Hdi nghi khoa hoc kT thudt md quoc te 2010 Cong nghiep md tien tiin vi su phdt trien ben vung N G H I E N C U T J A N H H l T C T N G C U A G O C D O C V i A D E N V U N G A P L U C T I T A T A I T R[.]
Trang 1Hdi nghi khoa hoc kT thudt md quoc te - 2010 Cong nghiep md tien tiin vi su phdt trien ben vung
N G H I E N C U T J A N H H l T C T N G C U A G O C D O C V i A D E N V U N G
A P L U C T I T A T A I T R U B A O V E C H O L O D O C V I A
• S • • • •
TS Dao Hong Quang
V i e n K h o a hoc C o n g nghe M o - T K V
TS R u d r a j i t M i t r a , GS Bruce Hebblewhite
T r u o n g D a i hoc N e w South Wales, Australia
K S Pham V a n H o a Cong ty T N H H M o t T V than N a m M a u - T K V
Torn tat: Bdi bdo nay trinh bay ket qua nghien cuu su dnh hudng cua gdc ddc via den su
phdn bd dp luc tua tqi tru bdo ve Id doc via khi khai thdc via than bang he thdng khai thdc cot ddi theo phuong, Id cho khau ldp tru, ha tran thu hdi than lap ndc Muc dich cua nghien ciru nay Id so sanh sir khdc biet ve sir phdn bo dp luc tua tqi tru bdo ve Id doc via khi khai thdc cdc via cd gdc ddc via khdc nhau Kit qua cua nghien cuu se giup cdc nhd thiet ke md trong viec xac dinh chieu rong cua tru bdo ve, dam bdo Id doc via van tdi cua tdng tren cd the duy tri de lam Id doc via thdng gid cho tdng tiep theo trong qua trinh khai thdc
1 Dat van de
T r u bao ve giua 16 cho va 16 doc via dong vai tro rat quan t r o n g trong viec dam bao
an toan va hieu qua khai thac T r u bao ve giua g u o n g 16 cho va 16 doc v i a van tai duoc tao
ra nham muc dich duy t r i o n d i n h 16 doc via van tai trong suot t h o i gian t o n tai tir 16 doc via cua tang tren, sau do la 16 doc v i a thong gio N g o a i ra, t r u bao ve cung duoc dung de each ly anh h u o n g cua g u o n g khai thac hien tai den g u o n g khai thac trong t u o n g l a i , giam thieu nhung r u i ro ve nuoc, k h i
Cac nghien c u u l y thuyet va thuc nghiem deu chi ra rang viec khai thac l a m thay doi trang thai ap luc cua dat da va tao ra cac v u n g ap luc bao quanh k h u vuc khai thac N h u n g vung ap lire do la ket qua true tiep cua su thay d o i trang thai u n g suat lien sat guong khai thac K i n h nghiem thuc te cho thay 16 chuan b i neu duoc bo t r i trong k h u vuc ap luc tua Ion nhat thuong k e m on d i n h h o n k h i nam trong k h u vuc khac D o do cac d u o n g 16 chuan
bi khi thiet ke t h u o n g duoc bo t r i nam ngoai v i i n g anh h u o n g cua v u n g ap luc tua 16n nhat Rat nhieu nha khoa hoc tren the g i o i da nghien c u u su phan bo ap luc tua tai tru bao ve 16 doc via van tai T u y nhien, nhung nghien ciru thiet ke chieu rong t r u bao ve truoc day chu yeu tap trung ap dung cho cac v i a bang Su anh h u o n g ciia goc doc v i a den su phan bo ap luc tua Ion nhat tai t r u bao ve chua duoc nghien ciru chi tiet D o do, viec nghien c u u su anh huong cua goc doc v i a den su bien dong ciia ap luc tua tai t r u bao ve 16 doc v i a trong qua trinh khai thac v i a day doc la rat can thiet nham ho t r o cho cong tac thiet ke
