开口管桩贯入特性的大尺度模型试验
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摘要
开口管桩由于其承载力高、质量可靠、施工方便等优点得到越来越广泛的应用.土塞的生成使得开口管桩沉桩阻力不同于闭口管桩,不仅包括桩外侧摩阻力、桩端阻力,桩内侧摩阻力亦是其重要组成部分.针对开口管桩沉桩受力特性,采用自主研发的大尺度模型试验装置,进行不同桩靴形式下开口管桩的贯入试验,并与闭口管桩进行对比分析.研究表明,开口管桩随沉桩深度的增加趋于闭塞,沉桩阻力随沉桩过程基本呈线性增加,桩内、外侧单位摩阻力均存在"侧阻退化"效应;桩体贯入时桩周地表隆起量随径向距离增加逐渐减小,隆起速率随沉桩深度增加逐渐变缓,桩周土影响范围约为5～7倍桩径;桩靴对开口管桩土塞生成、沉桩阻力和挤土效应均有重要影响,内30°桩靴土塞生成高度、桩内侧摩阻力及其所占总沉桩阻力比例最大,桩周土地表隆起量最小,外30°桩靴与内30°桩靴情况相反,直角桩靴居中;闭口管桩沉桩阻力、外侧摩阻力与挤土程度均大于开口管桩.
The open pipe pile is widely used because of its high bearing capacity,reliable quality,and convenient construction.The formation of the soil plug makes the total resistance of the open pipe pile different from that of the closed pipe pile. The bearing capacity of the open pipe pile includes three parts: the external friction of the pile,the pile end resistance,and the pile inside the friction. According to the stress characteristics of open pipe piles during installation,a self-developed large-scale laboratory test apparatus was used to test the penetration of open pipe piles under different forms of pile boots,and based on the results,the open pipe pile was compared with closed pipe pile. The results show that the open pipe pile tends to be occluded with the increase of pile depth. The resistance of pile increases linearly with the pile sinking process,while the frictional resistance inside and outside the pile has "lateral degeneration effect. "The influence range of surface displacement decreases with the increase of radial distance. The uplift rate gradually reduced with the increasing depth of pile sinking. The influence range of soil around pile is about 5 to 7 times of pile diameter. The pile shoe affects the height of the soil plug,pile resistance distribution,internal and external frictional resistance,and the effect ofpushing against soil. The pile of 30° inside pile boots has the largest height of soil plug formation,as well as the maximum friction resistance and the maximum proportion of total pile resistance. The amount of surface soil uplift around the pile is the smallest. The outer 30° pile boot is opposite to the inner 30° pile boot,while the right-angle pile boot is centered. The resistance,lateral friction,and soil compaction of closed-end pipe pile are greater than those of the open pipe pile.
The open pipe pile is widely used because of its high bearing capacity,reliable quality,and convenient construction.The formation of the soil plug makes the total resistance of the open pipe pile different from that of the closed pipe pile. The bearing capacity of the open pipe pile includes three parts: the external friction of the pile,the pile end resistance,and the pile inside the friction. According to the stress characteristics of open pipe piles during installation,a self-developed large-scale laboratory test apparatus was used to test the penetration of open pipe piles under different forms of pile boots,and based on the results,the open pipe pile was compared with closed pipe pile. The results show that the open pipe pile tends to be occluded with the increase of pile depth. The resistance of pile increases linearly with the pile sinking process,while the frictional resistance inside and outside the pile has "lateral degeneration effect. "The influence range of surface displacement decreases with the increase of radial distance. The uplift rate gradually reduced with the increasing depth of pile sinking. The influence range of soil around pile is about 5 to 7 times of pile diameter. The pile shoe affects the height of the soil plug,pile resistance distribution,internal and external frictional resistance,and the effect ofpushing against soil. The pile of 30° inside pile boots has the largest height of soil plug formation,as well as the maximum friction resistance and the maximum proportion of total pile resistance. The amount of surface soil uplift around the pile is the smallest. The outer 30° pile boot is opposite to the inner 30° pile boot,while the right-angle pile boot is centered. The resistance,lateral friction,and soil compaction of closed-end pipe pile are greater than those of the open pipe pile.
