Dilatancy Behaviour in Standard and Constant Strain Rate of Consolidation Test

B. Sompie, B. I. Setiawan,   Erizal

Abstract


Embankment requires relatively good soil bed as bearer, where the soil consolidation can subside due to excessive loading. Two problems are usually encountered in the consolidation process, i.e., magnitude of the subsidence and time interval required to reach maximum subsidence. One of the promising methods in soil consolidation test is constant strain rate consolidation (CSRC) test. Although CSRC assures rapid consolidation test, the time dependence on the response of stress-strain such as secondary compaction has not been properly understood. An experiment was conducted in order to study the behavior of the time dependency. Based on the remolding of young clay soil, the test indicated a considerable time dependency behavior as shown in standard consolidation (SC) and CSRC. The behavior was systematically explained with simple assumption of dilatancy time dependency. In the early stage of SC test, each addition of load resulted in small dilatancy and increased several minutes after the loading step. At the end of each loading step, dilatancy occurred proportionally with the addition of logarithm time, which can be observed as secondary compaction. In the CSRC test, some period of time after the stress condition entered the normally consolidation area, the dilatancy tended to occur rapidly with the addition of stress ratio. Since most of the dilatancies had taken place at the earlier stage of consolidation, only small dilatancy occurred at the latter stage of CSRC process. This tendency made the specimen more rigid with time, and made the vertical stress and pore stress increase significantly at the end of the CSRC process. The behavior could be effectively explained on the result of the CSRC test.

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