The selected high-span continuous rigid frame bridge for studying is Mangjiedu Bridge in this paper. Based on the principle of structure dynamics and the method of seismic response analysis, the finite element model of the main bridge in Mangjiedu Bridge under Midas-civil was built according to the structural features, site conditions and seismic fortification intensity of the bridge. Then the characteristics of main bridge structure were studied using Lanzcos modal analysis method, and the seismic responses of main bridge are studied by earthquake response spectrum analysis and time history analysis respectively. The results show that the fundamental frequency of the main bridge is 0.1943Hz, and the transverse vibration mode shapes are most remarkable in the former 10 ordered types of vibration of main bridge. The main bridge is in the conditions of elastic range and does not failure under E1 earthquake. Both response spectrum analysis and time history analysis show that the largest displacement along the main bridge appears at the top of pier and the largest transverse displacement appears in the central position of main span. It also shows that the maximum shear and maximum moment occur at the bottom of main pier.

Based on the heat-resistant mechanism, the orthogonal experimental method and the requirements for physical-mechanical performances of heat-resistant concrete, one mixing process project was taken as the target for analysis on the mixture ratio design of heat-resistant concrete. The conventional raw materials such as normal Portland cement, common crushed aggregates, fly ash and concrete admixture were adopted to manufacture the C30 heat-resistant concrete which gets the limit heat-resistant temperature of 500°C subsequently. And the influencing factors on the strength of heat-resistant concrete were also studied in this paper. Experimental results show that the mixture ratio design of heat-resistant concrete in this paper is reasonable. The engineering application results also show it is financially viable that adopting the normal Portland cement to manufacture the heat-resistant concrete with limit heat-resistant temperature of 500°C.

The shear strength properties of sediments are relevant to many practical problems, including those related to predicting the bearing capacity of the man-made crust lying over dredged disposal sites and those associated with estimating the erosion resistance and the bearing capacity of sediments. In this study, an experimental apparatus and method is developed for sedimentation. This apparatus consists of a settling column, pore measurement apparatus, shear vane apparatus, and multilayer extraction sampling apparatus. The change regulation of interface height, density, excess pore pressure, peak undrained shear strength, residual undrained shear strength, and sensitivity varies before and after the excess pore pressure dissipates to zero in the self-weight consolidation stage. The higher the water content, the greater the particle segregation degree. Particles are mainly segregated in the settling stage, and they are not segregated further in the self-weight consolidation stage. Before excess pore pressure dissipates to zero in the self-weight consolidation stage, shear strength is related to water content, effective stress, and the formed structure of sediments. After excess pore pressure dissipates to zero, peak undrained shear strength is mainly associated with the structure (thixotropy) of sediments. Residual undrained shear strength increases because of the slight decrease in water content. The mechanisms of thixotropy can be expressed as the increase in the original and curing cohesions of sediments with time as determined from microscopic aspects.

According to the geological conditions of mine and mine’s surrounding construction, the geological mechanical model of explosion area and the structure model of surrounding civil architecture were established. Based on the monitoring blasting vibration result of mining explosion process, the dynamic response character and structural stress of surrounding civil architecture which have been caused by blasting vibration of mining were studied by means of the Finite Element Method (FEM) and the method of fast Lagrangian analysis of continua three dimensions (FLAC 3D). The results show that calculated results coincide with the monitor results collectively, and the influence caused by blasting vibration on the stress and strains of civil architecture is smaller. But at the civil architecture roof, the transient amplification acceleration caused by blasting is 25%.

In this paper, based on the experimental measured cooling curves, it was solved that the inverse problem of non-linear heat conduct equation for Steel 1045 quenched by water using finite difference method and nonlinear estimate method. The volume fraction of constituent of austenite, pearlite, bainite, martensite and the non-linear surface heat-transfer coefficients in continuous cooling during quenching were calculated and simulated by mathematical transformation. The volume fraction of phase constituents in the quenched work piece of 1045 steel was tested subsequently. Then the temperature field and thermal stress field of Steel 1045 cylinder during water quenching was simulated by ANSYS. The study results show that the 2D transient temperature field of the cylinder specimen calculated by ANSYS during quenching coincides with the practical quenching process, and the results of thermal stress field simulated by ANSYS can guide quenching process.