Chng 1: Nhng cng tc xy dng v bin php cng ngh trong thi cng ng hm

Chng 1: Nhng cng tc xy dng v bin php cng ngh trong thi cng ng hm.1.1. Cng tc khoan l mn trong ng hm.

1.1.1 Cc thit b khoan:

Khoan l mt trong nhng yu t quan trng nht quyt nh n tin thi cng cng trnh ngm. N ph thuc vo trnh k thut, tnh cht t . Thi gian khoan chim 15 ( 60% tng thi gian ca mt chu k khoan n. ng thi n cng l mt cng vic tng i nng nhc ging nh bc d.

V vy tng tin thi cng cng trnh v gim bt mc nng nhc ca cng nhn th khu khoan l mn cn c c gii v t ng ho v mi mt.

Cc loi my mc thit b phc v khoan l mn:

- Phn chia theo mc c gii ho ca my c cc loi : khoan th cng, khoan my.

+ Khoan th cng: thng c 2 cch c l bng ba ng chong v dng chong. Ni chung phng php ny c tc chm v chiu su nh nn hin t c s dng trong thi cng hm hin nay.

+ Khoan my : Da theo hnh thc cung cp nng lng hot ng c 2 loi ch yu l my khoan dng kh nn v khoan thu lc.+ Gin khoan : Khi lp nhiu my khoan trn mt thit b di ng, cc my khoan ny hot ng ng thi, iu khin tp trung.

Mi gin khoan c th lp 1 n 4 cn khoan v c 1 cnh tay ch gin cng tc. Phm vi hot ng ca loi my ny theo phng ngang c th t 10 n 15m v c th vi n tm cao 7 n 12m.

V vy loi gin khoan ny c u im phm vi hot ng rng nn trn cng 1 v tr ng ca my nn tin khoan nhanh. Tuy nhin n bt tin khi di chuyn ra vo trong hang o do c din tch chim dng ln nn nh hng n s di chuyn ca cc loi thit b khc. V vy, loi ny thng c p dng cho cc ng hm c kch thc gng ln

C th phn ra loi c xe khoan chy trn ray, bnh lp v bnh xch.

- Phn chia theo nng lng ca my khoan c cc loi :

+ My khoan chy bng kh nn: loi my ny c u im l cu to n gin tuy nhin n c nhiu nhc im nh: gy nhiu ting n ln, tiu hao nhiu nhin liu, tc ca loi ny thng thp hn my thu lc.

+ My khoan thu lc: My khoan thu lc c u im l t ting n v c tc khoan tng i nhanh. Tuy nhin n c cu to tng i phc tp v gi thnh tng i t.

My khoan thu lc Boomer-352 chy trn bnh lp1.1.2 T chc khoan l mn trn gng o:

- nh du l mn trn gng: Vic nh du l mn trn gng o thng c thc hin bng chm sn trn mt gng.

Thng thng cc cnh tay c gn sn cng tc ca cc my khoan s h tr cho vic xc nh bin hang o v v tr cc l khoan.

(Nu cch nh du bin hang v v tr cc l khoan trn gng bng th cng v my lazer)- Tin hnh khoan cc l mn trn gng: trnh t khoan, cc bin php gim ting n v bi khi khoan...1.2. Cng tc n mn trong thi cng hm.

1.2.1. Vt liu n.

Cc yu cu i vi cc cht n s dng trong thi cng cng trnh ngm:

- Thi ra lng kh c ti thiu.

- An ton trong ch to v vn chuyn v cha kho.

- Hiu qu kinh t cao.a. Tnh nng n:

N l 1 qu trnh phn ng ho hc tc cao, khi thnh phn ca thuc n hnh thnh khi khi ln phng thch nhit nng rt ln c tc dng xung kch, p co, ph hoi v bn tung cc gii cht xung quanh. Vic nm vng cc tnh nng n ca thuc n c ngha rt quan trng i vi vic vn chuyn v cha cht an ton, s dng chnh xc v nng cao hiu qu n ph.

Cc tnh nng n ca thuc n gm: nhy, tc n, sc n, mnh,

- nhy: th hin kh nng pht n ca thuc khi c tc ng kch thch bn ngoi. C cc loi nhy chnh sau:

+ nhy vi nhit .

+ nhy vi ngn la.

+ nhy c hc (va p, ma st).

+ nhy vi sng n.

