Advanced Materials Research Vols. 838-841

Abstract: The complexity of metro construction in the aspect of safety is prominent in nowadays, are need to introduce a new effective management methods in urgent. Safety collaborative management of metro construction, based on partnership, will introduce the collaborative organization to the safety management work, and provide the reference for the metro project. This study, which is based on Shenzhen metro line No.3 cover property in the needs of security coordination, analyzed the characteristics of safety coordination management in metro construction, put forward the realization form and organization model of safety coordination management in metro construction, constructed the security assurance model on the basis of partnership, developed metro safety collaborative management platform which on the strength of project information portal (PIP), then effectively implement combined the near outer layer and outer layer of metro construction safety management, enhanced information sharing, cleared working process, improved the efficiency of collaborative group work.

Abstract: Silty fine sand is the second smallest sand with a particle diameter ranging from 0.0625 to 0.120 mm.This kind of sand exists in a large amount in Beijing subway excavation project. Due to the poor self-stabilization of this stratum,seeping , sand flow and collapse take place frequently. Grouting materials such as Portland cement and soluble glass (also called sodium silicate) are employed in most of excavation projects to reinforce this sand stratum. However, the reinforcement is not effective, leading to a large amount of accidents in the process of construction. The reason may be attributed to the fact that Portland cement is unable to penetrate into the stratum and the strength of soluble glass (0.6MPa) is too weak to resist the stratum pressure. To solve this problem, a modified microfine cement grouting material able to penetrate into silty fine sand stratum is developed in this paper. A combination of suspension and diluent is used to increase the penetration extension of the grouts,and the experimental results reveal that the addition of the mixture of suspension and diluent in microfine cement grouting materials improves the penetration property substantially.

Abstract: The paper introduced the Bayesian networks briefly and discussed the algorithm of transforming fault tree into Bayesian networks at first, then regarded the structures impaired caused by tunnel blasting construction as a example, introduced the built and calculated method of the Bayesian networks by matlab. Then assumed the probabilities of essential events, calculated the probability of top event and the posterior probability of each essential events by the Bayesian networks. After that the paper contrast the characteristics of fault tree analysis and the Bayesian networks, Identified that the Bayesian networks is better than fault tree analysis in safety evaluation in some case, and provided a valid way to assess risk in metro construction.

Abstract: To evaluate the earthquake resistant behavior of the nuclear island buildings of new generation PWR, in this study we formed the three dimensional finite element model of nuclear island structures ,which incluse shield building, the auxiliary building, the containment vessel, and the containment internal structures. Modal analysis was performed to to reveal the structural dynamic characteristics.And with the auumption of hard bedrock support media ,the dynamic response nanalysis of the nuclear structures under earthquake was conducted,respectively with response spectrum method and time history method.It shows that the seimic response of the strucures conform with the design level.Under the input excitations of SSE(safe shutdown earthquake) level, the iner forces and deforamtions can be well controlled in linear elasticity.

Abstract: Based on the actual inspection to typical Stilt timberwork residence in Puer of Yunnan.This paper find that many places still inadequate, of which the most outstanding part were lack of plinth , the defects of support in the node , the lack of beams and columns ,etc. A contrast analysis of maximum sheers in every storeys and storey drift are made between unreinforced and reinforced slopes by using the finite element software of etabs , which verified the rationality of the strengthening scheme.

Abstract: By small earthquake records from the Gansu broadband digital earthquake network, five regional source and crustal medium parameters, stress drop Δσ, quality factor parameters Q₀ and η, geometrical spreading parameters R₁ and R₂, are inversed for the Lanzhou area. Envelops of Fourier spectra are adopted as the objective function, the values of those parameters are 34.625bars, 95.665, 0.360, 58.188km and 105.650km, respectively. These values are adopted to calculate Fourier amplitude spectra, and complex spectra are formed by combining with random phase spectra. Acceleration time histories can be simulated, and PGAs on different moment magnitude-distance pairs are obtained previously. Compared with several observed strong ground motion data, the result is lower in the case of M_w=5.0, passes through the data in the case of M_w=6.0 and higher than the record of M_w=7.0. It is adopted in regional seismic zonation. Compared with The Zonation Map of Earthquake Ground Motion Parameters in China (GB18306-2001), the result is close to the map when PGA is lower than 0.2g.

Abstract: 33 records of Japanese earthquake are extracted in this paper (referred to as 3.11 seismic waves in the article).Then, through studying the basic characteristics, spectrum characteristics and anisotropic of 3.11 seismic waves, as well as the similarities and differences of the response spectrum of 3.11 seismic waves contrasting with the response spectrum of the code. The results show that: a) 3.11 seismic waves have rich spectral components almost near the predominant frequency and its energy mainly concentrate in 0.1~10Hz.b) By analyzing the spectrum distribution of the seismic waves, its destruction strength on different structures can be evaluated. c) Damaging strength of horizontal seismic waves is much larger than the vertical seismic waves. Serious damage to the structure can be caused by the horizontal seismic waves’ excellence spectrum components focusing on the frequency of the structure in the engineering. Vertical seismic waves have greater damage to the structures’ periods between 0.02s to 1s, but much smaller to other structures. d) it can effectively assess the damaging strength on the structure,in time history analysis ,when make 3.11 seismic waves as the input earthquake waves.

Abstract: In this paper, using the finite element software PERFORM3D to establish the finite element analysis model for isolation and seismic frame structure with special-shaped column and rectangular column frame structure, and the overall structure of the moderate and strong elastic and nonlinear earthquake time-history analysis to get the dynamic characteristics, from two aspects of the damping coefficient in horizontal direction and the energy dissipation, investigation structure in earthquake and rare earthquake of superstructure stiffness attenuation. It can be drawn only seismic resistance measures are taken, the special-shaped column structure under rare earthquake stiffness attenuation speed is greater than the rectangular column, if after using base isolation technology, although the special-shaped column stiffness attenuation rate is still greater than the rectangular column, but the two energy dissipation ability.

Abstract: Seismic attributes have been widely used in seismic object detection. While no unique attribute is expected to perfectly identify the targeted object, various attributes contributing to the same purpose should be utilized simultaneously when performing detection. Artificial neural network has been successfully applied in seismic object detection by combining multiple attributes into a single object-sensitive attribute. An optimized neural network fault detection approach was introduced by a case study from Stratton field, south Texas, United States. Results indicate that the new produced fault probability attribute could suppress the surrounding noises and highlight the faults. Application of ant-tracking to the fault-cube shows more convincible results than to individual attributes. In addition, several potential cross-strike fractures increase the structural complexity. The neural network-based fault detection contributes to better structural interpretation and is of great significance to hydrocarbon exploration, especially in area with complex fault system.

Abstract: This paper brings up the improved elastic stiffness method to the energy dissipation system with buckling restrained brace design in high-rise buildings and super high-rise buildings, Introducing amplification factor technology by improving the original elastic stiffness method can amplify seismic action regularly and the iteration was notably reduced by the seismic action which was calculated from the amplified coefficient so that solving the problem of relatively slow iterative speed. According to the demand of displacement limit value and the stiffness distribution in main structure, the demand of lateral stiffness in general structure can be directly worked out so that it can get the effective stiffness which should be added to the energy dissipation with buckling restrained brace. By the practical engineering example which height of frame-core tube is 144m, the design steps and user principles of the method are clearly illustrated. Meanwhile the application of response spectrum method on the basis of the elastic stiffness is expanded.