1859-4905S42014050.pdf

TAP CHI KHOA HOC & CONG NGHE. ra. Journal of Science and Technology 4(13) (2015) 50-58. TRlfCtNGB.UH0CDUYT.4fi 1 1 ^ l-l'Wf 1«'l>'lk13iBia. DU bao kha nang phun trao day ho mong sau do cat chay khi thi cong trong trim tich Q, bao hoa nifdc thuoc lanh tho dong bang thanh pho Da Nang Risk Prediction of Eruption at the Bottom of Excavation due to Sand Movement during Construction Process in Saturated Quaternary Deposits of Deltaic Coastal Plain, Da nang City. LUdng T i n Ltic Faculty of Civil Engineering, Duy Tdn University, Vietnam Khoa Xdy Dung, Dai hoc Duy Tdn. Viet Nam. Tom tat Bai bao trinh bay van de dU hao kha nang phun trao day ho mting sau do cat chay khi thi cong trong cac thanh tao dat raeni r6i Q, bao hoa n\Xdc thuoc lanh thn dong bang thanh pho Da Nang,TOdo nhatn ban che den miic thap nhat anh hitrlng cua chung den cong tac an toan trong qua trinh thi cong bo mong sau co ap dung bien phap chong gifl thanh ho mong bang tiTdng be tong cot thep, dong tbbi de xuat chieu .sau ebon cfl bdp ly. Tii khoa: bo mong sau, moi tntftng dia ky thuat, tang ham. Abstract The article presents the forecast of the risk of eruption in deep excavation bottom due to sand movement during construction process in saturated quaternary deposits of dehaic coastal plain, Danang city. Therefore, we could minimizs their influence lo the safety in deep excavation construction process with reinforced barrette wall and we can propose the appropriate depth for piling. Keywords: deep excavation bottom © 2014 Ban quySn thuoc Dai hpc Duy Tan. 1. Dat van de. lech miCc nu6c 6 trong va ngoai h6 mong tao nen. Bdi VI khi nirdc ngam chay tii di(6i len ben trer. Khi dao hd mong sau ma day ho mong nam trong 16p cat mjn, cat bui bao hoa nifdc, dxidi tac. rnat day hd mong, thifc te la dong thSm tii bet ngoai ho mong doc theo than tubng cii, qua char. dung cua ni(6c nglm CO the gay ra qua trinh phun. tilcing va tham nguoc len d ben trong ho monf. trao cat min, cat bui tii day h6 mong do sU chenh. ^?i ^^Y ho mong, cac hat dat tai n6n dSt day hi. Email: l i a n g t a n l u c Q g m a i l . com (LUdng i t n Life). Luong Tdn Life/Tap chi Khoa hpc vd Cdng nghe - Dai hpc Duy Tdn 4(13) (2015) 50-58. mong se chiu \\lc day not cua ap liic nUdc tham thau (dong th4m ngUdc txi difdi len), trong trUcfng hdp ap ItJc nude tham thau I6n, cac hat dlt se 6 vao u-ang thai id liing co tinh chat nhif huyen phu trong nude dang lUu dpng, gay nen hien tUdng phun trao.. Vi vay, viSc kiem tra, tinh toan va dii bao van d6 phun trao day h6 mong do cat chay khi thi cong ho mong sau trong cac thanh tao dat mIm rdi tram tich Q, bao