Bài thực hành: Cơ học của đất pps


A. PHẦN LÝ THUYẾT
BÀI 1:
THÍ NGHIỆM XÁC ĐỊNH ĐỘ ẨM TỰ NHIÊN
 !""#$%&'$%()*+,)**-
1. Mục đích
./012#3&4"560!7
2. Thiết bị thí nghiệm
'89":;2/0<=>=)7
3?5@"A2<==

'7
B&4"7
'CDEF"G H2;I:7
JKL#;M&'&'N7
O;8NP)7
'C?MQ..?M;R"E& ?"7
B&ST57
3. Các bước thí nghiệm
3.1 Chuẩn bị mẫu thử
S/012#3&5UV4"3;8CN8 W)-7' 4"5
Q. CD3&EF;I:>X0?C>/018CN
YZQ.X?587[&";&;:IQ.!89":S
/018CN3&2Q4"57
3.2 Cách tiến hành
\6I2;M&4"Q.?5WI 3?5<8CN8
]7%2?5,CQ5N ?^Q.0

_)=`a`

'>CQ5M&& Q.

5M&.Nb"TYc-dZ_e=a`

'7
&?5 0N 5f"1?&",
-CQ5?^Q.?^&0
CQ50Q.0&?^
eCQ5&& c-d
B/012#3&5M&5b"Tc-dKW?586 _e=a
`

'Ngh )`YCQ0N ?^ZQ.eYCQ5N 0Z
[&"PNR?5>N5C&8D3?5>:INQ.HC4"Q. EK
L#;M&'&'Ni(-j+=LSN."24"k7
%"l$mn ) \[[$=e-))`===`

C;4"kX?58<8CN8]!89":
Y

Z758CND5 0NRS8<f"W7
3.3 Tính toán kết quả thí nghiệm
d)==7
`
`)
C
WW
WW
W
−
−
=

 ;,
o,2#3&5YdZ7
o
)
,8CN3&2Q.4"5YZ7
o
`
,BCN2Q.4"5X?5YZ7
o
'
,8CN27
Ghi chú:Thí nghiệm này được thực hiện lặp lại hai lần để xác định giá trị trung
bình7
%"l$mn ` \[[$=e-))`===`
JW),B<f"W2#3&5

BÀI 2:
THÍ NGHIỆM XÁC ĐỊNH DUNG TRỌNG TỰ NHIÊN
 !""#$%&'$%(`=`,)**-
1. Mục đích
.S/01U"!3&57"
!N.8CN3&2TQ1S5!7
2. Thiết bị thí nghiệm
& Qp>& `>8+7
'k>2/0=>=)7
8q7
r&"G7
3. Các bước thí nghiệm
V8q/018 Q.8 .>@"& 3&
U& Qp>S3&U& Qp7

018CN3&U& QpEFk7
VU& Qp5?"Q. 4"5 @"sM> 5Q. RU&
Qp>LtWb U& QpN"N"sM7
VU& Is56&R"U& Qp7
018CN3&U& QpQ.57
4. Tính toán kết quả thí nghiệm
V
GG
w
`)
−
=
γ
 ;,
γ
u
,U"!3&5Yv

Z7
w
)
,8CN4"5Q.U& QpYZ7
w
`
,BCNU& QpYZ7
$,SU& QpY

Z7
%"l$mn  \[[$=e-))`===`


BÀI 3:
THÍ NGHIỆM XÁC ĐỊNH GIỚI HẠN CHẢY, GIỚI HẠN DẺO
 !""#$%&'$%()*x,)**-
1. Mục đích

01X o


01Uy o
z
2. Cơ sở lý thuyết
wUg 3&5TMQ2#.5N ?^;8<5"E10 
"Si0M?&0Ug 7wUg oHEF2
#YdZ3&5?&"8X. 2@"QQ.Nm.f";8>
Kf"EIR"MQ.M.0 I;@"U.8 W{)=7
wW'&?&&U3&5N.2#E25. >/01EF
Uhhf"&:'&?&&U>8X58) R)`7x?&"`-0
:
3. Thiết bị thí nghiệm
o
hh'&?&&U
o
& IX
o
B0(=/+=
o
O;8NP)
o
'C?MQ..E& ?"
o