Bai bao nay t r i n h bay ket qua nghien c u u su anh h u o n g cua goc doc v i a den su phan
bo ap luc tua tai t r u bao ve 16 doc via tren co so ket qua phan t i c h tren m o h i n h so K e t qua nghien c u u se ho t r o cac nha thiet ke mo lap ke hoach, thiet ke chieu r o n g t r u bao ve 16 doc via, dam bao 16 chuan b i nam ngoai viing ap luc tua I o n nhat, giup nang cao m u c do on dinh trong thoi gian t o n tai, giam thieu cong tac cung co, g i a m ty le ton that than
357
Trang 2Hpi nghi khoa hoc ki thudt md qudc ti Cdng nghiep md tien tien vi sir phdt triin
- 2010 ben virng
2 X a y d y n g m o h i n h so
M o h i n h m o phong dat da va
qua trinh khai thac duoc xay d u n g
bang phan m e m so F L A C do hang
Itasca ( M y ) [2] san xuat phuc v u
cho cong tac nghien c u u m o B o n
mo h i n h khac nhau m o phong cac
via than co cac goc doc t u o n g u n g
la 0°, 15°, 30° va 4 5 ° M o i m o h i n h
bieu dien g o m 1 v i a than co chieu
day 6,0m va cac l o p dat da vach va
tru via Chieu cao k h a i thac ciia
lop tru gia d i n h la 3,0m, lop than
noc phia tren (3,0m) duoc t h u h o i
ciing v o i qua t r i n h k h a i thac
L o cho xay d u n g tren m o
hinh so sir dung he thong khai thac
v o i 1 16 doc v i a thong gio va 1 16
doc v i a van tai V i t r i 16 cho m o phong duoc xay dung tai k h u v u c pha hoa ma 6 v i tri do, dat da tai luong pha hoa da sap do hoan toan, va cac v u n g ap luc x u n g quanh guong khai thac da t r o ve trang thai on d i n h So do v i t r i xay dung m o h i n h so hoa sir dung phan mem
F L A C the hien tren h i n h 1
B e m o phong v i a than, da vach va da t r u trong m o h i n h so, bon loai vat lieu khac nhau da duoc xay d u n g L o a i vat lieu bien dang deo (Strain-Softening) duoc dung de the hien via than nham the hien cac trang thai bien dang khac nhau t r o n g qua t r i n h chiu ap luc Loai vat lieu dan h o i deo tuyen t i n h ( M o h r - C o u l o m b ) duoc dung de the hien dat da vach va tru v i a than N h i r n g k h u vuc nam xa h o n duoc the hien bang dan h o i deo (Elastic) Loai vat lieu bien dang dan h o i ( B o u b l e yield) duoc dung de the hien dat da pha hoa trong vung sap
do, n o i ma the t i c h g i a m k h i xuat hien ap luc nen
B e m o h i n h m o phong t u o n g t u n h u dieu k i e n dia chat k y thuat m o thuc te, cac gia tri cuong do khang nen cua than va da trong phong t h i nghiem duoc h i e u c h i n h theo huong giam k h i t i n h them m u c do nut ne trong trang thai nguyen k h o i C u o n g do khang nen cua than va dat da duoc hieu c h i n h de dam bao sao cho buoc sap do ban dau cua guong khai thac duoc gia d i n h se la 10-15 m K h o a n g each sap do nay duoc chon theo k i n h nghiem thuc te k h i khai thac cac 16 cho tai cac m o than h a m 16 v i m g Quang N i n h , V i e t N a m Mot
so t i n h chat co l y khac cua dat da n h u trong l u o n g the tich, m o d u n dan h o i , goc n o i ma sat cua than va vach t r u v i a duoc lay n h u cac loai dat da co dieu k i e n t u o n g t u viing Quang
