Papers by Author: Zhan Ping Song

Abstract: In tunnel construction process, Because monitoring points setting always get behind with tunnel heading and occurred space effect which induces displacement loss and affects the monitoring accuracy. Studying tunnel space affect has important meaning to the monitoring data analysis. The paper takes Dalian Metro Station as research back ground, adopted three dimensional elastic-plastic numerical test method and carried out the excavation process simulation. Studied the convergence displacement and sedimentation displacement variation regulation along with the distance to tunnel heading face. The simulation results state that the nearer to the tunnel heading, the displacements of surrounding rock are smaller. Analyzed the ratio of displacement loss induced by space effect and amended the monitoring displacements of Dalian Metro Station.

Abstract: The article analyzed the forced state of the surrounding rock and the tunnel lining for Fu longping double-decked tunnel by the Elasto-plastic finite element method. In the analysis, DP’s yield criterion was employed for the elasto-plastic characteristics of materials. It studied the construction method with the theory, and guided the construction for the double-decked tunnel ,too.

Abstract: Aiming at the complexity and uncertainty of rock and soil body, the paper proposed a tunnel surrounding rock parameters identification method combining numerical simulation, particle swarm optimization and artificial neural network. The method acquired data set between rock soil parameters and monitoring displacement and trained artificial neural network. The analytical theory and method are introduced in detail, analyzes the tunnel of Dalian Metro by the proposed method, and gets satisfied results. Which states that the parameters identification method based on PSO-ANN is feasible and has good foreground.

Abstract: Bridge engineering concrete’s Freeze-thaw damage is the main durability diseases which take place in the service process of north China. Aiming at the Songhuajiang Highway Bridge being located in the cold-warm alternant area, According to this environmental characteristics, a batch of concrete samples were made in the construction site by using Material and ratio of the Bridge’s practical construction, they were shipped back to the laboratory and then were used in freeze-thaw test and carbonization test under the influence of freeze-thaw. Obtained the dynamic elastic modulus and compressive strength variation regulation according to the freeze-thaw circles of the concrete specimens. Analyzed the relation between laboratory experiment and field atmospheric exposure test, the paper constructs the durability degradation appraising model and predicts the maintenance-free life of Songhuajiang Highway Bridge. It has important meaning for the maintenance and repair measures in the process of this bridge.

Abstract: Aiming at that general Finite Element Method is difficult to simulate the complex tunnel excavation inducing the second stresses adjusting, the paper proposed the simulation methods combining loading releasing and stress mapping return arithmetic. After the introduction of relative theory, the FEM code has been developed by VC++ . The excavation process of a large section tunnel engineering CRD construction is simulated by the code, the displacements contour, arc top and arc shoulder settlement, horizontal convergence and ground face settlement corresponding to each excavate step have been obtained by the simulation. The regulation of the results are compared with monitoring data, which stated the method is feasible. The simulation has guiding meaning to the tunnel engineering construction.

Abstract: The finite element method combines with differential evolution algorithm to develop the displacement back analysis program. For the field excavation of Dalian subway tunnel, the ground subsidence, crown settlement and convergence displacement are monitoring measurement, then data fitting and regression analysis; Using the independent development program and monitoring data to back analysis so that we can address rock mechanics parameters are not accurate "bottleneck"; According to the inversion parameters, the forward analysis of the finite element numerical simulation, to form a comprehensive monitoring and information feedback system based on the field monitoring - displacement back analysis - being analyzed - field monitoring. The results show that the mechanical parameters of displacement back analysis program are very close to the project survey, while the monitoring and information feedback system has an important theoretical and practical value for safety of surrounding rock and stability of construction process.

Abstract: The seepage of rock and soil is a common problem in geotechnical engineering, because of the uncertainty property of rock and soil, how to ascertain the seepage parameter of rock and soil becomes a problem to solve. Aiming to the problem, after introducing the theory of seepage parameter identification, the paper combines unstable seepage finite element method (FEM) and difference evolution (DE) arithmetic, constructs intelligent identification FEM method of seepage parameter, and develops the procedure. The hydraulic head distribution of seepage field can be calculated accurately by FEM and the optimal solution can be obtained by DE, the seepage FEM being embedded in DE, overcoming the local optimization problems of conventional methods and improving the precision of identification. A tam sample is calculated by the method, it states that the convergence speed is quick and result is satisfied. It is a powerful method for seepage parameter identification.

Abstract: Aiming at the characters of high ground stress and high pore water stress, which resulting in water invasion risk in excavation of subsea rock, FLAC is adopted to simulate the strain localization phenomena of surrounding rock with different pore water pressure and confining pressure. In calculation, the strain soft constitutive relation and “first loading then unloading” pattern are used. Simulation result states that, the bigger the confining pressure is the more destruct the surrounding rock is, and the water invasion risk is more serious. In high confining pressure condition, shortly after excavation, the destroy zone is thin ring, subsequently, the arc shoulder and arc bottom occurs shallow hole, the destroy zone increasing, which presents zonal disintegration. Pore pressure has obvious influence at plastic strain of rock, the high pore water pressure results in surrounding rock destroy zone enlarging, which changing the seepage field of rock, and probably lead to seepage instability.

Abstract: Aiming at the complexity of high arc dam, and the limitation of conventional methods static and rigid body hypotheses of conventional slope stability analysis, which bring great difference with true engineering state. The paper proposed a concept of “abutment safety degree” considering the affection of dam body, and developed the model including dynamic contact element reflecting local rock crack and quasi continuous medium reflecting large deform. Based on above model, combing with 3D element strength reduction method and strain control criterion, the resist safety degree calculation method for dam shoulder high slope of high arc dam system has been constructed, which can fit the complex geo-mechanical engineering. Finally, the method is used in the dam shoulder slope analysis of Xiaowan arc dam system with height of 300m, the result is satisfied, the calculated safety degree is decreasing 20% to the result of conventional method. The method provides a powerful way to the safety evaluation of complex engineering.

Abstract: Vibration characteristics of partially liquid-filled or partially liquid-surrounded composite cylindrical shells are investigated in this paper. Using Rayleigh-Ritz energy method and Love’s shell theory, eigenvalue equation of the problem is derived, and the polynomial for natural frequencies of such shells is further obtained. The external work by the hydrodynamic pressure, which is introduced by liquid sloshing, is taken into account in the energy function. Hydro-elastic vibration characteristics of a composite cylindrical shell are studied by using the present method. Effects of liquid level, liquid density, fiber orientation, length-to-radius ratio, and thickness-to-radius ratio on the natural frequencies are analyzed and graphically presented.