Direct shear test performed with Casagrande box

The specimen is placed in the Casagrande box that consist of two half-boxes. The test is carried out on at least three specimens of the same soil, consolidated at three different pressure values. At the end of the consolidation we go on with the cutting phase, under drained conditions, recording the resulting effort. Three different values of shear strength are obtained, proportional to the three different consolidation pressures applied. The values obtained are used to estimate the break envelope in the σ_n-τ diagram.The values of the friction angle φ' and the cohesion C' are evaluated from the test, which are used for the dimensioning of the foundation. Our soil laboratory software “CiviLab” facilitates the processing of the Direct shear test and reduces the time required. Also, CiviLab provides high quality reports and archives them properly. In this test, CiviLab supports the following standards:

• ASTM D3080-04;
• NF P 94-071-1;
• NA 16218.

In the Direct shear test you can use CiviLab to:

• plot the curve of shear stress versus the horizontal displacement with several methods namely:
  • Linear;
  • Culic spline;
  • Culic spline Akima;
  • Culic spline Pchip;
  • B-spline.
• Compute τ;
• plot the the diagram σ_n-τ;
• Compute the friction angle φ' and the cohesion C' ;