N i n h B e so sanh, t i n h chat co l y da, ap luc ban dau trong 4 m o h i n h so duoc giir nguyen khong thay d o i v o i chieu sau khai thac trung b i n h la 6 0 0 m A p luc thang d i i n g duoc xac dinh theo cong thiic (1), ap luc ngang duoc thay d o i de phan t i c h m i i c do anh huong den vung ap luc tua 16n nhat
o-v = p.g.H (1)
Chain pillar Cross section modelled in FLAC analysis
Gate roadway will be driven
liinh 1 So" do chi vi tri xdy dung md hinh sd
sir dung phdn mem FLAC
Trang 3Hdi nghi khoa hoc ki thudt mo quoc te - 2010 Cong nghiep md tien tien vi sir phat trien ben vimg
T r o n g do:
o \ - A p lire thang dung;
H - Chieu sau khai thac;
p - T r o n g l u o n g the tich ciia than/da
Qua trinh khai thac guong 16 cho duoc mo phong bang each xoa lan luot 2 m chieu dai theo huong doc, chieu cao 3.0 m tai lop tru cua v i a than theo huong tir 16 doc via thong gio xuong 16 doc via van tai Tong chieu dai tien guong cua 16 cho trong 4 m o hinh deu la 100m Qua trinh sap do than l o p noc va da vach duoc xay d u n g dua tren tieu chuan miic do yeu va do v o cua loai vat lieu dan h o i deo tuyen t i n h ( M o h r - C o u l o m b ) , t u o n g tir n h u phuong phap sir dung trong nghien ciru cua n h o m tac gia Hebblewhite va nnk [ 3 ] Sau m o i buoc tien ciia g u o n g khai thac (2 m chieu dai), trang thai bien dang cua tat ca cac v u n g thuoc k h u vuc than l o p noc va lop da vach phia tren g u o n g 16 cho deu duoc k i e m tra Bat
ky khu vuc nao dat trang thai m o i hoac do v o , no se duoc x e m la sap do, va trang thai l i n g suat ciia via than va da vach, da t r u x u n g quanh k h u vuc khai thac se duoc phan bo lai den khi dat trang thai can bang
L 6 chuan b i duoc bo t r i trong phan than nguyen k h o i va nam phia d u o i guong khai thac, sau k h i 16 cho k h a u het 100m va k h u vuc khai thac o trang thai u n g suat can bang Muc dich cua viec xay dung 16 chuan b i trong m o h i n h so str dung phan m e m F L A C la nham xac d i n h anh h u o n g cua 16 chuan b i den v u n g ap lire tua I o n nhat tai t r u bao ve trong dieu kien goc doc v i a khac nhau L 6 chuan b i duoc bo t r i bam t r u v i a than va each guong
da khai thac lan l u o t la 5 m , 10m, 15m va 2 0 m v o i 2 dieu k i e n goc doc: via nam ngang (0°)
va via doc nghieng (30 ) Cong tac chong g i u 16 chuan b i duoc m o phong dua tren cac cong cu ho t r o co trong phan m e m F L A C
3 P h a n t i c h d a n h gia ket q u a m o h i n h so
Hinh 2 Dudng phdn bo dp luc tua tqi tru than phia tren Id chp trong
cdc dieu kien gdc doc via
3 5 9
Trang 4Hpi nghi khoa hoc kT thuat mo quoc te - 2010 Cong nghiep mo tien tien vi su phat trien ben virng
K e t qua phan t i c h trang thai ap lire phan bo x u n g quanh k h u virc k h a i thac k h i khai thac v i a bang sir dung he thong khai thac cot dai theo p h u o n g cho thay, ap lire tua I o n nhat tap trung d phia t r u than bao ve sat ngay g u o n g khai thac, trong do v i t r i ap lire tua l d n nhat nam trong v i a than
