A Failure Criterion for Weak Cemented Soils

Natural soils have inter-particular cemented bonds resulted from chemical reactions between soil particles that are called soil structure. The main distinctive aspect of the failure behavior of structured soils is the change of their behavior from a rock like brittle response to a soil like ductile response. Griffiths and Mohr-Coulomb failure criteria were used to describe the brittle and ductile failure behavior of structure soil superimposed using binary state functions. The state functions describe the phase transfer of structured soil from brittle to ductile response. The state functions derived based on the experimental data available in the literature for structured soils. The proposed failure criterion was verified by failure envelopes reported for naturally structured clay and shale, artificially cement treated gravel. Also, laboratory tests conducted on cement treated sand for further verifications. The results of the laboratory tests and verifications indicated that the proposed failure criterion is capable of describing the failure envelopes of natural structured clay and shale and artificially cemented gravel and sand.