KHOA HOC VA CtNG NGH| MO J^^
NGHllN Clhl HOAN THIEN PHUtTNG PHAP XAC DjNH CHICU S^U L 6 MlN KHI THI CONG DUdNG H^M
r
hieu sau 16 min \d mdt thong so ky thuat, cong nghe quan trpng anh hu'O'ng 16'n td'i ' • ^ ^ cac eong viee eua mgt chu ky dao-chong giu' du-ofng him. Chieu sau lo min hgp ly lam gia tang t i c d6 dao-chong giu-, tang nang suit lao dpng va giim gia thanh xay dyng du-ong him,... Chieu sau lo min "1" phu thupc vao to hgp nhilu yeu t6 ky thuat-c6ng nghe-to chu-e thi e6ng khac nhau [1], [2].1. Mot so phirong phap xac djnh chieu sau lo min Tren thyc t l , chilu sau 16 mln co the lya chpn theo mpt s6 phu'ong phap sau day:
• Phirang phap xac dmh theo yeu ciu toe d6 tiln girong;
• Phu-ang phap xae dinh theo kinh nghiem thi cong thyc t l ;
• Phu'ong phap xac dinh theo eac cdng thu'C thyc nghiem.
N l u t i c dp dao 16 trong mgt thang "Vth"
(m/thang) du'gc djnh truo-c thi chilu sau 16 min "1"
ed the xac djnh theo c6ng thu-c sau [1], [2]:
1= ^th-Tck .m. (1) T.(25-;-30).ii
Trong do: Tck - Thd'i gian mot ehu ky dao-ching 910 du'd'ng him, gid'i T - Th6'i gian lam viee eua cae dpi thg thi cong trong mot ngay dem, gid'i (25-^30) - S6 ngay lam viee trong mot thang, ngay; TI - He so sir dung lo min.
Hien nay e6 nhilu phu'ong phap xac djnh chieu s§u 15 min bang cac cong thire thyc nghipm khac nhau. Phu'ong phap nay x§y dyng tren ca sd" cac yeu t l sau: so do to chu'c chu ky edng tae da du'gc chgn tru'oc; cac tinh ehit, nang lye, chung loai cua cac trang-thiet bj thi eong s3n co; cac dilu kien md, dia chat, dia co hge cy t h l cua khu vyc xay dyng cong trinh nglm; kha nang bao dam ky thugt (cung cap nang lu'gng, dien, khi nen, thong gid, v§n tai,...) o miyc do c i n thilt cho qua trinh thi cong;
khong xet den nhirng sy c l xay ra trong qua trinh thi eong c6ng trinh ngam. Cac ylu t l ciu thanh
GS.TS. VO TRONG HCING^
Trwdng Dai hoc Md-Dja chat
nay khong thay doi trong nh&ng dieu kien thi cong nhlt djnh khi xac djnh cong thu-c thyc nghiem. Vi vgy, kha nang su- dung cua cac cong thOc thyc nghiem rit hgn ehl tr§n thyc t l . Ve ban chit chung la nhii'ng Id-i giai rieng cho nhu-ng bai toan cy the.
Trong cac cong thiic thyc nghiem, cong thu-c do Pokrovski N.M. d l xuat du-gc sir dung rpng rai nhlt. TCf thyc t l thi cong dud-ng ham, Pokrovski N.M. nhgn thiy, chilu sau l5 min hgp ly "I" phai xac djnh theo thai gian "T^^" eua mot ehu ky dao-chong du'dng ham. NghTa la [1], [2]:
i = f(Tck) = f(ti + t2 + ta + U + ts + te). (2) Tai day: f - Ham so xac dinh mli quan he giira cac thdng s l anh hu-o-ng den ehilu sau lo min; Tci<
- Thdi gian cua mgt chu ky thi cdng du-ang him; U - Thd'i gian eho cac cong tac phu trg khac nhau;
t2 - Thdi gian cho cdng tae khoan lo min; ta- Thai gian cho edng tac nap lo min; t4 - Thai gian no min, thong gi6; t4 - Thai gian du'a gu'ang vao trang thai an toan; ts- Th6'i gian xuc boc dat da; ts - Thd'i gian chong giu' dirdng him.
Ngoai ra, Pokrovski N.M. va mpt so tac gia con du-a them vao he so xac dinh phan cdng tac cu the du'gc thye hien song song vdi cae cdng tac khac trong chu ky.
