Microsoft Word - TCVN 9351 2012
TIU CHUN QUC GIA
TCVN 9351:2012T XY DNG - PHNG PHP TH NGHIM HIN TRNG - TH NGHIM
XUYN TIU CHUN (SPT)Soils - Field testing method - Standard
penetration test
Li ni u
TCVN 9351:2012 c chuyn i t TCXD 226:1999 theo quy nh ti khon 1
iu 69 ca Lut Tiu chun v Quy chun k thut v im a khon 1 iu 7 Ngh nh s
127/2007/N-CP ngy 01/8/2007 ca Chnh ph quy nh chi tit thi hnh mt s
iu ca Lut Tiu chun v Quy chun k thut.
TCVN 9351:2012 do Vin Khoa hc Cng ngh Xy dng - B Xy dng bin son,
B Xy dng ngh, Tng cc Tiu chun o lng Cht lng thm nh, B Khoa hc v Cng
ngh cng b.
T XY DNG - PHNG PHP TH NGHIM HIN TRNG - TH NGHIM XUYN TIU CHUN
(SPT)
Soils - Field testing method - Standard penetration test
1 Phm vi p dng
1.1 Tiu chun ny quy nh phng php xc nh sc khng xuyn ca t ti y h
khoan khi xuyn ng mu bng cch ng ba theo tiu chun v ly mu ph hu lm
cc th nghim phn loi.
1.2 Tiu chun ny c s dng ch yu nh gi cc tham s v cng v bin dng ca
t ri, tuy nhin mt s s liu c gi tr c th thu c trong cc dng t
khc.
1.3 Tiu chun ny bao gm cc quy nh v thit b v phng php thc hnh th
nghim khi kho st a cht cng trnh. Gii thch, nh gi v s dng kt qu th
nghim cho tnh ton nn mng c th tham kho trong cc ph lc.
2 Ti liu vin dn
Cc ti liu vin dn sau l cn thit cho vic p dng tiu chun ny. i vi
cc ti liu vin dn ghi nm cng b th p dng phin bn c nu. i vi cc ti liu
vin dn khng ghi nm cng b th p dng phin bn mi nht, bao gm c cc sa i,
b sung (nu c).
TCVN 4419:1987, Kho st xy dng - Nguyn tc c bn.
TCVN 9363:2012, Nh cao tng - Cng tc kho st a k thut.
3 Thut ng v nh ngha
Trong tiu chun ny c s dng cc thut ng v nh ngha sau:
3.1
Th nghim xuyn tiu chun (Standard Penetration Test - SPT)
Mt trong cc phng php kho st a cht cng trnh phc v xy dng cc cng
trnh khc nhau. Th nghim c tin hnh bng cch ng mt mi xuyn c dng hnh
ng mu vo trong t t y mt l khoan c thi cng ph hp cho th nghim. Quy
cch mi xuyn, thit b v nng lng ng c quy nh. S ba cn thit ng mi xuyn
vo t cc khong su xc nh c ghi li v chnh l. t cha trong ng mu c quan
st, m t, bo qun v th nghim nh l mu t xo ng.
3.2
Sc khng xuyn tiu chun (Standard Penetration resistance), NsptS
ba cn thit ng mi xuyn vo trong t nguyn trng 30 cm vi quy cch thit b
v phng php th nghim quy nh nh iu 5 v iu 6.
4 Quy nh chung
4.1 Th nghim SPT nn c s dng khi kho st a cht cng trnh trong iu
kin a tng phc tp, phn b lun phin cc lp t dnh v t ri hoc bao gm ch
yu cc lp t ri vi cht, thnh phn ht khc nhau.
4.2 Khi lng c th ca th nghim SPT v tng quan gia SPT vi cc phng
php kho st khc trong qu trnh kho st c xc nh theo cc quy nh trong
TCVN 4419:1987 v TCVN 9363:2012 hoc cc tiu chun lin quan khc.
