Applied Mechanics and Materials Vols. 638-640

Abstract: Combined with recent observation data, the paper conclude that the debris flow break-out in high frequency in Jiangjia Ravine, and they belong to rainstorm type, which concentrated in the rainy season, especially during Jun to Aug. As a typical gully of viscous debris flow, the debris flow move with the bed process and obvious feature of surge. The intermittent flow possesses features of high intensity of delivery and long intermittent period. There have obvious relevance between the amount of sediment delivery and the surges of debris-flow break-out at the same year.

Abstract: The city underground common trench plays a more and more important role in the disaster prevention of the city lifeline engineering system, improving the resilience of the city lifeline engineerings and speeding up its recovery from disasters. In this paper, we start from the concept of the underground common trench with analysis on its inherent characteristics and the advantages in the prevention of natural disasters. According to the analysis on the development of the underground common trench in China, we try to point out the existing problems. And finally, some reasonable advice is proposed for addressing these problems.

Abstract: Based on the analysis of different urban communities, and the study of a large number of domestic and foreign literatures, the basic principle of urban community evaluation index selection system with the characteristic of completeness, measurability and comparability is proposed in this paper. This paper constructs the evaluation index system of disaster prevention of the community from basic characteristics, inherent risk to disaster mitigation resources, including three first grade assessment indexes, 12 second grade assessment indexes and 24 third grade assessment indexes.

Abstract: The impact force is one of the most weak link of the dynamics studies of debris flow for many years. To make the structure or components are better able to suffer the impact load such as debris flow, explosions, a new debris flow dam is designed by introducing this new type model with spring. It is simulated under boulder impact by using finite element software LS-DYNA.The stress distribution, impact and displacement time history curve under typical conditions are obtained. The results show that the resist impact effect of new debris flow dam is very obvious.

Abstract: The requirement for the utilization of a subway station as a temporary shelter is promptness. In this regard, it is necessary to make different preparations prior to the occurrence of a disaster. This study aimed to calculate the acceptable occupancy rate per space area and the acceptable sanitary provisions, to classify subway stations, and to develop a subway station selection program based on the identified standards. The subway station selection process is classified into four steps: regional understanding, acceptable-ability calculation, subway station identification, and temporary shelter building. The program thus involves these four steps. It is necessary to continuously manage and control the drawings and programs of each subway station for the efficient use of the selected system.

Abstract: To establish the possibility and risk assessment system of Three Gorges Reservoir Region tankers oil spilling through identifying the risk of tankers oil spilling and the sensitivity of environment resource. Introducing the fuzzy mathematics theory based on the traditional AHP theory then establish the fuzzy AHP model of the Three Gorges Reservoir Region oil spilling risk assessment. According to that, get the bigger water area of the oil spilling risk so that supply to the maritime administrations with the basis of the key point of the controlling oil spilling and optimizing the allocation of the anti-pollution resources.

Abstract: Debris flow is one of the major geological disasters in mountain areas. This paper systematically analyzes the influence of steep terrain conditions, the development of regional structure, neotectonic movement and earthquake, wide distribution of debris, human engineering activity and rainfall concentrated climate conditions in debris flow area. The dominant factors inducing Zhaohe debris flow were revealed, providing guidance for the debris flow disaster prevention, as well as reference for the same area debris flow cause analysis.

Abstract: Indoor air quality in a public transport interchange station in rush hour has been studied. Carbon monoxide is selected as the main pollutant for description of air quality. Ventilation systems, bus traffic and passenger flow, air quality have been investigated by on-site survey. Large eddy simulation technology has been used to analyze indoor air quality of public transport interchange station. The boundary conditions are determined according to the measured date. Indoor air quality results at heights of 0.8m and 1.6m in rush hour and two operating conditions of public transport interchange station are calculated. Results have shown carbon monoxide concentrations at height of 0.8m are higher than those at height of 1.6m. Air quality would reach the harmful degree within 5min to 10min if the ventilation system is not operating. The ventilation system should be operated continuously during the peak hour in order to meet the requirement of indoor air quality standards.

Abstract: Thermoelastic response due to a line heat source is analog to poroelastic reaction caused by a fluid line sink. In this study, the strata are modeled as a thermoelastic or poroelastic half space bounded by horizontal surface in the mathematical model. Thermomechanics and poromechanics are applied on the formulation of basic governing equations, and an analogy is drawn to show the similarity. Using Hankel transform technique and approaching symbolic integral through Mathematica, the closed-form solutions of the horizontal and vertical displacements due to a fluid line sink are obtained. The displacements produced by the line heat source are described through analog quantities between thermoelasticity and poroelasticity. The solutions can be applied to dewater operations and build waste repository.

Abstract: VAV (VAV) air-conditioning systems always have the characteristics of nonlinear, strong coupling, large time delay, thus the conventional PID control method can't meet the requirement of control performance. In order to adapt to the changes of the load in air-conditioning systems, and make an accurate rapid response, this paper proposes a fuzzy adaptive PID control method. The temperature control by terminal air valves in VAV air-conditioning systems was selected as a control object, through collecting the deviation between setting value and room temperature, the parameters of the PID controller were selected to realize the accurate control of the temperature. In order to evaluate the effectiveness of the proposed control method, it was compared with conventional PID control method by simulation experiment, the results show that the proposed Fuzzy adaptive PID control method has more shorter setting time, less overshoot and more steady state performance than the latter.