Thpng tin khoa hpc cong nghe mo
\4JGHIEN CI)U LU'A CHON GIAI PHAP DAM BAO ON DjNH CHO ztfma nan no THfiN t>EO Nfii
Recently, in the coal mining process, at the South slope of Deo Nai coal mine, there have the failure phenomena.
Basing on the determined reasons causing failures, the researchers have selected the solutions for ensuring the stability at the South slope to the level of -345m as its scheduled design
TS L U U V A N T H I / C KS. Le XUAN THU ThS D6 KI^N CLJ'6'NG Vi$n Khoa hoc Cdng ngh$ M6 - Vinacomin
Bien tap: KS. Ph^m D$i Hai
Bd try Nam, md than Deo Nai, trong qud trinh khai thdc, nhieu ndm dd lien tyc xdy ra trugl Id.
Tren eo sd nguyen nhan tnj-gt da duge xdc tSnh, tien hdnh nghien ciru lya chpn giai phdp dam bao I n djnh cho bd try khai thdc den k i t thue -345m theo thiet k l .
Cdc k i t qua nghien ciru trudc day ve on d\nh cua bd md Deo Nai da xdc dmh nguyen nhan gdy trugt Id cua bd try Nam, md than Deo Nai.
Theo dd, vigc trugt Id cua bd try Nam dugc quylt djnh bdi cde y l u t l ty nhien vd cdng nghe, nhu c l u triic dja tang, tinh ehIt b i n , dae tinh ehira nudc vd tdng tru nudc nglm cung nhu luu thdng nudc trong dja t i n g [1 ], [2]. Cdc thdng s6 cua hg thong khai thdc, nhu chilu cao bdm try lien tyc vugt qua chilu cao I n djnh gidi han cho phep.
Bd try Nam dugc c l u tgo bdi cae Idp da elm vdo khdng gian khai thdc vdi gdc doc tir 25-^35°, trong dja ting t i n tgi ede mat giam y l u t y nhien theo tilp xiie Idp vdi dp ben rat thap (C'=0,017 MPa; cp=17.0°), nudc nglm cd mgt trong dia tang dudi dgng khdng dp, h l u nhu khdng dugc hg thap trong qud trinh khai thdc xuong sau, khi do, chilu cao I n djnh gidi han khi cat tang theo mgt Idp (a = p) H £ 120m. De nang eao on djnh cho bd try cd t h i lya chpn dp dyng mot s l gidi phdp chu ylu sau:
1. Gia cudng khdi dd bdng be tong phun Be tdng phun dugc su- dyng rpng rai d l nang cap I n djnh cdc bd doc, tudng cdc h i ddo sdu vd cac cdng trinh nglm.
Bd tdng phun sir dyng chu y l u d l tdng mu-c dp on d^nh cho cdc mat Ip dd, be mat dd nirt ne n l u khdng dugc xir ly b l mgt 10 dd ed t h i bj hu hgi dudi ede dieu kign biln d l i do udt vd khd.
Be tdng phun cOng cd hieu qua doi vdi dit, edt vd dd dam rdi rac.
Be tdng phun dgc bigt ed hieu qud d l nang cao on djnh d cae cdng trinh nglm, thudng kit hgp vdi ludi thep vd khi c l n thiet, kit hgp vdi khung thep nhe; nd Id vgt ligu eo ban trong thi edng dudng ham Ao kilu mdi. Hg thing do be tdng phun duy tri sy tiep xue chat che vdi mat dd vd cung giam sy djch chuyin eiia dd d i n mire dp nhd nhit. Cd hai phuong phdp phun be tdng, phun khd vd phun udt.
2. Gia c u v n g khdi da va cac mgt y l u bang giai phap xi mang hoa sau
Xi mdng hod sau Id bom phyt dung djch xi mang lap day cde lo rdng, khe nut eua d i t dd.
Dudi dp lye bom phyt nhat dinh, thdng qua ede lo khoan hay gieng dirng nham tang cudng dp bin, kha ndng ehju tdi vd ngdn chan ddng ngam, nang cao dp on djnh eho bd md, giam hg so tham nude cua dat dd phan bo sau trong dja tang.
