Applied Mechanics and Materials Vol. 577

Abstract: In this paper, using the Sap2000 analysis software, established the analysis model of high-rise reinforced concrete filled steel tube frame structure, in allusion to the damping effect in different number, different layout and different spectral characteristics, and carried out the optimization of damping wall configuration scheme. According the calculations, comparing the influence of seismic performance between the original structure and after optimization of concrete filled steel tube structure in the condition of earthquake, the results showed that the viscous damping walls in the structure damping control effect is obvious.

Abstract: In recent years, more and more attentions are paid to risk monitor and safety management technique due to the increasing underground engineering accidents. Compared to the rapid progress of underground engineering, the development of engineering risk management is backward. Engineering risk management has become a problem that must be solved in the first place to ensure construction safety. To solve this problem, a study was conducted on the safety issues encountered in Jinan underground engineering. In this paper, for the purpose of ensuring safety, reducing risk and controlling engineering quality, construction risk distribution disciplines were summed up while concept of safety and risk management was put forward.

Abstract: The calculation of sliding cable is difficult because it can dynamically pass through prescribed nodes and the length is variable. In order to solve the above problem, a calculation method based on tension distribution and temperature compensation for sliding cables was put forward. At first, the sliding cable was supposed to be fixed cable and the internal force of each cable segment was calculated. Then, the unbalanced tensions between neighboring cable segments were distributed to make the tensions equal. And then different temperatures were applied to the corresponding cable segments, which could cause temperature stress to compensate the unbalanced tensions between the initial calculated tensions and distributed tensions. At last the calculation was carried on again after applying the temperature to each cable segment. Moreover, an example was presented to verify the precision and validity of this method. The results show that the calculation method based on tension distribution and temperature compensation for sliding cables is effective.

Abstract: Box culvert affected by mining subsidence is exposed to damage potential in relation to the lateral earth pressure. This study intends to specify and compare different ground deformation by the mining subsidence effect in box culvert. For this purpose, a finite-element software (ANSYS) is used to generate models incorporating the soil and a box culvert. The results shows that the lateral earth pressure of box culvert was related to the way of ground deformation, In addition, the kind of soil also affected the distribution and value of the lateral earth pressure.

Abstract: To solve the problem of gas accumulation in thick-seam top-coal caving mining face, goaf gas migration equations were established based on seepage theory and the law of mass conservation. Taking No.7602 working face of Wuyang coal mine as the study object, gas migration rules of goaf in ventilation of U + I and Y+I were simulated by Fluent, and comparative analysis and verification were carried out by in-situ monitoring data. Test indicates that after gob-side entry retaining, average gas concentration value of No.7602 working face Return airway decreased by 39% compared with similar working face, decreased by 39% in gas emission roadway, decreased by 42% in upper corner. Ventilation of U + I can successfully resolve the problem of gas accumulation in upper corner and working face. The conclusion has a good instruction value to gas control in thick-seam top-coal caving mining face.

Abstract: Evaluate the reliability for the deformation of structure is a hard work. Usually stochastic finite element method or response surface method was adopted. In this paper, a new way by combining of numerical method and modified reliability analysis method is proposed. The modified first order second moment method (FOSM) was introduced and three examples are employed to verify the feasibility and the effectiveness of this method. The examples showed the modified FOSM had the advantage of faster convergence rate, higher calculation accuracy in comparison with FOSM, response surface method and optimization algorithm method. Combining finite element method program with modified FOSM method is applied to analyze the reliability index of deformation of a tunnel. The results showed this approach was a successful method to analyze the reliability of complex structure.

Abstract: The study area was located in central coast of Jiangsu Province, China. The coast between Wanggang estuary and Chuandonggang estuary belonged to a typical accumulation muddy coast. When the Yellow River flowed into the Yellow Sea using the Huai River course, the coast deposited rapidly and the coastline advanced to the sea about 60 km. The deposition source stopped after the Yellow River returned to the north and flowed into the Bohai Sea. The entral coast of Jiangsu still maintained a high deposition rate in the supratidal zone because of the erosion supply of the abandoned Yellow River delta. But the subtidal zone was in the erosion state. The coast entered into the adjustment period in the 21st century and showed the equilibrium of the erosion and deposition. In recent years, the supratidal area decreased because of the reclaimation. The living space of the salt marshes was limited. The reclamation potentiality will be limited too in the future.

Abstract: In this article, data of stations distributed over China was used to calculate tropospheric delay. The result was compared with the tropospheric zenith delay calculated from model. The rules and Characteristic of tropospheric delay over China was analyzed from the aspect of altitude, climate, and change. The results showed that the tropospheric zenith total delay decreased from the coast to the central and western regions, the Tibetan plateau is minimum. Zenith wet delays computed from the models also show an absolute bias of over 20 mm with respect to that of sounding data. The standard deviation is more than 30 mm in the tropical monsoon zone.

Abstract: Using GPS observations, this article studied the global TEC’s effect and its variation characters during the magnetic storm on August 5^th, 2011. Results show that after sudden commencement and deep main phase of the magnetic storm, there are strong positive ionospheric TEC disturbances in the area along middle and low latitude with local time of 12:00 at noon. Besides, compared with TEC reference value, the maximum increase values are respectively 21.26 TECU and 25.29 TECU. TEC’s abnormal decline appeared in some area of high latitude at mid night on the northern semi-sphere. The analysis results reflect that the ionospheric disturbances are dependent on the local time. Moreover, observations on the BRMU GPS station show that the rate of TEC (ROT) rose and fell quickly, and its standard deviation ROTI index increased from less than 0.5 TECU/min to lager than 1.5 TECU/min, which meant that TEC temporal and spatial gradient had become larger and larger during the storm. The global ROTI map reflects the strong irregularity of the ionosphere density structure in the high-latitude area with higher time resolution in case of storm sudden commencement, and the maximum value rose up to 6 TECU/min. Then, the ionospheric irregularity appeared in wide area of the globe after noon.

Abstract: The physical characteristics are compared between shallow and deep water, in physics and acoustics, respectively. There is a specific sound speed profile in deep water, which is different from which in shallow water, resulting in different sound propagation law between them. In this paper, the sound field distributions are simulated under respective typical sound speed profile. The color figures of sound intensity are obtained, in which the horizontal ordinate is distance, and the vertical ordinate is depth. Then we can get some important characteristics of sound propagation. The results show that the seabed boundary is an important influence on sound propagation in shallow water, and sound propagation loss in deep water convergent zone is visibly less than which in spherical wave spreading. We can realize the remote probing using the acoustic phenomenon.