hoa nUdc thuoc lanh tho ddng tu bang Da Nang la rat cin thiet va la cd sd cho viec Ilia chon chieu dai tUdng ctt phii hdp de han che cac rui ro va hau qua xau do qua trinh phun trao day ho mong sau gay ra.. 2. Dac tnmg cd ly trung binh dat da ti'nh toan phun trao day ho mong sau do cat chay Tai khu viic nghien cdti thuoc lanh tho dong bing thanh ph6 Da Nang phan Idn cd mat cac thanh tao dat mfim rdi cd thanh phan cat tho den min nguon goc sdng, sdng - bien, bien gid, xen kep la cac ldp dat mem dinh cd be day bien ddi. Tai mot so khu \\tc nhiT Thanh Khe, Cam Le, Lien Chieu cd mat cac thanh tao dat yeu cd bd day khdng Idn. Chung phan bo tren mat va dang xen kep, thau kinh. Su phan bo cua cac thanh tao dja chat khu vUc nghien ciJu va tinh chat cd ly trung binh cac ldp dat da phuc vu ti'nh toan, dUdc phan chia thanh cac kieu, phu kieu va dang cau true moi trUdng dia ky thuat cong trinh ngam (CTMIBKTCTN) va dUdc the hien trong Bang 1,2, 3 va 4.. Luong Tdn Luc / Tap chi Khoa hoc vd Cong nghi • Dal hpc Duy Tdn 4(13) (2015) 50-58. Bang 1. Dac tnlng CTMTDKTCTN lanh iho dong bang khu vuc Da N5ng Kilu. PhV kieu. D^ng. la. Ngudn g6c, tufil, thinh pti^n tli;cli h^c dfc trung, b4 dAy. Kyhl^. (eQ). Ned phfin bd. D ^ dip nhin sinh. Bi diy 2.0 - 2,6in,. Li&i. Ldp 1: C ^ min, rdi din digt vilra, ngudn gdc sdng - biin, diy 4ni.. e l m L$, hi]. L[ip2 S i t p h a i l n dim svu dCo Cling d ^ cOng, ngudn gdc phcaig hda, diy 4.0. Chiiu,. Chftu.. - 16.0ni. PQ CatnbQi'). (aQi"). I. D i gdc Idt diy. thu^C nlidm &i nln ciJrng. Ldp 1: D&t y6u - bdn s ^ pha, sit pha, trgng thii nhHo. ngudn gdc sfing - biJn -. Ihanh. tihia Ay, diy 3,1 -4.5m.. elm Li,. Khe.. Ldp 2: Cit thd, kit ciu rdi den ch$t vfn. diy 1.9in. Ldp 3: Cit mm. ttii din chgt viira. ngudn gdc sdng - biin, diy 2,0 - 2,9m. Ldp 4: Cii bill iSn di tich thvc vjt, chit vCra, ngudn gdc s6ng - biin - dim lly, diy 1,2-1,5m.. r,b. L6p 5: Sdi. dim s«n. Icit d u ch$t. ngudn gdc s€ng -10 tich. diy 1,6m. (spQi) (eQ). Ldp 6: Sit pha lln dim s^n. tr^ng ihii dio i ^ g d6n cung. diy 5.0 - 9,0m, Ngudn gdc phong hda B i gdc Idt diy.. PQ (amQ,'-^. (mvQj'-^. Ldp 1: Cit h9t thd. kit c4u chSt vCra, ngudn gdc sdng - biin, diy 5.2 - 6.5m. Li&i. Chiiu,. L£p 2. Cit ^fiJi, din min. chft via din chSI, ngudn gdc blin - gid, diy 5,0 -. Hii. Chiu.. 6.0m,. CimLt.. Ldp 3: Cit b»t vi^adin mjn. chit, ngudn gdc sdng - biin. diy 2.1 - 8.0m U,a.l. (amQ,'). (eQ). Ldp 4: SU pha iSn dim sjn, nOa aJmg din cling, ngudn gdc phong hda, diy 10mdin20-25m. Di gdc Idt diy.. PQ (anQO (ravQ,'). n.a. (amQ,'-^ II. (inbQ,'). Bat d i p nhSn sinh, diy 1,0 - 2.0m,. Libi. Ldp 1: Cit tmi. chjt vilra. ngudn