The Land Subsidence Characteristic Following the Termination of Groundwater Pumping to Different Aquifers
Land subsidence is particularly critical in Tanggu, due to its flat-lying topography and large thickness of the soft clay. The subsidence up to 140mm/year reached its most critical state in the mid-1970s. To mitigate this hazard, some strict measures resulted in a drop in groundwater use, especially banning the exploitation of groundwater, were exerted. Accordingly, the subsidence indeed had a decreased trendy in this time interval. Meanwhile, a GPS-based monitor data also revealed that light uplift phenomena emerged in some individual monitor series. For discussing the relationship between this abnormality and the termination of groundwater, and analyzing the deformation characteristic after exerted this measure, this article with the aid of numerical method predicts the land subsidence. The result reveal that the settlement is ceased and obvious uplift phenomenon only emerges in the central region of the stop mining well, due to various supply resource the water level could have a rapid recovery after banning. Meanwhile, own to the time-dependant behavior of the soft layer and clay aquitard, the most region far form the ban well also emerges subside, but the subsidence rate switches to decreased trendy with time. Generally, the subsidence or uplift is stabilized in a finite time interval after the termination of groundwater pumping. Meanwhile, due to the different hydrogeologic and stratum conditions, the stabilized subsidence and uplift value are also different from unit 2 to unit 5.
Qing Yang, Li Hua Zhu, Jing Jing He, Zeng Feng Yan and Rui Ren
F. S. Ma et al., "The Land Subsidence Characteristic Following the Termination of Groundwater Pumping to Different Aquifers", Advanced Materials Research, Vols. 368-373, pp. 164-168, 2012