gifor apluc dat iS\'-' Hinli 2. Phiin loai mot so ttiiet bi dao ham co ban [11
Pham VI ap dung ciia cac loai thi^t bi dao ham cho cac loai dat co cd hat khac nhau the hien trong Hinh 3a
- TBM Slurry la ly tudng trong cac loai dat chda hat roi de dang tach ra d be mat TBM Slurry thudng duoc ap dung cho dia chat la cat, phan tram dat set thap. dac biet hieu qua voi dia chat cat duai mUc nuoc ngam NgUoc lai, bun va dat set rat khd phan biet va cd the cUc ky kho giai quyet cho viec tuan hoan bun. Oay la trudng hop dac biet neu luong hat mm (hat nho hon 60|jm) Ion han 20%
- Ddi VOI EPB, phan tram hat mm cao hon (> 10%), hoac khi bun, cat chiem uu the, se lam cho TBM EPB de dang kiem soat ap luc dat trong budng Cac loai may TBM EPB dac biet phu hop voi cac loai dat co ket Trong trUang hop nay, ty le hat sieu mm <0,06 mm nen chiem it nhat
?" De van chuyen bun dat nhu mong mudn, nuoc ngam phai co mat
hoac phai t h e m nudc. Viec bd sung b e n t o n i t h o a c p o l y m e r , . . . segiSm dang ice cac nguy ca bam dinh.
Pham vi ^ p dung cda cac loai t h i ^ t bi dao ham cho cdc loai dat cd he s d t h a m khac nhau n h U t r o n g H r n h 3 b . Xet ve h e s d tham, TBM Slurry se la sU lUa chon t d t hOn khi he so t h ^ m cua dat Idn hon 10-7 m/s; trong khi EPB c6 the ap dung dUoc khi he sd tham nhd hon (Hinh 3b).
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• 0010.002 0 006 0.02 DOB 0.2 06 20 60 200 60 0 Foam va Slury ap It^c c h l l Idnq can bang be mat g u a n g dao
Hinh 3. Pham vi ap dung c Ja cac loai thiet bi dao ham cha cac loai dat khac nhau' (a) Kha nang thich hop ciia TBM dila tren kich thuoc hat. (b) Kha nang thich hop cua IBM dua tren he so tham ciia dat |3]
Hinh 4 gioi thieu so dd lUa chon thiet bi dao ham qua cac budc dieu tra ban dau, co ban va chi tiet.
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2.2.2. Cdc tiiu chill/a chpn
• Dieu kien dja chSt:
Cac dieu kien dat nen dif kien dgc theo tuyen dudng ham dUoc de xuat lei rat quan trpng ddi vdi qua trinh lua chgn thiet bi TBM. Loai dSt, da va sued mat hoac nUdc ngam la cac tieu chico ban. Vi ly do nay, viec khSo sat hien trudng rdng hon la dn thi^t de lUa chon TBM tdt hdn.
• Tuyen dudng ham:
TBM dddc lUa chon phSi bao phili dadng ban kinh cong tdi thieu va tdi da. Hau het cac TBM deu cd the thi cdng nhOng dudng ham cd ban kinh cong Idn hdn 300m. Ban kinh cong nhd hon nCra se ddi hdi phSi cd them mgt may tuy chinh nOa.
• Dudng kinh ham:
Trong khi hau het c^c loai TBM deu cd s i n cho cac dudng ham cd kich thudc Idn thi Ida chon TBM cd the bj gidi han trong dudng h i m dddng kfnh nhd 0,6-;-2,0m.
• Han che tren cdng trUdng:
Nhieu cdng trUdng dac biet la d cac khu do thj dong due co nhCfng han che ve ca di&n tich va kha nang tiep can. Cac cd che li^n quan den viecvanchuyen, I3p rap TBM, cung nhu van hanh ndti^ dudng ham hoan thanh, se Snh hudng den loai TBM dUoc sd dung. Lieu mdt TBM cd the dugc khdi phuc t d mot d u a n de ban lai hay tai sCrdung secdSnh hUdng dang ke den kinh te trong viec lUa chon TBM? Ngoai ra, cac loai TBM dac biet nhuTBM Slurry ddi hdi mdt khu vuc rdng Idn cho hethdng tuan hoan bCin. Trong nhdng trudng hop nhu vay day cd the la tieu chi Ida chon quan trgng.
