NGHIEN CUu sue CHjU TAI, 0 0 LUN CUA fiAT NEN THEO KET QUA THf NGHIEM
Tran Xuan Tho Nguyen Le Du
ABSTRACT
The article study the correlation between the results of laboratory experiments between result in laboratory and field with 2 sandy clay with soft plastic and sandy
clay with hard plastic to find a correlation between the bearing capacity, settlement of the ground deformation and modules to support the design calculations with behavior similar to the ground reality.
Keywords: Plate load test, plate bearing test TS Tran Xuan Tho Khoa xay diTng Trirdng Dai hoc Bach Khoa TP.HCM Email: [email protected] KS Nguyen Le Du Khoa Cong trinh Trirdng Oai hoc Giao Thong Van Tai TP.HCM Email: nguyenledu@
hcmutrans.edu.vn Di dong: 0983.152.524
1. Tom tat
Bai bao di vao nghien cCiu tuong quan giCfa ket qua thi nghiem trong phong vol ket qua thi nghiem ban nen tinh hien trudng v6i 2 loai dat set pha cat trang thai deo mem va set pha cat trang thai deo cUng de tim ra moi tuong quan giUa sure chiu tai, dp lun cua dat nen va mo dun bien dang nham ho tro cho viec tinh toan thiet ke vcji u'ng xLf dat nen gan giong vol thuc te.
2. Gidi thieu
Ngay cang nhieu cac cong trinh cao tang duoc xay dUng bang phuong phap mong be tren cac nen dia chat tot tai TP. Ho Chi Minh. Mot so cong trinh tieu bieu nhU:
Tru sd lam viec cue trinh sat ngoai tuyen A21 - 39 Le Quy Don - Quan 3, Chung cU
cao tang - 13/2 Duong Au Co - Quan Tan Phu, Cong trinh Toa nha lam viec cong ty Ha Do 4 - 60A TrUdng Son - Quan Tan Binh,...
Tuy nhien trong giai doan thiet ke ban dau chi CO so lieu tCf ket qua thi nghiem trong phong cho nen qua trinh tinh toan thiet ke se sai lech so vdi ung xCr dat nen tren thuc te d hien trudng. VI the viec nghien cdu xac lap nen moi quan he tUcac ket qua thi nghiem trong phdng va hien trudng la mpt cdng viec het sUc cd y nghia, nd gdp phan giup cho cac ky su thiet kecd cai nhin tdng quan hon khi tinh toan thiet ke cdng trinh.
3. Phan tich sijrc chju tai, do lun cua dat nen va mo dun bien dang trong phong va hien trUcrng
3.1 Ket qua thi nghiem trong ptidng
Cdng trinh Tru sd cue trinh sat ngoai tuyen 39 Le Quy Ddn - Quan 3 Loai dat: Set pha cat, trang thai deo mem
w = 2 1 . 4 4 % y= 20.2k m ^ y ( j = 16.6k m ^
G = 2 . 7 S, = 2 . 3 %
n = 38.6 eo = 0.628
Wp = 1 4 . 8 % w = 2 6 % lp = 1 1 . 2 %
1 = 0 . 5
(\>= 4 1 ' c = 1 .2k m^
Cdng trinh tru sd lam viec cdng ty Ha Od 4 - 60A Trudng Son - Quan Tan Binh Loai dat: Set pha cat, trang thai deo mem
w = 20.5%
y= 20.4k m ^ 7jj = 17.0k m ^
G =2.7 5, = 0.0%
n = 37.0 eo = 0.588
w =23.6%
Wp ~17%
lp = 6.6%
1 =0.53
(t)= 13 24' c = 15k m^
Cdng trinh Chung cU cao tang 13/2 Au C o - Q u a n Tan Phu
Loai dat: Set pha mau xam vang, nau vang, xam xanh, trang thai deo cdng w = 21.7%
y= 18.8 k m ^ y j = 15.52k m ^
G =2.68 S, = 7 .6%
n = 42.3 Co = 0.733
w =31.8%
Wp =16.1%
lp = 15,7%
1 =0.36
!(.= 13 55' c - 26.2k m '
12.201 Oli^WnTlOT 5 7
Cdng trinh Chung cuThai An 3,4, Quan 12,TP. Hd Chi M i n h Loai dat: Set pha cat, trang thai deo cdng
w = 21.1%
7= 20.3k m ^ 7 j = 16.8k m '
G =2.78 S r = 0%
n = 40 eo= 0.655
w = 3 6 . 1 % Wp = 17.2%
