A Coupled Thermal–Hydrological–Mechanical Damage Model and Its Numerical Simulations of Damage Evolution in APSE
This paper proposes a coupled thermal–hydrological–mechanical damage (THMD) model for the failure process of rock, in which coupling effects such as thermally induced rock deformation, water flow-induced thermal convection, and rock deformation-induced water flow are considered. The damage is considered to be the key factor that controls the THM coupling process and the heterogeneity of rock is characterized by the Weibull distribution. Next, numerical simulations on excavation-induced damage zones in Äspö pillar stability experiments (APSE) are carried out and the impact of in situ stress conditions on damage zone distribution is analysed. Then, further numerical simulations of damage evolution at the heating stage in APSE are carried out. The impacts of in situ stress state, swelling pressure and water pressure on damage evolution at the heating stage are simulated and analysed, respectively. The simulation results indicate that (1) the v-shaped notch at the sidewall of the pillar is predominantly controlled by the in situ stress trends and magnitude; (2) at the heating stage, the existence of confining pressure can suppress the occurrence of damage, including shear damage and tensile damage; and (3) the presence of water flow and water pressure can promote the occurrence of damage, especially shear damage.
DECOVALEX-an international co-operative research project on mathematical models of coupled THM processes for safety analysis of radioactive waste repositories
Abstract An international co-operative research project has been established under the name DECOVALEX for theoretical and experimental studies of coupled thermal, hydrological and mechanical processes in hard rocks. The capability of modelling coupled phenomena is of particular importance to the safety assessment of geologic disposal of radioactive waste materials. Different mathematical models and computer codes have been developed by different national research teams and these are used to study the so-called bench mark test and test case problems developed within this project. Bench mark tests are defined as initial-boundary value problems of a generic nature, and test cases are experimental investigations of part or full aspects of coupled thermo-hydro-mechanical processes in hard rocks. Presented in this introductory paper are the motivation, organization and approaches of the project, definitions of bench mark tests and test case problems and descriptions of mathematical models used in Phase I of the DECOVALEX project. A brief introduction to the Phase II and Phase III of the project is also presented.
Research on Control and Planning of Soft-Wing UAV for Haze Removal
The existence of fog and haze has caused great pollution to the environment. The research of removing haze is a hot topic in recent years. In this paper, a special haze removal algorithm based on Soft- Wing UAVis proposed. In this algorithm, two track control strategies are designed based on the Soft-Wing UAV model transfer function. A SIMULINK platform based mathematical model of Soft-Wing UAV is built to testified effectiveness of the two track control strategies. An autonomous ergodic-planning algorithm with greedy strategy and foldback algorithm for Soft-Wing UAV is designed. Within the algorithm, the haze regional has been modelled, the cost matrix is constructed, and the planning and ergodic strategy is proposed. Finally, the experimental results validates the reliability of the algorithm in the application of haze removal with the proposed evaluation Index.