gdc biin - gid. diy 1.7 - 10.5m.. llianh. Khe,. Hii. aiu.. Ldp 2: Cii thfl. d i « vira. ngudn gdc sflng • biin, diy 1,9 - 6,5m.. Chiiu,. Son Tri, NgQ L ^ 3: Cit bui, dijl vita, affiha gdc sflng - b i i n - dim lly, diy 2,2 - 5,4m.. Hinh Son,. Lip 4: Cit mjn. chW viradfai chflt. ngudn gdc sflng - biin, diy 2.1 - 9,7m, {unQ,") lIJLl (amQj"). Ldp 5 Sdt, dio mim din dio cilng, ngudn gdc song biin, diy 3.5 - 14.0m. Ldp 6: s a pha dio mim, ngjdn gdc sflng - biin, diy 3.8 - 5.8m. Ldp 7: c a thfl. chBt din ril chjl, ngudn gdc sdng - biin. diy 3.5 din 4,9m.. (amQ,*). Ldp 8: Sit pha lln dim sjn, dto cOng din ctag, ngudn gdc ptaong hda, diy 3.5 -16,5m,. (amQ,'-») (eQ). n.b. (ambQa*). Lip 1, Biln i cit. biln i sit. ngudn gdc hfln hgp sflng - biin - dim lly. diy 0.8m din 3.1-5,0m.. (arnQs'-^). Ldp 2: Cit h3l thd, ch?l vira din chit, ngudn gdc sflng blin, diy 1,9m.. n.b.i. Lifri. Chiiu.. d m Li. luong Tdn Luc/Tap chi Khoa hpc vd Cdng nghe - Dai hpc Duy Tdn 4(13) (2015) 50-58 Ldp 3: Cit hft vtra. chit vita, ngudn gdc sdng -bi£n, diy 4,2m (amQj') (amQj'-^ {ambQ,'-=). Ldrp4 Citm|n,ch4IvO«din chit, ngudn gdc s o n g - b l i n , diy 4.0m. Ldp 5: Cit by i, kit clu rtn din dijtvfra. ngudn gdc s d n g - b i i n - d i m lly. diy 1,2m, Ldp 6: Sit, dio mim. ngudn gdc sflng - biin, diy 6.0m,. (amQi'-') (eQ) PQ. Ldp 7: S6t pha lln dim sgn, tin lidi, dio cdng din cihig. d i y 7,8 - 10.0m din 23.0m. D i gdc Idt diy.. (anQD. Dit dip nhin sinh diy 1.0 - 2.0m.. e l m L i . Hfla. (ambQi^. Ldp 1: Btin sU pha, n g u ^ gdc sdng - biin -<llm lly, diy 1,0 - 2,0m.. Vang (xi Hda. (amQi'*). Ldp 3: Cit bui,-chit vita, ngudn gdc sdng -- biin - d i m lly, diy 2.0 - 8.5m.. Chiu),. Ldp 2: Cit mjn, chit vtJa, n g u ^ gdc stag - biin. dayf4,5 - 17.5m.. (ambQi'*). NgQ. SonlVi.. Ldp 4: sa. sH ] ^ % tivig thii dio chiy din diiy. ngudn gdc sflng - biin. d i y 4,0-6.0m. il I 1. n.b 2. Ldp 5: Cit thfl, chit vilra din diil. n g u ^ gdc sdng biin, diy 2.0 - 8,0m. Ldp 6 Sit, stl pha dio cimg, ngu&i gdc sflng biin. diy 4,0 - 6,0m. Ldp 7 S i t p h a l i n d f i m s v i . tin tldi,n£ra cdng din dmg, diy 1,0-9.0m.. Bang 2. Tfnh chat cd ly nhom dat co tinh chat dac biet tram ti'ch De Tvt thanh pho Da N§ng. Nguon goc, tudi. nr. Tengta. nhien,. 4 a ch^. W,%. amWJa'. Bim set pha Set, deo chay. amQi". 60,8 40,2. Modun. Khdi. Khdi. Khdi. lugng. luong. luong. Hesd. the lich. the tich. neng.,. rong.. tv nhien,. (!h3,T.. T, g/cra'. g/cm'. g/cm'. 1.62. 1.00. 2,70. 1.70. 16,4. 1,17. 0,03. 4'^5'. 21,3. 0,106. 1,75. 1.25. 2,70. 1,16. 16,3. 0,893. 0.11. 4°40'. 27,5. 