4.3 Th nghim SPT phi do cc k thut vin thnh thc nghip v thc hin v
kt qu th nghim cng phi do nhng nh chuyn mn c kinh nghim gii thch v
nh gi.
5 Thit b th nghim
5.1 Mt b thit b th nghim SPT bao gm cc b phn c bn sau:
- Thit b khoan to l
- u xuyn (Hnh 1)
- B ba ng (Hnh 2)
5.2 Thit b khoan dng to l khoan th nghim. C th s dng bt c my v
phng php khoan no min l h khoan t cc yu cu k thut v ng knh, thnh h
khoan n nh, m bo ti a tnh nguyn trng ca t di y h khoan v t c ti su
cn thit th nghim.
5.2.1 ng knh h khoan phi trong khong 55 mm n 163 mm.
5.2.2 Cn khoan thch hp nht cho th nghim l cn c ng knh ngoi 42
mm, trng lng 5,7 kg/m.
5.3 u xuyn l mt ng thp c tng chiu di n 810 mm, gm ba phn: phn
mi, phn thn, phn u ni v c ni vi nhau bng ren (Hnh 1). Quy cch c
th:
- ng knh ngoi: (51,0 1,5) mm;
- ng knh trong: (38,0 1,5) mm.
A (mm)B (mm)C (mm)D (mm)E (mm)F (mm)G()
(25 75)(450 750)(35,00 0,15)(38,0 1,5)(2,50 + 0,25)(51,0 1,5)(16
23)
CH DN
1 Mi xuyn 2 Phn u ni 3 Phn thn 4 Vin bi
Hnh 1 - u xuyn
5.3.1 Phn mi xuyn l phn di cng ca u xuyn dng ct khi xuyn vo t.
Cc c trng c bn ca mi xuyn nh sau:
- Chiu di t 25,0 mm n 75,0 mm;
- ng knh trong bng (35,0 0,15)mm;
- B dy li ct bng (2,5 0,25) mm;
- Gc vt li ct t 16,0 n 23,0.
5.3.2 Phn thn ca u xuyn di t 450 mm n 750 mm dng cha t kh mi
xuyn xuyn vo t. Phn thn gm hai na bn nguyt p li thun tin cho thao
tc tho lp khi ly t cha trong chng ra ngoi. Hai u ca ng phn thn c
ren ngoi lp rp vi phn mi v phn u ni.
5.3.3 Phn u ni ca u xuyn dng ni u xuyn vi cn khoan, c chiu di n
175 mm. Ti y c c cu bi, l thot hi gi chn khng bn trong u xuyn, hn
ch tt mu trong qu trnh nng h mi xuyn v thot hi, nc trong qu trnh
xuyn.
5.4 B ba ng dng to nng lng ng mi xuyn vo t, bao gm: qu ba, b gp
ba v cn dn hng (Hnh 2).
5.4.1 Qu ba hnh tr trn xoay, bng thp c l gia chnh tm c th ri trt
t do theo thanh dn hng. Ba phi c cu to ph hp vi b gp nh, sao cho c
th d dng c gp, nh ri t do t cao cn thit.
Trng lng ba: (63,5 1,0) kg;
- cao ri t do: (76,0 2,5) cm
CH DN:
1 Thanh dn hng 2 B gp 3 Qu t: (63,5 1,0) kg 4 e
Hnh 2 - B ba ng
5.4.2 B gp l b phn dng nng, h ba mt cch t ng, ng quy nh, m bo ba
ri t do, hn ch tiu hao nng lng trong qu trnh ri.
5.4.3 Cn dn hng nh hng ri ca ba, gm c e v thanh dn hng. e l mt
thp tip nhn nng lng ri ba, truyn xung mi xuyn thng qua h cn khoan.
Thanh dn hng c ng knh ph hp vi ng knh l gia ca ba v c cu to c bit
gip cho b nh gp nh ba ng lc, t cao ri ng quy nh.
5.4.4 Cc dng c ph tr khc cng cn thit trong qu trnh th nghim. l
hp mu, thc, phn, ti nylon, biu ghi, dng c o mc nc...