(Tham kho cc bng thng k nhy n trong cc bng thng k trang 37 - Nguyn Xun Trng)

- Tc n: L tc chuyn sng ca sng n trong ni b thuc n. Thng thng tc n t l thun vi mt ca thuc n, trong cng 1 loi thuc n n chnh l mc cht khi np thuc n.

- Sc n: L kh nng sinh cng i vi cc gii cht xung quanh n, ni chung sc n cng cao th kh nng ph hoi v phm vi ph hoi cng cao.

- mnh: th hin mc ph hoi cc b i vi gii cht rn xung quanh. N th hin mc vn nt v phm vi ph hoi ca gii cht rn.

- Cc tnh nng khc: tnh n nh, ng knh ti hn (ti thiu) ca gi thuc, cht tt nht, hiu ng ng ng, c ly n theo, tnh an nh...b. Cc loi thuc n thng dng trong thi cng hm.Vi cc yu cu nh trn, kt hp vi xu hng s dng rng ri hin nay trong xy dng cng trnh c cc loi thuc n ph bin sau:

+ Amonit: thng s dng loi c s hiu No 1 v No 6- WB (s dng cho ng hm khng c kh mtal).

+ Thuc n dng tng (keo nc): c s dng rng ri trong khong 10 nm tr li y. Loi ny c tnh chng nc cao, cht cao, sc n mnh, nguyn liu sn c, gi thnh h, thng c dng trong nhng trng hp n l thin di nc.

+ Thuc n dng sa: loi ny c tnh nng n tt, chng nc tt, an ton cao, t nhim mi trng. Cc nguyn liu sn xut rt ph bin nn gi thnh r...Ni chung c th ni loi thuc n ny khi s dng s tit kim v an ton hn cc loi thuc Amonit.+ Thuc n dng keo (Trinitroglycerine): loi ny c tnh nng n v kh nng chng nc cao nn thng c s dng cho cc loi rt cng. Tuy nhin n li c nhy vi va p cao nn km an ton v gi thnh ca n cng tng i t.

Thuc n trong thi cng ng hm thng c ch thnh dng gi thuc c ng knh ph bin 22, 25, 32, 40mm, ...Chiu di ph bin t 165mm -:- 500mm.c. Vt liu gy n.Mc ch ca h thng gy n l nhm chuyn n c ly an ton.

- Dy chy chm v kp thng:

+ Dy chy chm: nhm chuyn ngn la cho kp thng gy n.

+ Kp n thng:

Kp thng

1- V kp; 2- M tng cng; 3- Thuc gy n chnh;

4- Thuc gy n ph; 5- lm t nng lng

Kp n loi ny n gin, s dng tng i n gin, khng b nh hng bi dng in bt thng; nhng d gy n nu nh c tc ng va chm mnh hoc tia la.

- Kp in:

+ Da trn kp thng v c b tr thm thit b pht ho bng in.

Kp in c th chia ra kp n ngay v n chm. Kp n chm c thc hin bng cch lp thm thuc n chm vo trong kp n ngay. Thi gian n chm ca kp c th hin bng s khong biu th, di y l bng thi gian n chm ca kp Trung Quc (chia lm 7 khong).

Bng thi gian n chm ca kp Trung Quc

S khong1234567

Thi gian chm li (giy)2D th n ch lm cho b bin dng do.

b. L khoan ph:

L khoan ny c vai tr n ph rng thm vng cn o, tin gn n hnh dng hang cn o, ng thi to thun li cho l n to bin.

c. L khoan n to bin.- N mn to bin c cng dng m bo s ph hu khi bin l nh nht, l bin php n mn vi phng php np mn phn tn, cc thi mn ng knh nh trong cc l khoan ng knh gn nhau. V mt cng ngh, n to bin l cng tc khoan n chuyn dng ng vin cc cng trnh nhm to ra b mt thch hp ca khi . u im ca n to vin l to kh nng c mt b mt vin, trnh to khe nt do cc tc ng ca n mn, gim kch thc o vt; o thiu trong so vi bin thit k. Lm gim tc ng a chn n n khi sau bin.

1.2.3. Tnh ton lng n v b tr l mn trn gng o:

a. Tnh s lng l mn trn gng o:- Xc nh s l khoan trn gng o.

+ Cng thc Ibraep: N = N1. S (ph hp vi gng kch thc nh)

Trong :

N1 S lng l khoan trn mt n v din tch

N1 = 41.

d- ng knh bao thuc, mm (tra bng).

a H s ph thuc loi ng o v tit din gng:

+ ng hm o ngang, a = 0,25 0.3.