• Kinh nghiem va tinh s i n cd cua dia phuong:
Lua chon TBM cd the b i ^ n h hddng dang ke bdi sued s i n cua TBM d mpt vung lan can cu the Tr&n thuc te viec c6 s3n mot TBM cd the anh hudng den thdi gian, viec trien khai va thiet ke mot dUan dudng ham cu the. d nhieu khu vUc, viec lUa chon TBM bi han che bdi viec thieu lao ddng CO kinh nghiem de van hanh cac TBM tien tien hon,
2.2.3. Ddnh gid lUa chpn thiet bi vd phuang phdp thi cong dao hdm d Viet Nam, hai loai may TBM thudng duoc diing nhieu nhat de thi cong ham tau dten ngam la EPB va Slurry, Chung ta thay rang, TBM EPB thudng diing khoan dat, cd the sCrdung ca trong moi trudng dat yeu Vi vay, tuyen tau dien ngam sd 6 tai TPHCM nen ap dung cong nghe nay Thiet bl TBM nay cd the khoan khoang 12m duong ham/ngay. Sau khi khoan duoc 12m se lap dat tam be tdng vach ham xong mdi khoan tiep Sau khi khoan xong dddng ham t h d nhat, thiet bi se duoc dUa trd lai de khoan dudng ham t h d hai.
Phan tich qua trinh lam viec cua may khoan TBM cd the chia ra theo Sgiai doan nhusau;
Giai doan 1: Khu vUc xa phia sau guong dao khu vUc nay dat da van 6 trang thai nguyen sinh va t u dn dmh vdi cac thanh phan ap luc xung quanh VI tri gdong deu la po=vH(7; trong luong the tich dat nen. H chieu sau dat ham)
Giai doan 2: Tai khu vdc ngay phia sau mat guong dao: tai khu vUc nay van de dn dinh mat guong dao ddoc dat ra la chu yeu. Nhu vay giai doan nay cd the xem xet tuong t u nhu giai doan 1 khi coi nhu ap luc giu can bang du dam bao khong gay ra bien dang mat guong,
Giai doan 3 Khi phan mui cat cua may dao da vucrt qua: do cau tao dang hinh non cua may va khien dao (nham giam ma sat xung quanh glCip khien dao ti&n len dedang) va khi may dao thi cdng qua doan dudng cong b i n g , nen da tao ra mdt khoang trdng gida vd khien va dat nen (Hinh 51 Vdi gia thiet vd khien tuyet ddi cdng thi d giai doan nay can xem xet hien tuang bien dang t U d o cua bien hang dao cho tai khi ap sat vao mat vd khien, khi do ap luc dat xung quanh hang dao bi giam di (goi la hien tuong giai phdng ung suat]
Giai doan 4 Khien dao tiep tuc tien len: luc nay a phia dudi khien da tien hanh lap dung ud due sSn, phan vd nay phai duoc ldp d ben trong dudi khien, vi vay se cd them mdt khoang trdng nda do be day cua duoi khien Doi hdi phai cd bien phap lap day khoang trdng giCra bien dao va
ket cau vo vCfa dudc lap dSt. Giai doan nSy thudng sCrdung phdcing ph P bom VLB phfa sau v6, vat lieu thay t h ^ cd Xh4 Ik vOa xl m5ng ( ^ ^ " ' " " j ^ ^ mang; dung dich xi mang - vOa s e t » m a n g dp phdi h a t , . . . C6 ra n phi/dng phap bom viia sau vd cd the chia ra hai loai b d m doc va nga y.
DUdi tac dung cua ap luc vda b d m (Hinh 5) cd t h ^ lam cho dat nen chuyen vi trdi len va dong t h d i tac d u n g v^o k^t cau v d dCic s i n dddc iap trU6c d d .