3. Gia cud'ng mai d i e bdng neo Vigc diing neo de dam bao on djnh eua mai doc da mdi hoac da cd vd cdc ho dao nglm trong dd dd dugc thilt lap tot cho hau hit cde loai dd. Tuy theo hoan canh quy djnh, cdc neo cd t h i disac diing lam phuong tien rieng d l tao on djnh hogc ehung sir dyng phli hgp vdi cdc dang gia c l khdc nhu be tdng phun, xd thep, k i t c l u giu bdng be tdng.
Cdc kilu phd hoai chinh phai k l d i n trong mdi doc vd cdt da dugc the hign tren hinh 1. Cac eo c h l sau day cd t h i dugc ghi nhgn, don le hoae phoi hgp:
- Pha hogi theo mat tilp xiic dd y l u ; - Phd hogi djnh trudc dgc theo mgt hogc
KHCNM S 6 2/2015* DIA CO MO
Thong tin khoa hpc cong nghe m d
Phan IIJC phdp tuyfr
a) Trt/gf diy hoic cic mit phing lOp;
b) Tnfot trin cic khe nOt;
c) Trupt trin chd dui doan hoic cic mit phing nghlOng; d) Lit; e) Ndm phi ho$i;
Hinh 1. Cic kliu phi ho^i nguyin tic trong mii ddc vi chd cit di
nhilu khe nirt;
- Phd hogi kilu nem dgc theo cae khe nirt giao nhau;
- Phd hogi dpc theo cdc c h l phan each yeu cdc viing cat hogc be mat phd hogi cd tip trudc;
- Pha hogi Igt trong dd cd cdc khe nirt an sau.
Phdn tich khli dd hoac nhO'ng viing cd khd nang khdng I n djnh cd t h i thuc hien bang cdch xem xet cdc lye ngodi tdc dgng tren khoi vd cdc vung don khi diing phdp phdn tich dOng hgc don
W = Trpng lupng kh6i
Hinh 2. Phin tich dan giin dn dinh ciJa cic mii dOc trong di
gian (hinh 2),
De chl ddn, do sau cua neo ed t h i dugc xdc djnh bing cdch diing cdc thdng so thich hgp trong cdng thCyc cua bang 1.
Trong dd:
T - Dg b i n ehju eat eua da, kN/m^;
St - Hg so an todn ve phd hoai (trong thyc t l diing gid trj tip 2-5-3),
s - Khoang cdch gitra cae neo, m;
O' - Gde ma sdt cd hieu qua di qua eae cho nirt gay trong khoi dd, dp;
Tw- Tdi trpng lam vigc tren neo, kN;
Y - Trpng lugng don vi cua dd, kN/m^;
yw - Trpng lugng don vj eua nude, kN/m^.
Kinh nghi$m thuc t l vdi cdc neo nghieng hudng xuIng trong dd cho thiy, phd hogi ehung cCing vdi b l mgt lop tren khdng xay ra d l i vdi t j s l dp manh (h/D) vugt qua 15, (h Id dg sau tinh d i n dinh cua bau neo va D la dudng kinh cua
Lo^i da
Di khflng dong nhit
Bd niPt ne kh6ng theo quy ludt oa nirt ne bj ngdp kh6ng
theo quy lu$t
Cong thOv cho d^ siu cdn Mdt neo
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Tuyin nhiiu neo
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KMCNM 5 6 2/2015* D|A CO MO
Thong tin khoa hoc cong nghe mo
CO bio v$ neo cd djnh
(a) Ki^u A (b) Kilu 8 (c) tGiu C (d) Kilu D Cic kliu neo phun vQ'a xl ming Hinh 3. Neo diin hinh trong di, khdng dinh bim trdn sudt chidu dii diy neo ti/ do b l u neo). Ooi vdi cae neo manh (h/D>15) co che
pha hogi trong da cd xu hudng cue bg d viing b l u neo. Da nirt ne bj ngdp khdng theo quy luat.
Hi$n nay d l gia co cae mdi doe, bd md ngudi ta dp dyng p h i biln hai logi neo' Neo be tdng cot thep vd neo chat deo c l t thep. Tinh chat co ban cua chiing dugc t h i hign tren hinh 3.
Khi sudn ting dugc cau tgo bdi cdc khoi da phan Idp cdm vao khdng gian khai thdc vdl gdc nghieng p = 20•^50° [3], d l dam I n dinh eho cdc cdc tang khi cat gdc doc sudn tang Idn hon gdc nghieng cua Idp at > p, ed the ap dung giai phap gia cudng sudn tang bang cpe neo be tdng elt thdp, so do b l tri cac cgc neo tren tang diyoc gidi thi§u tren hinh 4.