+ Ging ng

a = 0.12 0.15.

b H s ph thuc vo kh nng sinh cng ca thuc n Amonit N0 6B, b = 1,0.

Cng thc Protodjiaconop gn ng N1= 2,7. =

Chnh xc N1 = ()2N1 = ..( ci)

+ T gi tr ca N1, la chn gi tr thch hp tnh s lng l khoan cn thit N (l).

+ Cng thc VNIIOMSX. N = (thng s dng cho kch thc gng ln).Trong :

q- Tiu hao thuc n n v, kg/m3.

.

Kd- H s nhi:+ Vi fkp= 1.5 - 6 ly Kd= 0,95.

+ Vi fkp= 7 - 9 ly Kd= 0,9.

+Vi fkp= 10 - 14 ly Kd= 0,8.

( - Mt thuc n trong ng, kg/m3;

a: H s ph thuc vo hng ng o v tit din gng:

+ ng o ngang v xin: a=0,25 0,30

+ i vi o ng : a = 0,12 0,15

(Din tch ln ng vi gi tr a nh)

Cng thc ny c th cho lng thuc n tng i nh, c bit l khi fkp nh v din tch gng o l ln.Bng mt thuc n ca mt s loi

Loi thuc nMt

(g/cm3)Tiu tn thuc n trn 1m chiu su l khoan (kg)

(ng hm khng nguy him do hi v bi)

ng knh ng thuc (mm)

323645

Amnt No11,0-1,1-1,1-1,251,7-2,0

Amnt No31,0-1,1-0,7-0,851,1-1,35

Amnt No61,0-1,10,62-0,750,75-0,951,1-1,35

ynamit 62% khng ng cng1,4-1,450,80-1,00-1,6-2,0

- Xc nh l khoan vin (l khoan to bin).

+ N mn to bin c cng dng m bo s ph hu khi bin l nh nht, l bin php n mn vi phng php np mn phn tn, cc thi mn ng knh nh trong cc l khoan ng knh gn nhau. V mt cng ngh, n to bin l cng tc khoan n chuyn dng ng vin cc cng trnh nhm to ra b mt thch hp ca khi . u im ca n to vin l to kh nng c mt b mt vin, trnh to khe nt do cc tc ng ca n mn, gim kch thc o vt; o thiu trong so vi bin thit k. Lm gim tc ng a chn n n khi sau bin.

+ C hai phng php n mn to bin : trc v sau. Theo kinh nghim c kt t cc cng trnh ngm thu cng ca Nga cho thy: N to bin trc thng i hi b tr cc l mn dy hn, nhng c bng phng cao hn n to bin sau.

S l khoan vin ly theo cng thc : Nv = .

Trong :

P - Chu vi gng o, m

B Chiu rng gng o, m.

b : Khong cch gia cc l khoan vin, b = 0,5 0.8m.

m bo to vin chnh xc ta khoan thm cc l khoan khng np thuc xen k gia cc l khoan vin.

b. Xc nh tc khoan.

Thng thng trong thit k ch tnh ton s b tc khoan, cn tc thc t s c xc nh li trong qu trnh khoan n.

Thi gian khoan:

+ Thi gian khoan trc tip: l thi gian tiu tn trc tip khoan cc l khoan.

+ Thi gian khoan chung: gm c thi gian khoan trc tip v thi gian cho cc thao tc ph tr (di chuyn, t my, thay chong)

Ni chung t l gia hai thi gian ny nn nm trong khong 0,4 - 0,75 (().

Cng thc ca A.F. Xukhanp (thng s dng vi cc loi my khoan va p) :

Vk= 0,06 k(. l. ( (m/h)Trong :

l Tc my khoan, mm/pht, s dng my khoan CBY - 4

c l = 1000mm/pht.

k( - H s iu chnh. k( = A.B.C.D = 2,4.1,1.1.1,1 = 2,9.

( - T s gia thi gian khoan trc tip v thi gian khoan chung,

c. Xc nh chiu di l khoan.

Chiu su l khoan l mt trong nhng yu t c tnh cht quyt nh thnh phn cc loi cng tc khoan n trong o hm v n xc nh tt c cc khi lng cc cng tc ch yu, do n l mt thng s t - chc k tht c bn.

