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土壤水泥技術改良廢棄土及渥太華砂之性質

在文檔中 1.3 研究流程 (頁 117-140)

第五章 廢棄土之性質

2. 在28 days 抗剪強度方面,其凝聚力 c 與內摩擦角 φ 分別為如下:

6.3 土壤水泥技術改良廢棄土及渥太華砂之性質

試體在養護28

days後,

其凝聚力 c 與內摩擦角

φ分別為如下:

當 水泥含量為2%時, c

=5.24

kPa

、φ=35.3°

;當水泥含量為4%時,

c

=14.79

kPa

、φ=32.5°

;當水泥含量為8%時,c

=76.53

kPa

、φ=28.4°

; 當水泥含量為12%時,c

=129.04

kPa

、φ=59.3°

;當水泥含量為16%

時, c

=280.61

kPa

、φ=56.8°

由試驗結果可以看出,抗剪強度隨著水泥量的增加而有提升,

不論齡期是7天或是28天都有此趨勢。但是,內摩擦角隨著水泥量

的增加之關係,就沒有那麼明顯。在水泥含量 a

w=

2%及4%時,由

添加水泥含量低,又因齡期短及材料為砂質等原因下,水分不足而

使水化反應不佳,使其強度在7天及28天有相同之趨勢;而在水泥

含量 a

w=

8%以上時,其抗剪強度也隨齡期增加而提升。

試體而言,廢棄土之凝聚力 c 分別約為渥太華砂之0.51倍、0.79倍、

3.22倍、3.01倍及0.57倍;而對養護齡期28天之試體而言,廢棄土 之凝聚力c 分別約為渥太華砂之12.23倍、3.74倍、1.27倍、1.48倍 及1.08倍。

由此可知,在

土壤水泥

改良技術上,施行無圍壓縮試驗時,以 渥太華砂為標準值,是為可行方案之一;但施行直接剪力試驗時,

卻仍有待研究。但整體觀之,渥太華砂又稱標準砂,其建立起一組

標準比較值仍是有其潛力性。在此,吾人只是做初步之探討,仍有

其諸多改善之空間,故此研究結果能為他處有所參考。

表6.1 土壤水泥夯實試驗結果 Cement content

aw (%)

Moisture Content

w (%)

Dry unit weight γd (kN/ m3)

0 15.1 17.40

12.5

(Dry side) 17.23

14.5

(Optimum) 17.55

2

16.5

(Wet side) 17.05

11.8

(Dry side) 17.08

13.8

(Optimum) 17.35

4

15.8

(Wet side) 17.12

13.3

(Dry side) 17.04

15.3

(Optimum) 17.18

8

17.3

(Wet side) 16.95

11.3

(Dry side) 16.83

13.3

(Optimum) 17.12

12

15.3

(Wet side) 17.02

13.5

(Dry side) 16.77

15.5

(Optimum) 17.15

16

17.5

(Wet side) 16.98

表6.2 無圍壓縮試驗結果一覽表 Cement

content aw (%)

Moisture content w (%)

Dry unit weight γd (kN/m3)

Curing time tc (days)

Axial strain at

failure

ε

f (%)

Unconfined compression

strength qu (kPa)

Secant modulus

E50

(MPa)