S O D O B O T R I C . ^ C I - W
Hinh 4. So dd bd tr! h$ thdng cic cgc neo bO tdng cdt thip gia ci/Ong suxyn ting kdt thuc
Trong trudng hgp ndy, cdc cgc neo can dugc ddt sau hgn mgt trugt thir d p (cdc mat yeu) trong ting tip 3-H5m.
Sire ehju tai cua cgc neo vd cdc thdng so neo theo Iln lugt duge tinh todn xdc djnh theo cdc c6ng thirc:
- Sire ehju tdi cua epc neo Q:
Q = RaFa + RbFb, T; (1) Trong dd:
Ra - Khdng lue cat tinh todn cua cot thep, kG/em^;
Fa - Dign tich mat cdt cua cot thep, em^;
Rb - Khdng lye cat cua be tdng, kG/cm^, Fb - Dien tich mat cat cua cpe be tdng, cm^;
- So lugng epc neo theo mat cat:
" = - ; (2) Trong dd:
AT - Lye gay truot eua khoi dd, T;
Q - Sire ehju tdi eua epc, T;
L - Chieu dai eua mgt y l u , m;
D l i vdi bd try Nam, md than Deo Nai, de dam bao on dvnh eho sudn tang bang phuong phdp neo bang cgc be tdng c l t thep, cac thdng so neo duge xdc djnh nhu sau:
- Dudng kinh lo khoan neo: DK = 230mm;
- Dudng kinh epc neo: DN = 200mm (tilt dign trdn hoac vudng);
KHCNM s d 2/2015* DIA CO MO
Thong tin khoa hoc cong nghe m d
- Chieu ddi neo: Li = 14m; L2 = 8m;
- Khoang cdch giii'a eae epc neo tren mat tang ai = 7m;
- Khodng each tir mep tang d i n hang neo thir nhat: 3m;
- Khoang each gCra eae hang neo: az = 5m.
Doi vdi cdc bd md Ip thien Viet Nam, giai phdp ndng cao on djnh bang neo ehua dugc dp dyng do chi phi Idn vd thi edng phirc tgp.
4. Phu'cng phdp d i l u k h i l n I n djnh Dam bdo dp on ^nh cho cdc bd md trong qua trinh md rpng vd ddo sdu cde md lg thien bang giai phdp dieu khien tire Id sir dyng cde gidi phdp cdng nghg d l dieu chfnh trgng thdi vd cdc thdng s l hinh hgc cua bd md trong tirng giai dogn khai thdc cy t h i , dam bao cho bd md ludn on djnh.
Trong qud trinh thilt ke khai thdc, c l n ldm rd cdc khu vye ed t h i bj biln dgng can cu vdo sy cd mgt cdc Idp dat dd y l u , cde mat y l u ty nhien nhu mat Idp, phan Idp, mat pha huy elm vao khdng gian khai thac. Trong qua trinh khai thde, trinh ty khai thde c l n tinh tdi cdc khu vyc nay Cde hao md vfa c l n duge dat trong viing dat da I n djnh Trong dilu kign cho phep cde viing cd c l u trOe mlm yeu nen dua vdo khai thac sau ciing de dam bao thdi gian ton tgi Id ngan nhat.
Trinh t y khai thdc can dugc lya chgn sao cho bd c6 djnh khdng edt chdn cde Idp dd cam vao khdng gian khai thde, tao gde doe sudn tang theo gde die mat Idp vdi chilu cao gidi hgn on djnh cho tirng khu vuc cy the.
Trong khu vye y l u , c l n tang eudng dp khai thac d l dam bdo kit thiic khai thde khi bat d i u xay ra pha biln dgng tieh cue mdi (nhu cudng dg djch ehuyin tuyen edng tdc, t i e dp xuong sau...). Khi edng tdc md t i l n g i n tdi bien gidi k i t thiic bd dirng tgm thdi, n l u dieu kidn eho phep thi khai thde theo Idp ngang va n l min tap bien bang cac Id khoan nghieng.
Trong thyc t l khai thdc, nhilu khi khdng the dipng dugc qud trinh khai thae, ma can phai khai thdc trong viing bj bien dgng, vdi toe dp biln dgng chua vugt qud toe dp biin dang gidi han, khi dd, vigc khai thae can dugc tiln hanh vdi thilt bj boe xuc cd tinh eg ddng cao, nhu may xiic thuy lye g i u ngugc, mdy xiic tai.
