2.Current status and main features Tianjin implemented the first subsidence-controlling project in 1986.The land subsidence has been also basically controlled as well.The average annual subsidence always fluctuate at 14 mm (Hu,2002).The entire Tianjin region showed a small amount of subsidence each year since 1986(Fig.2). 2. Current status and main features Tianjin implemented the first subsidence-controlling project in 1986. The land subsidence has been also basically controlled as well. The average annual subsidence always fluctuate at 14 mm (Hu, 2002). The entire Tianjin region showed a small amount of subsidence each year since 1986 (Fig. 2)