'89":2/0=7=)
o
p?5@"A

o
& S. 2
%"l$mn ( \[[$=e-))`===`
Hình 1.1: Dụng cụ Casagrande để xác định giới hạn chảy W
L

4. Các bước thí nghiệm
4.1 Chuẩn bị mẫu thử
%<"4"5X8 @"8!>UVT0&
SN58 W== Q. .;R"E& ?"SSD7' 5X@
f"&)Q.N EDR!75XNf"&Q. E0>;5
Q. E05>UVU& 2@" <0|H7[&";H4"
Q. EK3>:8 8 W&c`87
4.2 Tiến hành thử
a. Xác định giới hạn chảy theo Casagrande
VU& 2@"> 2#5TW
VU&  5X. 2Q. r&8"S0E8N"b 
4"7B 5Q. Rr&.S28 W6R!P</LQC
i)v83&r&>WEW 2U.3&WN5c)=7
Vf""!UVS5 r&.)XU.8 W
(=>Q";Qhf"&7
}"&:QC2`Qpv?Q.<?CNR:R<SRU3&
X5Qi&8^N) U.)7
55 r&&>. NQ5pU E07[&";NHN!
S/01NRM&7
58 W)=5/"f"&XX8^8 Q. 2S/0

12#7
'M<hQN&] @"mN!701
5NR/012#MQ?C0:i)`{-
'mMQ. ?CN">Qyh"MQ2#>h .N &
ES"Ul?CNR:7}"&b&LN.s72#MQ?C0:N.
`-N.W'&?&&U
%"l$mn - \[[$=e-))`===`

b. Xác định giới hạn dẻo
[kUhR5pN3&KX 7
5)5Q.N5Hs NpE.& H0R";&Nmq
.!80 <8.f";8EF7
%<"Q8;>f"5Q4pbN!8<Q.Ug >KQ;
.pQ.<hNm<88EIR"MQ.X.
b&DU.{)=7
%H0 f"Qi&M>EDQ. 2:IN 58DE187
%&?&"85 2CS")=><./012#3&5
 2YdZQ2/0<=>)d7
CQP4"5>W<.8T`NR? ? 
S/01Ug 7
501"EK2&NRN.Ug 3&4"57
[&N ^Q@2# 0NR/01? ? ~`d7
5. Tính toán kết quả thí nghiệm
5.1 Kết quả thí nghiệm giới hạn chảy theo Casagrande
wW3&5 '&?&&UocW/01EFf"WU
mEFo

7}"&boQ.o
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<N: M,

o

_&7ojE
 ;&Q.EN.0?Ch"2Q. iN 57CQ5;
Wi`={)==d;SN5&_=7xQ.E_+7(xd
5.2Kết quả thí nghiệm giới hạn dẻo
wW3&5o

>d M,
) `
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L
m m
W x
m m
−
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−
 ;,

)
8CN5#Q.2>

`
8CN58Q.2>
 8CN2>
STT Hộp TL.hộp TL hộp+đất ướt TL hộp+đất khô W PL
PL-1
D8

11.52 23.12 20.22 33.33 33.33
PL-2
1B 11.96 15.32 14.6 27.27 23.71
5 11.93 15.03 14.51 20.16
PL-3
32 6.55 12.4 11.65 14.71 14.80
47 6.59 12.07 11.36 14.88
%"l$mn + \[[$=e-))`===`

BÀI 4:
THÍ NGHIỆM CẮT TRỰC TIẾP
 !""#$%&'$%()**,)**-
1. Mục đích
01;2&?0ϕQ.NUYI&8 0Z7
2. Thiết bị thí nghiệm
2.1 Máy cắt trực tiếp
 8S""@Nf"&QVME<Q.f"&0&pYU X[ N?{
n?W/"5Z7'0E2:3&0|,
•2'&?&&U,M&4"57
•$p 0N, ?M1"I3&57
2.2 Dụng cụ
J& |,U& >55>8 >Q&?N>gN&">&"M&?>E&W|
0>89":>8q>8s-=/-=>U& QpQ0?C,
•'@"& ,`
•8 ,+7)
•,)7)x`
`
•N,)=x7 
•SM&,+`7((