Thc t thi cng cng trnh ngm cho thy rng chiu su l khoan ph thuc vo tit din gng v loi t ph c chn. Nu chn t ph vng, chiu su khoan ch yu ph thuc vo kh nng ca thit b khoan. Cn i vi t ph p th nu chiu su l khoan nu ln hn 4 m s gy ra gim h s s dng l mn t ph v nh th c ngha l lm gim h s s dng l mn trn ton gng. Da trn kinh nghim thng k ca Vin Orgenergostroi v Gidrospesproek ca Lin X c cng nh cc s liu thc t c st n tnh nng ca cc loi my khoan hin ti th chiu su l khoan trong hm c tit din b l 2 2,5m, i vi hm tit din ln v trung bnh l 3 4 m.

Chn s b theo cng thc :

Lph= (m).

Cng thc tnh chiu di l khoan ph :

,m.

Trong :

TCK Thi gian mt chu k khoan n ( t chc 3 ca mt ngy ly

Tck = 8h).

N* - S lng l phi khoan, ci.

N - S lng l c nhi thuc, ci .

t1 Thi gian nh giu l khoan, di chuyn, t thit b, h ; t1 = 0,4 - 0,6 (h).

t2 Thi gian nhi thuc cho mt l khoan v n, h; t2 = 0,04 - 0,08 (h).

t3 Thi gian n v thng gi, h; t3 = 0,3 0,5 (h).

t4 Thi gian kim tra v a gng v trng thi an ton, h; t4 = 0,2 0,3 (h).

n S ngi nhi thuc vo n khoan, n= 10 ngi (ph thuc b tr thit b).

m S my khoan ng thi lm vic trn gng.

VK Tc khoan, m/h.

( - H s s dng l mn.

S Din tch gng, m2.

Kn H s tha tit din.

( - H s phn phi lm vic gia khoan v vn chuyn, khi dng dn khoan ta c ( = 1.

Pbd- Nng xut bc d, m3/ h.

- Kt hp gi tr tnh ton trn vi kinh nghim chn chiu di l khoan ph lph.

- Xc nh chiu di l khoan t khu: khi s dng t khu xin c th tham kho bng sau y:FkpGc nghing gia cc l t khu () tng chiu di l khoan (%)

3 64010

8-165015

>166020

d. Xc nh ng knh l khoan.

ng knh bao thuc d0.

( ng knh cui cng ca l : d = d0 + 2-3mm.

ng knh chnh lch gia u v cui ca l khoan ly trung bnh bng 5mm : dc = d + 5mm

e. Xc nh trng lng thuc n.

- Trng lng thuc n ca mt ln n ; Q = q.S.1K (Kg)

Trong :

1K chiu di trung bnh ca l khoan, m;

q tiu tn thuc n n v, kg/m3.

- Trng lng thuc n trung bnh ca mt l khoan

qtb =

- Trng lng thuc n l khoan t khu.

qdk = 1,25 . qtb kg .

- Trng lng thuc n l khoan ph :

qph = 1,1 . qtb = kg .

- Trng lng thuc n l khoan vin.

qv = 0,85 . qtp = kg.

Kim tra thuc n theo mc y ca l khoan ph:

1d ( Kd.1phTrong :

lph: Chiu di l khoan ph

ld: Chiu di b tr thuc trong l khoan

Kd : H s y ln nht +Tra bng sau vi db = 32 36mm:TTfkpKd

14-60,55 - 0,60

27-90,60 - 0,65

310-140,65 - 0,70

415-200,70 - 0,75

Vi l khoan t khu : h s y Kd = 0,65 0,75

Nu lng thuc tnh ton ra khng m bo iu kin v mc y th phi tin hnh tnh ton li v tng s lng l khoan. Tng chi ph thuc n cho mt ln n chnh xc;

Q = qdk.Npk+ qph.Nph + qv.Nvf. Cu to lng n.

Tu theo cch b tr cc ng thuc n trong l khoan, ngi ta chia ra cc loi:

Dng hnh tr (dng ct) (a): cc gi thuc c b tr st cnh nhau. Dng lm (b): C u im nng cao hiu qu n ph, c bit trong cng. Dng phn on (c): thng b tr cho cc l n vin, khong cch gia cc on thng thng l 5 30cm.

