| 摘要 |
<p>The present invention relates to pre-cast segments 10a, b, c, d for use in vacuum column construction (100 figure 1) and are used for vacuum flushing a column of a water storage tank (500 figure 1). A pre-cast segment comprises an outer surface (11 figure 3), an inner surface (12 figure 3), and a first (lower in use) surface (20 figure 3) and a second (upper in use) surface (30 figure 3) extending between. The first and second surfaces are complementary surfaces adapted to mate with the respective second and first surfaces of adjacent segments. The first surface comprises an outer peripheral section 21, and an inner recessed region 22 bounded by a peripheral lip 23, the recessed region being adapted to receive a sealing strip 24. There is provided one or more bolting holes and one or more grout holes 40 extending from the second surface to the recessed region of the first surface. The segments also comprise one or more vent holes 60 extending from the recessed region of the first surface to the inner surface of the segment.</p> |