3. Trình tự tiến hành thí nghiệm
)7'"#E1<E1>Uhh,
%"l$mn x \[[$=e-))`===`
Thiết bị cắt trực tiếp và hộp nén Casagrande

•\4"5N58/0 2iCN54"57
•'0W|Q.2^ 7
`7V&I4"5;8TMQ8U& Qp7
7€U& QpN!4"5XI>UVU& &&SI4"5?&  4"
5?&"8IF . . U& Qp7
(7' W|0Q. U2'&?&&U> &Q&?NQ. H</L
b&Q.8"!Q.U3&2'&?&&7
-7&"VU& Qp??y>NU& QpQ.4"57[&";
4"5Q. 2'&?&&UEF0SU& QpL!H2Q. W
|0N!!S5q4"5Q.  27
+7B 02'&?&&UEF`C8 0>hb R!Q.U
2sIQ.8E1U1"S7
x70 `C8 01Q12I!"!7
e7H2'&?&&UQ. 0I<7BS? 0?</Lb&2Q.
Qp 0N7
*7H0NsMQ. 00!Q0N"RN.=7`8v
`
•=7(
8v
`
•=7+8v
`
 4"57
)=7C2IN.)vL71?C!QpA0NNL4"5E10

 Y1?C3&Qp0NZi1?CQ.?&"8f"&1?C7
τ_'7O
4. Tính toán kết quả:
iEW?CN":L&?yM?"5IτTMQi
50Np7
<.QyES"|f"&b&M?"5ItTMQi50Np
S/01;&?0 ϕQ.NUc7
5. Kết quả thí nghiệm
B<f"W '$%()**,)**-
Mẫu thử - Specimen Mẫu thử
1
Mẫu thử 2 Mẫu thử
3
First Trial Second
Trial
Third
Trial
Ban đầu Initial Độ ẩm - Moisture Content, % 74.2 74.2 74.2
Dung trọng ướt - Wet Density, g/cm
3
1.52 1.52 1.52
Dung trọng khô - Dry Density, g/cm
3
0.87 0.87 0.87
Giai đoạn cắt Shear
Stage
Ứng suất chính - Normal stress,
kG/cm
2
0.2 0.4 0.6

%"l$mn e \[[$=e-))`===`

Ứng suất cắt - Max. shear stress,
kG/cm
2
0.11 0.11 0.13
Chuyển vị ngang - Hor. Displacement,
mm
3.75 3.25 2.75
Sức kháng cắt Góc ma sát trong - Internal Friction
Angle φ
2°08'


Shear Strength Lực dính - Cohesion c, kG/cm
2
0.103
BÀI 5:
THÍ NGHIỆM NÉN CỐ KẾT
Y !""#n[\`(->
'$%(`=={)**-Z
%"l$mn * \[[$=e-))`===`

1. Mục đích
01?C^NL&
01A?C^'
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>A?C6'
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>A?CNLiE<'

α
01?CC8<'
Q

01 U"N]E<U
2. Dụng cụ thí nghiệm
•hhC8<
•hh4",2>&EFU.>U&
•hhH4"kQ.2M&
•'89":2/0=7=)
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3. Trình tự tiến hành thí nghiệm
)754"5k,N58C5EF0UVCN54"57€8"Q.
8C5S;4"58+7`-Q.& `7-7
`75m4"5Di)={)-S/012M&7
7V&U. HU& SEFH!Q.U4"57
(7H4"0E60XQ. 02Q.]N!& 8D
<0E7
-7H4"kQ.QpM&N!!<0EQi&;?&";#:H
Qp& ?">0E>N!!4"57
%"l$mn )= \[[$=e-))`===`
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+7$HHCIQ. 0Q.SQ. 0CQ.QpM&7
x7H2M&;4"kQ. UhhC8<7

