Applied Mechanics and Materials Vols. 256-259

Abstract: The soft rock roadway support is one of difficult problems in the mineral engineering. For making the stress and strains of support system to be effective forecasted in the process of roadway support. The Adina finite element software is used to do numerical simulation about the strains of the supports system in the process of the Hama mountain roadway, and compare with the date which was got from the field monitoring. The date comparison shows that the results of simulation is basic anastomotic with the examination at present. So that it can be well predicted the effectiveness of the support measure when using the finite element simulation software –Adina.

Abstract: The irregular face mechanized mining is one of the difficult problems in the field of mining engineering. In this thesis, the roadways of 4324 extremely irregular face in DaiZhuang Mine were taken as research object. Through on-site mine pressure observation, the deformation characteristics of the surrounding rock and support force was analyzed. Next the mine pressure appeared rule of the roadways was study. This study benefited that the production of 4324 mining face went on wheels, at the same time, it had important significance to production safety of irregular working face with similar conditions.

Abstract: It is the key to success or failure of the construction that we control the ground surface settlement, vault sink and supporting force by the choice of the reasonable construction method in the subway construction process. Based on the project profiles of the tunnel in Nanjing orbit traffic line 1 from South Yan'an road to NingDan road, the article mainly carries on the numerical simulation to construction program by using ANSYS finite element software according to the joint arch tunnel construction of the double and triple arch in the entry end .The article mainly has an analysis from the ground surface settlement, the strata, axial force of supporting structure, bending moment and other aspects. The results show that the program is feasible. The article provids guidance to the future construction of similar projects .

Abstract: The FLAC-3D software was used to study the surrounding rock displacement and the side abutment pressure distribution laws about roadway in thick coal seam. Based on this model, through change the mining height, working face length and mining depth, the differences of roadway underground pressure characteristics were analyzed between thick coal seam working face and normal working face. The results indicate that: ①the displacement of roadway surrounding rock increases with the increase of mining depth and mining height, the closer to the coal wall the larger of the increase range of roadway displacement. ②the peak of side abutment pressure increases with the increase of mining depth and mining height, the peak district of the stress will move toward the inner department of rock body. ③ the effect of working face length on the roadway displacement and the side abutment pressure is very feeble.

Abstract: Recently rigid-frame bridges have been built for only twenty years in China and they have been used as the preferred bridge type in complicated terrain mountainous areas. Based on the fiber model in Opensees, the typical nonlinear numerical analysis model of a rigid frame bridge with super high-rise piers is presented. IDA method is adopted for the nonlinear dynamic history analysis for the structure. The failure mode and the characteristic of plastic development are investigated under longitudinal seismic actions. The results show that multiple key sections of the piers enter the plastic state simultaneously and the structure will become dynamic instable inevitably.

Abstract: Dynamic behavior of a vehicle-bridge system model is presented. A set of time-varying equations of the system considering roughness surface of bridge are given. The equations are rewritten in the form of matrix for numerical simulation. Modal analysis of the equations is carried out. Simulation and visualization of the equations are given. Effects of different speeds and accelerations of moving vehicle and roughness surface of bridge on the vertical displacement of mid-span of bridge are studied.

Abstract: In order to grasp the force performance and stress distribution of shaped pylon steel anchor box under the action of the cable tension, with a main span of 555m length of three towers cable-stayed and self-anchored suspension combined system bridge as the engineering background, through the ANSYS APDL command stream parametric programming, the different finite element models of pylon steel anchor box is established by the spatial solid element and shell element, the mechanical properties of cable-pylon anchorage zone were studied under the most unfavorable load combination, considering the stress state and distribution characteristics of steel anchor box under different orthodontic force. The results showed that, under the most unfavorable combination of loads, the stress was concentrated at the position of the anchor plate and pressure plate using the initial strain mode; the calculation results of solid element and shell element were consistent by uniform loading mode, which could reflect the real stress state of steel anchor box, but the shell element corner contact area prone to stress calculation distortion. The results provide the basis for the design and have some design reference value for the design of the same type bridge.

Abstract: Cable-stayed bridges have seen a wider application in recent years, with many having longer and longer spans. Modern cable-stayed bridges are using numerous cables to support the stiffing girders. Many cable dampers are installed to mitigate cable vibration. This paper focuses the attention on the effect of cable damper on the dynamic characteristics of the whole cable-stayed bridge, especially the modal damping. A practical model comprised of the cable, girder, and damper is developed to analyze the relationship between system modal damping and the performance of cable damper with complex mode method. A test model with cable, girder and damper was made to verify the theoretical results. A finite element model of a simplified cable-stayed bridge based on test model is adopted to assess the effects of cable dampers on the anti-seismic performance and wind-resistant behavior of the cable-stayed bridge. The results show that the cable dampers of cable-stayed bridge can increase the modal damping of the whole bridge.

Abstract: In order to ensure safety of long and huge bridges in deep water under earthquake action, it is significance to consider water and bridge pier dynamic interaction. Analysis method of water-bridge pier dynamic interaction under earthquake excitation is established using radiation wave theory, and earthquake induced hydrodynamic pressure apply program is complied. Considering different earthquake wave input, earthquake induced hydrodynamic pressure influence on dynamic responses of bridge pier in deep water is further studied. The results indicate that: Dynamic response of bridge pier in deep water is augmented because of hydrodynamic pressure action. Earthquake induced hydrodynamic pressure influence on seismic responses of bridge piers in deep water will change with different input earthquake wave.

Abstract: In order to put forward a durability assessment method of concrete structure based on the engineering calculation and analysis, combining with the characteristics of northern freezing coastal areas and the non-navigable spans bridge construction，the paper built the Ottosen strength criterion on concrete under freeze-thaw and erosion coupling effect. By the application of strength criterion, calculation and analysis, it has been evaluated the crack resistance at a few key points of the concrete pile cap on the bottom. The result illustrates that there will appear concrete cracks at the middle of the cushion cap bottom after a 130-year serviceable period when the bridge is attacked by the once-in-a-century wave load or ice load, that is, the safety serviceable period of the bridge pier is 130 years.