ABSTRACT
To examine the geotechnical properties of salt backfill which had been compacted for more than 8 years at high temperatures of 90°C to 170°C in the TSDE test drifts in the Asse salt mine, post-tests were carried out on drilled cores. The triaxial compression behavior of the backfill was investigated on large samples of 280 mm diameter and 510 mm to 710 mm lengths. The bulk modulus increased with decreasing porosity. The strength measured on the pre-consolidated samples is comparable to that obtained on the same material but without pre-compaction. Coupled to the mechanical tests, permeability measurements by nitrogen gas were conducted at different porosities. The permeability decreases exponentially from 1 · 10–12 m2 at a porosity of 26% to 1 · 10–13 m2 at a porosity of 7%. The post-test results confirm the in-situ measurements and the constitutive models used for the prediction of the backfill behavior.