e7\I|| E<UMQ.@"AS;1?CE&R"EF87
*70UhNS;20?"5EF=7-8v`!4"kQ.EIR"
&Q.E<UM71?C^;S608 W&‚>)>
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YMN.2NL*=d2NL .E2Z7
)=7L"C6&`(>1?C^!2NRQ.?&";m0?"5
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))7…b.8<<>0Uh3&N`8v
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Ne8v
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7\P0N.
5 (8R&NL56N7
)`7 ?"C&>2M&Q.CCN"N"bR
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H4"kQ.7
)(7H4"5XQ. Np5 8S/012M&7
4. Tính toán kết quả
4.1 Vẽ đường cong nén theo thời gian e – p
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4.2 Vẽ đường cong nén theo thời gian e - logp
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•010N@C8< 5?^
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4.3 Tính hệ số cố kết C
v
theo hai phương pháp
?CC8< TsMY'
Q
Z/01 &T0
,
Y&ZzT0&N &pN.T07
YEZzT0'&?&&U&pN.T0N YZ7
zT0'&?&&US/01?C'
Q
TMQ2C8<-=dQ.T
0&N UVS/01?C'
Q
TMQ2C8<*=d7
a. Phương pháp Casagrande
%<"?kUhT0'&?&&UK?C|| "SQ1ES"
Ul!|1 N YZ7'5"L'&?&&U80UhQ.Q/01'
Q

%"l$mn )) \[[$=e-))`===`


?&",/01)==d2C8<?T5N.& S3&YHình 7-2)7}"&;/0
12E<U6U
)==
Q.f"&U
=
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)==
&/01U
-=
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-=
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h ./01
-=
7?C'
Q
/01U&!f"&?&",
-=
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Q
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 ;,

Q
{?C&MQC8<-=d>

Q
_=7)*x
j@"U.5>

-=
{&R<S<2C8<-=d>L
b. Phương pháp Taylor
 T0&N >?C|| "SQ1: ?"C
f"0KC8<Q.Qy!|1 mE:&&(Hình 7-3). R"3&|
1N. sC8<57B^ U.R"<3& R"|1Ih"
SE<UU
=
7iU
=
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3& sC8<5Y? Qh"Z7w& S3&sU
Q:Q^ &?y &S;2E<UU
*=
XC8<*=d>M
Q;&;
*=
7i;&?CC8<'
Q
 M?&",
*=
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Q
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'
=
 
 ;,

Q
{?C&MQC8<*=d>
Q
_=7e(e
j@"U.5>

-=
{&R<S<2C8<*=d>L
%"l$mn )` \[[$=e-))`===`
0.000
0.010
0.020
0.030
0.040
0.050
0.060
0.070
0.1 1 10 100 1000 10000
Th?i gian, phút
Bi?n d?ng, mm
d
100,
t
100
d

0
,t
0
d
50
,t
50

Kết quả thí nghiệm
 !""#n[\`(-j`===7
%"l$mn ) \[[$=e-))`===`

B. PHẦN THỰC HÀNH
BÀI 1 THÍ NGHIỆM XÁC ĐỊNH ĐỘ ẨM TỰ NHIÊN
[CNR

BCN2
>o
'
YZ
BCN2
•5>
o
)
YZ
BCN2
•5?58
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d-x>-*
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EK
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g=(>+
g*->`x
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d)==7
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C
WW
WW
W
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−
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o
)
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o
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,BCN2Q.4"5X?5YZ7
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⇒
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*->`x=(>+
d)==7
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=
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−
=
−
−
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WW
WW
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
Bài 2 THÍ NGHIỆM XÁC ĐỊNH DUNG TRỌNG TỰ NHIÊN
[CNR
BCNU&
Qp>w
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BCNU&
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)
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
(`>e )e>=-
"EK
ge(>(`
g+x>)e
"!,
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cmg
V
GG
w
−
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γ
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γ
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⇒
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π

⇒
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cmg
V
GG
w
=
−
=
−
=
γ
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
BÀI 3 XÁC ĐỊNH GIỚI HẠN CHẢY , GIỚI HẠN DẺO
Giới hạn chảy :
[CNR

[C0:
BCN
2>
YZ
BCN
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>
)
YZ
BCN