Tren thyc t l , Pokrovski N.M, va nhieu tac gia khac cho din nay chi mdi xet tdi cdng tac chong tgm (hoac chong c l djnh) bang mgt s6 hgn ehe eae toai khung chong the hien qua dgi lu'gng thdi gian
"tg" khi tinh ehilu sau lo min. Nhilu chung loai k i t ciu chdng giu', to hgp kit elu ching giii' van chu'a du'gc xem xet khi tinh chieu s§u 16 min. [1], [2].
Rd rang, bieu thirc (1) chi cho ngu-di thilt k l gia tri phap lenh doi vdi tirng cdng trinh cu t h l theo thdi gian yeu ciu hoan thanh thi cdng du'dng ham. Sau khi xac djnh "I" theo (1), ngu-di thiet ke phai lam bai toan ngu-ac: tien hanh lya chgn so d l to chu-c cdng tac, thdi gian chu ky cdng tac, chung logi, s l lu'gng cae trang thilt bj thi e6ng,... nham dam bao ehilu sau lo min can thilt cho mdi chu ky cdng tae. Day la vin d l phii'C tap chu'a ed ldi giai tren thyc t l .
CdNGNGflllPIIII0,SA4-20]8 |
KHOA HOC VA CdNG NGHl MO
Viec lya chon chieu sau " I " theo kinh nghipm mac dil eho kit qua nhanh chdng, nhung phyong phdp nay lam cho cdng tdc quy hoaeh, to chirc thi cdng trong chu kJ trd nen phirc tap. Trong nhieu trydng hop, ngydi thilt k l rit khd tpo nen cac chu ky thi cong nhip nhang, hoan chinh phu hpp vpi nhii'ng dilu kien trang-thilt bj thi edng va nhu'ng dac tinh elu tae cu the cua dydng him.
Tren thyc t l , hai phypng phap chpn chieu sau Id min theo yeu ciu toe dp tiln gyong hope theo kinh nghiem chi sir dgng khi thyc t l bat bgpc^hopc trong nhiing dleg kipn thi cdng phirc tap, tien dp gyong phdi thay doi theo tirng chg ky cong tac cu the trdn nhO'ng doan cdng trinh nglm ed cau tap dac tarng (vi du thi cong cae dudng Id giao cat nhau). Hai phyong phdp nay phai^dypc nghiSn ciru hoan thien, vi rit nhilu vin de vin chya dypc giai dap v l kha nang hpp ly cua chung tren thyc te;
•:• Sau khi xac djnh xong gia trj "I", iam each nao ngypi thilt k l cd the dam bao dypc gid trj "I" da xae dinh cd the hodn thanh dypc tren thyc te?
• Hal phyong phap nay mdi chi chpn ra gid tri.
chilu sau lo min "I" thilu rat nhieu chimg cir Juan giai;
•;• Lam each nao ngydi thilt k l ed t h l giai bai toan ngypc "phai tim ra cac dilu kien t l chire, ky thuat, cong nghe,... phu hpp de cd t h l dat dupe gia trj "I" can thilt tren thyc t l " . OSy la bai toan rdt phirc tpp vi chilu sau lo min phg thupc vao rat nhieu ylu t l , thay doi lien tgc tren thyc te.
Cac cdng thirc thyc nghiem tinh chilu sau 16 mln cua nhilu tac gia chi mdi gidi quylt cho tirng trypng hpp rieng ie, khdng mang tinh tong quat ndn ITnh vye sir dung ehung bj hpn chi bdi nhirng dilu kien ap dung cg t h l cho timg cong thirc [2], [3], [4], [5], [6], [7]. Vi vay viec nghien ciru hoan thidn phyong phap xac djnh chieu sau Id min cho tardng hpp tong quat cd y nghTa thye t l va ly thuyet rit cao.
2. Nghien ciru hoan thien phifoing phap xac djnh chieu sau Id mln
v l nguyen tac, cdng tac thi cdng cdc dudng ham phai tien hanh theo nhirng chu ky thi cdng chuin xac, nghiem ngat. Thdi gian eua mpt ehu ky thi ccng dudng him "Tck" dypc lya chpn sp bd theo kinh nghiem tuy thupc vap quy md elu tpo dydng him, cac kich thydc mat cat ngang ciia dydng him theo dilu kien sau:
T„k=(nca.T„)<24 giP. (3) Tai day; nca - Sd lypng ca cdng tac trcng chu ky thi
cdng; Tea - Thdi gian eua mdt ca cdng tac, gid;
T„=6; 7; 8 gid.