1: ng thuc n3. Nt

2. Kp n

4. Hnh lm

5. Khong trngVt liu nt mn: nt mn c nh hng nhiu n hiu qu n ph, chiu du nt mn thng t l thun vi ng knh ng thuc (vi cc ng thuc loi 40-42mm th chiu du nt khong 0,6 0,8m. Thng thng ngi ta s dng t st trn ct t l 1:4, hin nay cn s dng cc loi nt mn tylen dng ti nc loi ny theo thng k to ra hiu qu n ph ln hn t st trn ct.

g. Xc nh thi gian khoan v bc d t .

Thi gian khoan: gm nh du l khoan, th my khoan, di chuyn my, khoan cc l, lm sch l khoan

(h)

- N: s lng l khoan trn gng

- l: Chiu di trung bnh l khoan (m)

- m: S lng my khoan ng thi lm vic trn gng.

- Vk: Tc khoan (m/h). Thi gian bc d t :

Cng thc tnh ton :

tbd = (h)

Trong :

V= : khi lng t cn bc d trong mt chu k sau khi khoan n - m3

+ w: H s ti ca t sau khi n, thng ly = 1,11 1,15

+ KN: H s tnh n s thay i tit din gng o sau khi n (h s tha tit din): i vi tit din gng ln v trung bnh: KN=1,1-1,15; tit din gng nh KN = 1,15-1,25.

+ S: Din tch gng o (m2)

+ l: Chiu di mt bc o (m)

+ : H s phi hp (theo thi gian kt hp gia khoan v vn chuyn t )- thng ly = 1 khi khoan v my bc d thng l cc my c lp.

+ nbd: S lng my bc d ng thi lm vic trn gng.

p- Nng xut bc d (m3/ h).

h. Lp biu chu k khoan n.

Thnh phn cng vic ca mt chu k khoan n g:

1. Cng tc chun b: nh du l khoan, di chuyn v nh v thit b khoan, thi gian ca cng tc ny k hiu l t1 = 0,4 0,6h.

2. Khoan cc l khoan (tk)

3. Thu dn thit b- ly theo nh mc

4. Np thuc v tin hnh n (t2 = 0,04 n 0,08h cho mi l khoan)

5. Thng gi ti gng o, t3 = 0,3 0,5h

6. Kim tra gng v a gng v trng thi an ton, t4=0,2 0,5h.

7. Bc xc v vn chuyn t , tbd8. Chng tm.

Thi gian ca mt chu k ; Tck = t1 + t2 + t3 + t4 + tbd+ tct + tkTrong :

t1 : Cng tc chun b (nh du l khoan, di chuyn v t thit b.

t2 : Thi gian np thuc v n.

t3 : Thi gian thng gi.

t4 : Thi gian kim tra v a gng v trng thi an ton.

tk : Thi gian khoan

tbd :Thi gian bc d tct :Thi gian chng tmtph :Thi gian d phng

Biu chu k khoan n.

TTCc cng vicKhi lngThi gian (h)Thi gian 1 kp

123456

1

2

3

4

5

6

7

8Cng vic chun b

Khoan

Np thuc v n

Thng gi

Kim tra gng

Bc d t

Khoan,cm neo

Phun b tng303,75m

135 (l)

164,2m3

26 (neo)

2.5 m3

i. Tc o hm.

S b xc n theo cng thc:

U = .l.n

: H s s dng l khoan.

l: Chiu di l khoan

n: S chu k trong 1 ngy hoc thng.

j. nh gi hiu qu ca cng tc khoan n.Cc ch tiu nh gi: H s s dng l khoan, h s tit din, vng nh nht ca t , mc p vn.- H s s dng l khoan:

+ llk: Chiu di l khoan (m)

+ lhq: Chiu di l khoan hiu qu (thc t) (m).

Trong thit k thng ly lk= 0,8 0,9. tng hiu qu s dng l khoan ngi ta s dng thuc n dng lm y l, vic ny c th lm t lk= 1 1,1.

- H s tha tit din:

c nh gia thng qua cc h s: H s tha tit din , h s khng ph ht 1, h s khng trn chu 2:

;

;

+ Stc: Din tch tit din thi cng (yu cu)

+ Stmax: Din tch tit din thc t (k n phn ph tha thm)

+ Stmin: Din tch tit din thc t (k n phn cha ph ht)

- t vng xa v p vn nh: y l yu t nh hng ln n cng tc bc d v vn chuyn t .

+ t vng xa khi gng hm s lm tng thi gian dn ng bc d, ngoi ra n cn nh hng n cc yu t khc: cn ch vic i li ca cc my mc khc, tc rnh thot nc, hng ng thng gi v cc thit b khc trong hm gim vng xa ca t ngi ta thng s dng cc dng l moi p vn.