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5>oYdZ
) +
)(7(e =7+` `7*`
d*x>x=
` `-
)(7-x `x7(+ `)7*)
d+)>x-
 `=
)(>-e `-7+= `=7xe
dx(>xx
012#3&WM),
) `
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)==
L
m m
W x
m m
−
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−
 ;,


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8CN5#Q.2>
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8CN58Q.2>
 8CN2>
⇒
d*x>x=)==7
(e>)(*`>`
*`>`+`>=
)==7
`
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=
−
−
=
−
−
=
mm
mm
W
L
012#3&WM`,
YdZ)==7
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mm
mm

W
L
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=
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8CN5#Q.2>
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8CN58Q.2>
 8CN2>
⇒
d+)>x-)==7
-x>)(*)>`)
*)>`)(+>`x
)==7
`
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=
−
−
=
−
−
=
mm
mm
W

L
012#3&WM,
YdZ)==7
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mm
mm
W
L
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
 ;,
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)
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8CN58Q.2>
 8CN2>
⇒
dx(>xx)==7
-e>)(xe>`=
xe>`=+>`-
)==7
`
`)
=

−
−
=
−
−
=
mm
mm
W
L
i|1!%_`-&/01o

_x->+d
Giới hạn dẻo :
[CNR

BCN2
>YZ
BCN2
•5>

)
YZ
BCN2
•5?5
8>
`
YZ
2#3&5>
o

z
YdZ
) )(7-` `+7( `7+x
d)e>`*
Xác định độ ẩm :
⇒
d)e>`*)==7
-`>)(+x>`
+x>`(>`+
)==7
`
`)
=
−
−
=
−
−
=
mm
mm
W
P
Chỉ số dẻo : †
z
_o

jo
z
_x->+{`*>)e_(+>(`

sChỉ số sệt :
+->=
)e>`*+>x-
)e>`*-x>-*
=
−
−
=
−
−
=
PL
P
WW
WW
B

%"l$mn )x \[[$=e-))`===`
%

⇒
560Ug @
Bài 4 THÍ NHGIỆM CẮT TRỰC TIẾP
%"l$mn )e \[[$=e-))`===`

BCNU& QpM)>
UQ)
_(`>ee
BCNU& QpM`>
UQ`

_(`>e
BCNU& QpM>
UQ
_(`>e
BCNU& Qp"EK>
g
mmm
m
dvdvdv
dv
e(>(`

e>(`e>(`ee>(`

`)
=
++
=
++
=

BCNU& Qp)•5>
UQ)•"
_)(=>`x
BCNU& Qp`•5>
UQ`•"
_)x>x
BCNU& Qp•5>
UQ•"
_)e>=-

BCNU& Qp•5"EK>
g
mmm
m
udvudvudv
udv
+x>)e

=->)ex>)x`x>)(=

`)
=
++
=
++
=
+++
+

BCN5>
)
_
UQ)•"
{
UQ)
_)(=>`x{(`>ee_*x>*
BCN5>
`
_
UQ`•"

{
UQ`
_)x>x{(`>e_*(>*
BCN5>

_
UQ•"
{
UQ
_)e>=-{(`>e_*->``
RN&
)
_*x>*Q. 0I<QWz
)
_-=Bz&_=>-8v
`

≈
=>+x8
⇒
&!8||)+Q
⇒
)
τ
_=>)*`8v
`
RN&
`
_*(>*Q. 0I<QWz
`

_)==Bz&_)8v
`

≈
)>`x-8
⇒
&!8||`=Q
⇒
`
τ
_=>`(8v
`
RN&

_*->``Q. 0I<QWz

_`==Bz&_`8v
`

≈
`> 8
⇒
&!8||=Q
⇒

τ
_=>+8v
`
%"l$mn )* \[[$=e-))`===`


iES"|
τ
jz6!&/01NU'_=>)`Q.
)))>==
ϕ
tg
⇒
w;&?0 
e(>*`x+
‡=
=
ϕ

Bài 5 THÍ NGHIỆM NÉN CỐ KẾT
1. Độ ẩm trước khi thí nghiệm :
[CNR

BCN2
>

YZ
BCN2
•5
8>

)
YZ
BCN2
•5?58
>


YZ
2#3&5
8
>o
=
YdZ
) )(> *>`* =>)x
d-x>-*
` )(>(( `>x* `->x
"
EK
x>)(

g=(>+
g*->`x
%"l$mn `= \[[$=e-))`===`


)==7

)
=
hn
mm
mm
W
−
−
=

YdZ
 ;

