Study of Model Experiments on Uplift Piles in Clay under Oblique Loads

YANG Ming-hui, YANG Xue-wen, ZHAO Ming-hua

Abstract

 Laboratory model tests on steel piles embedded in cohesive soil were carried out to study the transformation law in relation to ultimate uplift capacity and displacement patterns of uplift piles subjected to oblique loads. The test results show that the side of the pile near the oblique load is always under pressure, while the other side is in tension all the time, which differs from the uplift pile subjected to vertical loads. After reaching the ultimate capacity, soil in some depth is cracked only around the side close to oblique load. The failure surface occurs below the top of the pile. The failure area on the earth surface is distributed as a fan, whose range becomes larger with the increasing inclination of loads. Meanwhile, the ultimate capacity of piles increases with the increase of the inclination angle. On this basis, the calculation model of uplift piles subjected to oblique loads and the formula of failure surface around the pile were established based on the failure mode. Moreover, according to the analysis on the equilibrium conditions of the soil element, a formula for estimating the oblique capacity of uplift piles in clay soil subjected to oblique loads was also proposed. The predictions agree well with the test results so that the formula can be used in practical engineering.

 

 

Keywords: clay,  oblique loads,  uplift piles,  laboratory tests,  ultimate capacity


Full Text:

PDF


References


НЕ Si-ming. Study on bearing capacity and failure of uplift pile [J]. Rock and Soil Mechanics. 2001, 22(3);308-310. (In Chinese)

ZHU Bi-tang, YANG Min. Calculation of displacement and ultimate uplift capacity of tension piles [J]. Journal of Building Structures,2006,27(3): 120— 129. (In Chinese)

AYOTH1RAMAN R. REDDY К M. Model experiments on pile behaviour in loose-medium dense sand under combined uplift and lateral loads [J]. Tunneling and Underground Construction, 2014, 212:633 — 613.

PATRA N R, PISE P J. Model pile groups under oblique pull-out loads-an investigation [J]. Geotechnical and Geological Engineering, 2006. 24:265 — 282.

SHIN E С. DAS В М. PURI V К. et al. Ultimate uplift capacity of model rigid metal piles in clay [J]. Geotechnical and Geological engineering. 1993, 11:203 — 215.

KRISHNA B. PATRA N R. Effect of compressive load on oblique pull-out capacity of model piles in sand [J]. Geotechnical and Geological Engineering. 2006. 24s 593 — 614.

ACHMUS M, THIEKEN K. On the behavior of piles in non-cohesive soil under combined horizontal and vertical loading [J]. Acta Geotechnica. 2010. 5:199 — 210.

GB 50007 —2011 Code for design of building foundation [S]. Beijing: China Building Industry Press. 2011:136 — 138. (In Chinese)

JTG D63 — 2007 Code for design of ground base and foundation of highway bridges and culverts[S]. Beijing: China Communications Press. 2007; 66—111. (In Chinese)

LIU Zu-de. Uplift pile foundation [C]//L1U Jin-li. Pile Foundation Engineering Technology. Beijing: China Building Materials Press, 1966:642 — 671. (In Chinese)

MEYERHOF G G. YALCIN A S. Pile capacity for eccentric inclined load in clay[j]. Canadian Geotechnical Journal. 1984. 21(3):389 — 396.

DAS В M. SEELEY G R. RAGHU D. Uplift capacity of model piles under oblique loads_JJ. Journal of Geotechnical & Geoenvironmental Engineering. 1976. 102(9): 1009 — 1013.


Refbacks

  • There are currently no refbacks.