Hinh 5. Mo phdng thi cong ham b^ng TBM (PLAXIS, 2001)
Giai doan 5: Khi vOfa bOm phia sau v 6 da d d n g cdng (Hinh 5): Khi yUa duoc bom vao vdi dang Idng va h i m lugng nUdc cao, khi vda ddrig cdng (chieu day cda I6p nay gia thiet la bSng be day t ciia vd khien) se gay ra bien dang ciia dat xung quanh hang dao va sau dd IS q u ^ trinh lam viec t u o n g tac giOfa dat nen va ket cau vd ham (cOng cd t h ^ phSI xem xet den trang thii cua dat nen xung quanh hang dao da bi x^o t r d n t r o n g qua trinh dao ciing se thiet lap trang t h i i cdng chac lai t r o n g giai do?n nay).
2.2.4. LUa chon md hinh phdn tdhdu han
Plaxis la' bd ph5n mem giSi quyet cac b a i t o a n dia ky thuSt t h u d n g gap trong thuc te. ChUdng trinh nay d u n g de t i n h toan dc bai toan ve mai ddc, hd dao, dUdng ham, dUdng hao ky t h u a t [collector), dUdng ^Su dien ngam va cac dang cdng trinh ngam khac, dac biet la t i n h toan blen dang va lun be mat do thi cdng ham.. Mot so dang bai t o ^ n t h u d n g gap trong thuc te bao g o m : cac bai toan ve dn djnh, bai toan bien dang, bai toan phan tich dpng cua cac cdng trinh dia ky thuat. Plaxis cd nhdng dac t i n h dac biet cho phep tao ra d d d n g ham cd mat cSt ngang dang trdn hoac do nhieu cung trdn ban kinh khac nhau tao t h a n h . Dac biet cd the md hinh duoc qua trinh xay dUng mot dUdng ham trong dat yeu, va phan mem nay da ddoc sd dung rdng rai tren the gidi t r o n g t i n h toan d u d n g ham xay dUng trong nen dat yeu.
2.2.5. Xdy dUng cdc kich bdn tinh todn
Nghien cdu nay da xay ddng m o hinh 2D de phan tfch trang thai dng suat - bien dang cua nen dat yeu xung quanh d d d n g ham. Chung tdi da md phdng vdi 7 do sau dat d u d n g ham h = (12 5,14.5,! 5, 20,28,30,40)m, dng udl mdi do sau dd ta thay doi ban kinh cua d u o n g ham theo cac gia tri R = (2.75, 3,0, 3,25, 3,5, 3.9,4 0, 4 5)m.
3. Xay d u n g m d h i n h p h a n tiJr hQu han 3.7. Thiet lap dp lUc can bdng be mat guang ddo
Giai phap lua chon blen phap can bang ap lUc mat g u o n g dam bao anh hddng cua mat mat the tich d mat g u o n g dao la khdng dang ke hay ndi each khac co the gia dinh la khdng anh hddng den bien dang lun cua nen. De md phdng ap luc can bang be mat g u o n g dao trong Plaxis bang each xem ap luc can bang nay la lUc tac dung len mat gdOng dao theo phuong z va duac dua vao tham sd tai trong Y M ^ ^ (Hinh 6)
Hmh 6. Cila so nhap ap lUccan bang be mat guong da Trong do y„.i la cao do dinh ham, p,„ la i ham, p— la dung trong neng cua uda set
2 2 2 ^ > ^ A ^ ' 1 ^ V 03.2017
3 J. LUa chgn titdng sShdp If cda mo hinh vat lieu - M d h i n h vat iieu cho die Idp dat: s d d u n g md hinh M o h r - C o u l o m b - Thdng so dSt nen ddoc lay t i l Bao cao Dja chat
BJing1:B5nglorigliapcacth6ngi6datnen T h d n g s ^ d i i t nen
Mb hinh vat lieu Dunq tronq t u nhien Dung trong bao hoa M d d u n dan hdi He sd Poisson LUc dfnh c' Gdc ma sat trong' Gdc trddng nd H e s d t h a m k ( l O ^ ) Chieu day Idp dat
Ldtp1 MC 15,8 16,1 1040 0.35 7,3 5,72 0 1,83 X
16,7 Ldp 2
MC 20,2 20,4 15330
0,27 14,1 27,58 0 0,5x
16 Ldrp3
MC 20,9 21,02 12105 0.32 80,4 21.3 0 1,36x
15 Dan
vi k N / m ' k N / m ' k N / m ' k N / m ' Do Dd m/s m - Md hinh vat lieu cho vd dudng ham: sd dung md hinh dan hdi Sang 2 Thong so vatheu