+ Mc vn nt lm nh hng n nng xut bc d v vn chuyn.

1.3. o ng hang bng my o.

Khi thi cng mt cng trnh hm xuyn ni, a s cc trng hp v hu ht cc cng on thi cng u c thc hin trong cng. Tuy nhin do c th v a kin to nn a hnh v a cht cc khu vc ny thay i rt phc tp. V vy, lun xut hin nhng on, khu vc hm i qua vng a cht mm yu. Trong nhng on nh th khng th s dng phng php n ph mn c m phi s dng phng php o hang bng cc thit b o t thng thng nh: th cng, my o dng gu1.4. bc xc v vn chuyn t .

1.4.1. Bc xc t .

a. Cc loi thit b bc xc t :

- C th chia ra 2 loi ch yu : bc d th cng - bn c gii (cng sut thp, khng s dng hin nay) v bc d c gii ho.

- Cc thit b bc d c gii gm c: my bc d, my xc v thit b cp t .

- My bc d t c th phn chia ra cc loi:

+ Theo nng lng cung cp: my in, my hi p.

+ Theo hnh thc di chuyn: bnh xch, bnh lp, di chuyn trn ray.

+ Theo nguyn l tc dng: my bc d lin tc, my bc d chu k, my bc d hn hp

+ My bc d chu k:

My bc d kiu gu lt

+ My bc d lin tc:

+ Thit b co t :

b. Tnh nng sut bc xc t :

Nng sut bc d t ph thuc vo nhiu yu t, c th:

- Cht lng ca cng tc khoan n: mc vn nt u, mc vng xa ca t .

- La chn phng thc vn chuyn v cch t chc sn xut : phng tin vn chuyn, b tr ng di chuyn, tc thay i cc phng tin ra v vo ly t . Thc t cho thy, thi gian vn chuyn t chim ti 35-60% tng thi gian bc d vn chuyn.

- Tay ngh cng nhn v kh nng ca cc thit b thi cng.b.1. Nng sut bc d ca my chu k:

Nng sut bc d t trc tip:

V: lng t cn bc d trong 1 chu k (m3)

V= : khi lng t cn bc d trong mt chu k sau khi khoan n - m3

+ w: H s ti ca t sau khi n, thng ly = 1,11 1,15

+ KN: H s tnh n s thay i tit din gng o sau khi n (h s tha tit din): i vi tit din gng ln v trung bnh: KN=1,1-1,15; tit din gng nh KN = 1,15-1,25.

+ S: Din tch gng o (m2)

+ l: Chiu di mt bc o (m)T2: thi gian bc d t trc tip bng my

T2= TI + TII + TIII + TIV .

+ TI : thi gian bc d t bay vng trn gng o sau khi n;

(pht)

- : phn t vng ra sau khi n (thng ly = 15-20%V)

- t1: thi gian mt chu k lm vic ca my bc d t bay vng (=0,3 0,4 pht, tu tng loi my c th)

- ko: H s ti ca t sau khi n

+ TII : thi gian bc d phn t chnh;

(pht)

- : phn t fi bc d, p v bng tay (10-15%V)

- q: th tch gu (m3)

- q: H s y gu, khi t p vn 100mm q= 0,75-0,8.

- t: thi gian ca 1 chu k bc d t trong iu kin bnh thng (0,15 0,25pht).

+ TIII : thi gian ngng tr do vn chuyn trong khi bc d t (thi gian thay th gong hoc xe).

(pht)

- t2: thi gian dng my thay i thng vn chuyn

- v: h s y ca thng vn chuyn (0,95 1).

- v: th tch ca thng vn chuyn (m3).+ TIV : thi gian dn t bng th cng.

(pht)

- n: s ngi lm vic.- p: nh mc dn t , xc vo phng tin vn chuyn 1m3 t :b.2. Nng sut ca my bc d lin tc (co v):

+ Tin hnh bc d t bng my bc d lin tc (co v)

Nng sut k thut ca my c tnh theo cng thc:

P = z.n.Vtg (m3/pht)

Trong :

z : l s thanh gt , thng z = 2 thanh

n : s lng bc ca mi thanh gt trong mt pht , vi t nng

n = 20 -:- 25 , vi nh : n = 30 .