Tong thdi gian ciia mdt ehu ky thi cdng dydng ham 'Tck' phai dypc hinh thdnh tir tong cae khoang
thdi gian ciia cae edng vi^c thir "I" "Ti.k," thyc h l i nil tilp nhau trong chu kJ thi cdng;
1=1 i .! » . Tpi day; T( - Thdi gian can thilt de hoan thl cdng vi|c thir "I", gid; K - He so t h l hien mirci.
ddc lap thyc hien phin cdng vl$c thir "i"; n - Tea,, bd s i lypng cdng vipc phai hodn thanh trpri|
khoang thdi gian cua mpt ehu ky thi cdng "Tck".
Gia trj ciia h§ s l "k" khdng Idn hpn 0<k!<1,0. He so "k," xac djnh gia trj thdi l y ? . ^
"(Ti.ki)" trong toan bd thdi gian "T," c i n thiet m hoan thanh cdng viec thir "i" phai thyc hidn hojii toan dpc ldp (thyc hien noi tilp) so vdi cdc cdng vide khac trong chu ky thi cdng dydng him (H.1);
• Khi ki=0; toan bd thdi gian 'T" can thidt de hoan thanh cdng viec thir "i" se dype thye hi^p hoan toan song song vdi cdc cdng viee khde troi)g:
chu ky cdng tae (H.1 .a); ^ ^ _
•:• Khi ki=1,0; todn bd thdi gian "T," can thiet de hoan thdnh cdng viec thir "I" se dypc thyc hien hoan toan noi tiep vpi cdc cdng vide khac trong ctiu ky cdng tac (H.l.b);
•:• Khi 0,0<k,<1,0; phan thdi lypng "(T,.k,)" cua cdng viec thir "I" trong todn bd thdi gian "T," c9n thilt de hoan thdnh cdng vide thir "I" se dypc this;
hien nli tiep vdi cdc cdng vide khac trong chu ky thi eong. Phan cdn ipi ciia thdi lypng hoan thdnh cong viec thir "i" •lT,.(1-k,)]" se dypc thyc hien song song vdi cac cong viec khac trong chu ky thi cong dydng him (H.l.c).
a) Trydng hpp k,=0
H 1 Mii quan hi giira hai cdng viec Hen kenhau thue hiin trong chu kf thi cing duvng ham CONG NGHIEP MO, SO 4 - 2 0 1 6
KHOA HOC VA CONG NGHE MO |!jyilll
T o a n bp t h d i gian "T," can t h i l t de h o ^ n thanh cdng vide thCr " i " se d i r g e hinh thanh tu' hai thanh p h i n t h d i gian:
• P h i n t h d i gian cho cac cdng tac chuan bi cho cdng tac thu-"i": "Tcb.";
• P h a n thd'i gian eho viee t h y e hign cong tac thCr " i " : "Tet.,".
edng vide phu thude vao chieu sau lo m i n " I " s d i r g e tinh nhu' sau:
To.,=(T|,cb,+T|.c..i),gid'. (9) TCr day:
Nhu- vgy:
T,=(Tcbi+Tct,), gid.
TCr day:
X(Ti)-'S(Tcb.i + T,t,:
i=l i=1 i^i i==n -Z(Tcb.i)+Z(Tcti)-
(5)
(6)
Tuy thupc vao m l i quan hg v d i e h i l u sau Id m i n
"1", t o a n b g cac cdng viec trong ehu ky thi edng du'gc phan chia thanh hai n h d m s a u :
• N h d m " m " eac cdng viec thLF " i " "To," (i=1^m) khdng phu thuge vao c h i l u s a u lo m i n " I " ;
• Nhdm "p" cae cdng viec thir " i " 'Tn" (i=1-p) phu thupc vao c h i l u sau Id min T . Trang do: n=(m+p).
C a c edng viee thu' " i " 'To.i" (i=1-i-m) trong nhdm
"m" cdng viec khdng phu thupc vao e h i l u sau Id m i n " I " se du'gc tinh nhir s a u :
To ,=(To.cb.i+To.cL,), gio'. (7) TCr day:
2:(To.i 1.1 1
"StTo.ob.
1=1 i=m
I(To.ot To.ctl)-
(8)
Tai day; To cbj - T h d i gian hoan thanh cac cdng tac c l i u l n bi cOa cdng vide t h y " i " khdng phu thupc vdo c h i l u s d u la m i n " I " , g i d ; T o n , - T h d i gian hoan thanh cdng viec thir " i " khdng phu thude vdo chieu sau Id m i n " I " , g i d ; i=1+m.