T h o n g so Md hinh Bd cdng D d c d n q c h d n q uon Ddday Trong luong don VI He so Poisson
Ky hieu Kieu vat heu EA El d w
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Gia t r i Dan hdi 2,4x10' 7,2x10' 0.6 14,40 0,15
D c m v i kN/m k N m ' / m kNm/m m
- Tai mat tiep xuc nen dat - duong ham sd lam viec cua cac phan t d dat khac so vdi nen dat ben ngoai, Hien tdong nay duoc xet den thdng qua he so he so be mat tiep xuc (R.ni.,). Chung tdi chon R.ni«, = 1 cho dieu kien dat nen tai TP HCM
3.3. Dieu kien bien Co hai loai dieu kien bien-
- Dieu kien bien xac dinh. chang han nhd cac dieu kien bien quy dinh [va chuye'n vi quy dinh) Hai bien ben canh cho phep dich chuyen theo chieu t h i n g diJng theo huong Z. Tuy nhien, bien dudi cung bi ngan khdng cho chuyen vi theo hudng Z
- Oieu kien bien t d nhien, chang han nhu dieu kien bien ve ap luc va mdmen.
3.4. LUdi phdn tdhUu ban
Ludiphan t d hdu han, bao gdm phan tLlvd ham, phan t d dat da xung quanh ha pha t ' d a t d a t g l " n Ud kh dao Ca p h a n t d n a y c d dang tam g a hoa u g a Luo nh bao gom 050 pha a 8750 nut Kich t h u d u n g b n h ua a phan U khoang 2 5 H h
A-
bien dang cua khdi dat xung quanh ham {cac gia tri dich chuyen ddng (do lun), gia tri dich chuyen ngang, gia tri bien dang ddng, gta trj bien dang n g a n g , , . . ) t h e o cac kich ban da de xuat n h u sau.
4 . 1 . A n h hu'dng cija duimg k i n h ham
Nghien cdu nay da md phdng vdi 7 ban kinh cua dudng ham theo cac gia tri R = (2,75; 3,0; 3.25.3,5,3,9,4,0,4,5)m.
Kich thudc cua ham anh hUdng rat nhieu tdi quy md lun be mat, Vdi gia tri t d n hao dat la 2,5%, dd sau dat ham 28m, S™. se cd mdi tUong quan vdi dudng kinh ham bleu dien bdi dd thi trong H i n h 8.
Chung tdi da d u d o a n d d lun Idn nhattai truc trung tam tren mat dat Sr>.„ chuyen vi S, tai dinh ham theo chieu sau va d u d n g kinh ham. Nghien cdu nay da xay ddng bieu do quan he gida ty sd dd lun Smsi/Si) va ty sd chieu sau dat ham - dUdng kfnh ham (z/D) (Hinh 9) Tir so lieu tinh toan bang md hinh, chung toi da thiet lap quan he gida ty sd Sma^Si va z/D nhU tren Hinh 9. Phuong trinh dai dien quan he tren cd dang t u y e n t i n h voi R' - 0 , 9 6 ,
= 0,0935 + 1,2702 (1)
O u o n g k i n h f i i m D(r 5 0 55 6 0 6 5 7 0 7S
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Hinh 8 EiPu do quan lie giUa do lun Ion nhai S™ «a duong kmh ham D Ty s6 chi^u s3u dat ham - du'ong kinh hSm (£/Dl
Kinh 9. Bieu do quan he giiia ty so do lun ','j t^ io chiei, uu dai nam - duang kinh ham 4.2 Anh hudng cua chieu sau dat ham
Chung tdi tien hanh phan tich trang thai ung suat - bien dang va dn dmh cua nen dat yeu xung quanh ham khi thay ddi chieu sau dat ham dOn Khao sat udi duong ktnh ham 7 8m, vdi chieu sau dat ham tang dan CO the thay rang khi cang xudng sau thi gia tn lun ben mat dat nen cang giam va o mdt do sau nhat dmh thi gia tn lun nay la khong dang ke (trong truong hop nay la z = 20m (Hinh lOi
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Hinh 10. Bleu do quan hi giira do Idn be mat S (m) va dd sau dat ham z(m) bang mo hinh 2D
Og lun be mat S se gi3m di khi ham duoc dat sau hon. Gia tri chuyen vl ngang giam rat nhanh theo chieu sau dat h^m va xap xi bSng 0 khi chieu sau Z220m (Hinh 11).
