Experimental and Numerical Analysis of Axially Loaded Bored Piles Socketed in a Conglomerate Rock Mass

This paper presents the details of an experimental and numerical analysis performed on two 1.0 m and one 0.9 m diameter bored piles socketed in the conglomerate rock mass. The study investigates how shaft and base resistance contribute to load settlement behavior of piles built in poorly and well-cemented conglomerate rock mass. Two of the piles were constructed as complete sockets, and the third one is a shear socket only. The testing procedure included measuring pile cap settlement and deformations along with the pile (telltales and strain gauges). The results indicate that not only well cemented but poorly cemented conglomerate as well can sustain heavy surcharge before settlements indicating the commencement of full slip were reached. Numerical simulation of the socket with explicitly modeled roughness was applied to assess the influence of socket side surface strength on the behavior of the test pile. The parameters of numerical models were derived from back analysis of field pile load test combined with recorded socket side roughness and the strength parameters obtained by the direct shear tests of conglomerate intact specimens. The results were compared with the experimental observations, and a good level of agreement with measurements was confirmed.