IN-SITU TESTING METHOD FOR INVESTIGATION OF GROUND IMPROVING EFFECT BY DRAIN

摘要

PURPOSE:To perform a test without disturbing an in-situ ground, by a method wherein a large pipe having an open lower end is penetrated into an in-situ ground, and after drain is poured into a ground within a pipe, the pipe is excited to measure a surplus gap water pressure generated in the ground within the pipe is measured. CONSTITUTION:A steel pipe 1 is driven into a ground 2, and a ground within a steel pipe 1 is excavated by means of an earth auger 3 with a casing 5. After gravel 4 is charged into the excavated hole, the casing 5 is pulled off to form a drain G. An internal ground 2a between the steel pipe 1 and the drain G is bored, meters 7, such as gap water pressure gauges, accelerometers, are buried in the ground 2a, and holes 8 are excavated in spots in the outer periphery of the steel pipe 1. Further, the ground 2a is liquefied by exciting the steel pipe 1 by means of a vibro hammer 9, and a water pressure and acceleration are measured by means of the meters 7.