PURPOSE: To prevent subsidence of a buried pipe conduit simply at low cost while using a civil engineering work sheet by arranging a pipe on the upper surface of a basic floor material and a lower foundation material arranged on the bottom part of an excavated groove in a condition that the periphery is surrounded/covered with an upper foundation material and the civil engineering work sheet.

CONSTITUTION: In order to prevent subsidence of a buried pipe conduit, after a basic floor material 2 is inputted on the bottom part of an excavated groove 1 and the foundation is solidified in the first place, a civil engineering work sheet 3 and a pipe 4 are arranged in order on the upper surface of these. Next, after both end parts of the civil engineering work sheet 3 are covered once with the pipe 4 and a lower foundation material 5 is inputted up to prescribed height around the pipe 4 and the foundation is solidified, both the end parts of the civil engineering work sheet 3 are spread on the upper surface of the lower foundation material 5, and are erected along both side walls 6 of the excavated groove 1. In succession, after an upper foundation material 7 is inputted up to a top part of the pipe 4 on the upper surface of the civil engineering work sheet 3 and the foundation is solidified, the erected parts of the civil engineering work sheet 3 are folded back, and are spread on the upper surface of the upper foundation material 7. Afterwards, the excavated groove 1 is backfilled with a backfilling material 8.