Triaxial Tests On Weak Cohesive Soils – Some Practical Remarks (Part 1)

Standard procedures of triaxial testing recommended e.g. in Eurocode 7 are often unsatisfactory in case of weak cohesive soils (soft and very soft clays, clayey soils with organic content, etc.), mainly due to the high deformability of these soils. Forming a specimen from material sampled in situ and installation of the necessary equipment (a membrane, filter paper strips or on-sample sensors, etc.) may be very difficult and can influence the quality of the test results. This paper (part 1/2) presents detailed description and discussion of the issues related to weak soil sampling and forming of triaxial specimens, based on the Authors’ own experience and literature review. Some solutions, which make the work with weak soils easier and, at the same time, increase the reliability of the results, are suggested e.g.: an “extra consolidation” in a sampler or alternative preparation of the specimen from slurry. Due to the ampleness of the problems related to testing of weak cohesive soils, another issues, such as installation of a triaxial specimen in a chamber or equipping it with different accessories, have been described in part 2 of this paper. In the Authors opinion, the text (parts 1 and 2) may constitute an important hint for researchers completing a triaxial testing system designated for testing weak cohesive soils.