Field tests on excess pore pressure and soil pressure of pile-soil interface for a single pile during pile-sinking in clay
WANG Yong-hong1,2, ZHANG Ming-yi1,2, LIU Jun-wei1,2, BAI Xiao-yu1,2, YANG Su-chun1, SANG Song-kui1, YAN Nan3
1. School of Civil Engineering,Qingdao University of Technology, Qingdao 266033, China; 2. Cooperative Innovation Center of Engineering Construction and Safety in Shandong Blue Economic Zone, Qingdao 266033, China; 3. School of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China
Abstract：Stress change of pile-soil interface for jacked-in piles during pile-sinking in clay is a topic of concern in the geotechnical engineering. A full-scale jacked-in pile is penetrated into the clay in Dongying city of China and studied by monitoring the laws of the excess pore water pressure and soil pressure of pile-soil interface with depth at different pile locations of h/L. The relationship between the excess pore water pressure of pile-soil interface and the effective pressure of superimposed soil at different pile locations of h/L and the characteristics of soil pressure of pile-soil interface at the same penetration depth are analyzed. Especially the causes to influence the distribution of the effective soil pressure of pile-soil interface are studied. The test results show that the maximum ratio of the excess pore water pressure of pile-soil interface to the effective pressure of superimposed soil during pile-sinking is 1.08 at different pile locations of h/L and decreases gradually along the pile from pile tip to pile top. The soil pressure of pile-soil interface presents “lateral pressure degradation” with the relative depth of the increasing pile tip（h/L）at the same penetration depth. The “lateral pressure degradation” presents obviously with the relative depth of the increasing pile tip（h/L）. The effective soil pressure of pile-soil interface is only 10 kPa at the location of h/L=11/12, and that of certain interface at other different pile locations of h/L is 1.88~2.20 times the excess pore water pressure of pile-soil interface. The proposed solution is of great engineering significance for jacked pile construction and bearing capacity design in clayey foundation.
王永洪, 张明义, 刘俊伟, 白晓宇, 杨苏春, 桑松魁, 闫楠. 黏性土中单桩贯入桩-土界面超孔压和土压测试现场试验[J]. 岩土工程学报, 2019, 41(5): 950-958.
WANG Yong-hong, ZHANG Ming-yi, LIU Jun-wei, BAI Xiao-yu, YANG Su-chun, SANG Song-kui, YAN Nan. Field tests on excess pore pressure and soil pressure of pile-soil interface for a single pile during pile-sinking in clay. Chinese J. Geot. Eng., 2019, 41(5): 950-958.
