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Field Comparative Experiments of Pipe Pile Composite Foundation with Different Cushion Layers

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书 书 书

53

 

2018

       

西

 

 

 

 

 

 

 

JOURNAL OF SOUTHWEST JIAOTONG UNIVERSITY

        Vol. 53  No. 2 Apr. 2018

稿

20150908

:中

2682015CX008EM

:邵

1975

),女

,副

,博

,研

Email

shaoguoxia@ 126. com

:尹

1971

),男

,副

,研

Email

71yzh@ 163. com

:邵

,苏

,尹

,等

西

2018

53

):

279285. SHAO Guoxia

SU Qian

YING Zihong

et al. Field comparative experiments of pipe pile composite foundation with different cushion layers

. Journal of Southwest Jiaotong University

2018

53

):

279285.    

02582724

2018

02027907    DOI

10. 3969 / j. issn. 02582724. 2018. 02. 009

不同垫层下管桩复合地基现场对比试验研究

 

 

 

 

 

 

 

 

1.

西

,四

川成

610031

2.

,四

川成

610031

 

:为

、管

、管

,开

,分

,结

:路

,桩

、坡

,土

2. 47 ~ 5. 42

,土

2. 30 ~ 6. 25

;钢

8. 05 ~ 14. 81

;随

,土

、土

,路

,相

,稳

68. 46%

72. 56% .

:土

;土

;管

;沉

;桩

TU473   

Field Comparative Experiments of Pipe Pile Composite

Foundation with Different Cushion Layers

SHAO Guoxia

  SU Qian

  YING Zihong

  LI Ting

  XIE Kang

  CAO Zhengguo

1. School of Civil Engineering

Southwest Jiaotong University

Chengdu 610031

China

2. China Railway Eryuan Engineering Group Co. Ltd.

Chengdu 610031

China

Abstract

In order to compare the stress and evaluate the ability to control deep soft soil settlement of

three kinds of composite foundations

field experiments were carried out. Each pipe pile composite had

a different cushion layer

a reinforced concrete slab

a geocell

and a geogrid

respectively. For the

geocell and geogrid composites

a pile cap was added. Both the stress response

and the settlement

of

the pipe pile composite foundations

under different cushion layers

were analyzed. The results show

that the stress of both the pile's top surface and the soil between the piles was gradually reduced

from

the subgrade center to the shoulder. The pilesoil stress ratios were 2. 47 - 5. 42

2. 30 - 6. 25

8. 05 - 14. 81 for the geogridreinforced cushion layer

the geocellreinforced cushion layer

and the

reinforced concrete slab cushion layer

respectively. As the load of the subgrade filling increased

the

tensile strength of both the geogrid and the geocell gradually increased

and maximum tension occurred

at the shoulder. The tensile strength of the geocell was greater than that of the geogrid

under the same

load. The composite foundation of a pipe pile

plus a reinforced concrete slab is the best for controlling

the settlement of the subgrade filling

and the settlement of the ground surface contributes 68. 46% and

(2)

西

 

 

 

 

 

 

 

53

72. 56% of entire settlement of the pipe pilepile capgeogrid and the pipe pilepile capgeocell

composite foundations

respectively.

Key words

geocell

geogrid

pipe pile composite foundation

settlement

pilesoil stress ratio

   

线

15 mm

,为

,在

线

、土

,使

,提

,减

,为

,对

、桩

115

,但

线

、管

、管

、沉

,研

,并

,指

,达

、经

1 

 

 

某无砟轨道客运专线的设计时速为

350 km / h

,管

复合地基试验段范围覆盖层由黄

,表

4 al

)黏

、粉

,其

3 al

)黏

、粉

(可

)厚

30 ~ 49 m.

了预应力管桩

钢筋混凝土板复合地基

DK280 + 228

)、预

DK280 + 651

)、预

DK281 + 347. 10

2 

   

DK280 + 228

,采

PHC

,桩

0. 4 m

,桩

2. 4 m

,正

,长为

35. 0 m

,桩顶铺设

0. 2 m

的碎石垫

,其

0. 6 m

C45

)预

)预

)预

1 

(单

Fig. 1  Foundation profile and test component layout

unit

   

DK280 + 651

,采

PHC

,桩

0. 4 m

,桩

2. 2 m

,正

布置

,桩长为

32. 0 m

;桩帽截面为

0. 8m ×

0. 8 m × 0. 3 m

,混

C45

;桩

0. 6 m

的碎石垫层

,其内铺设抗拉强度不低于

200 kN / m

,在

部设置盐渍土隔

,由

0. 2 m

厚中粗砂夹铺一层复合土工膜

(3)

