Investigation of the hydraulicked layer of a high-grade loess soil fill

Abstract

1. The hydraulic fill layer of loess soil in its central section is characterized by the following features: a) It possesses complete water saturation over the whole depth; b) with increasing depth, the density of the poured soil increases and, accordingly, the moisture content diminishes; each depth has its corresponding density and moisture content; c) the top 3-m of the layer takes the form of a soil mass with moisture contents above the yield point (W=34–60%), being a small layer of poured soil with a low compaction pressure. This layer must be artificially dewatered if the hydraulic-fill structure has to be brought quickly into service. 2. The density and moisture content of the soil through the depth of the hydraulic-fill layer in its central section, starting from 3 m and lower, can be determined from the data of compression tests on the soil mass, assuming a depth of hydraulic fill numerically equal to the compaction pressure in accordance with Eqs. (9) and (10). 3. Prolonged stoppage of hydraulicking has an unfavorable effect on compaction of freshly poured layers and continuous pouring over the height favors more solid placing of the soil in the structure. 4. Stability of the outer slopes of the hydraulic fill during construction, starting from a depth of 3–4 m from the hydraulic-fill surface and lower, should be carried out by the usual methods of soil mechanics, disregarding fluidity of the core and pore pressure. For the layer from the hydraulic-fill surface to a depth of 4–5 m, where the freshly poured soil is unstable and presses on the side shells like a heavy liquid, the strength calculation has to be carried out for the dry embankments.