引文
[1] Kishida H,Isemoto N. Behaviour of sand plugs in open-end steel pipe piles//Proceedings of the 9th International Conference on Soil Mechanics and Foundation Engineering. Tokyo,1977:601
[2] Paikowsky S G,Whitman R V. The effects of plugging on pile performance and design. Can Geotech J,1990,27(4),429
[3] Brucy F,Meunier J,Nauroy J F. Behavior of pile plug in sandy soils during and after driving//Offshore Technology Conference.Houston,1991:145
[4] Lehane B M,Gavin K G. Base resistance of jacked pipe piles in sand. J Geotech Geoenviron Eng,2001,127(6):473
[5] Xie Y J,Wang H Z,Zhu H H. Soil plugging effect of PHC pipe pile during driving into soft clay. Rock Soil Mech,2009,30(6):1671(谢永健,王怀忠,朱合华.软黏土中PHC管桩打入过程中土塞效应研究.岩土力学,2009,30(6):1671)
[6] Zhou J,Chen X L,Zhou K M,et al. Model test and numerical simulation of driving process of open-ended jacked pipe piles.Chin J Rock Mech Eng,2010,29(Suppl 2):3839(周健,陈小亮,周凯敏,等.静压开口管桩沉桩过程模型试验及数值模拟.岩石力学与工程学报,2010,29(增刊2):3839)
[7] Zhang Z M,Liu J W,Yu F,et al. Research on plugging effect of jacked prestressed concrete pipe pile. Rock Soil Mech,2011,32(8):2274(张忠苗,刘俊伟,俞峰,等.静压预应力混凝土管桩土塞效应试验研究.岩土力学,2011,32(8):2274)
[8] Zhan Y X,Yao H L,Dong Q P,et al. Study of process of openended pipe pile driven into sand soil by particle flow simulation.Rock Soil Mech,2013,34(1):283(詹永祥,姚海林,董启朋,等.砂土中开口管桩沉桩过程的颗粒流模拟研究.岩土力学,2013,34(1):283)
[9] Cao Z H,Kong G Q,Liu H L,et al. Model tests on pipe pile penetration by using transparent soils. Chin J Geotech Eng,2014,36(8):1564(曹兆虎,孔纲强,刘汉龙,等.基于透明土的管桩贯入特性模型试验研究.岩土工程学报,2014,36(8):1564)
[10] Wang J Q,Peng T,Huang L Y,et al. Model test research on soil plug effect of open-ended pipe pile in red clay ground. Ind Construction,2016,46(12):73(王家全,彭泰,黄柳云,等.红黏土地层开口管桩土塞效应模型试验研究.工业建筑,2016,46(12):73)
[11] Yang J H. The Analysis of PHC Piple Pile's Soil Compaction Effect[Dissertation]. Hefei:Hefei University of Technology,2016(杨靖晖.预应力混凝土管桩挤土效应研究[学位论文].合肥:合肥工业大学,2016)
[12] Paik K H,Lee S R. Behavior of soil plugs in open-ended model piles driven into sands. Mar Georesour Geotechnol,1993,11(4):353
[13] Iskander M G,Olson R E. An axperimental facility to model the behavior of steel pipe piles in sand[R/OL]. Offshore Technology Research Center(1996-03)[2018-04]. https://otrc. tamu.edu/research/publications/seafloor-engineering-and-characterization/an-experimental-facility-to-model-the-behavior-of-steel-pipepiles-in-sand/
[14] Choi Y,O'Neill M W. Soil plugging and relaxation in pipe pile during earthquake motion. J Geotech Geoenviron Eng,1997,123(10):975
[15] Gavin K G,Lehane B M. The shaft capacity of pipe piles in sand. Can Geotech J,2003,40(1):36
[16] Yegian M,Wright S G. Lateral soil resistance displacement relationships for pile fundation in soft clays//Offshore Technology Conference. Houston,1973:893
[17] Rao S N,Ramakrishna V G S T,Raju G B. Behavior of pilesupported dolphins in marine clay under lateral loading. J Geotech Eng,1996,122(8):607