,等

:不

DK281 + 347. 10

,采

PHC

0. 4 m

,桩

2. 4 m

,正

,桩

32. 0 m

;桩

1. 2 m × 1. 2 m ×

0. 35 m

,强

C45

;桩

0. 6 m

,其

250 kN / m

工格栅

,在垫层上部设置盐渍土隔断层

,由

0. 2 m

3 

3. 1 

、土

   

,测

沿

,因

线

(即

线

,“路

”左

2. 5 m

)、

、管

、管

线

DK280 + 228

DK280 + 651

DK281 + 347

2 

线

Fig. 2  Soil stress curves between the piles

DK280 + 228

DK280 + 651

DK281 + 347

3 

线

Fig. 3  Piletop stress curves

   

:不

,桩

、桩

,随

,受

线

,桩

,主

(4)

西

 

 

 

 

 

 

 

53

,在

,在

;由

,路

、线

、路

,同

,桩

;在

线

,在

,说

,路

,复

;在

,桩

,而

;由

,并

,说

,上

部荷载逐渐由桩间土转向管桩承

;填

,桩

,逐

,由

)可

,由

,筏

,说

3. 2 

   

,图

线

:在

,上

,管

,桩

、土

,桩

;随

,由

间土刚度

,管桩分担的荷载越来越

,不

;在

,桩

,路

、路

,但

,根

]研

,管

、稳

DK280 + 228

DK280 + 651

DK281 + 347. 1

4 

线

Fig. 4  Pilesoil stress ratio curves

   

:同

;桩

;土

,筏

,土

、土

、梁

,对

,将

,提

,在

1 

Tab. 1  Pilesoil stress ratios at the pipe pile area

after soil filling

心 路

肩 坡

心 路

肩 坡

心 路

肩 坡

/ kPa 604. 3 520. 5 178. 0 233. 1 198. 2 73. 0 288. 6 238. 6 67. 2

/ kPa 40. 8 38. 6 22. 1 43. 0 39. 0 29. 5 46. 2 41. 3 29. 2

14. 81 13. 48 8. 05 5. 42 5. 08 2. 47 6. 25 5. 78 2. 30

(5)

,等

:不

3. 3 

、土

   

、抗

,通

土工格室垫层所具有的强抗剪能

,改

,使

,达

,增

,提

,相

,将

、土

,距

线

、土

填土高度和预压时间下

,垫层土工格

、土

工格室拉力沿路基横向分布规律如图

DK280 + 651

DK281 + 347. 1

5 

线

Fig. 5  Tension curves of the reinforced material

DK280 + 651

DK281 + 347. 1

6 

沿

Fig. 6  Lateral tension distribution of the reinforced material

   

:随

,各

、土

,增

速率正相关

;当填土荷载处于稳定

,土

、土

,在

,路

、土

,线

,路

、土

(6)

西

 

 

 

 

 

 

 

53

2.

,路

、路

、坡

,与

]和

13

]研

,路

、土

1. 04 kN

,土

2. 5 cm × 2. 5 cm

,沿

线

1. 0 m

40

,则

沿

线

路纵向

1. 0 m

范围内土工格栅最大拉力为

41. 47 kN.

拉力最大值为

4. 39 kN

,土工

40 cm × 40 cm

,考

线

45°

,故

沿

线

1. 0 m

1. 55 kN

;单

0. 45 mm

,网

50 mm

,网

68. 4 MPa.

2 

、土

Tab. 2  The tension of the geocell and geogrid

kN

·

- 1

/ kN

心距

3. 3m

处靠

2. 5 cm × 2. 5 cm 250 0. 461 0. 922 0. 653 0. 250

40 cm × 40 cm × 5 cm 200 1. 080 2. 800 3. 870 1. 910

3. 4 

   

线

7 

线

Fig. 7  Surface settlement curves of the pipepile composite foundation with different types of cushion layer

:管

(土

)复

,其

(土

)的

68. 46% ~ 72. 56%

;桩

,主

,垫

,从

;在

,随

,地

,填

,并

线

、缓

4 

 

   

)路

,桩

沿

、坡

2. 30 ~ 6. 25

2. 47 ~ 5. 42

,说

,现

8. 05 ~ 14. 81

,混

)对

、土

,随

,土

、土

;稳

,路

,在

)两

,土

,混

68. 46%

72. 56% .

 

,龚

2008

29

):

712. LIAN Feng

GONG Xiaonan. Field test study on the improvement mechanism of pilenet composite foundation

. China Railway Science

2008

29

):

参照

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