K e t qua phan t i c h m d h i n h sd sir dung phan m e m F L A C cho thay v i t r i ap lire tua ldn nhat tai t r u bao ve loc doc v i a b i anh h u d n g b d i gdc ddc cua v i a than H i n h 2 va H i n h 3 mo
ta trang thai c u d n g do ap lire thang d u n g tac ddng len cac t r u bao ve dau va chan l d cho cua he thdng nghe k h a i thac g u o n g l d cho dai
So do phan bd ap luc tren H i n h 2 cho thay, k h i gdc ddc v i a tang len, ap lire tua ldn nhat tren t r u bao ve phia tren l d cho d i c h chuyen dan dan tir giira v i a than x u d n g k h u vuc ldp da t r u v i a than T i r ket qua phan tich nay cd the nhan d i n h l d doc v i a thdng gid d 16 cho
cd gdc ddc l d n cd n g u y co b i bung nen cao h o n l d doc v i a thdng g i d tai v i a cd goc doc thoai hon
c, a = 30° d, a = 45°
Hinh 3 Dudng phan bo dp luc tua tqi tru than phia dudi lb chp
trong cdc dieu kien goc doc via
A n h h u d n g cua gdc ddc v i a t d i sir phan bd ap luc tua the hien r d h o n tai t r u bao ve phia d u d i g u o n g k h a i thac n h u the hien trong H i n h 3 So do phan bd ap lire dung tren Hinh
3 cho thay, k h i gdc ddc v i a tang, v u n g ap luc tua l d n nhat d i chuyen tir k h u virc v i a than len v u n g vach da
H i n h 4 t r i n h bay trang thai ap lire theo p h u o n g dung d giua v i a than tir v i t r i 4m trong v u n g sap do den 40 m chieu rong t r u than bao ve 16 doc v i a van tai trong cac dieu kien goc doc v i a khac nhau K e t qua phan tich tir H i n h 4 cho thay, t r u bao ve 16 doc v i a van tai d via ddc nghien c h i u ap lire tua nho h o n so v d i cac v i a ddc thoai
Trang 5Hpi nghi khoa hoc kT thudt mo quoc te - 2010 Cong nghiep mo tien tien vi su phdt trien ben vung
40
J5
10
g 20
>
& 15
10
5
u t /
hi j ,*i /
**»**«
• 0 degree
• 15 degree
* 30 degree
— 45 degree
-4 0 4 8 12 IS 20 24 28 32 J6 40
The distance torn the edge o< longv/all panel, m
Hinh 4 So do dp luc dirng giira via than tqi cdc vi
tri khdc nhau trong tru bao ve lb doc via trong cdc
dieu kien gdc doc via
- c,k = 2.0
Hinh 5 So do phdn bo dp luc tua tqi tru bdo ve
vdi cdc he so k =cr h /o v khdc nhau d via bang
Ba t r i so khac nhau cua he so giira ap lire ngang va ap lire thang d u n g (ah/ay) la 0,33, 1, ya 2 trong hai dieu
k i e n goc doc v i a (nam ngang va v i a co
do doc 30°) da duoc m o phong de nghien c u u anh h u o n g cua ap luc ngang den v i t r i v i i n g ap lire tua tai t r u bao ve 16 doc ,via K e t qua phan tich tren m o h i n h so cho thay ap luc ngang cung co anh h u o n g den su phan bo ap lire tua tai t r u bao y e 16 doc, v i a k h i khai thac v i a day bang he thong khai thac cot dai theo p h u o n g T r o n g t r u o n g hop v i a nam ngang, ap lire ngang anh
h u o n g k h o n g nhieu den su phan bo ap luc tua,tai t r u bao ve 16 doc via H i n h 5 cho thay d u co sir khac biet ve he so giua ap luc ngang va ap lire d u n g la 0,3,3; l j va 2, v i t r i v u n g ap luc tua I o n nhat van nam cung 1 v i t r i ben trong via than
Ket qua phan tich chi ra rang, trong dieu k i e n v i a n a m ngang, cuong