[18] Iskander M. Behavior of Pipe Piles in Sand:Plugging&PoreWater Pressure Generation during Installation and Loading. Berlin:Springer-Verlag Berlin Heidelberg,2011
[2] Paikowsky S G,Whitman R V. The effects of plugging on pile performance and design. Can Geotech J,1990,27(4),429
[3] Brucy F,Meunier J,Nauroy J F. Behavior of pile plug in sandy soils during and after driving//Offshore Technology Conference.Houston,1991:145
[4] Lehane B M,Gavin K G. Base resistance of jacked pipe piles in sand. J Geotech Geoenviron Eng,2001,127(6):473
[5] Xie Y J,Wang H Z,Zhu H H. Soil plugging effect of PHC pipe pile during driving into soft clay. Rock Soil Mech,2009,30(6):1671(谢永健,王怀忠,朱合华.软黏土中PHC管桩打入过程中土塞效应研究.岩土力学,2009,30(6):1671)
[6] Zhou J,Chen X L,Zhou K M,et al. Model test and numerical simulation of driving process of open-ended jacked pipe piles.Chin J Rock Mech Eng,2010,29(Suppl 2):3839(周健,陈小亮,周凯敏,等.静压开口管桩沉桩过程模型试验及数值模拟.岩石力学与工程学报,2010,29(增刊2):3839)
[7] Zhang Z M,Liu J W,Yu F,et al. Research on plugging effect of jacked prestressed concrete pipe pile. Rock Soil Mech,2011,32(8):2274(张忠苗,刘俊伟,俞峰,等.静压预应力混凝土管桩土塞效应试验研究.岩土力学,2011,32(8):2274)
[8] Zhan Y X,Yao H L,Dong Q P,et al. Study of process of openended pipe pile driven into sand soil by particle flow simulation.Rock Soil Mech,2013,34(1):283(詹永祥,姚海林,董启朋,等.砂土中开口管桩沉桩过程的颗粒流模拟研究.岩土力学,2013,34(1):283)
[9] Cao Z H,Kong G Q,Liu H L,et al. Model tests on pipe pile penetration by using transparent soils. Chin J Geotech Eng,2014,36(8):1564(曹兆虎,孔纲强,刘汉龙,等.基于透明土的管桩贯入特性模型试验研究.岩土工程学报,2014,36(8):1564)
[10] Wang J Q,Peng T,Huang L Y,et al. Model test research on soil plug effect of open-ended pipe pile in red clay ground. Ind Construction,2016,46(12):73(王家全,彭泰,黄柳云,等.红黏土地层开口管桩土塞效应模型试验研究.工业建筑,2016,46(12):73)
[11] Yang J H. The Analysis of PHC Piple Pile's Soil Compaction Effect[Dissertation]. Hefei:Hefei University of Technology,2016(杨靖晖.预应力混凝土管桩挤土效应研究[学位论文].合肥:合肥工业大学,2016)
[12] Paik K H,Lee S R. Behavior of soil plugs in open-ended model piles driven into sands. Mar Georesour Geotechnol,1993,11(4):353
[13] Iskander M G,Olson R E. An axperimental facility to model the behavior of steel pipe piles in sand[R/OL]. Offshore Technology Research Center(1996-03)[2018-04]. https://otrc. tamu.edu/research/publications/seafloor-engineering-and-characterization/an-experimental-facility-to-model-the-behavior-of-steel-pipepiles-in-sand/
[14] Choi Y,O'Neill M W. Soil plugging and relaxation in pipe pile during earthquake motion. J Geotech Geoenviron Eng,1997,123(10):975
[15] Gavin K G,Lehane B M. The shaft capacity of pipe piles in sand. Can Geotech J,2003,40(1):36
[16] Yegian M,Wright S G. Lateral soil resistance displacement relationships for pile fundation in soft clays//Offshore Technology Conference. Houston,1973:893
[17] Rao S N,Ramakrishna V G S T,Raju G B. Behavior of pilesupported dolphins in marine clay under lateral loading. J Geotech Eng,1996,122(8):607
[18] Iskander M. Behavior of Pipe Piles in Sand:Plugging&PoreWater Pressure Generation during Installation and Loading. Berlin:Springer-Verlag Berlin Heidelberg,2011