0,06. C3ii. sd. m set, B. den chay. Luc kit,c kG/cm'. Goc. sat, (ft. tong dang, Eo,. d$. Hisd. cm^/kG. kCTcm'. Bang 3. Tinh chat cd ly dat mem di'nh tram tich De TiJ thanh pho Da Ning Khdi. Ngudn gdc. ludi dia chit aniQi* •mQ)' amQ,'. Tftigoi. tinngihi. ti/qng. Udiiir. Uiitldi. %. fchd.T( g/ni.'. Sit.dioin^ s a pha. dio m^ Sit.dioclhig. Khdi. Dfllm tir nhi&i. W.. g/cm'. Khdi hrgng ning,.T^. H«s6 rdng.. g/cm'. Chl sd dio, Ip.^. Lire sH. B. Ode. Modun. Hfsd. dinh. idng biin. nin liin,. kil,C,. ding. Eg,. kCcm^. sit, If,. kG/cm'. cm'IcG. 138,14. 0.031. dd. 30.9. 1.86. 1.43. 2,68. 0,86. 18,2. 0.44. 0,14. JQOJJ.. 30.1. 1.89. 1.46. 2.71. O.SS. 13.6. 0.60. 0,16. n'li. 97.7. 0.037. 18,9. 1.92. 1.45.. 2.72. 0.82. 19.1. 0.19. 0.18. is'so-. 141.3. 0.034. 20.9. 1.95. 1.61. 2.71. 0.68. 8.2. 0.14. 0,21. 20°58'. 105.2. 0.025. saphalk eQ amg. Luong Tdn Luc / Tap chi Khoa hpc vd Cong nghe • Dai hpc Duy Tdn 4(13) (2015) 50-58. Bang 4, Tinh chat cd ly dat rcii tram tich DeTOthanh ph6 Da Ning. i. i t|-s *5 „. -5. _ 7>. "=|. '1. J. 1.. f.. u.. -= « « ^ " "^ K. s. .j;. o. =. -S. S. „. w. „. JJ. =. S. •5. „. „. -. M. •o. ». =. 3. " ^. 1?. (9. a-SS i i 3-Sf B ^ § s »s RS »s 1 1 S-g B iifi J i%-i i I f l IS 3-i! I S. ISfS. H S V. -s. « " ^. ^'. „. s. o,. ". K. e s. 1. w. ^ i:s. „. p. o,. s. -S. s. _ ". : -4. hi. u.. «. " _ ^ " . o. 5. \. a. « ^. 1. •o. s. » s. J. " " " _ _ , " _ ^ .. ft. fc. ^. * * %.. ". ". s. "2. 3. 'B. s. %. a. «. «. -I. s. 1. ^. 1. =. s. S. 1. = ^. ft. -« f!. 1. „. " I. r-. ". "3. s. la. ,^. y. "8. "a. 3. iS. s. Jjj. «. «. N. «. ^f. §. 3. 5. 4^". g. 5^1. 1. 1. 1. « 1 s ~ » " 1 1 1 1. .;. g. e. §. 8. i. 5. {. e. 1. s. £. g. 3. ". O. „. Q. •". -5 1. » 1. I. f. -j. S. •5. .;. {. 5. »l. W? Pi |3 Is f 5.. Lumg Tdn Luc / Tap chi Khoa hoc vd Cong nghe - Dai hpc Duy Tdn 4(13) (2015) 50-58. (*) He SO nha n\idc (i;) xac dinh theo cong thiic thiic nghiem cua D. A. Biecinski (1960):, trong do K la he so tham, m/ngay dem. 3. Ly thuyet va ap dung tinh toan phun trao day ho mong sau do cat chay Kiem toan tra on dinh chong phun trao hoac chong chay tham phai thoa man dieu kien he s6 an toan K^ < 2vk dildc xac dinh nhif sau (Hinh 1). h,H - chenh lech cot midc giiia trong va ngoai day ho mong; L - do dai dtidng chay cua dong tham ngan nhat, L = LLf, -i- tnEL^; ELf, — tong do dai nam ngang cua chay tham; ZLh - tong dp dai thang diing cua chay tham; m - he so khi tfnh doi doan thang diJng cua dilfJng chay thkm thanh doan nSm ngang. Khi tUcJng mang quay mot hang, lay m = 1.5; khi tu5ng mang quay nhieu hang m = 2.0. Ch6ng chay tham (phun trao) cua khoi dSt c) day hd mong dUdc tfnh theo cong thiic sau:. J. _ _Eliln bti i p KKS ihim l U. Hinh 3.1. Sddo kiem tra chong phun trao day ho mong Do tUcJng