6 Phng php th nghim6.1 Th nghim SPT bao gm ln lt cc cng vic sau
ti mi v tr th nghim:
a) Khoan to l n su cn th nghim v ra sch y h khoan;
b) Tin hnh th nghim;
c) Quan st v m t.
Cc cng vic trn li c tip tc cc su tip theo. Th nghim c tin hnh ln
lt 1 m n 3 m su cho ti su cn thit tu theo mc ch kho st v tnh phc tp
ca a tng.
6.2 Khi khoan to l, cc phng php khoan sau c th c p dng:
- Khoan gung xon;
- Khoan xoay vi nc ra bng nc hoc dung dch st.
trnh sp thnh h khoan, khi cn cc ng chng vch c th c s dng.
L khoan phi ng v tr, thng ng, ng knh ln t 55 mm n 163 mm. Thnh h
khoan phi n nh v hn ch ti mc ti a ph hoi t y h khoan.
6.2.1 Khi khoan su khng ln, trn mc nc ngm nn s dng khoan gung
xon. S dng ng chng, nu c mt t yu, t c kt cu khng cht trnh sp thnh h
khoan.
6.2.2 Khi khoan di mc nc ngm nn s dng khoan xoay vi nc ra bng nc
trong t dnh v vi nc ra bng dung dch st trong t ri.
6.2.3 Trong qu trnh khoan phi thng xuyn theo di tc khoan, c im
dung dch khoan nhn bit kp thi s thay i a tng v quyt nh hp l su th
nghim. Mc dung dch khoan phi lun lun nm trn mc nc ngm.
6.2.4 Khi khoan gn ti su th nghim, nn gim tc khoan, thao tc nng,
h nh nhng nhm hn ch ti a s ph hoi tnh nguyn trng ca t di y h khoan,
lm sai lch kt qu th nghim.
6.2.5 Khi khoan n su th nghim, tin hnh vt y h khoan, kim tra su,
n nh ca thnh h khoan. Khi cn thit, c th ra v lm sch y h khoan bng
cch tun hon dung dch khoan.
6.2.6 Khi h khoan su, y sch, thnh vch n nh, tin hnh rt li khoan
ln v thay th n bng u xuyn.
6.3 Th nghim bt u khi mi xuyn t ti y h khoan, ng su yu cu m khng
gp bt k cn tr no do sp thnh. Th nghim tin hnh nh sau:
6.3.1 Lp b ba ng v kim tra kh nng gp nh, cao ri t do ca ba.
Thanh nh hng phi thng ng, n nh v ng trc vi h cn khoan.
6.3.2 Chn im chun v o trn cn khoan ba on lin tip, mi on di 15
cm, tng cng l 45 cm pha trn im chun cn c vo xc nh sc khng xuyn.
6.3.3 ng ba. Ch cao ri ca ba, thng ng ca thanh dn hng.
6.3.4 m v ghi s ba cn thit h mi xuyn cn khoan xuyn vo t mi on 15
cm vch trc trn cn khoan.
6.3.5 Khi s ba ng cn thit cho 15 cm vt qu nm mi ba (hoc mt trm
ba tu theo yu cu ca thit k kho st), o v ghi li xuyn su, tnh bng
centimt (cm) ca mi xuyn nm mi ba (hoc mt trm ba).
6.3.6 Trong t ct ht th ln dm sn hoc dm sn ln cui si, trnh hng mi
xuyn, nn dng mi xuyn c hnh nn cng kch thc thay th mi xuyn thng
thng. Gc nh mi xuyn hnh nn l 60.
6.3.7 Trong qu trnh ng, mc nc hoc dung dch khoan phi nm trn mc
nc ngm hin c.
6.3.8 Sau khi o v ghi s ba tng ng vi xuyn su 45 cm ca mi xuyn,
tin hnh ct t bng cch xoay cn khoan, rt mi xuyn ln mt t, thay th n
bng mi khoan. Cng tc khoan li tip tc cho ti su mi.
