A spherical template indenter for a frozen soil long-term shear strength test

• A spherical template indenter (STI) was used to analyze mechanical properties of frozen soil.
• The long-term strength of frozen soil and its forecasting can be analyzed by the impression of STI on soil.
• The capabilities of the STI apparatus are shown using a series of test results.

Certain mechanical apparatus have long been considered indispensible to practical engineering design. In particular, the spherical template indenter (STI) has been widely used for permafrost soil testing in the former USSR and Russia. Over the last 60 years, experimental engineering theories and methods have been greatly improved. But the STI has gone largely unchanged, the long-term strength and total deformation modulus analyzed by the impression of STI on soil, simple as it is to use, and effective as it is at quickly measuring the properties and forecasting the long-term strength of frozen soil. This paper makes a brief introduction to the STI apparatus. The capabilities of the STI are shown through a series of test results. It is evaluated under the pretext of being a promising tool for the investigation of frozen soil strength property. Three different methods were used to yield results predicting the long-term strength of frozen loess.