chan chi la ket cSu chan dSt tam thbi, de ddn gian trong viec tfnh tfnh loan, co the lay gan dting difcJng chay ngan nhat (Hinh 1), ttie la dircfng chay thSm sat tiicJng chan de tim lUc chay tham Idn nhat: J = Iy^ = -pTw. (3.1). Trong do: 1- do d6c ihuy lufc chay thSm cua day ho mong, / = /iw/L;. ly. (3.2). Trong do: ic - do doc thuy hie tdi han cua khoi dat 6 day ho mong; CT(3) ys - khoi lUdng rieng cua dat; e - he so rong cua dat; De tfnh toan, 6 day chiing toi chon chieu sau h6 mong 16n nhat la 9m (tUdng diJdng 3 tang ham), mo Hinh ch3n gifl la tucing cir be tong cot thep day Im, chi6u dai tudng L diidc tinh theo cong thiic kinh nghiem L = (1,8 -^ 2,2)H, d day liy L = 1,8H, chi6u sau chon til6ng D = L - H. Trong qua trinh tinh toan, ap dung ket qua co the thay thdi chieu dai tu5ng cii (tang) de day ho mong dUdc on dinh, Cac thong s6 tinh toan cho d Bang 5.. Bang S. Cac thong so mo hinh tinh toan phun irao day ho mong sau Chieu sau ho mong, m. Chieu dai tuong cir, L, m. 3 6. 5,4 10,8. Chieu sau chon mong, D, m 2,4 4,8. 9. 16,2. 7,2. Trong khuon khd bai bao tac gia lUa chon 2 phu kieu/dang CTMTDKTCTN dac trdng de phuc phu cho viec kiem toan van de phun trao day ho mong sau do cat chay khi thi cong trong. cac thanh he tram tich mem rcJi Q, bao hoa nifdc tai khu vtfc nghien ciiu do la phu kieu I.a (thuoc kieu I) va dang n.a.l (thuoc kieu II).. Luong Tdn LUc / Tap chi Khoa hpc vd Cong nghe • Dai hpc Duy Tan 4(13) (2015) 50-58. 3.1. Kieu CTMTDKTCTN I, phu kieu La Trong phu kieu La, miic nUdc ngam ben ngoai ho mong nam each mat dat 0,1m, miJc. nu6c ngam ha thap ben trong ho nam diidi da; ho 1,0m. Cac chi tieu cd ly trung binh tinh toar cho phu kieu I.a cho 6 Bang 6.. Bang 6. Cac chi ticu cd ly trung binh tfnh toan phun trao day ho mong sau cho phii kieu [.a Lop dat. Be day, m. Khoi lining rigng, y,, g/cm^ 2,65. 0,8. Catm)n,chat vira. 2,3 4,0. 2.66. 0,67. Set pha Ian dam san. 10,0. %n. 0,68. Dat d^p nhan sinh (cat tnuig). 3.1.1. Ho mong sau 3m (luong duong 1 tdng ham) Khi thi cong h6 mong sau 3m trong phu kieu I.a, day ho mong nam trong ldp cat min, chat vita. Ket qua ti'nh toan chong chay tham ho mong 3m dupc the hien nhU sau: Dp doc thuy lite tdi han cua khoi dat 6 day ho mong dUdc tfnh theo cong thiic 3: 2,66-1 '. l+e. - = 0,99. i-f0,67. Dp d6c thuy lUc thuc te ciia dong thSm vao ho mong:. L. £U + mZL^ (3+ 1 ) - 0 . 