Limiting force profile for laterally loaded piles in clay
Response of a laterally loaded pile is normally dominated by limiting force mobilised along the pile to a depth of 10d (d = pile diameter). The limiting force profile (LFP) varies from pile to pile in different sites. In order to provide guidelines for establishing the LFP, in this paper, an extensive back-estimation has been made against measured data of 32 piles tested in-situ. It was fulfilled using a spreadsheet program called GASLFP, which in turn was based on closed-form solutions. The solutions and the GASLFP were developed by the first author in 2001, and 2002, respectively. Parameters obtained through the back-estimation were presented for each individual pile. The results demonstrate difference between the current LFP and existing one for a lot of piles; provide range of the (slip) depth where the soil has predominant effect on pile response; and offer the ratio of subgrade modulus over shear modulus or undrained strength for piles in different clay. The result from this investigation may be directly used to design laterally loaded free-head piles. Especially, the slip depth of each pile should be helpful to plan a detailed soil investigation and any possible ground improvement.