,BCN2>•

_)(>x

)
,BCN2•58>•
)
_+>=(


,BCN2•5?&"8?58>•

_`x>*-

⇒
d-x>-*)==7
x>)(*->`x
*->`x=(>+
)==7

)
=
=
−
−
=
−

−
=
hn
mm
mm
W
2. Trọng lượng thể tích trước khi thí nghiệm :
[CNR

BCN
U& Qp>

U
YZ
BCNU&
Qp•58
>
`
YZ
BCNU&
Qp•5?58
>
(
YZ
NS
8
>
=
γ
Yv


Z
) (`>=x )*>x
)=`>=) )>+xv

` (>** )+>e
 (`>(` )->`
"EK (`>e )x>`x
Trọng lượng thể tích trước khi thí nghiệm :

ZvY

`
=
cmg
V
mm
d
−
=
γ
 ;
`
,BCNU& Qp•58>•


U
,BCNU& Qp>•
$,SU& Qp>


•
``
-`>-+Z7Y)(>7` cmRhV ===
π

⇒

`
=
v+x>)
-`>-+
e>(``x>)x
cmg
V
mm
d
=
−
=
−
=
γ
3. Hệ số rỗng và độ bão hòa ban đầu :

)
Z=)>=)Y
=
=
=
−

+∆
=
γ
γ
W
e
n
 ;
∆
,G3&

⇒
h
h
n
h
γ
γ
γ
γ
===∆
)

n
γ
,BCN!3&>v

•
n
γ

_)v


o
=
,2#8>d•o
=
_-*>-xd
%"l$mn `) \[[$=e-))`===`


=
γ
,NS8>v

•
=
γ
_)>+xv



(
,BCNU& Qp•5?58>•
&;,
gm
m
mm
mm
mm

m
m
mm
mm
W
d
=)>)=`
xee)>)+`-*-x>)
-)e)>`-`x>)x-*-x>=
`x>)x-)e)>` *-x>=
`x>)xZe>(`Y-*-x>=
`x>)x
)==
Ze>(`Y-x>-*
)==7
(
(
((
((
((
(
(
(
(`
=
=⇒
=⇔
+=+⇔
−=−⇔
−=−⇔

−=
−
⇔
−
−
=
\H80

(`
`+>-=)>)=``x>)x
)
cmmmm
mm
V
V
m
n
n
n
n
n
n
n
n
=−=−====⇒=
γ
γ
\.$

_$

UQ
j$

_$
UQ
j$

_-+>-`{$

_-+>-`{->`+_`)>`+




(
vxe>`
`+>`)
e>(`=)>)=`
cmg
V
mm
V
m
h
d
h
h
h
=
−

=
−
==⇒
γ

⇒
++>))
+x>)
Z-x>-*7=)>=)Y)7xe>`
)
Z=)>=)Y
=
=
=
=−
+
=−
+∆
=
γ
γ
W
e
n

x+>**
++>)
xe>`7-x>-*
)==7
)==7

7
=
7=
=
=
=
====
e
W
e
W
G
ρρ
4. Biến dạng của mẫu :

nnn
Mrrh ∆−−=∆
=
YZ
 ;
n
M∆
,J<U3&065WM>•

=
,[CE&R"6|| E<U>•


,[C65WM6|| 8X]1E<U^
3&4"5>•

z_=>`-
⇒
mmMrrh
nnn
*`>===*`>=
=
=−−=∆−−=∆
z_=>-
⇒
mmMrrh
nnn
(*>)==(*>)
=
=−−=∆−−=∆
z_)
⇒
mmMrrh
nnn
(+>`==(+>`
=
=−−=∆−−=∆
z_`
⇒
mmMrrh
nnn
xx>==xx>
=
=−−=∆−−=∆
z_(
⇒

mmMrrh
nnn
`>-==`>-
=
=−−=∆−−=∆
5. Sự thay đổi hệ số rỗng :
%"l$mn `` \[[$=e-))`===`