Ip = 1 % 1 =0.21
4)= 15°26' c = 22k m^
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3.2 Ket qud thi nghiem hien tritdng
Cdng trinh Tru sd cue trinh sat ngoai tuyen 39 Le Quy Odn - Quan 3
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5 8 BtE^nVl^V 12.2010
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Biem nen tinh NTS Hinh 4: Ket qu^ nen tinh bang ban nen hien truong cong trinh 13/2 Au Co
Cdng trinh Chung cUThai An, Nguyen Van Qua, Quan 12, TR Hd Chi Minh
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Dp sau t h i nghiem: 1.5m. Muc nUdc ngam trung binh: 4m
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12.201 O^CHlVi^l 5 9
3.3 Phdn tich site chiu tdi
Sdc chiu tai (klsl'/m^
Lpai dat
y= 20.2kN/m ^ w = 21.44% G^ = 2.7 WL = 26% Wp = 14.8% eo = 0.628 y= 20.4kN/m ^ w = 20.5% G^ = 2.7 WL = 23.6% Wp = 174.8% eo = 0.588 y= 18.89kN/m^ w = 21.7% Gj =2.689 WL = 31.8% w p = 16.1% e o = 0.733 y= 20.3kN/m^ w = 21.1% 0 ^ = 2 . 7 8 WL = 3 6 . 1 % Wp =17.2% eo=0.655
Terzaghi (FS = 2)
132.4
135.2
224.4
214.9
Vesic (FS=2)
93.6
96.8
154.7
150.3
TCVN
94.8
92.0
142.8
134.6
T N b a n n e n H T
286.4
332.9
550.0
515.7
mp = ^PLT RTN
2.16^3.06
2.46 ^3.62
2.45 ^3.85
2.40-3.83
Ap lUc trung binh len day
m d n g P,'^
115.2
131.3
180.4
193.5
Ghi chu
39LQO 60A Trudng
San 13/2AU
C a Thai An
Q12
-Tong hop ket qua thu nhan dupe khi so sanh sdc chiu tai cua dat nen t d t h i nghiem ban nen tinh hien trudng va ket qua nen cd ket trong phdng:
Set pha cat, trang thai deo mem e = (0.588+ 0.628) y = (20.2 +20.4) kN/m^
w = (20.5%+ 21.4%) I L = ( 0 . 5 3 : 0.59)
He SO tLfang quan mp
m p - 2 . 3 + 3.3
Set pha cat, trang thai deo eUng e = (0.655+ 0.733) 7 = (18.89 +20.3 )kN/m^
w = (21.1% + 21.7%) I I =(0.21 + 0.36)
He sd t t f o n g quan m?
mp - 2 . 4 + 3.8
3.4 Xdy dung mdi quan tie md dun bien dgng tifthingliiem hien tntctng vd trong phdng Cdng trinh Try sd cue trinh sat ngoai tuyen 39 Le Quy Ddn - Quan 3
Cap nen P (kN/m^)
0 50
100
200 400
M d d u n bien dang Nen cd ket Eoed
(kN/m-) 1334.696
2063.942
3147.543
4904.734
Ban nen EPLT (kN/m^) 5794.079
5708.468
6408.132
8686.037
mpLT mg = '-'
'^oed 4.34
2.77
2.04
1.77 Cdng trinh Tru sd lam viec cdng ty Ha Od 4 - 60A TrUdng Son - Quan Tan Binh
Cap nen P (kN/m^)
0 50
100
200 400
Md dun bien dang Nen cd ket Eoed
(kN/m-) 2748.462
2445.577
3863.077
6787.088
Ban nen EPLT (kN/m^) 14671.751
9173.742
10236.671
11650.503
mpLT mg =
"^oed 5.34
3.75
2.65
1.72
6 0 ^•^"'f iVSiV 12.2010
Cdng trinh Chung cU cao tang 13/2 Au CP - Quan Tan Phu C a p n e n P
( k N / m ^ ) 5 0 1 0 0
2 0 0 4 0 0
M d d u n b i e n d a n g N e n e d k e t Eoed
( k N / m ^ ) 1 8 0 6 . 9 2 3
3 3 7 2 . 9 2 3
6 6 2 1 . 2 3 1
B a n n e n EPLT ( k N / m ^ )
8 7 7 1 . 9 2 1
1 4 4 3 9 . 4 3 8
2 1 0 7 0 . 5 2 8
mpLT m ^ = '-
"^oed 4.85
4.28
3.18
Cdng trinh Chung cUThai An, Nguyen Van Qua, Quan 12, TP. H d C h i M i n h C a p n e n P
( k N / m ^ ) 0 5 0
100
2 0 0 4 0 0
M d d u n b i e n d a n g N e n c d k e t Eoed
( k N / m ^ ) 1 2 5 1 . 7 4 6
1 6 6 1 . 8 9 7
2 5 5 6 . 2 9 9
5 1 2 6 . 5 3 8
B a n n e n EPLT ( k N / m ^ )
