Embankment reinforced with limited life geotextiles on soft clay

Abstract

This paper focuses on the behaviour of a full-scale test embankment with silty sand backfill on soft ground reinforced with kenaf limited life geotextiles (LLGs). Slide 5·0 software is used to analyse the stability of the embankment with kenaf LLGs and indicates a higher factor of safety than without kenaf LLGs. Surface settlements, subsurface settlements, excess pore water pressures and deformations of kenaf LLGs reinforcement are monitored and predicted. The predicted settlements agree well with measured values in the field but are overestimated by the Terzaghi one-dimensional consolidation method, as expected. There is close agreement between the measured and predicted settlements by Asaoka's method, as well as the predicted pore pressures using Skempton–Bjerrum predictions. Deformations are observed for LLG reinforcements which mobilised reinforcement tension up to 20 kN/m following the settlement pattern. After construction, the rates of settlement increase up to 250 days owing to the dissipation of excess pore water pressures. The time to 90% degree of consolidation (t90) is 250 days, which is less than the estimated life of kenaf LLGs. Based on the performance of the test embankments, kenaf LLGs can be used for soil reinforcement on soft clay for short-term applications.

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