Pore-water pressure and liquefaction response of layered fine soils undergoing cementation

Abstract

Cemented paste backfill (CPB) is fine-grained soil undergoing cementation. It is widely used in mining operations for ground support and tailings disposal. In the field, CPB may be placed in one layer (continuous filing), or multiple layers (discontinuous or sequential filling). Until now, no studies have addressed the effect of the different filling strategies on the CPB response during cyclic events by using the shaking table technique. This paper presents new findings regarding the effect of the different filling strategies of CPB on its geotechnical response to dynamic loading. Samples were prepared with different scenarios, including one layered-CPB sample (discontinuous filling), in which each layer was cured for a different duration, and two unlayered-CPB samples (continuous filling), one of which was cured for 2.5 h and the other for 4.0 h. All samples were exposed to the same cyclic loading conditions using a one-dimensional shaking table. Geotechnical parameters, including pore-water pressure, settlement, volumetric water content and liquefaction susceptibility, were monitored or determined before, during and after shaking. The results indicate that layered-CPB samples are resistant to liquefaction under the studied loading conditions, while the unlayered-CPB samples are prone to liquefaction under the studied conditions when they are cured for less than 4.0 h.