Impact value

I v

0 15.1 17.40 0 1.7 57 5.3 - 16.5

(Wet side) 17.05 7 1.0 254 25.6 13.4

12.5

(Dry side) 17.23 1.1 621 62.4 25.1

14.5

(Optimum) 17.55 1.0 548 55.0 19.7

2

16.5

(Wet side) 17.05

28

1.0 649 81.4 18.8 15.8

(Wet side) 17.12 7 0.9 708 89.0 26.6

11.8

(Dry side) 17.08 0.9 848 106.4 27.3

13.8

(Optimum) 17.35 1.1 859 107.8 25.5

4

15.8

(Wet side) 17.12

28

1.0 1081 90.5 28.7 17.3

(Wet side) 16.95 7 0.9 813 102.1 21.8

13.3

(Dry side) 17.04 1.0 1508 126.1 33.6

15.3

(Optimum) 17.18 1.5 1480 123.8 39.7

8

17.3

(Wet side) 16.95

28

1.4 1852 132.8 26.9 15.3

(Wet side) 17.02 7 1.1 1167 117.2 29.8

11.3

(Dry side) 16.83 1.2 1670 167.7 35.0

13.3

(Optimum) 17.12 1.1 1589 132.4 35.6

12

15.3

(Wet side) 17.02

28

1.3 2313 193.5 47.7 17.5

(Wet side) 16.98 7 1.3 1747 146.2 44.4

13.5

(Dry side) 16.77 1.3 2259 189.0 47.7

15.5

(Optimum) 17.15 1.0 2042 205.1 50.3

16

17.5

(Wet side) 16.98

28

1.4 2484 207.8 52.1

表6.3 直接剪力試驗結果一覽 Cement

content a (%) w

Moisture content

w (%)

Dry unit weight γd (kN/ m3)

Curing time t (c days )

Cohesion c (kPa)

Friction angle φ (°) 0 15.1

(Optimum) 17.40 0 0 40.9

7 2.67 43.7 2 16.5

(Wet side) 17.05

28 64.12 24.7 7 12.38 53.4 4 15.8

(Wet side) 17.12

28 55.36 53.1 7 56.07 49.0 8 17.3

(Wet side) 16.95

28 96.89 50.2 7 94.71 49.7 12 15.3

(Wet side) 17.02

28 190.73 39.2 7 119.48 55.3 16 17.5

(Wet side) 16.98

28 302.09 23.7

表6.4 乾濕試驗結果

乾濕循環後 土樣 水泥含量

(%)

含水量

(%) 重量損失率 (%)

重量變化率 (%)

2 10.34 -8.58

4 2.67 -1.82

8 1.28 -0.11

12 0.72 0.25

16

OMC

0.68 0.46

2 12.99 -11.05

4 3.31 -2.31

8 1.47 -0.17

12 0.89 0.03

Material A

16

+2 OMC

0.86 0.14

表6.5 渥太華砂無圍壓縮試驗結果一覽表 Cement

content a (%) w

Moisture content

w (%)

Dry unit weight

γd

(kN/ m3)

Curing time

t c

( days )

Unconfined compression

strength qu (kPa)

Secant modulus

E50

(MPa)

7 - - 2 17.08

28 45 22.6 7 156 78.5 4 13.06

28 334 83.9 7 567 95.0 8 12.32

28 1150 96.2 7 1625 116.6 12 11.44

28 2401 120.5 7 2677 134.4 16

16

16.55

28 5418 143.1

表6.6 渥太華砂直接剪力試驗結果一覽表 Cement

content a (%) w

Moisture content

w (%)

Dry unit weight γd (kN/ m3)

Curing time t ( days ) c

Cohesion c (kPa)

Friction angle

φ(°)

7 5.25 26.8 2 17.08

28 5.24 35.3 7 15.65 31.7 4 13.06

28 14.79 32.5 7 17.41 37.9 8 12.32

28 76.53 28.4 7 31.51 63.2 12 11.44

28 129.04 59.3 7 209.33 52.1 16

16

16.55

28 280.61 56.8

表6.7 廢棄土與渥太華砂無圍壓縮試驗比較結果一覽表 Waste soil Ottawa

Cement content a (%) w

Curing time

t c

( days )

Unconfined compression

strength qu (kPa)

Unconfined compression

strength qu (kPa)

7 254 -

2 28 548 45

7 708 156 4 28 859 334

7 813 567 8 28 1480 1150

7 1167 1625 12 28 1589 2401

7 1747 2677 16 28 2042 5418

表6.8 廢棄土與渥太華砂直接剪力試驗結果比較一覽表 Waste soil Ottawa Cement

content a (%) w

Curing time t ( days ) c

Cohesion c (kPa)

Friction angle

φ(°)

Cohesion c (kPa)

Friction angle

φ(°)