Vdi cac bd md cd ehilu cao Idn hon 200m va
duge eau tao bdi eae idp ddt dd cam vdo khdng gian khai thdc vdi gdc d i e p > 20°, c l n cat gde doc sudn tang bang gdc doe mat Idp (a = p).
Trinh ty dp dyng giai phap dilu khiln SLP dyng edng nghe khai thde d\xqc thyc hign theo tuan t y sau:
- Bang thye nghi$m, xdc djnh t i e dp biln dang gidi han cho phep (Vgh) cho tirng khu vyc bd md cy the.
- Thilt ke bd md cdt tang vdo tm vdi hg so dy tru on djnh n = 1,11.
- Tiln hdnh lap cdc tuyln quan trie djch dgng vd quan trac (^nh k>f, xac djnh tie dp djch chuyin cua bd V.
- Khi t i c dg djch ehuyin V > 10mm/ngdy dem vdo miia khd vd > 20 mm/ngdy dem vgo miia mua, kilm tra Igi dp I n djnh cua bd md. Neu hd so on djnh tinh todn cua bd n < 1,05 ein dilu chfnh ede thdng so hinh hpe cua tang bang cdch md rpng chieu rdng mat tang, giam chieu cao ciia ting. Tiln hdnh kiem tra dO I n djnh eua todn bd, dua bd ve trgng thdi I n djnh vdi hg s l dy tru'n = 1,10.
Ap dyng giai phap dilu khien on dinh bd mo trong qua trinh khai thdc cho phep hodn todn chu dpng dieu khiln qud trinh biln dang cua bd dam bdo khdng nhO'ng an todn eho qud trinh khai thac xuong sau ma edn cho phep giam d i n mirc it nhat khli lugng dat bde xir 1;^ ngoai gidi hgn trong ting giai doan khai thac xuIng sdu cua mo.
5. LiKa chpn giai phdp dam bao I n djnh cho b d tru Nam
Can cir vdo thilt ke khai thde vd nguyen nhan trugt Id tgi bd try Nam, bd try se khdng dam bao on djnh khi tien hdnh khai thdc bdm try lien tyc den k i t thuc -330m theo thilt k l (chilu cao bd md 450^80m; a = p = 25^33°).
Vdi c l u tn^c dia tang cua bd try Nam cho phep xem xet dp dyng gidi phdp gia eudng khli dd bdng neo be tdng e l t thep, neo irng suit trudc bing thanh neo, day neo hay neo chit deo; han che eua giai phdp nay Id chilu sdu neo bi hgn che. Hien nay, phin Idn cdc logi neo dugc che tao cd chilu dai khdng qud 10m. Vige dp dung giai phap neo dk gia cudng khli dd theo mat Idp gap phai nhimg hgn che sau: Chilu sau mat trugt tir 30+50m bi pha huy do trugt Id vdi KIIC\iMSO2/20l5*D!ACa.M6
Thong tin khoa hoc cong nghe md
chieu cao tip SO^ISOm, khdng dam bao an todn cho qua trinh thi cdng. Do vay, giai phdp neo d l i vdi bd tn,! Nam chl cho phep xem xet k i t hgp vdi giai phdp hg thip gdc d i e cua bd d nh&ng khu vyc xay ra bien dang thir c i p vdi chieu ddy khoi trugt nhd hon 5m de ehong lai qua trinh bong Idp va sir dyng epc neo be tdng cdt thep khi tien hdnh cat ting bd try d giai doan kit thiic.
Gidi phap dilu khien on djnh bdng cdng nghe khai thdc doi vdi bd tru Nam Id tinh todn dilu khiln cae thdng so hinh hpe eua bd, dua bd v l trgng thai on djnh mdi, do vgy, giai phdp ndy thudng dugc dp dyng phli hgp vdi giai phdp hg thip gdc doc eua bd.
K i t qua nghien ciru cho thay, bd try Nam, md Deo Nai hien nay dang d trong trgng thai I n djnh gidi han (n = 0,983). Qua trinh khai thdc xuong sdu d i n kit thuc -330m theo thilt k l bam tn^ lien tyc (a = p) bd try Nam cd chilu eao tip 450-^480m, khdng on djnh (hg so on dinh n = 0,68-^0,85).