Z)Y
=
=
e
h
h
e
n
n
+
∆
=∆
z_=>`-
⇒

)``+>=Z++>))Y
`=
*`>=
Z)Y
=
=
=+=+

∆
=∆ e
h
h
e
n
n
⇒
-x+(>))``+>=++>)
=
=−=∆−=
nn
eee
z_=>-
⇒

)*e)x>=Z++>))Y
`=
(*>)
Z)Y
=
=
=+=+
∆
=∆ e
h
h
e
n
n

⇒
(+)e>))*e)x>=++>)
=
=−=∆−=
nn
eee
z_)
⇒

`x)e>=Z++>))Y
`=
(+>`
Z)Y
=
=
=+=+
∆
=∆ e
h
h
e
n
n
⇒
`e`>)`x)e>=++>)
=
=−=∆−=
nn
eee
z_`

⇒

-=)()>=Z++>))Y
`=
xx>
Z)Y
=
=
=+=+
∆
=∆ e
h
h
e
n
n
⇒
)-e-*>)-=)()>=++>)
=
=−=∆−=
nn
eee
z_(
⇒

+*)+>=Z++>))Y
`=
`>-
Z)Y
=

=
=+=+
∆
=∆ e
h
h
e
n
n
⇒
*+e(>=+*)+>=++>)
=
=−=∆−=
nn
eee
Hệ số cố kết :
%"l$mn ` \[[$=e-))`===`
JS"|{z
z
YBv
`Z

-=
`
)*x>=
t
H
C
v
=

Y
`
v?Z
 ;,E@U. 0_ˆ@"& 4"5

⇒
_)

-=
,&62^UR-=d2^ .E23&4"57
*=
`
e(e>=
t
H
C
v
=
Y
`
v?Z
 ;,E@U. 0_ˆ@"& 4"5

⇒
_)

*=
,&62^UR*=d2^ .E23&4"57
Hệ số thấm,
ZvY

)
77
scm
e
aC
K
tb
nv
P
+
=
ρ
 ;
n
ρ
,8CN!3&>N5EF=>==)8v

•

v
C
,?CC8<>
`
v?•
&,?C^NL3&5 8 W0N>EF)=
{-


`
v8•


`
) nn
tb
ee
e
+
=
−

zY8v

Z =>`- =>- ) ` (
ZYmmh
n
∆
mm*`>=
mm(*>)
mm(+>`
mmxx>
mm`>-
Z)Y
=
=
e
h
h
e
n
n

+
∆
=∆
)``+>=
)*e)x>=
`x)e>=
-=)()>=
+*)+>=
nn
eee ∆−=
=
-x+(>)
(+)e>)
`e`>)
)-e-*>)
*+e(>=
)
)
−
−
−
−
=
nn
nn
n
PP
ee
a
= =>=`( =>`-e=` =>)x(` =>=*-=*-

`
) nn
tb
ee
e
+
=
−
-x+(>)
)>(**x- )>*x`- )>`(-x=- )>=+(*-
-=
`
)*x>=
t
H
C
v
=
Y
`
v?Z
(>)7)=
{(
ZvY
)
77
scm
e
aC
K

tb
nv
P
+
=
ρ
)>+)+7)=
{)`
)>+(7)=
{)`
)>x)7)=
{)`
)>e7)=
{)`
)>**7)=
{)`
%"l$mn `( \[[$=e-))`===`

*=
`
e(e>=
t
H
C
v
=
Y
`
v?Z
`>*(7)=

{-
ZvY
)
77
scm
e
aC
K
tb
nv
P
+
=
ρ
)>)+7)=
{)
)>)e7)=
{)
)>`7)=
{)
)>)7)=
{)
)>(`7)=
{)
iES"|!&/01z
'
_)`=Bz&
Phương pháp Casagrande
Phương pháp Taylor
%"l$mn `- \[[$=e-))`===`

z