7 2.67 43.7 5.25 26.8 2 28 64.12 24.7 5.24 35.3

7 12.38 53.4 15.65 31.7 4 28 55.36 53.1 14.79 32.5 7 56.07 49.0 17.41 37.9 8 28 96.89 50.2 76.53 28.4 7 94.71 49.7 31.51 63.2 12 28 190.73 39.2 129.04 59.3

7 119.48 55.3 209.33 52.1 16 28 302.09 23.7 280.61 56.8

15.0 15.5 16.0 16.5 17.0 17.5 18.0

6 8 10 12 14 16 18 20 22 24

Moisture content (%) Dry unit weight (kN/m3 )

0 2 4 8 12 16

aw (%) Material A

圖6.1 不同水泥含量之夯實曲線

圖 6.2 無圍壓縮試驗之試體破壞情形

0 500 1000 1500 2000 2500 3000

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Axial strain (%)

Axial stress (kPa)

0 2 4 8 12 16 w(%) = OMC +2 tc = 7 days

aw (%) Material A

圖 6.3 試體之無圍壓縮應力-應變行為(tc=7 days

0 500 1000 1500 2000 2500 3000

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Axial strain (%)

Axial stress (kPa)

0 2 4 8 12 16 w(%) = OMC-2 tc = 28 days

aw (%) Material A

圖6.4 試體之無圍壓縮應力-應變行為(tc= 28 daysOMC−2%)

0 500 1000 1500 2000 2500 3000

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Axial strain (%)

Axial stress (kPa)

0 2 4 8 12 16 w(%) = OMC tc = 28 days

aw(%) Material A

圖6.5 試體之無圍壓縮應力-應變行為(tc= 28 daysOMC

0 500 1000 1500 2000 2500 3000

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Axial strain (%)

Axial stress (kPa)

0 2 4 8 12 16 w(%) = OMC+2 tc = 28 days

aw (%) Material A

圖6.6 試體之無圍壓縮應力-應變行為(tc= 28daysOMC+2%)

0 500 1000 1500 2000 2500 3000

0 2 4 8 12 16

Cement content (%)

Compression strength (kPa)

OMC-2 OMC OMC+2

Material A tc= 28 days

圖6.7 試體於養護二十八天不同含水量下

a

w

q

u之關係

0 500 1000 1500 2000 2500 3000

7 28

Curing time (days)

Compression strength (kPa)

2 4 8 12 16

Material A w (%) = OMC+2

圖 6.8 試體於不同齡期時

a

w

q

u之關係

圖6.9 割線模數定義

0 50 100 150 200 250

0 2 4 8 12 16

Cement content (%)

Secant modulus (MPa)

OMC-2 OMC OMC+2

Material A tc= 28 days

圖 6.10 割線模數與水泥含量關係(

t

c= 28days

0 50 100 150 200 250

7 28

Curing time (days)

Secant modulus (MPa)

2 4 8 12 16

Material A w (%) = OMC+2

圖 6.11 割線模數與齡期關係(

OMC

+2%)

圖6.12 直接剪力試驗之試體破壞情形

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

Normal stress = 150kPa

100kPa 50kPa

Material A w(%) = OMC+2 tc = 7 days aw = 2 %

圖6.13 剪位移與剪應力關係圖(

a

w=2%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

Normal stress = 150kPa

100kPa

50kPa

Material A w(%) = OMC+2 tc = 7 days aw = 4 %

圖6.14 剪位移與剪應力關係圖(

a

w=4%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

100kPa 50kPa

Material A w(%) = OMC+2 tc = 7 days aw = 8 %

Normal stress = 150kPa

圖6.15 剪位移與剪應力關係圖(

a

w=8%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

100kPa 50kPa

Material A w(%) = OMC+2 tc = 7 days aw = 12 %

Normal stress = 150kPa

圖6.16 剪位移與剪應力關係圖(

a

w=12%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

Normal stress = 150kPa

100kPa 50kPa

Material A w(%) = OMC+2 tc = 7 days aw = 16 %

圖6.17 剪位移與剪應力關係圖(

a

w=16%)

0 100 200 300 400 500 600

0 50 100 150 200

Normal stress (kPa)

