Abstract
Abstract. Nowadays several parts of the world suffer from land subsidence. This setting of the earth surface occurs due to different factors such as earth quakes, mining activities, and gas, oil and water withdrawal. This research presents a numerical study of the influence of land subsidence caused by a single water extraction well and rapid water infiltration into structural soil discontinuities. The numerical simulation of the infiltration was based on a two-phase flow-model for porous media, and for the deformation a Mohr–Coulomb model was used. A two-layered system with a fault zone is presented. First a single water extraction well is simulated producing a cone-shaped (conical) water level depletion, which can cause land subsidence. Land Subsidence can be further increased if a hydrological barrier as a result of a discontinuity, exists. After water extraction a water column is applied on the top boundary for one hours in order to represent a strong storm which produces rapid water infiltration through the discontinuity as well as soil deformation. Both events are analysed and compared in order to characterize deformation of both elements and to get a better understanding of the land subsidence and new fracture formations.
Highlights
Land subsidence processes can occur due to extraction of minerals in mining galleries, tunnels construction, fluids extraction from natural reserves, decrease of groundwater level during prolonged extraction, natural land dissolution, compaction of soil materials or tectonic activity
The results show that after 30 min of fast water infiltration through the high permeable fault zone a maximum horizontal displacement of approximately 1.8 × 10−3 m and a vertical displacement of 6.8 × 10−3 m take place (Fig. 8)
The present study is a conceptual model of land subsidence produced water extraction from a single well and fast water infiltration through a fault zone
Summary
Land subsidence processes can occur due to extraction of minerals in mining galleries, tunnels construction, fluids extraction (water, oil or gas) from natural reserves, decrease of groundwater level during prolonged extraction, natural land dissolution, compaction of soil materials or tectonic activity. In arid and semi-arid zones this has produced a deficit leading to a rapid decline of the groundwater table. In heterogeneous strata the fast decline of the groundwater table leads to a differential adjustment and in some cases to a formation of cracks and fractures on the surface of the ground. Since the 1970s, with the rapid growth of the city, the water demand increased rapidly and as a result the urban area is affected by differential compaction and formation of a reticular system of faults and fractures. Many of them appear on the surface and have caused economical damages in the last 40 years
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
