I. Loi s~tcua nam chiimdi~n; 2 LO xo; 3.Thanh SQC;
p= Gig e «/ y bien dQ rung (m)
y- bien dQ rung (m)
n- v~ t6c quay CllatlVc I~ch tam ( vong/philt) G- trQng Iuqng kh6i I~ch tam (N)
g- gia t6c trQng wang
0)-gia t6c Clla kh5i I~ch tam (IIs)
e- dQ I~ch tam (m) 7.2.6. ThU!'tbi khoan cQc nhoi
1. Khai quat v@thi cong cqc khoan nhAi:
Cong ngh~ khoan CQCnh6i be tong c5t thep dUQc (mg d\Ulg rQng rai d~ xu Iy n~n mong tren n~n dAt y~u cho cac cong trinh dan d\Ulg va cong nghi~p, la mQt trong nhUng giro phap mong duQC ap d\Ulg rQng rai trong xay d\fDg nha cao tAnga tren th~ giOi va a
Vi~t Nam. ChUng thuang dUQc thi~t k~ d~ mang tai Ian nen chAt Iuqng cua CQCluon luon la van d~ dUQc quan tam nhAt. Khau quan trQng nhAt d~ quy~t dinh chAt Iuqng cua CQCla khau thi cong, no bao g6m ca kY th~t, thi~t bi, nling l\fc cua dan vi thi cong, S\f nghiem ruc th\fc hien qui trinh cong ngh~ ch~t che, kinh nghi~m xu Iy khi g~p cac tmang hqp C\I th~.
May khoan CQCnh6i la mQt 10(limay xay d\fDg dUng d~ t(lO 16 CQCnh6i trong cong ngh~ thi cong CQCnh6i be tong hay Vlia xi mling (wc la lAy dAt len kh6i n~n d~ hinh thanh h5 dao) bfulg phuang phiip khoan.
Nguyen Iy gia c5 n~n mong b~ng CQCnh6i la vi~c t(lo ra 16 CQCtrong n~n dAt sau do rot lr\fc tiep v~t li~u (be tong, be tong c6t thep) vao 16 do d~ t(lOthanh CQC.Nhu v~y vi~c lam CQCngay t(li cong trinh khong pMi mAt cong v~ chuy~n CQCtu noi khiic tOi do t6n kern khau v~ chuy~n. Han nfta CQC dUQc ch~ t(lO vt'ra dUng vOi dQ sau cAn dong, di~u nay lam giam bOt chi phi cua ciit ho~c n6i CQC.
nh6i kieu thimg dao bao g6m h~ thdng cAn (1r\1c)khoan va dAu mill khoan (thimg khoan). Toan b{ih~ thdng nay thuemg dugc I~p vao cAn 1r\1cbanh xich I$lg khoang (30-80)T,De quay cAn khoan thuemg dugc dimg bAng d{ing co thuy hrc. cAn khoan lam bAng thep g6in 3 den 5 do~ 16ng vao nhau nhu c{it ang ten, chiSu dai cAn tir khoang til 12m den 18m. Khi khoan cac do~ phia trong cAn tg tho ra cho d~n khi ra h~t cit ca cae do~, chiSu sau khoan . khoilng tir (30-64)m. Thimg khoan c6 hinh d~g thimg phuy vm duemg kinh cac lo~ phd bi~n tir 600 mID d~n 2.500 mID.
Khi lam vi~c, thimg khoan xoay tron theo cAn khoan nha ngu6n d{ing 19c til d{ing co tMy 19c d~t tren mam khoan 7. Khi thimg khoan xoay tron thi d~t dugcc~t,nh6i dAy vao thimg dao va ti~n sau vao trong long d~t nha cAn khoan 6. Sau d6 d~t trong thimg diIo dugc dua len cimg v6'i thimg dao nha vi~c rut cAn khoan len. CU ti~p t\lcnhu v~y may khoan lam vi~c cho tm khi hoan thanh 16 de ph\lC V\l cho cong tac dd CQCnh6i.
