VACUUM CONSOLIDATION METHOD, VACUUM CONSOLIDATION DREDGING METHOD, AND VERTICAL DRAIN

摘要

In a vacuum consolidation method, it is important to maintain a high vacuum pressure. A theoretical limit is -101.3 kPa (gauge pressure), and the vacuum pressure under an airtight sheet at an actual site is about -70 kPa to -80 kPa, which has not been fully utilized yet. Furthermore, the limit improvement depth of the ground in the vacuum consolidation method is set to 10 m. Decompression that creates a high-vacuum state in the vacuum consolidation method is greatly affected by a pressurizing action of water vapor. A vacuum consolidation system according to the present invention achieves a network by adding an enhanced vacuum tank and a cold trap to intermediate portions of a plurality of vacuum paths from an air/water separation vacuum tank to a vacuum pump. Here, the effective utilization of the vacuum pressure is increased by about 20% to 30% compared to a construction method according to the related art. Furthermore, by replacing retained water in the vertical drain with air, a wall of a depth limit of 10 m for ground improvement by the vacuum consolidation method was removed. Furthermore, by removing the retained water, a high vacuum pressure causing interstitial water to be boiled can be directly transmitted to the viscous ground, thereby achieving a significant reduction in consolidation time and an increase in consolidation settlement by virtue of the synergistic effect of unparalleled decompression boiling and vacuum consolidation.