Advanced Materials Research Vol. 852

Abstract: The objective of this paper is exactly to assess the effect of anti-explosion for tunnels anchored outside under the condition of thin coating layer. To meet the similarity requirements, two groups of test models were made to simulate the responses of caverns under blast loading. It showed that: been anchored outside, displacements of the wall in caverns was decreased, so were the acceleration and compressive stresses with varying degrees, but the deformation stiffness and the overall stability were enhanced. This method does not take up space inside but it is beneficial to reduce the minimum thickness of protective layer and provides a new way to improve the anti-explosion performance for caverns under the conditions of thin coating layer.

Abstract: This paper presents an advanced computational modeling of natural fracture networks in hot dry rock (HDR) reservoirs. A mathematical model is developed for describing the heat energy extracted from a HDR in a multi-well system. The model stochastically simulates discrete properties of natural fractures, utilizing multi-set orientation and fractal mathematics. The simulated fracture networks are essential for further stimulation and fluid flow studies. The results show that the heat extraction effectiveness is affected significantly by the well spacing, well radius, reservoir thickness, and pumped flow rate in a multi-well system. The water temperature decreases with increasing pumping rate and increases with the well spacing, well radius, and reservoir thickness. This paper also examines the detrimental effects of the simulated natural fracture network on the stimulated fluid flow capacity. The effective permeability enhancement (due to hydraulic stimulation) is found almost proportional to the density of the reservoir natural fractures.

Abstract: In this paper, the responses of cavern underground reinforced by external cross-anchoring under blast loading were simulated by three-dimensional computational model made in software FLAC3D. It compared and supplementary analyzed the calculated displacement curves, the nephograms of maximum principal stress and destruction of cavern with that of model test, and analyzed the effect and mechanism of reinforced cable in this way comprehensively from deformation and destruction of surrounding rock outside, dynamic strain of cavern, energy absorption by anchor and energy consumption transferred through stress etc.

Abstract: Frost action leads to water movement toward frozen parts in soil matrix, and thus causes freeze heave and thaw weakening issues in many engineering works. This study was conducted as an attempt to investigate the analytical solutions to the water movement and distribution taken place in soil which was subjected to frost action. A geometry model was established by dividing the soil matrix into two individual parts in terms of the freezing progress each part takes. Model analytical solutions were sought with regard to the water movement over time that frost action takes. The analytical solutions were compared with the test results in a preceding investigation. It is indicated that the analytical solutions derived from the model is in good agreement with the test results and is reliable to predict the water movement in soil driven by frost action.