6.4 u xuyn c tho ra khi cn khoan, ra sch v tho ri thnh ba phn.
Tch i phn thn ca mi xuyn, quan st, m t t cha trong . Lp rp li mi
xuyn sn sng cho th nghim ti su mi.
6.4.1 t cha trong phn thn u xuyn c quan st, m t, so snh vi t cha
trong phn mi. M t r mu sc, m, cht, thnh phn ht, kin trc, cu to ca
t, cc d vt...
6.4.2 Chn mu i din, bo qun trong ti nylon khng thm nc, hi v kh.
Mi mu phi c nhn ghi r tn cng trnh, s hiu h khoan, su ly mu, s ba
cho ba khong xuyn, thi gian th nghim, c im thi tit.
6.4.3 Cc ti ng mu c xp theo th t su cho d quan st, kim tra, ni
thong mt v vn chuyn ngay v phng th nghim.
6.4.4 t ly c trong u xuyn c th c dng th nghim trong phng xc nh
mt s cc ch tiu vt l vi mc ch nhn bit v phn loi. C th l:
- m;
- Khi lng th tch ht;
- Thnh phn ht;
- Cc m gii hn.
6.4.5 Mu t ly c t mi xuyn phi c bo qun, ct gi trong phng th
nghim t nht ba thng k t khi nghim thu kt qu th nghim.
Mu ghi chp, quan st, m t (xem Ph lc A, B).
7 Chnh l v gii thch kt qu
7.1 Kt qu th nghim SPT thu t hin trng c chnh l theo tng h
khoan.
7.2 Ti mi su th nghim, tnh ton sc khng xuyn SPT (Nspt); Nspt l
tng s ba 30 cm xuyn sau cng ca mi xuyn.
7.3 Trn c s cc ti liu m t t hin trng, gi tr sc khng xuyn SPT, cc
ti liu th nghim trong phng trn mu t ly c, tin hnh phn chia a tng h
khoan, lp h s kt qa th nghim, v th gi tr sc khng xuyn theo su. Kt
qu th nghim tham kho Ph lc B.
7.4 Kt qu th nghim SPT c dng cho cc mc ch sau:
7.4.1 Phn chia a tng, pht hin cc lp kp, cc thu knh t ht ri, phn
bit cc t ht ri vi ch cht khc nhau theo din v theo su.
7.4.2 nh gi gi tr ca mt s ch tiu c l nh:
- cht, gc ma st trong ca t ht ri;
- st, bn nn c n hng ca t dnh;
- Mun bin dng ca t ri;
- Sc khng xuyn tnh ca t.
7.4.3 nh gi mt s ch tiu ng lc ca t nh:
- Kh nng bin long ca t ri;
- Tc truyn sng trong t.
7.4.4 D bo sc mang ti ca mt s loi mng:
- Sc mang ti ca mng nng trn t ri;
- Sc mang ti ca cc, ch yu l cc chng, c bit cc khoan nhi.
Ph lc A
(Tham kho)
Biu mu ghi chp hin trng cho th nghim SPT
TH NGHIM XUYN TIU CHUN (SPT)
BIU GHI CHP HIN TRNGn v th nghim: .........................
