40 5 ( ) Vol.40 No.5 2009 10 Journal of Central South University (Science and Technology) Oct. 2009 1, 2 2 2 1 (1. 410083 2. 430071) 2 3.7 mm 5.7 mm 3.1 mm 9.2 mm TU471.7 A 1672 7207(2009)05 1451 06 Test and mechanism of horizontal plastic drain in permafrost regions embankment HU Jian-hua 1, 2, WANG Ren 2, HU Ming-jian 2, ZHOU Ke-ping 1 (1. Hunan Key Laboratory of Mineral Resources Exploitation and Hazard Control for Deep Metal Mines, School of Resources and Safety Engineering, Central South University, Changsha 410083, China; 2. Key Laboratory of Rock and Soil Mechanics Institute of Rock and Soil Mechanics, Chinese Academy of Science, Wuhan 430071, China) Abstract: In order to solve the frost heave and thaw settlement, the model tests were made in Tibetan Plateau. Two kinds of model were designed to horizontal drain structure embankment and the ventilation embankment in suit. The effect of horizontal plastic drain was analyzed in contrast with the ventilation embankment. The mechanisms of horizontal plastic drain were studied in permafrost, such as gravity draining in the superficial layer and structure stiffing in the embankment in the theory. According to the design theory, the parameters of horizontal plastic drain were confirmed in the embankment. The values of deformation were inspected by fiber monitor system in the permafrost embankment. The results show that the time of the frost heave is shortened, the time of relatively steady freeze is prolonged. From the deformation, the range and value of the frost heave are decreased. In the embankment of the horizontal plastic drain, the max value of thaw settlement is up to 3.7 mm, and the cumulative value of the frost heave is up to 5.7 mm. To the contrast embankment, the values are 3.1 and 9.2 mm respectively. It is indicated that the rainfall seepage is controlled to the embankment in superficial layer, the influence of precipitation and evaporation are weaken, the deformation values of the frost heave are decreased in the horizontal plastic drain embankment. Key words: permafrost; horizontal plastic drain; fiber monitor; deformation 2008 09 12 2008 12 09 (KZCX12SW204) (07SDF10) (Z110703) (1975 ) 0731-88879965 E-mail: hujh21@126.com
1452 ( ) 40 2 3.5% [1] [2] [3] 1 ( 1) 1 Fig.1 Structure of horizontal plastic drain 1.1 [4] 2 2 1.09 [5] 1.2 [5] a. b.
5 1453 c. 2 3 [6 8] 2.1 [9 10] ( ) ( 2) 5 7 9 K 1 2 3 4 2 Fig.2 Relation between rainfall or vaporize and time in Tibet [11] [8] 2.2 ( ) 3 3.1 [12 13] d w
1454 ( ) 40 d w a + b = α 2 α a b 3 m 18 3.6 m d w 34 mm a. 1 b. 3.6 m d w 34 mm c. 15 cm w op 2%( w op ) 90% 3.2 3 4~11 11~1 1~3 3 ( ) [9] [14 15] 1.60 3.10 5.10 7.60 m( 3) 4 9 2 1 4 2 3 Fig.3 Picture of fiber probe position /m 1 1.6; 2 3.1; 3 5.1; 4 7.6 4 Fig.4 Distortion curves in horizontal drain embankments 4 1.6 m 4.3 mm ; 2.9 m ( ) 80% 3.1 m 4 mm 3.7 mm 1.7 mm 10 3.1 m 11 4 1 1 3.1 m 5.7 mm
5 1455 1.6 m 5.4 mm 1.6~3.1 m 3.1 m 3.1 m 5 5 a. b. c. 3.7 mm 5.7 mm 3.1 mm 9.2 mm /m 1 1.6; 2 3.1; 3 5.1; 4 7.6 5 Fig.5 Distortion curves in ventilation pipes embankments 5 1.6 m 3.1 mm 3.1 5.1 7.6 m 2.8 2.0 1.1 mm 10 1.6 3.1 5.1 m 1 1 3 8.0 mm 5.1 m 9.2 mm (9.2 mm) 2 (5.4 mm) 1.6~3.1 m 1.6~5.1 m [1]. [J]., 2002, 17(1): 21 25. CHENG Guo-dong. Interaction between Qinghai-Tibet railway engineering and permafrost and environmental effects[j]. Bulletin of the Chinese Academy of Sciences, 2002, 17(1): 21 25. [2],,. [J]., 2002, 24(5): 579 587. MA Wei, CHENG Guo-dong, WU Qing-bai. Preliminary study on technology of cooling foundation in permafrost regions[j]. Cold Regions Science and Technology, 2002, 24(5): 579 587. [3],,,. [J]. :, 2006, 37(3): 600 603. HU Jian-hua, WANG Ren, HU Mian-jian, et al. Thermo-mechanism of improved graded structural embankment in permafrost regions[j]. Journal of Central South University: Science and Technology, 2006, 37(3): 600 603. [4],. [M]. :, 1995. LI Shu-xun, CHENG Guo-dong. Problem of heat and moisture transfer in freezing and thawing soils[m]. Lanzhou: Lanzhou
1456 ( ) 40 University Press, 1995. [5],,. [J]., 1996, 18(4): 297 305. CHEN Lun, GUO Rui-ping, LI Guan-xin. Study on prevention of frost heaving of reinforced soils[j]. Journal of Glaciology and Geocryology, 1996, 18(4): 297 305. [6],,. [M]. :, 2001. XU Xue-zu, WANG Jia-cheng, ZHANG Li-xin. Frozen soil physics[m]. Beijing: Science Press, 2001. [7] ZHANG Yin-sheng, Ohata T, Kadota T. Land-surface hydrological processes in the permafrost region of the eastern tibetan plateau[j]. Journal of Hydrology, 2003, 283(1/4): 41 56. [8] Simonsen E, Isacsson U. Thaw weakening of pavement structures in cold regions[j]. Cold Regions Science and Technology, 1999, 29(2): 135 151. [9]. [D]. :, 2001. WANG Tie-hang. Study on embankment calculation principle and critical height in frozen soil zone[d]. Xi an: Highway School of Chang an University, 2001. [10] WU Qing-bai, LIU Yong-zhi. Ground temperature monitoring and its recent change in Qinghai-Tibet Plateau[J]. Cold Regions Science and Technology, 2004, 38(2/3): 85 92. [11],,,. [M]. :, 1998. WU Zi-wang, CHENG Guo-dong, ZHU Lin-nan, et al. Embankment engineering of frozen soils[m]. Lanzhou: Lanzhou University Press, 1998. [12],,,. [J]., 2002(4): 28 32. GAO Chang-sheng, ZHANG Ling, WANG Zhao-jing, et al. Equivalent diameter of prefabricated drains[j]. Hydro-Science and Engineering, 2002(4): 28 32. [13]. [J]., 2002, 31(1): 41 42. HE Kai-sheng. Foundation treatment technique of method of vibration and roller compaction of horizontal drain board[j]. Construction Technology, 2002, 31(1): 41 42. [14],,,. [J]., 2002, 24(5): 601 607. YU Wen-bing, LAI Yuan-ming, LIU Fu-jun, et al. Temperature field features in the laboratory experiment of the ventilated railway embankment in permafrost regions[j]. Journal of Glaciology and Geocryology, 1992, 24(5): 601 607. [15],,,. [J]., 2005, 26(8): 1288 1293. WU Zhi-jian, MA Wei, SHENG Yu, et al. Cooling effectiveness analysis of the vent-pipe, cast-detritus and heat preservation material on protecting embankment in permafrost regions[j]. Rock and Soil Mechanics, 2005, 26(8): 1288 1293.