Tutorial 4 demonstrates how the boundary element method can be used to analyse a pile group. The worked example involves a group of four piles in stiff clay overlying dense sand:
Ground conditions comprise 8m of stiff clay overlying dense sand. Both soils will be modelled as linear elastic materials.
The stiff clay has a vertical Young’s modulus of 40 MPa and a horizontal modulus of 20 MPa, with Poisson’s ratio equal to 0.5.
The dense sand has the same Young’s modulus vertically and horizontally, equal to 50 + 10z MPa (where z is the depth below the top of the sand in metres), and Poisson’s ratio equal to 0.3.
The piles are installed on a 2 x 2 grid, at 3 m spacing (centre-to-centre). Each pile is 20 m long, 1050 mm in diameter, with a free-standing length of 0.5 m, and Young’s modulus (vertically and horizontally) of 30 GPa.
A characteristic vertical force of 12 MN (permanent), horizontal force of 1 MN (variable), and moment of 2 MNm (variable) are applied at the centre of the pile group.
You want to determine the displacement and rotation of the pile cap under serviceability conditions.
This tutorial is written for users of the Professional, Enterprise, and Trial Editions of Repute 2 only. Users of the Standard Edition should look at Tutorials 1-3.
In Step 1, you will use the Project Wizard to enter project information and create a scenario to represent a persistent design situation.
In Step 2, you will use the Pile Group Wizard to create a 2 x 2 pile group and specify the piles’ properties.
In Step 3, you will use the Borehole Wizard to create a borehole containing the stiff clay and dense sand layers.
In Step 4, you will enter the stiffness parameters for Soils 1 and 2.
In Step 5, you will use the Action Wizard to create the actions applied to the pile group.
In Step 6, you will use the Calculation Wizard to create the calculation you want Repute to perform.
In Step 7, you will perform the calculation and review the results.
In Step 8, you will produce a report summarising the calculation.
In Step 9, you will close the project.
If Repute is not already running, double-click on the Repute icon on Windows’ Desktop to start the program. Once the splash screen has disappeared, Repute displays its Welcome page.
If you have an existing project open, click Close on the program’s Application menu. (You will be prompted to save your work if you have not already done so.)
Now you are ready to start the tutorial.
Step 1 - create the project