Cae cong viec thii' " i " " T , / (i=1+p) trong nhdm "p"
i(Ti.,:
i=i
= 2:(Tl.cb.i+Ti.c
= 'S(Tl.cb.i ^E(^i.ct.i)•
(10)
Tai day; Ti.cb r - T h d i gian hoan thanh cdc cdng tac c l i u l n bi ciJa cdng viec thir " i " phg thupc vao c h i l g sau Id min " I " , g i d ; T i c , - T h d i gian hoan thanh cdng viec thir " I " phg thude vao chieu sau Id m i n " I " , gid; M^p.
Thdnh phan •Tia,." trong cong thirc (9) ve c o ban khdng phu thupc hoac phu thupc khdng d a n g k l vao ehieu sdu lo m i n . Vi vpy, trdn t h y c t l ed t h l x l p chiing vao nhdm cac cdng tac khong phg thude vao e h i l u sau 16 m i n .
Gia tn khoang t h d i gian t h y e hien cong viec thii'
" i " "Tict.i" (i=1^P) phu thupc vdo c h i l u sau 16 m i n " I "
cd the xac djnh theo mdi quan he n h y sau;
V|.ct.i(l)1 P\cU i
(11)
Tir day;
'=1
1 Plot, J' VlctiO) (12)Tpi day; T c t i - T h d i gian d n t h i l t de hoan thanh ePng viec thti' "1" trong nhdm "p" eac cdng viec phy thupc vao c h i l u sdu Id min T , g i d ; Via,(l) - Ham s l xac dinh khdi l y p n g cua c6ng vipc thir " i " phu thupc vao c h i l u sau 16 mln " I " ; Pid., - K h l i l y p n g cua epng viec thir " i " phg thupc vao chieu sau 16 min cd the hoan thanh trong mpt d o n vi thdi gian.
Tren c o s d cac k i t qua nghien c i r u tren, tir cac cdng thirc (4), (6), (8), (10), (12) cd t h l riit ra moi quan hd sau day;
Tok=2;ft-ki)=KiI(To.cb.i 1=1 i=1
t-ki.2:(To,c,.l)+ki.X(T|.cb., i=pl
Vl.ct.i(l) Pi.cU
(13)
T i r day, gid t n c h i l u sSu lo m i n " I " cd t h l xac djnh tir Idi giai ciia p h y p n g trinh;
i = m ' - ' " . • . ; .
f ( | ) = T < * - k i . 5 ; ( T o . c b . l ) - l < i . Z ( T o . c t . i ) - k i . I ( T i . c b . i , I i=1 1.1 1=1 3. N g h i e n ciru de xuat phyo'ng phap xac djnh c h i l u sau |3 min m a n g tinh tong quat de tiii c 6 n g cong trinh n g a m
TLF nhO'ng k i t qua nghien c i r u tren day, ehung tdi de x u l t phu'ong phap xac djnh c h i l u sau 16 m i n v d i ndl dung cae b i r d e nhu' sau:
CdNG NGHIEP MO, SO 4-2016
^ ^ _
KHOA HpC VA CtNG NGHt MO .;. Bypc 1 - Lya chpn thdi gian ciia mdt ea cdngtae "Tc", s l lypng ea cong tac "nc,", thoi gian ciia mpt chu ky thl cong dudng him "Tck" thda man dilu kien (3);
•:• Budc 2 - Lya chpn tong sp lypng "n" ccng vide (n=m+p), tinli chit cua tirng eong vipc thir "i"
cin phdi hoan thanh trong mot ehu ky thi cdng dydng him;
•:• Bydc 3 - Xac djnh trinh ty can phai thye hien cae cdng viec thir "i" trong toan bd "n" cdng viee phdi thye hien mpt chu ky thi cdng dydng him;
•:• Bydc 4 - Xac djnh cac cdng vide thil' "I" trcng nhpm "m" cac ccng vide khdng phg thgdc vao chieu sdu lo min "I";
•:• Bydc 5 - xac djnh cae khoang thdi gian
"To.cb." de hoan thanh cac cdng tac chuan bj eua cac cdng vide thir "i" khdng phg thupc vao chieu sau lo min "I", gid; xdc djnh cac khoang thdi gian
"Tool." de hoan thanh c6ng vide thir "i" khong phu thupc vao ehilu sau 16 min "I";
• Bydc 6 - xac dinh cae edng vide thir "i" trong nhdm "p" eac cong viec phu thupc vao chilu sau lo mln "I";
• Bydc 7 - Xac djnh cac khoang thdi gian
"Ticbi" de hoan thanh cac cdng tac chuin bj cua cac c6ng vide thir "i" phu thude vao ehilu sau 16 min "I", gid;
• Bydc 8 - xae djnh "p" ham s l "ficti(l)" t h l hien mli quan he giii'a eac thdng so, biln so, h§ s6,...
