With the tailings dam reinforcement project newly built in Yakou as the example and limit equilibrium horizontal slice method as the methodology, this paper has researched the feasibility of applying geosynthetics in fine tailings dam reinforcement. The results from limit equilibrium horizontal slice method show that the stability of reinforced tailings dam with geosynthetics increases by 14~17%; while results from numerical simulation method show that the principal stress vector direction and the principal displacement vector direction of the dam body can be changed to be favorable to the stabilization of dam by using geosynthetics to reinforce the tailings dam.

Very large volume of mined ore materials are processed annually to obtain the various types of minerals that are essential to industrial processes, the upstream tailings dam is usually constructed to store these wastes. But with the increasing of dam quantities, the tailings dam collapsing in flood which are among the most dangerous hazards that affect mountainous and rural areas in a wide range of environments become more and more. Therefore it’s necessary to analyze the collapse mode of upstream tailings dam in flood situation. This paper using the physical model experiment and numerical simulation methods to research on the displacement, saturation line, stress and the broken processes, and the collapse mode of upstream tailings dam in flood water encountered in 100 years are explored. The results have very important significance and scientific support to understand the mechanism of collapse and broken mode deeply, and which have any new exploration for the prevention and control in flood hazard.

Every year, China suffers greatly from economic losses caused by rockfall hazards. The key to effectively control rockfall hazards is to obtain an accurate rockfall trajectory. However, not only is rockfall trajectory complex and unable to be described accurately in mathematical formula, but basic parameters influencing its movement are also unable to be measured directly. Therefore, the back analysis method combining laboratory rockfall simulation test with computer numerical simulation is adopted to study rockfall trajectory and its basic parameters. The results show that the method can not only get basic parameters of rockfall trajectory such as coefficient of restitution and angle of frication, but also precisely deduce true rockfall trajectory, which can provide help in effectively controlling rockfall hazards.

Rockfall is a frequent engineering disaster confronted in the capital construction engineering. The key for preventing rock fall is the evaluation of the rockfall trajectory. After extensive analysis, an innovative calculation method of rockfall trajectory, called segmented cycling algorithm, has been proposed in the paper. According to the contact relationship between the rolling stones and the slope surface, the movement divided into three sections which include the jumping phase, the rolling (sliding) phase and collision phase, the formulae to calculate the velocity of different phases of motion are proposed respectively by segmented cycling algorithm. A similar model, based on a rock slope in Chongqing-Wanzhou highway, is established to verify the capability and validity of the presented algorithm. Compared with existing algorithm, the new algorithm is simple and clear, easy to use and so on. The algorithm meets the law of the movement of rockfall and can be used to forecast the kinetic feature of rockfall. It is also used as the basis for rockfall disaster prevention.

The Wenchuan Earthquake of 8.0 magnitude at Richter scale hit large region of Sichuan, China on May 12, 2008. It was a terrible disaster that caused great casualties and serious damages, and largely destroyed natural mountainous ecosystems in the earthquake-hit areas. Since the restoration of those damaged mountainous ecosystems plays an important role in ecological security in this region, it is argued that the reconstruction of those earthquake-damaged ecosystems should be given greater attention before and during the ecological recovery process. Yet, to date, little effort has been made to review and summarize the major unresolved questions relating to the ecosystem recovery after the earthquake. Focusing on the priorities for future research in this subject, based on the study and comparison of literatures we identified and examined four important research questions that need to be addressed, even two years after the earthquake. All these questions need to be resolved before significant progress can be made in habilitating the damaged natural ecosystems, and perhaps more importantly, the results provide very useful information for cost-effective restoration decision making and policy planning for the earthquake-hit areas.