K thut vin:
........................Cng trnh: V tr: Tn h th nghim: To (Y-X):
Cao :Ngy khi cng: Ngy kt thc:
Ngy gi su
mS ba ng trong khong xuyn, BaMu lu tM t tMc nc ngm
mGhi ch
15 cm15 cm15 cm
15/83,0233SP-3-1St xanh, t, mmMy khoan 1T-2
9h306,0222SP-3-2Bn st, enGung xon 5,0 m
i tng 4,5 mXoay, dung dch
9,0222SP-3-3Bn st, enng knh 89 mm
12,0223SP-3-4Bn stXm en
15,0566SP-3-5St cng, nu vng14,3
17h3018,0565SP-3-6St cng, nu
16/8
11h0021,0577SP-3-7Ct pha, xm nu
i tng 19,0 m
24,0688SP-3-8Ct nh, xm xanh
i tng 22,3 m
15h2527,0888SP-3-9Ct nh, xm xanh
30,0889SP-3-10Ct nh, xm xanh
33,0899SP-3-11Ct nh, xm vng
36,09810SP-3-12Ct nh, xm vng
39,0121415SP-3-13Ct trung ln sn, vng
i tng 38,2 m
42,0151515SP-3-14Ct trung, sn nh
45,0202425SP-3-15Si, sn, ct th
i tng 43,8 m
19h3049,5242630SP-3-16Si sn, ct thKt thc ti 50,0 m
Ph lc B(Tham kho)
Biu mu trnh by kt qu cho th nghim SPT
KT QU TH NGHIM XUYN TIU CHUN (SPT)n v th nghim:
.........................
K s x l kt qu: ........................
........................Cng trnh: V tr: Tn h th nghim: To (Y-X):
Cao :Ngy khi cng: Ngy kt thc:
Hnh B.1- Biu mu trnh by kt qu cho th nghim SPT
Ph lc C
(tham kho)Gi tr sc khng xuyn tiu chun Nspt ca mt s loi t vng H
Ni Bng C1- Gi tr sc khng xuyn tiu chun Nspt ca mt s loi t vng H
NiTh tLoi tGi tr Nspt (Ba/30 cm)
1t loi st, sng, tng Thi BnhT 5 n 8
2t loi st, bin, tng Hi HngT 2 n 4
3t loi st, bin, tng Vnh PhT 10 n 25
4t bn st, h ly - bin, tng Hi HngT 1 n 3
5t ct sng, tng Thi BnhT 15 n 25
6t ct, sng - bin, tng Vnh PhT 18 n 30
7t ct th ln sn si, tng H NiLn hn 40
Ph lc D
(tham kho)Quan h gia sc khng xuyn tiu chun Nspt v sc khng xuyn
tnh u mi qcBng D.1- Quan h gia sc khng xuyn tiu chun Nspt v sc khng
xuyn tnh u mi qcTh tLoi tT s qc/Nspt
1St2
2St pha3
3Ct ht mn4
4Ct ht trung, thT 5 n 6
5Ct ht trung ln sn siLn hn 8
Hnh D.1 Minh ha cho ni dung ca Bng D.1.
Hnh D.1 - Quan h qc/Nspt v thnh phn ht
Ph lc E
(Tham kho)
nh gi gi tr mt s ch tiu c l ca t theo kt qu SPT E.1 i vi t
ri
Cc ch tiu tnh cht sau ca t ri c th c nh gi theo kt qu th nghim
SPT:
- cht tng i, Dr;
- Gc ma st trong, (;
- Mun bin dng, E.
E.1.1 cht tng i (Dr) v gc ma st trong (()
Bng E.1 - Quan h N30 v Dr, ((Theo Terzaghi, Peck)
Trng thiDr (%)Nspt(()
XpNh hn 30Nh hn 10T 25,00 n 30,00
Cht vaT 30 n 60T 10 n 30T 30,00 n 32,30
ChtT 60 n 80T 30 n 50T 32,30 n 40,00
Rt chtLn hn 80Ln hn 50T 40,00 n 45,00
p lc bn thn hay su, th nm ca t cng nh hng ti quan h ny. Hnh E.1
ch ra th quan h gia Nspt v Dr c k n yu t ny. Theo cc gi tr nu Bng
E.1 tng ng vi p lc bn thn l 0,144 MPa.
Quan h gia gc ma st trong v sc khng xuyn tiu chun, c th nh sau:
(Theo Terzaghi, Peck, Meyerthof...)
trong :
a l h s, ly gi tr trong khong t 15 n 25, xem Hnh E.2
E.1.2 Mun bin dng E, tnh bng Megapascan (MPa)
(Theo Tassios, Anagnostopoulos)
trong :
a l h s, c ly bng 40 khi Nspt >15; ly bng 0 khi Nspt