Vdi eo c h l trugt Id xay ra tgi bd tm Nam, theo cae k i t qua nghien ciru da dugc thye hien, giai phap xu ly duge kiln nghj ap dyng la cat ting vao try vdi cac thdng so ting duge xdc djnh nhu sau:
Chieu cao tang: ht = 80-^150m;
Gdc doc sudn ting: at = p = 25-5-33°;
Chilu rgng mat ting: bt = 20^25m.
Uu diem cua giai phap nay la dam bao on djnh cho bd md ( n = 1,145); qua trinh thi cdng su* dyng ngay cac thilt bj khai thac cua md va cae dang cdng nghg khoan n l min, b i c xiic van tai dang duge sip dyng se eho nang suit vd higu qua cao. Qud trinh XLP ly dugc thyc hien theo trinh ty khai thac xuong sdu da duge thilt k l , do vgy, trong qua trinh xu ly, ed t h i theo doi qua trinh on djnh cua bd d l dieu khien cho phep giam khli lugng theo tinh toan.
D I SO sanh higu qua kinh t l ky thugt cua giai phap dugc lya chgn, tiln hanh tinh toan so sanh gidl phap dieu khien I n djnh bang phugng phap c l t ting vdo try theo cdc thdng sd thilt k l da dir(yc xdc djnh tren todn bd md {phuong an XCF iy 1) vdi giai phdp neo bdng epc be tdng cot thep k i t hgp cat t i n g tir eao trinh - 200 den -100m (phugng dn xCr ly 2). K i t qua tinh todn eho thiy,
vdi 2 phugng dn XLP ly duge thilt ke, dg dn tSnh eua bd tru Nam dugc dam bao vdi he s l on ^ n h n>1,10
Ve mat kinh t l , kinh phi thyc hign ciia phuong dn XLP ly 1 Id 458 ty dong, phuong dn x\> ly 2 Id 487 ty dong, do do, ve hieu qua kinh t l , kinh phi xCr ly on djnh cua bd try Nam theo phuong an XLP ly 2 Idn hon phuong dn xu ly 11d 29 ty ddng.
Tip cdc tinh todn thu dugc cho thay, phuong an XLP ly dam bao on djnh cho bd try Nam khai thdc d i n kit thuc ddy md d mire -330m bdng eat tang vdo try (phuong an XLP ly 1) khdng ehf toi uu v l mat kinh t l - ky thugt md cdng tdc thi cdng cho phep sip dyng toi da cdng nghe khai thac hien nay md dang dp dung. Ket qua thir nghiem xip ly cdng nghg cat tang vdo try dugc thyc hign tgi 2 khu vyc tai bd try Nam trong ndm 2014 da xae nhdn tinh kha thi cua giai phap XLP ly dugc lua chgn.
K i t lugn
Dk dam bao on djnh cho bd try Nam, md than Deo Nai, trong qud trinh khai thae xuong sdu d i n k i t thiic theo thilt k l (-330m), giai phap xiy ly dugc lya chgn Id giam gdc doe cua bd bdng bign phap edt tang vdo try vdi gdc doe sudn ting bdng gdc doc mgt Idp (a = p).
Trong qud trinh khai thde xuIng sau tiln hdnh quan trie djeh ddng k i t hgp tinh todn dieu khien hg so on djnh eua bd theo tirng ehdng xuIng sau 50m vdi he so I n ^ n h n =1,1, cho phep dam bdo an toan eho qud trinh khai thac vd gidm khoi lugng dat bdc xie ly d i n mirc thap nhit tgi bd tnj Nam, md than Deo Nai./.
Tai lieu tham khao:
1. Bdo cdo k i t qua {^990y'Nghien cO-u on dinh bo mo IQ thien Vi$t Nam va kidn nghi cic glai phap nang cao Sn dinh bo mo", Vien Nghien ciru Khoa hpe Ky thugt Md - Hd Npl, 2003.
2. Bdo edo tong kit d l tdi "Nghien cCru bien dang ba mo va cac bien phap dam bao on dinh bo mo 16 thien a cac mo: Deo Nai, CQC Sau, Ha Tu, Na Duong, Nui Beo va Cao Son" Vien khoa hpe Cdng nghe Md, Hd Npi,
4. B.P Beliaeb 1973"Gdn ket dat da', Nhd xuat ban Nhetdra - Matscova .
KHCNM s o 2/2015* DJA CO MO