[1] 龚晓南, 李向红. 静力压桩挤土效应中的若干力学问题[J]. 工程力学, 2000, 17(4): 7-12. (GONG Xiao-nan, LI Xiang-hong.Several mechanical problems in compacting effects of static piling in soft clay ground[J]. Rock and Soil Mechanics, 2000, 17(4): 7-12. (in Chinese)) [2] VESIC A S.Expansion of cavities in infinite soil mass[J]. ASCE: JSMFD, 1972, 98(3): 265-290. [3] CAO L F, TEH C I, CHANG M F.Undrained cavity expansion in modified cam clay i: theoretical analysis[J]. Géotechnique, 2001, 51(4): 323-334. [4] 王育兴, 孙钧. 打桩施工对周围土性及孔隙水压力的影响[J]. 岩石力学与工程学报, 2004, 23(1): 154-158. (WANG Yu-xing, SUN Jun.Influence of pile driving on properties of soils around pile and pore water pressure[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(1): 154-158. (in Chinese)) [5] 王伟, 宰金珉, 王旭东. 沉桩引起的三维超静孔隙水压力计算及其应用[J]. 岩土力学, 2004, 25(5): 774-777. (WANG Wei, ZAI Jin-min, WANG Xu-dong.3D calculation of excess pore water pressure due to driving pile and its application[J]. Rock and Soil Mechanics, 2004, 25(5): 774-777. (in Chinese)) [6] 曹权, 施建勇, 雷国辉, 等. 基于孔压静力触探试验估算桩周土孔隙水压力[J]. 河海大学学报, 2011, 39(3): 306-310. (CAO Quan, SHI Jian-yong, LEI Guo-hui, et al.Prediction of excess pore water pressure caused by installing piles in soft clay based on piezocone penetration tests[J]. Journal of Hohai University, 2011, 39(3): 306-310. (in Chinese)) [7] 高子坤, 施建勇. 基于变分原理的静压沉桩挤土效应理论解答研究[J]. 岩土工程学报, 2009, 31(1): 52-58. (GAO Zi-kun, SHI Jian-yong.Theoretical analysis of soil squeezing effect due to jacked piles based on variation principle[J]. Chinese Journal of Geotechnical Engineering, 2009, 31(1): 52-58. (in Chinese)) [8] 高子坤, 施建勇. 考虑桩体几何特征的压桩挤土效应理论解答研究[J]. 岩土工程学报, 2010, 32(6): 956-962. (GAO Zi-kun, SHI Jian-yong.Theoretical solutions of soil-squeezing effect due to pile jacking considering geometrical characteristics of a pile[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(6): 956-962. (in Chinese)) [9] 高子坤, 施建勇. 岩土抗拉模量值修正与桩土作用理论解答研究[J]. 力学学报, 2013, 45(5): 739-745. (GAO Zi-kun, SHI Jian-yong.Research of constitutive relation correction of geotechnical materials and theoretical solution due to pile-soil interaction[J]. Chinese Journal of Theoretical and Applied Mechanics, 2013, 45(5): 739-745. (in Chinese)) [10] 李镜培, 方睿, 李林. 考虑土体三维强度特性的静压桩周超孔压解析及演变[J]. 岩石力学与工程学报, 2016, 35(4): 847-854. (LI Jing-pei, FANG Rui, LI Lin.Variation of excess pore pressure around jacked piles considering the three-dimensional strength of soil[J]. Chinese Journal of Rock Mechanics and Engineering, 2016, 35(4): 847-854. (in Chinese)) [11] 李林, 李镜培, 孙德安, 等. 考虑天然黏土应力各向异性的静压沉桩效应研究[J]. 岩石力学与工程学报, 2016, 35(5): 1055-1064. (LI Lin, LI Jing-pei, SUN De-an.Pile jacking-in effects considering stress anisotropy of natural clay[J]. Chinese Journal of Rock Mechanics and Engineering, 2016, 35(5): 1055-1064. (in Chinese)) [12] ROY M, TREMBLAY M, TAVENAS. Development of pore pressures in quasi-static penetration tests in sensitive clay[J]. Canadian Geotechnical Journal, 1982, 19(1): 124-138. [13] HWANG J H, LIANG N, CHEN C S.Ground response during pile driving[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2001, 127(11): 939-949. [14] PESTANA J M, HUNT C E, BRAY J D.Soil deformation and excess pore pressure field around a closed-ended pile[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2002, 128(1): 1-12. [15] 唐世栋, 何连生, 傅纵. 软土地基中单桩施工引起的超孔隙水压力[J]. 岩土力学, 2002, 23(6): 725-732. (TANG Shi-dong, HE Lian-sheng, FU Zong.Excess pore water pressure caused by an installing pile in soft foundation[J]. Rock and Soil Mechanics, 2002, 23(6): 725-732. (in Chinese)) [16] 唐世栋, 何连生, 叶真华. 