22-27 September 2019
Trade Fairs and Congress Center (FYCMA)
Europe/Madrid timezone

Evolution Characteristics and Driving Mechanism of the Land Subsidence for Typical Regions of the North China Plain

23 Sep 2019, 16:00
1h
Trade Fairs and Congress Center (FYCMA)

Trade Fairs and Congress Center (FYCMA)

Av. de José Ortega y Gasset, 201 29006 Malaga, Spain
Poster Topic 1 - Groundwater assessment and management Poster with refreshments

Speaker

Dr Haipeng Guo (China Institute of Geo-Environment Monitoring)

Description

The North China Plain (NCP) is one of the biggest groundwater systems in the world, and the development and utilization of groundwater has led to severe land subsidence. The NCP has more than 80% of the total area of severe subsidence in China, so the situation of prevention and control of land subsidence is severe. Due to diverse sedimental environment, different geological conditions, and intensive groundwater abstraction, the mechanism of land subsidence is complex. With the help of earth observing technique and traditional monitoring tools, the disaster process of land subsidence was monitored, and the developing history and current situation were analyzed. Also, the difference features of land subsidence and the mechanism of hysteretic deformation were analyzed with the help of strain-stress diagrams and soil mechanics tests. The results show that the subsidence areas are mainly located in the areas of the Quaternary sedimentary depressions, having characteristics of west-east sub-zone and north-south subsection. The major contribution layers to the land subsidence have varied with the change of groundwater abstraction layers. The drought is an important and indirect factor enlarging the scale of land subsidence by reducing natural recharge and leading to the increase of groundwater abstraction for emergency water supply. The hysteresis of land subsidence is obvious, and the time of hysteresis can last for twenty-five years. Besides the consolidation, the creep is another important reason for the hysteresis which can reach 28.3% of the total deformation for the Late Pleistocene strata in the Cangxian uplift. The deformation characteristics of the soil layer bear strong relationship to the physical characteristics and variation pattern of groundwater levels. The strata at different depths have distinct deformation characteristics such as elastic, visco-elastic, and visco-elastic-plastic deformations, and shallow aquifer groups indicate typical elastic deformation.

Primary authors

Dr Haipeng Guo (China Institute of Geo-Environment Monitoring) Dr Liya Wang (Beijing Institute of Hydrogeology and Engineering Geology) Mr Yunlong Wang (China Institute of Geo-Environment Monitoring) Dr Juyan Zhu (China Institute of Geo-Environment Monitoring)

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