Experimental study on pumping-induced land subsidence and earth fissures: a case study in the Su-Xi-Chang region, China

Land subsidence and earth fissures caused by excessive groundwater exploitation severely damage the surrounding property and environment. To examine changes caused by land subsidence and earth fissures, a large-scale physical-geological model was designed to simulate groundwater exploitation and the conditions of bedrock ridges. This model enables real-time monitoring of the groundwater level, soil strain, and changes to subsidence and fissures. It is based on a case study conducted on the ground surface of Guangming Village in the Su-Xi-Chang region, China. The results revealed the following: (1) the land subsidence lagged behind the decline in water level during the pumping process; (2) a strong agreement between the shape and location of the bedrock ridge and settlement was reached, and the region with the most severe subsidence corresponded to the distribution of the fissures; (3) the tensile-stress concentration of the soil mass was essentially the same as that during the stage when the fissures developed, (which is an important means of determining the fissure development); and (4) the rose diagram illustrating the fissures indicated the fissures in the area of the bedrock ridge propagated parallel to the contour lines of the bedrock ridge. These results are consistent with the changes in the earth fissures examined in the case study and, therefore, provide support for the use of the physical-geological model in future research on ground fissures.