Abstract:
According to the long-term observation data of groundwater in the Tianjin area, the current situation and dynamic change law of groundwater level in the Tianjin area were systematically analyzed. The maximum groundwater level in the central urban area of Tianjin was predicted by using the GM (1,1) grey prediction model, and the variation of the maximum water level elevation in the Tianjin area and the recommended anti-floating level were given. The determination method of anti-floating water level in mountainous and hilly areas, accumulation plain areas, coastal intertidal zones, and special areas in northern Tianjin was quantitatively analyzed, and the regional empirical value of anti-floating water level was given. The results show that: (1) the maximum groundwater level elevation in Tianjin in 2023 is 1.0~7.0 m, and the buried depth is 1.0~3.0 m, which is consistent with the distribution range and trend of the maximum groundwater level from 2019 to 2023. (2) The variation trend of the predicted water level in the central urban area is consistent with the original observation water level, and most areas show a downward trend. The anti-floating water level elevation is generally 1.8~3.6 m, which is generally high in the northwest and southeast, and low in the northeast and southwest. (3) For areas with low elevation without data such as the surrounding area of Tianjin city, the anti-floating water level can be taken as 0.50 m below the designed outdoor floor elevation. For areas with low-lying terrain, high ground filling, and low ground excavation, the anti-floating water level should be taken as the designed outdoor floor elevation.