Expansive soil-structure interaction and its sensitive analysis

Abstract

Several groups of direct shear tests of Nanning expansive soil samples were carried out by improved direct shear apparatus. The results of the characteristics of the ultimate shear stress and residual shear stress at the interface of expansive soil-structure are presented as follows: linear relation can approximately reflect changes between the both shear stress and the three factors: vertical load, water content and dry density, just different degrees from each other; increasing the vertical load from 25 kPa to 100 kPa (up by 300%) can cause the average increase of ultimate shear stress from 58% (for samples with 1.61 g/cm³) to 80% (for samples with 1.76 g/cm³), and an close average increase of 180% for the residual shear stress; increasing the water content from 14.1% to 20.8% (up by 47.5%) can cause the average decrease of the ultimate shear stress from 40% (for samples with 25 kPa) to 80% (for samples with 100 kPa), and the average decrease from 25% (for samples with 25 kPa) to 30% (for samples with 100 kPa) for the residual shear stress; increasing the dry density from 1.61 g/cm³ to 1.76 g/cm³ (up by 9.3%) can cause the average increase of ultimate shear stress from 92% (for samples with 25 kPa) to 138% (for samples with 100 kPa), and an average increase of 4% for the residual shear stress. Sensitive analysis was further made to explain reasons causing the differences of the both shear stress induced by the three factors.

Keywords

expansive soils / interface / direct shear friction test / ultimate shear stress / residual shear stress

References

[1] YinZ.-z., ZhuH., XuG.-hua.. Numerical simulation of the deformation in the interface between soil and structural material[J]. Chinese Journal of Geotechnical Engineering, 1994, 16(3): 14-22

[2] HuL.-m., PuJ.-liu.. Experimantal study on mechnial characteristics of soil-structure interface[J]. Chinese Journal of Geotechnical Engineering, 2001, 23(4): 431-435

[3] ZhangM.-y., DengA.-fu.. Experimental study on sliding friction between pile and soil[J]. Rock and Soil Mechanics, 2002, 23(2): 246-249

[4] CloughG. W., DuncanJ. M.. Finite element analysis of retaining wall behavior[J]. Journal of the Soil Mechanics and Foundations Division, ASCE, 1971, 97(12): 1657-1672

[5] PotyondyJ. G.. Skin friction between various soils and construction material[J]. Geotechnique, 1961, 11(4): 339-353

[6] XiongH., ZouY.-s., TianJ.. Dynamic finite-element analysis of pile-soil-structure system considering thin-layer contact element[J]. Journal of Hunan University: Natural Sciences, 2004, 31(1): 59-63

[7] LuanM.-t., WuY.-jun.. A nonlinear elasto-perfectly plastic model of interface element for soil-structure interaction and its applications[J]. Rock and Soil Mechanics, 2004, 25(4): 507-513

[8] DuC.-b., RenQ.-wen.. A new three-dimensional nonlinear interface element for modeling joints[J]. Journal of Southeast Unversity: Natural Science Edition, 2001, 31(4): 92-96

[9] ZhangD.-j., LuT.-hao.. Establishment and application of an interface model between soil and structure[J]. Chinese Journal of Geotechnical Engineering, 1998, 20(6): 62-66

[10] XIAO Hong-bin, LIU Jie, WANG Yong-he. Experimental and theoretic studies on the law of load transfer of large-diameter pile[J]. Geotechnical Engineering Technique, 2003(1): 47–50. (in Chinese)

[11] XiaoH.-b., FanZ.-h., WangY.-he.. Experimental study on swelling laws of expansive soil with water-addition in one-dimension[C]. Proceedings of Eighth National Symposium on Foundation Improvement, 2004, Hefei, Hefei University of Technology Press

[12] The Ministry of Water Resources of the PRC.SL237-1999. Test Methods of Soils[S], 1999, Beijing, China Water Power Press

[13] LiuT.-hong.Expansive Problems in Engineering Practice[M], 1998, Beijing, China Architecture and Building Press