1 1 + 1,5[(5,4 - 5,1) -F (2.4 - 1)] " ^'^^ He so an toan chong phun trao day h5 mong theo cong thiic 2:. He so rSng, e. Nhil vay, vdi ho mong sau 3m thi cong trong phu kieu I.a cd he so an toan chong phun trao Jf, = 2,83 > 2 nen day hd mong khong bi phun trito do chay tham. 3.1.2. Ho mong sau 6m vd 9m (ii/ong duongl vd 3 tdng ham) Khi thi cong h6 mong sau 6m trong phu kieu I.a, day ho mong n^m trong ldp cat mm, chat via, *I\iy nhien, vdi chieu dai tirdng cii da chpn 10,8m, chieu sau chon cii 4,8m, ttie la tUdng cii da elm vao Idp dat di'nh (set pha ISn dam san) mdt dop 4,8 - 0,3 = 4,5m. Nhu vay, day hd mong xem nhu khong cd dong tham tii day mong len tren nen khong xay ra qua trinh chay tham. Ddi vdi hd mong sau 9,0m, day hd mong dtidc dat vao ldp set pha lln dam san nen khong xay ra qua trinh chay tham (cat chay). 3.2. Kieu CTMTDDKTCTN //, phu kieu U.a, dang Il.a.J Cac chl tieu cd ly trung binh tinh toan phun trao day ho mong sau trong dang Il.a.l dtrdc the hien trong Bang 7 nha sau:. Bang 7. Cac chi tieu cd ly trung binhiinh toan phun trao day ho mong sau cho phu kieu I.a Lop dat. B6 day, m. Khoi luvng rigng, y„ g/cm^. He so rong, e. Cat tho, chat vira. 5,85. 2,66. 0,61. Cat vira, ch^t vira. 5,5. 2,66. 0,67. Cat vira, chat. 5,05. 2,66. 0.53. Set pha lan dSm san ,. 17,5. 2,71. 0,68. Luiing Tdn Life / Tap chi Khoa hoc vd Cdng nghe - Dai hoc Duy Tdn 4( 13) (2015) 50-58. 3.2.1. Ho mong sau 3m (tuang dudng J tdng ham) Khi thi cdng ho mong sau 3m trong dang n.a. I, day hd mong nam trong Idp cat tho, chat viia. Miic nUdc ngam nam each mat dat trung binh 2m. Miic nUdc ben trong ho mong nam dudi day hd mdng I m. Theo sd dd kiem tra chdng chay tham day hd mdng (Hinh I), cdng thiic 2 va 3, ket qua tfnh toan chong chay tham hd mong 3m difdc the hien nhu sau: Dp ddc thuy liic ldi han ciia khdi dat d day hd mdng ditdc ti'nh theo cdng thiic 3: 7,-1 2,66-1 1,03 1-^0,61 \-e Dp ddc thiiy liic thiic te cua dong tham vao hd mdng: .. _. Aw. L. ZLfi + m£Lv (3 + l ) - 2 = 0,24 1 + l,5(5,4-2) + ( 2 , 4 - l ) He s6 an toiin chong phun trao day ho mong theo cong thiJc 2:. - f =^ =Nhu vay, vdi hd mdng sau 3m thi cdng trong phij kieu Il.a. I cd he sd an loan chdng phun trao Ks = 4,2 > 2 nen day hd mdng khong bi phun trao. 3.2.2. Ho mong sau 6m (tuong duang 2 tdng hdm) Hd mdng sau 6m, day hd mdng nam trong Idp cat viia, chat vtta. Miic nUdc ngam ben ngoai hd mdng nam each mat dat 2m, miic nUdc ngam ben trong hd mdng nam each day hd mdng Im. Kel qua tinh loan chay tham diia theo sd dd Hinh I va cac cdng thitc 2, 3 nhiT sau: Dp ddc thuy liic tdi han cua khdi dai d day hd mdng dUdc ti'nh theo cong thiic 3: -=0,99 1+0,61 Dp doc thuy liic thUc td cua dong tham vao hd mdng:. Aw. (6+l)-2 = 0,25 l + l , 5 ( 1 0 , 8 - 2 ) + ( 4 , 8 - 1) He so an toan chong phun trao day ho mong theo cong thiic 2: L 0,99 ^• = 7 = 0 : 2 5 = " ^ Nhu vSy, vdi hd mdng sau 6m thi cdng trong phu kieu U.a. 1 