TZPILE implements the well-known method of soil-structure
interaction, commonly called the t-z method, where t-z and Q-w
curves are used respectively for load transfers in side
resistance and end bearing. The t-z and Q-w curves can be
internally-generated for both driven piles and drilled shafts
with the input of information on the supporting soil and on
the geometry of the pile.
Curves of short-term settlement as a function of applied loads
are essential for some engineering computations; for example,
when refined input is needed for the analysis of piles in a
group. If a field-load test is performed, the computed curves
can be "calibrated" by modifying input information to TZPILE
to reach agreement with the experimental curves. The
calibrated, site-specific curves can then be used with TZPILE
to design the production piles, which may vary from the test
piles in geometry and stiffness.
The main output provided by TZPILE is pile-head movement as a
function of applied load. However, for any given load, the
program can also present the load and movement along the
length of the pile. In addition, the program allows the user
to specify the settlement profile if the user would like to
consider negative skin friction caused by downdrag. The
program will use iterative solution to find the soil reaction
based on the relative movement between the soil and the pile
at the depth of interest. The neutral depth, which separates
the negative and positive skin frictions, will be generated.
Gallery
Features
Built-in axial load-transfer curves
Driven Piles
Clay (American Petroleum Institute, API)
Sand (API)
Clay (Coyle and Reese, 1966)
Sand (Mosher, 1984)
Drilled Shafts
Clay (Reese and O'Neill, 1987)
Sand (Reese and O'Neill, 1987)
Manually input linear or nonlinear load-transfer in
side resistence (t—z) and end bearing (Q—w) as
a function of depth.
Handle user-inputted soil-settlement profile that may
be produced from downdrag. A pile will be subjected to
downdrag when the soils in contact with the upper
portion of the foundation move downward relative to the
movement of the pile under its external loading. The
resulting downward force from the near-surface soils
will add to the force applied to the pile by the
superstructure and can lead to excessive settlement of
the foundation.
Specify shafts having different sectional properties
(cross-sectional area and modulus of elasticity) with
depth. This is helpful for controlled computations of
elastic deformations.
A short-term, load-settlement curve is generated for the
modeled pile using nonlinear soil models and elastic
pile material deformation. TZPILE generates the
load-vs-settlement curve based on the t—z
(load-transfer in axial side resistance as function of
movement) and Q—w curves (load-transfer in end
bearing as function of movement) that are either
generated internally by the program or specified by the
user.
TZPILE automatically outputs the internally-generated
nonlinear soil-transfer curves in skin friction (t—z curves) at
quarter depths on each soil layer. This can be useful when the user
needs the curve for input as spring on other models.
Specify modification factors on side friction
(t—z curves) and/or tip resistance (Q—w
curve) for each soil layer. This is useful for special
analytical cases, such as hypothetical computations of
load-vs-settlement for evaluations of losses of strength
during pile driving or to match measured load-test
data.
Graphs of load-distribution curves, axial
load-vs-settlement curve, t—z curves, and
Q—w curve are generated by the program.
Generate output including include program and data
file information, running date and clean echo printing
of all inputted parameters.