On the behavior of piles in non-cohesive soil under combined horizontal and vertical loading

Abstract

In many fields of application, piles are used for the transfer of both axial and lateral loads into the ground. This combined loading leads to interaction of the horizontal and vertical load-bearing behavior. However, in current engineering practice these effects are usually neglected, since a clear description of the interactions and of their quantitative importance dependent on system parameters is lacking. A numerical simulation model was therefore established to identify and quantify the effects of combined loading of piles in sand soil. The model is validated by comparison with the results of published model tests. The model results are of good quality. Moreover, deficiencies of the model tests and their assessment with respect to interaction approaches were identified. The results of the numerical study show that with combined compression loading mostly favorable effects arise, with combined tension loading mostly unfavorable ones. However, the interaction behavior is very complex, and, depending on loading conditions, opposite effects on system stiffness and ultimate load can occur. An interaction diagram is presented, which gives a good impression of the importance of interaction effects. A parametric study shows that compact piles with a small length-to-diameter ratio and piles with almost rigid behavior show particularly strong interaction effects.

A hypoplastic macroelement formulation for single batter piles in sand

“…The loading function Y ( t ), which controls the degree of nonlinearity of the system response, increases monotonically with the distance of the current stress state t to the assumed ultimate failure surface of the soil‐pile system: in the generalized loading space …”

“…in the generalized loading space. 5,15,61,[71][72][73] As in Li et al, 58 the loading function is defined as follows. For each loading state t inside the failure surface, an image state t * is defined on the failure surface by a simple projection from the origin of the loading space:…”

Failure Mode and Pullout Capacity of Anchor Piles in Clay

“…The methods to analyze the lateral capacity of anchor piles could be categorized into the limit state method (Broms, 1964), subgrade reaction method (Matlock and Reese, 1960), p-y method (Reese et al, 1974), elasticity method (Poulos, 1971) and plasticity method (Randolph and Houlsby, 1984). However, the pullout behavior of anchor piles under inclined loading is limited to empirical formulae (Yoshimi, 1964;Meyerhof, 1973), Finite Element (FE) analysis (Karthigeyan et al, 2007;Mroueh and Shahrour, 2007;Achmus and Thieken, 2010) and experimental investigations (Ramadan, 2011;Shin et al, 1993;Johnson, 2005;Sharma, 2011).…”

Untersuchung der Interaktionsbeziehungen kombiniert belasteter Pfähle in bindigen und nichtbindigen Böden

“…Pfahlbelastung hier insgesamt weitestgehend aus den horizontalen Einwirkungen ergibt (1). Vergleichbar belastete Pfähle sind auch im Onshore-Bereich anzutreffen, wo sie beispielsweise zur Gründung von Freileitungsmasten (5) eingesetzt werden.…”

“…Aus verschiedenen experimentellen und numerischen Untersuchungen ist bekannt, dass infolge der kombinierten Belastung durchaus relevante Interaktionseffekte auftreten können, d. h., sowohl das vertikale Tragverhalten ist durch die Horizontalkräfte als auch das horizontale Tragverhalten durch die Vertikalkräfte beeinflusst. Für eine detaillierte Darstellung der den Autoren bekannten Untersuchungen sei auf [1] verwiesen. Die vorliegenden Erkenntnisse zeigen, dass der Einfluss einer horizontalen Belastung auf das vertikale Tragverhalten deutlich stärker ausgeprägt ist als der Einfluss einer vertikalen Belastung auf das horizontale Tragverhalten.…”