do ap luc tua I o n nhat tai t r u bao ve 16 doc v i a se g i a m k h i he so giua ap luc ngang va ap lire d u n g tang T u y nhien khoang, each tir g i o i han g u o n g khai thac den v i t r i ap lire tua I o n nhat
k h o n g thay d o i k h i thay d o i cac gia t r i
he so giira ap luc ngang va ap lire d u n g
n h u the hien tai H i n h 6
T r o n g dieu k i e n v i a doc 3 0 ° , tir ket qua m o h i n h so cho thay v j t r i v i i n g
ap lire tua I o n nhdt thay d o i I o n k h i thay d o i gia t r i he so giua ap lire ngang
va ap luc d u n g T r u o n g hop k h i ap luc ngang thap h o n ap l u c d u n g , v i t r i v i i n g
ap luc tua I o n nhat n a m tren phdn l o p
da vach, each x a v i a than K h i tang he
so giua ap lire ngang va ap luc dirng, v i
t r i v u n g ap luc tua I o n nhat d i chuyen dan dan x u o n g v i a than n h u t h i hien trong h i n h 7 T i r ket qua phan t i c h co the nhan d i n h trong dieu k i e n goc d6c
v i a k h o n g d o i , t r u bao ve trong dieu ki?n he so giira ap lire ngang va ap lire thang d u n g thap h o n se c h i u ap luc tua
3 6 1
Trang 6Hdi nghi khoa hoc ki thudt md qudc te - 2010 Cdng nghiep md tien tien vi sir phdt trien ben virng
nho hon so v a i he so giira ap lire ngang
va ap lire dirng cao hon
H i n h 8 t r i n h bay trang thai ap lire
tua tai cac v i t r i khac nhau trong t r u bao
ve 16 doc via van tai K e t qua phan t i c h
tir H i n h 8 cho thay k h i he so giua ap luc
ngang va ap luc d u n g g i a m , cuong do
lan nhat cua v u n g ap luc tua tren tru
bao ve 16 doc v i a van tai se giam theo
X u h u o n g bien d o i trong dieu k i e n via
doc trai nguoc v o i dieu k i e n via bang,
k h i ma c u o n g do ap lire tua l a n nhat tai
tru bao ve tang k h i he so giua ap luc
ngang va ap luc dirng giam
a, k = 0.33
y.*r •*" vi*'"^*"~"™ ^T."'.V1?
=5
45.0
40 0 35.0 3O.0
| 250
5 20 0 ^
S 150
>
10.0
50
0 0 '
- 1 0 4
Hinh 6 Bieu do trqng thai dp luc dung vdi cdc he
so k=CTi/cr v khdc nhau trong dieu kien via bang
„~— \ | i ^
i p
b, k = 1.0
V " 1
\
' \
I P
/
c, k = 2.0
Hinh 7 So do phdn bo dp luc tqi tru bdo ve Id doe via van tdi vdi cdc he so k=o t /o v khdc
3 A O nhau trong dieu kien via ddc 30"
35 0
30.0
i 25.0
i 20.0
| 15 0
' 10 0
5.0
0.0
• ! J
4 8 12 16 20 24 28 32 36 40 Distance from the edge of nb pillar, m
k = 0.33
• k = 1 0
4 k = 2 0 //hz// 5. JB/<?« do ung suat len
chinh giu a via doc 30° vdi ti le true ngang/truc irng khdc nhau
Trang 7Hpi nghi khoa hoc kithudt mo quoc te - 2010 Cong nghiep mo tien tien vi su* phdt trien ben vung
70 ,
65 i
S 40
% 35
E
; :o
m
20
A n h h u o n g cua goc doc v i a den su phan
bo ap luc tua tai t r u bao ve 16 doc v i a cung co the nhan biet qua su thay d p i cua ap luc tac dong len v i chong tai 16 chuan b i trong 2 dieu
so * / \ , - k i e n goc doc khac nhau: 0° va 30 T r o n g
t r u o n g hop v i a bang, 16 chuan b i v o i t r u bao ve rong 10m k e m o n d i n h h o n so v o i cac tru bao
ve co chieu rong 5 m , 15m va 2 0 m V i du, ap lire v u o n g goc t o i da tac dong len v i chong 16 chuan b i k h i t r u bao ve rong 10m la 6 4 M N ,
0 5 10 15 20 ^5 * " " "
