Controls on initiation and propagation of pumping-induced earth fissures: insights from numerical simulations

Pumping-induced earth fissuring occurs in many localities and represents an important economic problem associated with damage to infrastructures. In this work, a descriptive analysis of the natural conditions of selected localities undergoing fissuring is first performed. Then, numerical simulations are developed using the finite-element code ABAQUS to analyze the evolution of stress induced by pumping that can favor the initiation and propagation of fissures. The scenario used in the numerical simulations is based on the observed features from the descriptive analysis. These natural conditions include a complex stratigraphy, a buried fault scarp and a fault zone cutting the entire sedimentary sequence. Both fault zones and buried fault scarps influence the accumulation of stresses at different times. The fault zone has more influence on the patterns of tension/compression, while the buried fault scarp has more influence on the patterns of shear stress. Results show that a tensile-induced fissure is initiated close to the fault zone in the hanging wall. This fissure originates near the surface and migrates downward, terminating near the saturated-unsaturated interface. Factors involved in the propagation path of the fissure are the occurrence of a fault zone, the location of pumping, and the hydromechanical properties of the vadose zone.