Abstract:For the socketed piles under vertical load, pile-rock joint shear dilation effect has a great influence on side friction. This issue is based on a nonplanar failure model of pile-rock joint. Firstly, the value of shear force is solved when asperity fails by means of the slip-line field theory, and the corresponding shear displacement is obtained. A shear function is established based on the shear dilation mechanism, and the comparison with the experimental results shows a good correspondence. Secondly, based on the derived shear function, the load transfer equations for the pile are established considering the dilation effects, and the expression for load transfer of the pile is deduced. Furthermore, the effect of several parameters on plastic shear force is analyzed, such as joint roughness and rock strength and normal stiffness. Finally, a project is taken as an example, and the load transfer curve of the pile is calculated and compared with the measured one. The results are in good agreement with the measured data, which verifies the availability of the proposed method.
[1] 梁晋渝, 史佩栋. 嵌岩桩竖向承载力的研究[J]. 岩土工程学报, 1994, 16(4): 32-39. (LIANG Jin-yu, SHI Pei-dong. Study of vertical bearing capacity of socketed piles[J]. Chinese Journal of Geotechnical Engineering, 1994, 16(4): 32-39. (in Chinese)) [2] ROSENBERG P, JOURNEAUX N L. Friction and end bearing tests on bedrock for high capacity socket design[J]. Canadian Geotechnical Journal, 1976, 13(3): 324-333. [3] PELLS P J N, TURNER R M. Elastic solutions for the design and analysis of rock-socketed piles[J]. Canadian Geotechnical Journal, 1979, 16(3): 481-487. [4] PATTON F D. Multiple modes of shear failure in rock[C]// Proceeding 1st Congress International Rock Mechanics. Lisbon, 1966: 509-513. [5] BARTON N, CHOUBEY V. The shear strength of rock joints in theory and practice[J]. Rock Mechanics, 1977, 10: 1-54. [6] ROWE R K, PELLS P J N.A theoretical study of pile-rock socket behavior[C]// Proceeding of the International Conference on Structural Foundations on Rock. Sydney, 1980: 282-293. [7] PELLS P J N, ROWE R K, TURNER R M. An experimental investigation into side shear for socketed piles in sandstone[C]// Proceeding of the International Conference on Structural Foundations on Rock. Sydney, 1980: 291-302. [8] JOHNSTON I W, LAM T S K. Shear behavior of regular triangular concrete/rock joints analysis[J]. Journal of Geotechnical Engineering, 1989(5): 711-727. [9] KODIKARA J K, JOHNSTON I W. Shear behavior of irregular triangular rock-concrete joints[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1994, 31(4): 313-322. [10] SEIDEL J P, HABERFIELD C M. Towards an understanding of joint roughness[J]. Rock Mechanics and Rock Engineering, 1995, 28(2): 69-92. [11] HASSAN K M, O’NEILL M W. Side load transfer mechanisms in drilled shafts in soft argrillaceous rock[J]. Journal of Geotechnical and Geoenvironmental Engineering, 1997, 123(2): 145-152. [12] GU X F, SEIDEL J P, HABERFIELD C M. Direct shear test of sandstone-concrete joints[J]. International Journal of Geomechanics, 2003, 3(1): 21-33. [13] RADHAKRISHNAN R, LEUNG C F. Load transfer behavior of rock-socketed piles[J]. Journal of Geotechnical Engineering, 1989, 111(6): 775-768. [14] 戴一鸣, 董金荣, 林胜天. 大口径钻孔灌注桩荷载传递性状[J]. 岩土工程学报, 1994, 16(6): 123-131. (DAI Yi-ming, DONG Jin-rong, LIN Sheng-tian. Load distribution characteristics of large diameter bored pile[J]. Chinese Journal of Geotechnical Engineering, 1994, 16(6): 123-131. (in Chinese)) [15] 龚晓南. 土塑性力学[M]. 2版. 杭州: 浙江大学出版社, 1997. (GONG Xiao-nan. Soil plasticity[M]. 2nd ed. Hangzhou: Zhejiang University Press, 1997. (in Chinese)) [16] AKGUNER C, KIRKIT M. Axial bearing capacity of socketed single cast-in-place piles [J]. Soils and Foundations, 2012, 52(1): 59-68. [17] 赵明华, 雷 勇, 刘晓明. 基于桩-岩结构面特征的嵌岩桩荷载传递分析[J]. 岩石力学与工程学报, 2009, 28(1): 103-110. (ZHAO Ming-hua, LEI Yong, LIU Xiao-ming. Analysis of load transfer of rock-socketed piles based on characteristics of pile-rock structural plane[J]. Chinese Journal of Rock Mechanics and Engineering, 2009, 28(1): 103-110. (in Chinese)) [18] 周 韬, 王星华, 巢万里. 大直径嵌岩桩的承载性状[J]. 湖南交通科技, 2006, 32(4): 85-87. (ZHOU Tao, WANG Xing-hua, CHAO Wang-li. Bearing characteristics of large diameter socketed piles[J]. Hunan Communication Science and Technology, 2006, 32(4): 85-87. (in Chinese)) [19] 刑皓枫, 孟明辉, 何文勇, 等. 基于结构面力学特性的嵌岩桩侧摩阻力分布分析[J]. 岩土工程学报, 2012, 34(12): 2220-2227. (XING Hao-feng, MENG Ming-hui, HE Wen-yong. Distribution of shaft resistance of rock-socketed piles based on mechanical properties of pile-rock interface[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(12): 2220-2227. (in Chinese)) [20] GU X F, SEIDEL J P, HARBERFIELD C M. Wear of sandstone surfaces during direct shear testing of sandstone/concrete joints[C]// Advances in Deep Foundations (GSP 132) Part of Geo-Frontiers Proceedings of the Sessions of the Geo-Frontiers Congress. Austin, 2005: 1-14.