P,n«rwtdih m trong k h i cac t r u o n g hop co t r u bao ve rong 5m,
15m, 2 0 m lan l u o t la 5 9 M N , 5 6 M N va 4 9 M N
- , n > u t**4> AS ' T r u o n g hop v i a doc co x u h u o n g t u o n g t u T u y
Hinh 9 Gia tri l f f n nhat tac dong len vi , A
6 / f , , # , &. 6, \ A , x , j, .A : ° , , nhien, gia t r i ap luc tac dung v u o n g goc len v i
chong lo chuan bi v f f i chieu rong tru bao , i ~ • *, • , f f , ^
„ , , , , , ' - 15 * , n o, chong trong t r u o n g hop v i a doc nho h o n truong
ve khac nhau trong dieu kien via bang (0 ) h g p y i ^ t r Q n g c { i n g ^ r 6 g ^ ^ y |
va via doc nghieng (30) T u y t q u ^ p M n tfch t r g n m 6 h i n ^ c 6 ^ khang d i n h trong dieu k i e n co cung chieu rong t r u bao ve, 16 doc v i a van tai o dieu kien v i a
doc chiu ap luc tua nho h o n so v o i dieu kien via bang H i n h 9 t r i n h bay gia t r i Ion nhat cua luc tac dung v u o n g goc len v i chong v o i chieu rong t r u bao ve khac nhau trong dieu k i e n
via bang (0 ) va v i a doc nghieng (30 )
4 Ket luan
Ket qua phan tich tren mo hinh so sir dung phan mem FLAC cho thay goc doc cua
via co anh h u o n g den v i t r i vung ap luc tua Ion nhat tai t r u bao ve 16 doc vi'a trong he thong
khai thac cot dai theo phuong, 16 cha khau lop t r u , t h u h o i than noc T r o n g dieu kien via
bang, v i t r i v u n g ap luc tua Ion nhat nam ngay tren t r u bao ve cua v i a than v o i cac gia t r i he
so giua ap lire ngang va ap luc dung khac nhau T r o n g t r u o n g hop v i a doc, v i t r i vung ap luc tua Ion nhat phu thuoc Ion vao he so giua ap lire ngang va dp lire dung K h i ap luc ngang nho h o n ap lire dung, v u n g ap luc tua Ion nhat nam,trong l o p da vach phia tren v i a
than Khi^ ap luc ngang tang, v i t r i vung ap luc tua I o n nhat tai t r u bao ve 16 doc via, dich
chuyen dan ve phia v i a than T u y nhien, tat ca cac ket qua phan t i c h tren m o h i n h so cho thay cuong do ap lire tua Ion nhat tac dong len t r u bao ve 16 doc v i a 6 t r u o n g hop v i a doc nho hon so v o i t r u o n g hop v i a thoai D i e u nay co nghTa la v o i cung chieu rong t r u bao ve,
16 doc via van tai 6 v i a doc c h i u ap lire tua nho h o n so v o i 6 v i a thoai
Huong nghien ciiu tiep theo nen tap trung xac dinh miic do khac nhau cua cuong do
ap luc tua Ion nhat tai t r u than bao ve trong cac dieu k i e n goc doc v i a bang va doc nghieng
Tdi lieu tham khdo
l.Whittaker, B and R Singh Design and Stability of Pillar in Longwall Mining, The
M i n i n g Engineer, 1979 139(214): 59-73
2.Itasca Consulting Group, L , F L A C version 5.0 User manual 2005, Itasca Cosulting
Group Inc: Minneapolis, Minnesota, U S A
3.Hebblewhite, B , Simonis, A and Y Cai Technology and feasibility o f Potential underground t h i c k seam m i n i n g methods, 2002 Technical report, School o f M i n i n g Engineering, The U n i v e r s i t y o f N e w South Wales and the Center f o r M i n i n g Technology and Equipment C R C , The U n i v e r s i t y o f Queensland
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