Vtg : khi lng t cho mi bc ca thanh gt (m3)

Vtg c tnh theo cng thc : (m3)

Trong :

B : l chiu rng bn (m)dt : khong cch gia cc qu o ca thanh gt , c th ly dt = d , vi d l ng tnh ca a ch .

hdd : Chiu cao trung bnh ca lp t d c co

vi t cng : hdd = (1,2 1,5).htg

vi t mm : hdd = (0,7 1,0).htg

ta c htg = (1/3 1/4 ).d (m)

Cc thng s ca my bc kiu lin tc

Nng sut khai thc ca my bc d c xc nh theo cng thc :

Trong : V: Ton b khi lng t cn dn m3.

: H s k n s ngng tr ca my, = 1,12.

T1: Thi gian bc d khi lng chnh,

Vi : : Phn t cn dn bng tay, ly bng 10%.

Ko : H s ti ca sau khi n, ko = 1.

Kp : H s ti ca khi bc d, kp = 1,12.

Pt : Nng sut k thut ca my bc d, m3/pht.

T2: Thi gian cn thit bc d t ti chn tng v p dn vo gng o,

Vi : H s k n s gim nng sut, ph thuc vo mc bng phng ca nn, coi nn phng th = 0,25.

T3 : Thi gian ngng tr do vn chuyn

Vi: t2 : thi gian dng my do vn chuyn

H s y thng xe, = 0,95

v : Th tch thng m31.4.2. Vn chuyn t .

a. Vn chuyn trong ng o ngang:

a.1.Cc phng tin vn chuyn trn ray:

Thng l cc loi gong chy trn ray c u my chy bng in, iezen hoc ti trn ray.

- Gong:

Theo cu to c th chia gong ra cc loi: gong c nh, gong lt,

Thng thng th tch ca gong 0,4 - 8m3, c th la chn loi gong theo th tch v nng sut ca gu xc:

+ Khi th tch gu xc v=0,2m3 th nn chn gong c VG2m3

- ng ray: + C ly cc ray thng thng l 600 750mm, khong cch nh nht gia hai trc ng l 1200mm vi ng kh 600 v 1500mm i vi ng kh 750mm.

+ Vic thay i gong nh hng rt ln n nng sut bc d v vn chuyn t . V vy trong ng hang ch b tr c 1 ng gong th c 60 100m phi b tr mt on trnh di 23-30m. Khi tit dn ng o ln nn b tr hai ng gong i v v.

+ Khi s dngcc thit b bc d t chy trn ray cn phi s dngcc loi ray tm c chiu di 2-4m m bo my bc d c th tip cn c st gng o, sau khi chiu di t ray chnh s thay th.

+ u ko: in, iezen, ti ko (tham kho ti liu)

- B tr ng ray vn chuyn trong hang:

(tham kho Ti liu Thy Trng)a.2.Cc phng tin vn chuyn khng dng ray:

b. Vn chuyn trong ng o xin v ging ng:

1.5. thng gi trong thi cng hm.

1.5.1. Mc ch ca thng gi trong thi cng v cc s thng gi.

a. Mc ch ca thng gi:

b. Cc s thng gi:

- S p (y):- S ht :

- S hn hp:

1.5.2. Tnh ton thng gi trong thi cng hm.

Lng khng kh c cung cp khi thng gi cho cc ng hm s khng c nh hn 3 m3 kh sch/ pht/ ngi.

H thng thng gi phi m bo rng tc khng kh trung bnh ti khu vc thi cng ln nht khng nh hn 0,15 m/giy. H thng thng gi phi m bo c hai yu cu khi lng kh sch nu di y c tho mn ta mi thi im:

3 m3/pht cho mt ngi hoc mt cng nhn lm vic trong hm.

6,5 m3/pht i vi mi KW ng c Diesel ca thit b hoc ng c lm vic trong hm.

Cc khi lng khng kh cn thit nu trn s c tnh cng dn li v tnh vi gi tr ln nht ca s ngi hoc thit b s dng ng c Diesel lm vic trong hm ti mt thi im bt k, khi lng khng kh cn thit s c s dng trong tnh ton thng gi ca Nh thu.

Cc s thng gi c s dng c th l s thng gi ht, s thng gi y, hoc s thng gi kt hp (ht - y). a. Tnh lu lng khng kh cn thit cung cp ti gng hm.

Lu lng khng kh cn thit cung cp ti gng hm (Q) c tnh trn c s cc yu t sau:

Theo lng ngi ti a trong hm .