Shear stress (kPa)

Material A w(%) = OMC+2 tc = 7 days

aw = 16 %

12 % 8 %4 %

2 % 0 %

圖 6.18 抗剪強度之比較(

t

c= 7days

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

Normal stress = 150kPa 100kPa

50kPa

Material A w(%) = OMC+2 tc = 28 days aw = 2 %

圖6.19 剪位移與剪應力關係圖(

a

w=2%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

Normal stress = 150kPa

100kPa 50kPa

Material A w(%) = OMC+2 tc = 28 days aw = 4 %

圖6.20 剪位移與剪應力關係圖(

a

w=4%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

100kPa 50kPa

Material A w(%) = OMC+2 tc = 28 days aw = 8 %

Normal stress = 150kPa

圖6.21 剪位移與剪應力關係圖(

a

w=8%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

100kPa 50kPa

Material A w(%) = OMC+2 tc = 28 days aw = 12 % Normal stress = 150kPa

圖6.22 剪位移與剪應力關係圖(

a

w=12%)

0 100 200 300 400 500 600

0 1 2 3 4 5 6

Shear displacement (mm)

Shear stress (kPa)

Normal stress = 150kPa 100kPa

50kPa

Material A w(%) = OMC+2 tc = 28 days aw = 16 %

圖6.23 剪位移與剪應力關係圖(

a

w=16%)

0 100 200 300 400 500 600

0 50 100 150 200

Normal stress (kPa)

Shear stress (kPa)

Material A w(%) = OMC+2 tc = 28 days

aw = 16 % 12 %

8 % 4 %

2 % 0%

圖 6.24 抗剪強度之比較(

t

c= 28days

0 100 200 300 400 500

7 28

Curing time (days) Shear strength (kN/m2 )

2 4 8 12 16

Material A w (%) = OMC+2 Normal srtess = 100 kN/m2

圖6.25 不同水泥含量在不同齡期下之剪力強度(

OMC

+ 2%)

0 2 4 6 8 10 12 14

0 5 10 15 20

Cement content (%)

Weight loss (%)

OMC OMC+2

圖 6.26 乾濕循環之重量損失圖

-12 -10 -8 -6 -4 -2 0 2

0 5 10 15 20

Cement content (%)

Weight change (%)

OMC OMC+2

圖 6.27 乾濕循環之重量改變圖

y = 54x - 429.6 R2 = 0.853

0 500 1000 1500 2000 2500 3000

0 10 20 30 40 50 60

Impact value

Axial stress (kPa)

圖6.28 衝擊值與無圍壓縮強度之關係

y = 4.1578x - 11.975 R2 = 0.8603

0 50 100 150 200 250

0 10 20 30 40 50 60

Impact value

Secant modulus (MPa)

圖6.29 衝擊值與割線模數之關係

圖6.30 渥太華砂無圍壓縮試驗之試體破壞情形

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Axial strain (%)

Axial stress (kPa)

4 8 12 16

Ottawa w(%) =16 tc = 7 days aw

圖6.31 渥太華砂之無圍壓縮應力-應變行為(

t

c= 7days

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Axial strain (%)

Axial stress (kPa)

2 4 8 12 16

Ottawa w(%) = 16 tc = 28 days aw

圖6.32 渥太華砂之無圍壓縮應力-應變行為(

t

c= 28days

圖6.33 直接剪力試驗之試體破壞情形

0 100 200 300 400 500 600

0 50 100 150 200

Normal stress (kPa)

Shear stress (kPa)

Ottawa w = 16 % tc = 7 days

aw = 16 %

12 %

8 % 4 % 2 %

圖 6.34 渥太華砂抗剪強度之比較(

t

c= 7days

0 100 200 300 400 500 600

0 50 100 150 200

Normal stress (kPa)

Shear stress (kPa)

Ottawa w = 16 % tc = 28 days

aw = 16 % 12 %

8 % 4 % 2 %

圖 6.35 渥太華砂抗剪強度之比較(

t

c= 28days

在文檔中 1.3 研究流程 (頁 117-140)