路基英文资料.doc

– The embankment construction on a group of piles. Attention here will not be focused on the type of piles (from the classical ones through to lime columns, gravel piles, sand-gravel geosynthetic piles – geotextile encased columns – etc.), but on ensuring the load transmission from the embankment to the pile heads. – The construction of the embankment from light weight materials – fill lightening. All the above given possibilities or at least some combinations of them will be demonstrated in practical cases. 6.2.2.1 Speeding up of Consolidation A very well described and documented example of speeding up of consolidation process was presented by Brenner and Pbebaharan (1983). In practice it was a large in situ model test in the scale 1:1 realized on 17m thick stratum of soft clay over stiff clay at Pom Prachul, Bangkok. A test embankment, 33m wide and 2.35m high, was built in two stages with a total length of 90m. The three test areas comprised a section with 1.5m vertical drain spacing, one with drain spacing 2.5 m, and a section without drains. The drains were wicks of 50mm diameter which were installed by the displacement method to the full depth of the soft clay. Such an example combines the two basic opportunities for speeding up consolidation: – Construction in 2 stages, allowing the dissipation of the excess of pore water pressure in the interim period, 10 weeks long, – Application of vertical drains. The embankment was well instrumented with settlement gauges and piezometers. For the purpose of predicting settlements and pore pressure, as well as for the backcalculation of consolidation parameters, a finite difference model was developed which could take into account a layered soil profile, two-dimensional water flow, time-dependent loading, a stress distribution varying with depth, and undrained deformations. All necessary soil parameters affecting compressibility and permeability were determined on samples obtained from 250mm piston samples. Index