Theo tc khng kh ti thiu dc hang

Theo lng kh c thi cng trong qua trnh n mn.

Theo lng bi c hi do hn in , do ng c t trong v do c thit b khc.

- Theo s ngi lm vic ng thi trong hm:

Cng thc tnh ton :

Q1=qn.N m3/pht

Trong :

qn: l lng cp kh tiu chun cho 1 ngi

theo quy trnh ta c :qn >= 3 m3/pht

N : l s lng ngi ti a c mt trong hm khi thi cng

- Theo tc khng kh ti thiu trong ng hm:

Cng thc tnh ton :

Q1=Vmin.S m3/pht

Trong :

Vmin: l tc gi ti thiu trong hm

Theo quy trnh Vmin = 0,15 m/s = 9 m/pht.

S : l din tch tit din gng o m2- Theo lng thuc n trong mt chu k:

Cng thc tnh ton :

m3/pht

Trong :

QTN: l lng thuc n chi ph cho mt ln n khi thi cng (kg)

S : l din tch tit din gng o (m2)t : l thi gian thng gi (pht).

- Theo tng cng sut ca cc thit b s dng ng c Diezen (ch tnh cho thit b ang hot ng - di chuyn):

Cng thc tnh ton :

Q1=K.qi. m3/pht

Trong :

n: l s lng my ng thi lm vic trong hm khi thi cng

qi : l khi lng kh thi do mt ngun (mt my) to kh c thi ra .

qi = W.k (m3/ph)

Vi: k: lng kh c n v (m3/ph.1KW)k ( 6,5 m3/pht cho 1 KW ng c diezen

k ( 7,8 m3/pht cho 1 KW ng c xngW: Cng sut ca ng c (KW)K : l h s hiu chnh c ly theo s my lm vic

Khi n = 1 ta c K = 1

Khi n =2 ta c K = 0,9

Khi n = 3 ta c K = 0,85

So snh Q1, Q2, Q3, Q4 ta ly lu lng khng kh ln nht tnh ton chn qut gi.

Tnh lu lng cn thit m qut gi phi m bo:

Qq = Q x (y y: Q - lu lng khng kh cn thit cp ti cho gng hm (m3/pht);

(y - h s xt n tn tht gi dc theo chiu di ng gi, c tnh theo cng thc:

Trong : R - sc cn khng kh ca ng gi,

Vi: : H s sc cn khng kh ca ng (ly theo bng)

d: ng knh ng thng gi (mm)

m: Chiu di mt t ng thng gi (mm)

k: H s ni ng n v;

Ni cht lng tt: k = 0,0005

Ni t yu cu : k = 0,002

Ni khng tt: k =0,005

Tnh p lc cn thit ca qut.

p lc cn thit ca qut:

H = 10.R.(Qq)2Trong :

R - sc cn khng kh ca ng gi

Qq - Lu lng gi qua hm, m3/s

1.5.3. Thit b thng gi trong thi cng hm.

(Tham kho cc ti liu)1.6. Chng bi, thot nc v chiu sng trong thi cng hm.

1.6.1. Chng bi trong thi cng ng hm.

C th chia ra hai loi bi trong qu trnh thi cng: bi nguyn sinh v bi th sinh.

+ Bi nguyn sinh: do cc cng on c bn ca qu trnh o khoan l mn, phun b tng, bc d t , )

+ Bi th sinh: do cc ngun nh giao thng i li, sng n mn lm cc bi to ra trc bay ln vo trong khng kh.

Tt c cc loi bi trong khng kh c bit n l nh hng rt ln n sc kho con ngi, n gy ra cc bnh nguy him cho ngi lao ng lm vic cho con ngi.

Cc quy nh v lng bi cho php tham kho trong ti liu.

Cc phng php chng bi:

+ Kh bi bng nc; bng khng kh v cht lng; tch bi bng phng php kh.

+ Kh bi bng thu lc : s dng cho cc l khoan

+ Khi bc d s dng cc kim phun nc.

+ Khi n mn: s dng cc mn chn bng cch phun nc qua cc kim phun t xung quanh chu vi hang o.

+ Chng bi do giao thng i li ngi ta s dng cch phun nc ti ng thng xuyn.

1.6.2. Thot nc trong thi cng ng hm.

Cc ngun nc cn phi thot i trong qu trnh thi cng hm c th phn chia nh sau:

- Nc nh git t nc v vch hang (lu lng