Be rong viing anh hudng lun la rat Idn va no ty le thuan vdi chieu sau dat ham Tuy nhien cang ra xa truc tim ham thi gia tri Idn cang gl5m nhanh. Vung inh hudng lun khi tinh toan theo so do bai toan phSng Idn h o n s o v d i k h i t f n h t o a n t h e o s o d d k h d n g g i a n va gia tri dd lun tang gap 1.3 lan den 2 lan.
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Hinhll. Bieu fl6guanhegiflachuyenvingangSh[m)vad6sau dat ham z(m)ban9m&hinh20 5, Ket luan
Chung tdi da phan tich va tdng hop cac tinh chat co ly cua nen dat cua tuyen dudng ham, t d d o thuc hien khoi luang Idn md hinh, dng vdi 7 dd sau dat ham khac nhau, 7 kich thudc ban kinh dudng ham khac nhau.
Vi vay ket qua thu nhan duac co do tin cay cao
Td md hinh tinh toan dudng ham bang chuong trinh Plaxis ta co the tinh toan duoc cac ndi lUc trong cac giai doan thi cdng va giai doan hoan thanh cdng trinh, Vi vay nd hoan toan cd the duoc ap dung de tinh toan cho cdng trinh dudng ham tai TP HCM
Do lun cUc dai d mat dat thay doi theo chieu sau dat ham do sau dat ham cang Ion thi dd lun d be mat cang be Voi do sau dat ham Idn hon 3 lan dudng kinh (3.D) thi bien dang be mat do su co mat ciia ham co gia t n khdng dang ke
Gia t n chuyen vi theo phuong ngang tai vi tn be n"
hon theo chieu sau dat ham so vdi chuyen vi ddng va ci dang ke khi d chieu sau dat ham Idn hon 20m,
Vdi ban kinh anh hudng R>6.D (D la duang kmh har ket cau v6 ham khdng thay ddi, nen dat va cong trinh xay dung ngo;
pham VI ban kinh anh hudng khdng tac ddng den sU lam viec cua ham Do do cac cdng trinh xay dung trong pham vi 6 D t u tim ham sang hai ben se anh hudng den dieu kien lam viec cua ham va nguoc lai
TAI LIEU THAM KHAO
[1] 1- AITES, Recommendations and Guidelines for Tunnel Boring Machines (IBMs), presented at the Recommendations and Guidelines for Tunnel Bonng Machines (TBMs), 2000 It dat gia 1nhanh )khong ill luc trong
[21 E. J. Cording and W. H. Hansmire, Dispkaements Around Soft Ground Tunnels. 1975 [3] L L Franco,'Tunnel Boring Madiines," 2016.
[4] A.J.H.,B E.T.,andP.H.."Cirilapseofstiallowunlinedtiinnelsindensesantls, lunneis andTunnelingm\.7fi,\>\i.%t-S7,W5. r r K il
fS] R. B. Pedi, "Deep Excavations and Tunneling m Soft Ground," m Proc, ?th Int. Cont. m Medi. Found. Engrg., 1969, pp. 225-281.
