A Microsoft Windows application for the analysis of piles and pile groups using various methods. UniPile considers bearing capacity, negative skin friction, drag force, and downdrag. Settlement of a single pile and pile groups is computed based on Dr. B.H. Fellenius’ unified theory. UniPile also simulates the load-movement response of a test pile in a static loading test performed by a conventional head-down test or bidirectional test.

All results are presented in tabular and graphical form. Tables and charts are designed to display depth, elevations, soil layers, and more.

Below are some of the features available in UniPile:

  • Define multiple soil profiles, fills, loads, and excavations within the same project file.
  • Define multiple piles of all types and embedment.
  • Stress distribution of elements as per Boussinesq, Westergaard, or 2V:1H distribution.
  • Soil consolidation is computed based on Terzaghi’s one-dimensional consolidation theory.
  • Import, interpret, and convert multiple CPTu datasets into a useful soil profile.
  • Import multiple SPT datasets.
  • Analyze most types of piles including CFA, tapered, step-tapered, and helical.
  • Specify various toe geometry such as cone, tapered, and expanded.
  • Pile response is obtained from the many pre-defined t-z and q-z functions.
  • Pile resistance may be computed from effective stresses or other popular CPT and SPT methods.
  • Long-term settlement of a single pile is computed based on the Fellenius Unified method.
  • Produce pile load-distribution diagram for various loads.
  • Compute long-term settlement of small rigid pile groups.
  • All input, results, and charts may be entered in either Customary US or SI units and be toggled back and forth on the fly.
  • All output may be exported to Word or Excel for custom editing and printing.

Soil Profile

UniPile can handle an unlimited number of soil profiles and soil layers within the same site. Preconsolidation may be included using prestress ratio (OCR), or prestress margin (Δσ’). Long-term soil settlement is computed using conventional Cc-e0 approach, E-modulus, or Janbu tangent modulus methods. Soil properties, including shaft and toe resistance, may be constant or vary linearly within the layer. Each layer may be assigned a unique t-z and q-z function.

Fills, Loads, and Excavations

All input data are presented and edited using an Excel-type grid and cell system. Stresses can be from a combination of point, line, circular, triangular, rectangular, polygon, cone, ring, or unsymmetrical embankment type loads. Fills, loads, or excavations can be set as initial or final condition.

CPT Data Interpretation

UniPile can import multiple CPT datasets. CPT data may be charted and interpreted to produce various soil properties and converted to soil profiles compatible with UniPile. Soil classification based on Robertson 1986, Robertson 1990, and Eslami-Fellenius 1996 may be produced and charted.

Pile Data

UniPile can handle an unlimited number of piles at various locations within the project site. Piles may be bored, drilled, or screwed. They may be CFA (Continuous Flight Auger), precast concrete of various geometry, straight, tapered, or step tapered pipe pile, H-Pile, wood pile, or helical, to name a few. Toe geometry may be defined as cone, tapered, or expanded.

t-z/q-z Functions

Pile-soil response is obtained via custom or preset models. Models include Gwizdala (Ratio), Chin-Kondner (Hyperbolic), Vander Veen (Exponential), Hansen 80%, Zhang, Vijayvergiya, and Rahman. Layers within the same soil profile may be assigned different t-z/q-z functions.

Pile Resistance

Pile resistance under various conditions may be computed from effective stresses or other popular CPT and SPT methods such as Lehane (UWA 2021), Bustamante-Gianselli (LCPC 1982 and 2012), Eslami-Fellenius (2000), Tumay-Fakhroo (1981), deRuiter-Beringen (1979), Schmertmann-Nottingham (1978), Meyerhof (1976), O’Neill-Reese (1999), and Decourt (1995).

Pile Settlement

Settlement of individual pile and pile groups is computed by combining the soil settlement and the pile response based on t-z and q-z functions. The force in the pile considering downdrag is computed based on the Fellenius Unified method.

Loading Test Simulation

The load-movement response of a pile in a static and bidirectional loading test may be simulated by selecting the appropriate t-z/q-z function for each soil layer. The simulation is particularly useful to prepare for a test or to back-calculate results of exiting data.