khac nhau trong mli lien quan d i n cac dai lupng
"Ti.ct-", "Vict" va "I" cho eac cdng viec thir "i" trong nhdm "p" cac cdng viec phg thgdc vao chilg sag 16 min "I";
• Bydc 9 - Xdc dinh cae khli lypng "Vi.ci" cua cac c6ng vide thir "i" trong nhdm "p" cac cdng viec phg thupc vdo chilu sau lo mln "I";
•:• Bydc 10 - xae djnh nguyen tie to chire thyc hien cae edng vide thir "i" trong mdt chu ky thi cdng dydng him thdng qua he s6 "ki";
• Bydc 11 - Xac dinh cac hd so "k" the hien mirc dd dpc lap thyc hidn cho tirng cong viec thir
"i" trong chu ky cdng tdc; k|=1 cho nhyng cdng viec thir "I" thye hien hoan todn nil tilp, dpc lap vdi cae cdng tdc ktiae; k|=0 cho nhdng cdng vipc thy "I" thyc hipn hodn toan song song vdi eae cdng tac khac; 0<k|<1 eho nhu'ng edng viec thir "i"
thyc hien mpt phan "k" noi tilp, dpc Ipp vdi cdc cdng tae khac;
• Bydc 12 - Xac djnh ehilu sau Id min "I" ttr phypng trinh (14).
O l sir dgng hieg qua cdng thirc xac djnh chieu sau lo min tren day, trong giai doan sap tdi ein tiln
hanh nghien ciru giai bai toan ngypc nham I kha nang sir dgng ciia chiing trdn thyc tl.l3
T A I U E U THAIM K H A O 1. Pckrovski N.M. Cdng ngh$ xay dyng i trinh nglm va md. NXB "Nhedra". M. 1977.
2. Nguyin Van Dydc, Vo Trpng HOng. i nghp xay dyng c6ng trinh nglm. T9p 1. Thi cdrii blng. Id nghieng va him tram. NXB "Giao th^
van tai". Ha NOi. 1997. 291 tr.
3. Vd Trpng Himg. Nghidn ciru xac djnh chf sau 16 mln khi sir dgng ccng nghp phgn be tp^
lydi thep va vi neo. Tap chi Cdng nghipp Md. i "
2003. Tr. 6+8.
4. Vd Trpng Himg. Nghidn cirg xac djnh (^^
sag lo min hpp ly khi sy dgng cdc Icpl kit a chong giu' dang khung vdi bydc chong k h 6 n g q dli. Tap chi Cdng nghipp Mo. So 5-2006. Ta 29+31.
5. Vo Trpng Hiing. Nghidn ciru xac dinh chi^
sdu 16 min hpp ly khi sir dgng k i t c i u chong giiivi neo vdi khoang each giu'a cac vdng neo khdng doi Tuyin tpp cdc cdng trinh khoa hpc Hdi nghi Co htf^f 1 da todn qu6c nam 2006. Tr.125+12B. ^ ^ |
6. Vd Trpng Hiing. Nghien cyu xac djnh chie^
sau 16 min hpp ly trong cdng nghe thi cdng gilng du'ng cd sir dung cac vdng ching tpm thdi. Tap chi Cdng nghiep Md. So 3. Nam 2011. Tr.1+5.
7. Vd Trpng Himg. Nghien ciru xdc djnh chilli sau 16 min hpp ly trong cdng nghp thi cdng gidng dirng sii' dgng to hpp vi neo-lydl thep-be tdng phgn. Tap chi Cong nghipp Md. So 4. Nam 2011 Tr.1+5.
Ngyo'i bien tap: H i ST Giao
Tif Ichoa; chilu sdu lo min; ehu ky thl cong;
tilp; song song
Ngay nhan bdi: 15 thang 10 nam 2015 Ngay duySt dang bai: 05 thang 7 nam 2
CONG NGHIEP MO, SO 4 - 2 0 1 6