cd he sd an toan chdng phun trao K; = 3,96 > 2 nen day hd mdng khong bj phun trao. 3.2.3. Ho mong sau 9m (tuang duang 3 tdng hdm) Ddi vdi hd mong sau 9m, day hd mdng van nam trong Idp.cat vita, chat vita. Mitc nUdc ngam ben ngoai ho mdng nam each mat dat 2m, miic nifdc ngam ben trong hd mdng nam dUdi day hd mdng I m. Kdl qua kiem toan diidc the hien nhir sau: Do ddc thiiy liic tdi han cua khdi dat d day hd mdng dUdc tfnh theo cdng thiic 3: 2.66-1 0,99 1+0.67 \+e Dp ddc thuy liic thiic te ciia ddng tham vao hd mdng: h^ _ ftw L ZLh + m£Lv (9+l)-2 = 0,25 l + l,5(16,2-2) + ( 7 , 2 - ] ) He so an toan chdng phun trao day hd mdng theo cdng ihiic 2: 0,99 3.96 ^0,25 '' Vdi hd mdng sau 9m, dUtJc dao trong Idp cat. vita, chat vCta cd ket qua kiem toan chdng phun trao day hd mdng la K, = 3.96 > 2 nen day hd mdng on dinh. Kel qua tinh toan phun trao day hd mong trong cac kieu (TTMTDKTCrrN khu viic ddng bang thanh pho Da Nang dildc tdng hdp trong Bang 8.. Luong Tan Life/Tap chi Khoa hpc vd Cong nghi • Dal hpc Duy Tdn 4(13) (2015) 50-58. Bang 8. Kel qua tmh loan phun trao day ho mong do cac chay trong cac kieu CTMTDKTCTN khu vilc dong bang ll pho Da Nang. Kieu. Ph\i kieu/dang. Chieu sau ho mong, m. H5s6K, 2,83. K& lujn. -. Khong Khong. 6. 4,2 3,96. 9. 3,96. Khong. 3 I. I.a. 6 9 3. n. n.a.l. 4. Ket luan Vdi viec chpn chieu sau lUdng cii theo cdng thiic kinh nghiem. mo Hinh chSn giii la tUdng cir be tdng cdt thep day Im. chieu dai tudng L dUdc tfnh theo cdng thiic kinh nghiem L = (1,8 + 2,2)H, d day 13y he sd an toan thdp nhat la L = 1,8H, chieu sau chdn tUdng D = L - H. NhU vay vdi chieu dai tUdng cii da chpn Iheo cong Ihiic tren ting vdi chieu sau hd mdng tUdng ling 1,2 va 3 tang ham la 3m, 6m va 9m la 5,4m, 10,8m va 16,2m vdi chieu sau chdn cif tUdng ling la 2,4m, 4,8m va 7,2m thi day hd mdng sau khdng bj xay ra qua trinh phun trao do cat chay Irong qua trinh thi cdng. Tuy nhien, lai nhiing ndi ldp d5l dinh cd chidu. Khong Khong Khong. sau phan bd thay doi Idn thi cSn cd bien phap thay doi chieu sau chdn ciia tiidng cut hdp ly. Tai lieu tham khao (11 Do Dinh Diic (2004), Ky thuat thi cong tap T, NXB Xay dung. Ha Noi. [2] Nguyen Ba Ke (2009), Thiet ke va thi cong h6 mong sau, NXB Xay dilng. Ha Noi. [3] Lomladze (1982). Dja chit cong trinh - Dia chal dong luc cong Irinh (ngiTcJi dich: Pham Xuan, Nguyai Thanh, nnk), NXB. Dai hoc va THCN, Ha Noi. [4] Nguyen Uyen (2002). Dia chat cong trinh, NXB. Xiy dung. Ha Npi. •[5| Nguydn Uyen (2006), Xuf ly cac hien tiTpng dia chat trong xay diing, NXB. Xay difng, Ha Noi. [6] Tran Van Viet (2004), Cam nang diing cho ky stf Dja ky thuat, NXB. Xay diJng, Ha Noi..