Abstract
A step-by-step load was utilized to mimic the load history of the backfill column in the in-situ curing process. The inner damage of the specimen during curing and uniaxial compressive testing was monitored by electrical resistivity and ultrasonic equipment. Results show that: 1) Uniaxial compressive strength (UCS) and elastic modulus (EM) of the samples curing under pressure are higher than those of the control samples without pressure, ranging in ratio from 0.5% to 20.2% and 7.1% to 52.3%, respectively, and are influenced by the initial loading age (ILA) and stress strength ratio (SSR). The SSR during curing should not exceed 80%. 2) The earlier the ILA is, the higher the total strain becomes. The higher the SSR applies, the larger the total strain gets. The creep strain increases with the increase of SSR and can be described by Burger’s viscoelastic creep model. When SSR is less than 80%, the earlier the ILA is, the smaller the creep strain becomes after the last step-loading. 3) The stability of the early age backfill column under pressure can be monitored based on the change of ultrasonic pulse velocity (UPV) and electrical resistivity.
Published Version
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