Device for in situ testing of soils that includes a vent valve adapted to close at a predetermined depth during installation

摘要

A module model pile tool in situ testing of soils. The tool has an upper instrument section, a lower anchor section, and an axial slip joint located between the instrument section and the anchor section. The anchor section may be configured to model either open-end or closed- end piles. In the open-end configuration, a vent and vent valve are provided to vent trapped fluid during the initial stages of installation by remaining open only to a predetermined depth so as to permit formation of an undisturbed soil plug and to close in order to prevent fluids from being vented into the actual soil to be tested. The instrument section includes instrumentation for measuring axial loads, axial accelerations, pore water pressure, and total lateral pressure. Instrumentation for measuring axial displacement are included in the slip joint. The tool is rugged enough to permit installation by pile driving, and the instrumentation may be monitored both during and after installation.