The failure in the slope will take the form of a circular slip surface.

It is not easy to include the fissures properties in the material properties.

I think that the behavior is different than that of disintegrated rock.

Non-linear elastic plastic finite element analysis is suitable

Thank you Mohammed. Can you expect the fissures to divide the soil mass into individual blocks? In this case if the stength of the clay is high enough then maybe the overall behavior will depend on the interaction of the individual blocks?

From the field remarks, the failure occurred in a circular manner when the tension cracks close to the edge of slope and in a linear manner if it far from the slope edge, in case of fissured clay and marl.

the fissures can get developped by the time into a failure circle. I used GEO5 to include the fissures in my slope stability analysis, the software suposses that the failure circle can start from the fissure, we call that fissures ''cracks tension'', you can add crack tension in your analysis (their depth and their ouverture for example) and you can find your new factor of safety.

you can also use GEOSTUDIO software for this analysis.

Dear Azealdeen and Mohamed, thank you for your responses. I am actually interested in fissures inside the soil mass and not above i.e. shrinkage cracks or tension cracks. I am adding photos and editing the original post to prevent such misunderstandings.

Best Regards

Bekir SF

Dear Neil, thank you for your response. I would expect exactly the same sliding mechanism as you said. However, I am concerned about the soil mass if it may act as a disintegrated rock mass with lots of discontinuities. In this case, behavior would be different as well as the methodology to model such condition. I am open to any idea.

Best Regards,

Bekir SF

I feel fissure properties definitely influence the over all behaviour of the slope..the slope may fail by toe failure mode with tension crack at the top..i choose the FEM based numerical model to simulate this type of clay..the advantages in using FEM, it is versatile and easy to simulate the fissured structure of clay by using interface element..ok all the best in your research..

Dear Karthigeyan, thank you for your suggestions. I will keep it in my mind.

Yes, I also agree with the sliding mechanism and again, I don't think you will be wrong in assuming the soil mass act as a disintegrated rock mass with lots of discontinuities. Just take care in deciding your choice of constitutive model that can accurately capture this.

Thank you for your interest Samuel J. Abbey , Which constitutive model do you recommend?