5 7 0 9 . 6 8 8
6 8 3 1 . 8 3 1
9 6 8 3 . 8 4 2
1 6 2 7 7 . 1 8 4
mpLT m j =
n^oed 4 . 5 6
4.11
3.79
3.18
-Tong hpp ket qua t h u nhan dupe khi so sanh m d d u n bien dang t d t h i nghiem ban nen tinh hien trudng va ket qua nen cd ket trong phdng:
Set p h a cat, t r a n g t h a i d t o m e m e = (0.588+ 0.628)
y = (20.2 +20.4 )kN/m^
w = (20.5%+ 21.4%) II =(0.53 + 0.59)
H e so t u ' a n g q u a n ms
m E - 1 . 7 + 4.8
Set p h a c a t t r a n g t h a i d e o c d n g e = (0.655+ 0.733)
y = (18.89 +20.3 ) k N / m ^ w = (21.1% + 21.7%) I I = ( 0 . 2 1 + 0.36)
H e so t u a n g q u a n mt
m ^ - 3 . 2 + 4.7
3.5 Xdy dtfng mdi quan he dd Idn dd't nen tit thi nghiem hien trUdng vd trong phdng
D p l u n t h e o T N n e n c d k e t ( c m )
5.21 2.80 6.41 7.90
O p l u n t h e p T N b a n n e n H T ( c m )
1.37 0.82 1.09 1.38
m s = ^ ™ 5pLT 3.80 3.41 5.88 5.72
G h i c h u 3 9 L Q D 6 0 A T r u d n g S a n
1 3 / 2 A u C a T h a i A n Q l 2
4. Ket luan
- Ket qua tinh tpan sdc chiu tai theo phupng phap Vesic va thep TCVN 45 -78 cho ket qua tuong duong nhau trong khi ket qua tinh toan sdc chiu tai theo phuong phapTerzaghi cd khac biet Idn hon khoang 30% so vdi 2 phuong phap tren.
- Tinh toan on dinh eac edng trinh de nghi tinh toan theo Terzaghi vdi he sd tuong quan la 2.5 lan.
- Ddi vdi dat set pha eat, trang thai deo mem vdi he sd rong trung binh e = 0.6 chenh lech ve dd lun mS trong khoang tii 3.4 den 3.8 lan
- Ddi vdi dat set pha eat, trang thai deo cdng vdi he sd rdng trung binh e = 0.7 chenh lech ve dp lun mS trong khoang t d 5.7 den 5.9 lan.
- U'ng vdi cap ap lUe nhd chenh lech giQa mddun bien dang tinh toan tU ket qua thi nghiem ban nen lech nhieu so vdi m d dun bien dang tinh t d ket qua t h i nghiem nen cd ket trong phdng nhung khi cap ap lUc cang Idn thi he sd m^ se giam dan.
- Ddi vdi dat set pha cat, trang thai deo mem vdi he sd rong trung binh e = 0.6 dao ddng he sd mE la tUPng ddi Idn giua E„.so va E,„„^o„. chenh lech gida thi nghiem trong phdng va t h i nghiem ban nen tinh hien trudng la tuong ddi Idn d cap dau tien (E„5j) tuy nhien cac cap tai tiep theo gia tri mE dao ddng it hon va chenh lech nay khoang t d 2 den 3 lan.
- Ddi vdi dat set pha eat, trang thai deo edng vdi he sd rdng trung binh e = 0.7 he sd m^ dn dinh hon va gia tri nay dao ddng
trong khoang tU 3 den 4 lan. •
- Tdng hpp ket qua thu nhan dupe khi so sanh d p lun dat nen t d t h i nghiem ban nen tinh hien trudng va ket qua nen cd ket trong phdng:
Set p h a eat, t r a n g t h a i d e p m e m e = (0.588+ 0.628)
y = (20.2 +20.4 )kN/m^
w = (20.5% + 21.4%) ll =(0.53 + 0.59)
H e SP t u a n g q u a n ms
ms - 3 . 4 1 + 3.80
Set p h a cat, t r a n g t h a i d e o e d n g e = (0.655+ 0.733)
y = (18.89 +20.3 ) k N / m ^ w = (21.1% + 21.7%) I I = ( 0 . 2 1 + 0.36)
He s d t u a n g q u a n ms
m s = 5.72+ 5,88
TAI LIEU THAM KHAO
1. TCXBVN 80:2002, Bat xay dung. Phuong phap xac dinh modun bien dang tai hien truang Wng tam nen phjng, NXB Xay Di/ng, Ha Noi - 2003
2. PGS. TS Chau Ngoc An, Co hoc dat, NXB Bai hoc guoc gia thanh pho Ho Chi Minh, Tp, Ho Chi Minh - 2009
12.2010 nmiiisiT 6 1
