Improving final settlement predictions of the observational method Available to Purchase

Preloading is a popular technique in ground improvement works on soft compressible soils. Observational methods such as the Asaoka or hyperbolic methods are widely used in practical applications to assess final settlement and the degree of consolidation during preloading. In this paper it is argued that the major cause of inaccuracy in the final settlement predicted by the Asaoka method, especially in the early stages of preloading (short assessment periods), is neglect of the effects of creep in Asaoka's solution. This may also be the cause of the lack of agreement between observational methods and the piezometer method at higher degrees of consolidation. In this paper a method is proposed that can improve ultimate settlement predicted by the Asaoka method, by considering the effects of creep. By applying this method to two sets of settlement–time data available in the literature, it was found that the final settlements can be estimated with greater accuracy compared with the Asaoka method, even in the early stages of consolidation. Additionally, the proposed method can predict future settlements accurately. The degrees of consolidation predicted by this method showed good agreement with pore pressures recorded in piezometers.