Experimental study on the vertical deformation of aquifer soils under conditions of withdrawing and recharging of groundwater in Tongchuan region, China

Wei, Ya-ni; Fan, Wen; Cao, Yanbo

Experimental study on the vertical deformation of aquifer soils under conditions of withdrawing and recharging of groundwater in Tongchuan region, China | Etude expérimentale de la déformation verticale des sols d’aquifère en conditions d’exploitation et de recharge des eaux souterraines dans la région du Tongchuan, Chine Estudio experimental sobre la deformación vertical de suelos de acuíferos bajo condiciones de extracción y recarga del agua subterránea en la región de Tongchuan, China 中国铜川地区地下水开采和补给条件下含水层土壤垂直变形实验研究 Estudo experimental da deformação vertical de solos aquíferos sob condições de bombeamento e recarga de águas subterrâneas na região de Tongchuan, China

2017

Wei, Ya-ni | Fan, Wen | Cao, Yanbo

Land subsidence due to aquifer-system compaction accompanying groundwater extraction is a global hazard. Rising urban construction and groundwater demand necessitate increased awareness and better understanding of the geological problem. Motivated by the lack of laboratory-scale studies on this issue, an experimental investigation on the newly developed Tongchuan region, China, is presented. The study addresses the deformation behaviors of three soil samples, with the lithology of silty clay, silt, and fine sand, under the conditions of groundwater withdrawal and recharge using the GDS Consolidation Testing System. Results indicate that all three samples were characterized by elastic–plastic deformation under the conditions of withdrawing and recharging. The vertical deformation of the silty clay in the aquitard above the first confined aquifer was larger than those of the other two samples, and its deformation is a gradual and long process; thus, considerable attention should be paid to deformation in this aquitard due to the apparent creep effect and tiny rebound deformation. However, the settlement of the fine sand in the second confined aquifer cannot be ignored due to the great thickness of the aquifer. For the same soil, as the pore-water pressure declined, the unit rate of vertical deformation decreased gradually, whereas the creep effect of deformation in the later declining stage of pore-water pressure was more apparent than that in the former declining stage. These observations are highly important to the local government, which is developing measures to prevent and control subsidence.

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