Applied Mechanics and Materials Vols. 71-78

Abstract: In the process of cantilever construction of the Longtan river bridge ,the WZP-035 thermally sensitive as measured points of temperature were buried into two segments of box-girder,and the temperature field of box-girder concrete was observed for three days. The temperature field and its variation laws of box girder bridge were discussed based on measured data. A vertical and transverse thermal gradient model of PC box girder,which could apply in central south China,was presented.This model was compared with the measured data and the thermal effect was analyzed.Results show that the calculated with the model agrees well with field test result and the modle is of some value for the measurement of sun light thermal difference effect on box girder bridge.

Abstract: Through simulation analysis of nonlinear finite element, research ideas on moment modulation coefficient of unbounded prestressed concrete (UPC) continuous beam is proposed ；Based on detailed analysis of the equivalent length of plastic hinge and curvature ductility, the two factors which influencing margin of moment modulation, calculating formulas of curvature ductility coefficient and moment modulation coefficient are established; Compared with the experimental data, the results which provided basic data for further research on plastic design of UPC continuous beam.

Abstract: For estimating the fatigue properties of orthotropic deck bridges, a finite element analysis method was provided. In the method, the models of orthotropic decks steel bridge were established by using Midas and Ansys finite element software respectively, the Midas software has tracked two kinds of live load positions that corresponding to maximum and minimum stress of the fatigue checking points, and the most unfavorable loads were loaded to the Ansys model, then the stress ranges of fatigue checking points were obtained and the fatigue properties of the bridge were estimated. The results show that, it is feasible that using the new finite element method to checking the fatigue performance of orthotropic deck steel bridge.

Abstract: Taking Wusongshan Tunnel in Tongling City as an example, two-dimensional numerical simulation of new large span highway tunnel directly through gob of steep coal seam were carried out to study the response of surrounding rock induced by mining. The actual location and scale of the ground fissure consistent well with the simulation results, which verified the analysis. The results showed that, different from those in gob of horizontal or gently inclined coal seam, the response of surrounding rock in gob of steep coal seam have the following characteristics: (1) shallow mining affects significantly on the values of settlement of earth surface and the tunnel, and deep mining on the scope; (2) in the shallow layer, a small scale coal being reserved or being effective filled after excavation can benefit greatly to the safety of structure and stability of the surrounding rock; (3) sharper uneven settlement would occour at the floor than the roof of coal seam, which can threaten the tunnel structure and should attract more special attention; (4) for this project, deep faults affect the safety of structure of tunnel and stability of surrounding rock also. Based on these results, treament plan were developed of Wusongshan Tunnel, which can also be refered for other similar projects.

Abstract: Taking Wusongshan Tunnel in Tongling City as an example, three-dimensional numerical simulation of new large span highway tunnel built directly through gob of steep coal seam is carried out to study the response of tunnel structure induced by mining. The results showed that, (1) Though immediately backfilling after extraction can prevent the tunnel structure from impact of mining below the tunnel, it is still necessary to forbid extraction below the tunnel consildering the duration time of the extraciton and backfilling activity. (2) Considering the long-term settlement of gob of steep coal seam, net height of the tunnel should be enlarged 50cm to ensure enough space for operation. (3) The tensile and pressive stress of the support structure in the bottom and roof section of the gob are obviously high than other, so comperihencive measures should be taken to reinforce the structure, especially to increase the tensile strength in axial direction. (4) Fortification intensity can be reduced but the fortification should be enlarged if the continuous reinforcement by steel bar is used at the radial construction joints. Based on these results, treatment plan were developed for Wusongshan Tunnel, which can also be refered for other similar projects.

Abstract: The use of intelligent double-skin facades, sometimes referred to as "double facades", is attracting increasing amounts of interests from the architects throughout the world, due to the characteristics such as ecology, durability, use of natural resources, etc. This paper is written from the architectural history point of view, and gives a brief description about the development of the intelligent double-skin façade systems, from the old storm windows to modern double-skin systems, and suggests further research possibilities in this field.

Abstract: A municipal solid waste treatment method named stacking landfill of garbage block is brought forward. Garbage blocks were made and a series of tests have been carried out by orthogonal tests method in lab. Test results indicate the early compressive strength of garbage blocks increases quickly, and more slowly in the later period. The compressive strength for 3 days curing age is about 40% ~ 45%s of that for 28 days curing age. The compressive strength for 5 days curing age is about 50%~ 60% of that for 28 days curing age. The compressive strength for 7 days curing age is about 60%~70% of that for 28 days curing age. The rank of the influence degree of the accession material to the compressive strength for 5 days curing age was are the mass of cement, the mass of waste type, compressive stress size, the mass of water, the mass of lime. Stacking landfill of garbage blocks differs from traditional landfill disposal which is a new type of classifier ecological landfill method. It can effectively reduce the volume of urban waste, and the waste can easily be stored and disposed.

Abstract: The deployment process of Astromesh is analyzed and the basic unit is defines, based on which overall coordinate system of Astromesh and the units local coordinate system are established. The role of synchronous drive mechanism hinges and motor are analyzed in the unit local coordinate system, and whose action principle is stated in the form of parameter.

Abstract: The area of the Cheng-hai valley, located in the centre of Yongsheng county Lijiang city Yunnan province, is an area with dense and frequent debris flow disasters due to unique geology, geomorphology and landform conditions. After in situ investigation and analyze the present data of these debris flows, we selected six factors, such as catchment areas, the length of main gully, average longitudinal slope of main gull, estimated outflow of every time, potential reserves of solid materials, percentage of grain diameter of solid materials above and beyond 200mm, as main factors for evaluating the risk degree of 6 chosen representative debris flows in the Cheng-hai valley. The multiple-factor comprehensive evaluation method is applied to evaluate the risk degree of debris flow and then the evaluation result shows a good correspond with the practical situation, i.e. this method has a valuable application foreground.

Abstract: In order to study on rock damage caused by the confining pressure unloading, different unloading rates have been adopted in tests on the rock under the constant axial load. Emphasis has been laid on discussing influences of different unloading rates on the elastic modulus, rock strength and failure mode of the rock. The research shows that the unloading rate has exerted a prominent effect on the elastic modulus evolution of the rock, stress level at rock failure and failure mode of the rock. The greater the unloading rate is, the smaller the variation in the elastic modulus of the rock will be, indicating smaller rock damage. Similarly, the greater the unloading rate is, the smaller the corresponding confining pressure at rock failure will be, implying the greater stress deviator imposed on the rock, in which case, the rock failure will be more abrupt and energy release more violent.