Applied Mechanics and Materials Vols. 368-370

Abstract: Firstly, the stability of the slope need to determine mechanical parameters of slope rock mass such as deformation modulus, Poissons ratio, cohesion and internal friction angle, etc. For intact rocks, the mechanical parameters mentioned before are easy to determined. While the stability of slope rock mass is controlled by the deformation and intensity. Therefore, how to determine the mechanical parameters of the structure is the key to analyze the stability of slope rock mass. This paper intends to set the slope rock mass below some extra-large bridge as the research object and use numerical calculation to determine the mechanics parameters of rock mass structure plane on the basis of rock sample mechanics test results.

Abstract: Prilling tower is the core structure in the technological process of Nitro-compound fertilizer plant, whose safety is directly related to the normal operation of fertilizer production. Prilling tower is a hollow high special structure which is constructed by concrete-filled steel tubular (CFT) columns bonded by annularity truss and widely used in fertilizer plant. The stability study of the tower is still a blank at present as the structure's specific form. In this paper, buckling analysis is used to analyze the structure in order to define the CFT prilling tower's effective length, according to its characteristics. Its effective length is calculated with equivalent negative stiffness method and the stiffness demands of annularity truss are identified. Elastic-plastic stable assessment of structural stability is carried on using advanced analysis method. A new load model and evaluation method (lateral loading method) has been proposed based on advanced analytical results, which is suitable for evaluating elastic-plastic stability of high-rise steel structure. The stability design methods of such structures are also presented according to the analytical results, providing reference for similar structures and projects.

Abstract: With the improved direct shear creep apparatus, the rheological material composition and its spatial distribution effects on aging deformation characteristics of soft soil. Four sets are finished including organic clay, quartz and feldspar with different weight percentages and rheological properties of different spatial distribution of sample testing in the same experimental conditions. Test results show that flow in any matter content ratio has significant effects on the rheological properties, the influence of the spatial distribution of waning gradually, and with the uniformity of the distribution and uniformity of the critical value. When a disguised form of size is less than the critical size of soil, soil aging deformation characteristics associated with the flow in a disguised form content ratio, and had nothing to do with the space distribution.

Abstract: Critical wind velocity of dynamic failure is an important factor for the wind-resistance design of three-way single-layer cylindrical reticulated shells. This paper investigates the elastoplastic dynamic failure of reticulated shells under three dimensional wind loads, the ultimate capacity, buckling mode and plastic development distribution of reticulated shells under wind loads are investigated. The influence of initial geometrical imperfections, initial static loads, supporting types, rise-span ratio, long-width ratio on the failure performance of reticulated shells are presented. The comparison of the ultimate bearing capacity shows that the critical wind velocities under dynamic wind loads are much lower than that under static wind loads for reticulated shells.

Abstract: For the aim to simplify the dynamic analysis responses of multi-storey steel frame structure under strong earthquake, the level participation ratio β of buckling restrained brace（BRB）as the main research, 6 multi buckling restrained braced frame（BRBF） models were established, and evaluate formula was given based on energy and story displacement. The results revealed that the static analysis responses of story displacement, shear and the energy distribution of buckling restrained brace and the relationship of hysteretic curve are in agreement with the dynamic when the level participation ratio β between 20% and 60%. So the static analysis value can evaluate the value of seismic response accurate under strong earthquake when the frame was designed with fixed equivalent base shear method and the level participation ratio β between 20% and 60%.

Abstract: An underground club in Xian is taken as the research object to explore the mechanical response of the internal poles of its high formwork support system during concrete pouring. The internal force static measurement of the high formwork support system is carried out. Each stage of the concrete pouring is simulated by the finite element analysis software ANSYS in the form of load step, whose results are contrasted with the measured results. The contrast reveals that the concrete pouring sequence has direct influence on the tendency of poles axial force and on the location of maximum axial force and that it is reasonable to adopt imaginary horizontal force which simulates the initial defects to carry out the overall stability analysis of the high formwork support system. It is pointed out that the program of setting up the formwork and the concrete pouring sequence should be determined with the finite element analysis.

Abstract: In Australia, the distortions of light structures in expansive soil are widely reported, often such damages are due to the soil settlement caused by expansive soil swelling and shrinkage. Expansive soil covers large areas of land in this country and its behavior is complicated. Generally the expansive soil behavior is closely related with the water content. This paper gives a preliminary discussion of soil-water interaction in expansive soil in three aspects: effective stress, soil suction profile and soil water characteristic curve (SWCC). Hopefully the investigation can help making the engineering guideline in real construction.

Abstract: Mega-sub controlled structure (MSCS) is a new structural configuration presented recently and has received widespread attention . To further improve the structural control effectiveness of MSCS, in this paper, a new hybrid control method is proposed which employ active control and adjust the stiffness of substructure together to form a huge hybrid controlled system based on the particular conformation characteristic of MSCS. The control law and dynamic equation to assembling parameter matrixes for the MSCS subjected to horizontal seismic excitation are presented. The result indicates that, compared with the corresponding status without actuators, the new structure employing hybrid control method proposed in this paper has the ability to develop a high level of response control effectiveness when subjected to seismic excitations and does significantly further reduce the responses of structure; a much better control effectiveness will be obtained after parameters optimization.

Abstract: In this paper, the 1/3 ratio model of reinforced concrete deformed column for low-cycle repeated load experiment is adopted, the common finite element software SAP2000 is used for analyzing the models performance of bearing capacity, ductility, Occurrence order of plastic hinge, the yield mechanism and inter-layer displacement. The results show that the selected madel can simulate the nonlinear performance of the shaped column frame accurate, the calculated value is in good agreement with the experimental values.

Abstract: Siding Lead-Zinc mining area located in Guangxi,was a large mining area belonging to the nation.Because of unreasonable mining in many years,The good ecological environment of mining area was destroyed.Land collapse in mining area is series.Basing on the factors,such as the geological environment of karst development,the characteristics of karst development,the formation stage of the cave,the conceptive model,this paper analyzed the cause of karst collapse in mining area.