软土地基中桩基施工引起的侧向土压力增量[J]. 岩土工程学报, 2002, 24(6): 752-755. (TANG Shi-dong, HE Lian-sheng, YE Zhen-hua.Increment of lateral pressure caused by installation of pile in soft foundation[J]. Chinese Journal of Geotechnical Engineering, 2002, 24(6): 752-755. (in Chinese)) [17] 唐世栋, 王永兴, 叶真华. 饱和软土地基中群桩施工引起的超孔隙水压力[J]. 同济大学学报, 2003, 31(11): 1290-1294. (TANG Shi-dong, WANG Yong-xing, YE Zhen-hua.Excess pore water pressure caused by installing pile group in saturated soft soil[J]. Journal of Tong Ji University, 2003, 31(11): 1290-1294. (in Chinese)) [18] 周火垚, 施建勇. 饱和软黏土中足尺静压桩挤土效应试验研究[J]. 岩土力学, 2009, 30(11): 3291-3296. (ZHOU Huo-yao, SHI Jian-yong.Test research on soil compacting effect on full scale jacked-in pile in saturated soft clay[J]. Rock and Soil Mechanics, 2009, 30(11): 3291-3296. (in Chinese)) [19] 胡向前, 焦志斌, 李运辉. 打设排水板后饱和软黏土中打桩引起的孔隙水压力分布及消散规律[J]. 岩土力学, 2011, 32(12): 3733-3737. (HU Xiang-qian, JIAO Zhi-bin, LI Yun-hui.Distribution and dissipation laws of excess static pore water pressures induced by pile driving in saturated soft clay with driven plastic drainage plates[J]. Rock and Soil Mechanics, 2011, 32(12): 3733-3737. (in Chinese)) [20] 张忠苗, 谢志专, 刘俊伟, 等. 淤质与粉质互层土中管桩沉桩过程的土压力[J]. 浙江大学学报(工学版), 2011, 45(8): 1430-1434. (ZHANG Zhong-miao, XIE Zhi-zhuan, LIU Jun-wei, et al.The earth pressure during pile driving in silty soil with mucky soil interbed[J]. Journal of Zhejiang University(Engineering Science), 2011, 45(8): 1430-1434. (in Chinese)) [21] 李国维, 边圣川, 陆晓岑, 等. 软基路堤拓宽静压PHC管桩挤土效应现场试验[J]. 岩土力学, 2013, 34(4):1089-1096. (LI Guo-wei, BIAN Sheng-chuan, LU Xiao-cen, et al.Field test on extruding soil caused of PHC pile pile driving by static pressure for improving soft foundation of widened embankment[J]. Rock and Soil Mechanics, 2013, 34(4):1089-1096. (in Chinese)) [22] 邓俊杰, 陈龙珠, 邢爱国, 等. 液压高频振动沉桩的饱和土超静孔压及单桩静载特性试验研究[J]. 岩土工程学报, 2011, 33(2): 203-208. (DENG Jun-jie, CHEN Long-zhu, XING Ai-guo, et al.Experimental studies on pore pressure of saturated soils and bearing capacity of piles driven by high-frequency hydraulic vibrator[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(2): 203-208. (in Chinese)) [23] BOND A J, JARDINE R J.Shaft capacity of displacement piles in a high OCR clay[J]. Géotechnique, l991, 41(3): 341-363. [24] BOND A J, JARDINE R J.Effects of installing displacement piles in a high OCR clay[J]. Géotechnique, l995, 45(1): 3-23. [25] LEHANE B M.Experimental investigations of pile behaviour using instrumental field piles[D]. London: University of London(Imperial College), 1992. [26] 郑华茂. 砂土中静压管桩模型试验及受力性能研究[D]. 郑州: 郑州大学, 2015. (ZHENG Hua-mao.Model test and analysis of jacked tubular pile in sand[D]. Zhengzhou: Zhengzhou University, 2015. (in Chinese)) [27] 李雨浓, BARRY M LEHANE, 刘清秉. 黏土中静压沉桩离心模型[J]. 工程科学学报, 2018, 40(3): 285-292. (LI Yu-nong, BARRY M LEHANE, LIU Qing-bing, et al.Centrifuge modeling of jacked pile in clay[J]. Chinese Journal of Engineering, 2018, 40(3): 285-292. (in Chinese))