Cac IO(li may khoan CQCnh6i dimg t(li Vi~t Nam cM y~t la Clla cac hang HITACHI, NIPON, SUMITOMO v.v. do NMt Biln san x~t. .
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Hinh 7.6: May khoan CQCnh6i dllllg khoan thimg 1. May ca So'; 2. Cap cAn; 3. cAn; 4. Puly ddu cAn; 5. Moc treo; 6. cAn khoan; 7. Mfun khoan; 8. Thimg khoan
2. Phan IO\li may khoan C4}CnhAi - May khoan xoAn ru{it ga
- May khoaD CQCnh6i kieu thimg dao
- May khoan CQCnh6i kieu bom philn tuAn hoan - May khoan tuAn hoan
7.2.7. Tinh nang suat cua bua dong CQC
*Cong suit cua bua diezen
P=A.n/(IOOO . 60) (KW) (7.3)
A- nang lugng wi cua bUa (N.m)
n- sA IAnrai cua bUa trong mQt pMt (lAnJpMt) *Cong suat bila rung
p,= p:y.n/(lOOO . 60) (KW) Trong do: p- l\fc ray rung (N)
p= Gig.e.(f/ y- bien dQ rung (m)
n- v~ tAc quay CllatlVc l~ch tam ( vong/pMt) G- trQng lugng k1iAiI~ch tarn (N)
g- gia tAc trQng truimg
Ol- gia tAc CllakhAi l~ch tarn(lIs)
e- dQ l~ch tam (m)
7.3. MAy EP CQC vA.MAY CAM BAc THAM
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7.3.1. May tip cQc
1.Uu nhU'Clcdiim va ph\lm vi sil d\lng: a. Uu diim:
- Miiy ep CQCdirng l\fc tiOOd6 nen CQCvilOnen nen khong gay chful dQng;
- Khong gay 6n ao, h~ ch~ OOiing anh huimg xfru d~n cac cong triOO Ian c~ duqc xay d\fng truac;
- Suc chiu tai cao do dfrt xung quanh CQCbi nen ch~t do ep CQC; - TAc dQ thi cong OOanhdo CQCduqc duc sfuI;
- Kha nang ki6m tra chfrt lugng tAt h(Jll: tUng do~ CQCduqc ep thir duai l\fc ep va ta xac diOOduqc suc chiu tai Clla CQCqua l\fc ep cuAi cung.
b. Nhll'lc diim:
- Khong thi cong duqc CQCco suc chiu tai Ian ho~c lap dfrt xfru CQCphai xuyen qua qua day
- ThOi gian thi cong dai, chieu sau ep 006, phai sir d\lIlg cac may khac d6 ph\lc V\I may ep OOucAn tf\lC t\f hanh, may bam thuy l\fc.
2. Ph\lm vi sil d\lng:
- May thich hqp d6 thi cong CQCtron, CQCvuong, CQCchit H ho~c cac lOiiliCQCki6u khac vm cac IOiilidia chfrt OOudfrt set thong thuimg, dfrt y~u, dfrt cat. DQ dai Clla CQCkhong bi h~ ch~, d~c bi~t dAi vm OOiingkhu V\fCda voi co tAng dllt pM khong day ho~c OOiing virng ven bi6n co tAng chiu l\fc tu(Jllg dAi sau;
- Khi thi cong khong gay ti~ng 6n, khong gay 0 nhiem nen thich hqp sir d\lIlg thi cong trong khu V\fCthanh thi.
- Khi thi cong khong gay chful dQng nen cho phep thi cong trong OOiing khu V\fCco quy diOOve chful dQng OOukhu V\ICgdn OOiingtoa OOacu, OOiingtoa OOaco d\lng C\l thiet bi d~c bi~t, ven song, duimg s~t, diu vuqt ...
3. ciu t\lOva qua trinbtip cf}c: