Applied Mechanics and Materials Vols. 638-640

Abstract: As a important tension member, high strength bolts having crucial effect for bearing capacity of grid structure. Especially for in-service engineering, when high strength bolt tensile load doesn’t meet the standard requirements, how to determine the structure bearing capacity influence is particularly important. The article is aimed at the situation of the design review and analysis, through the bearing capacity reduction, reducing the high strength bolt bearing capacity, and the reduction of bearing capacity and the actual force are compared, to determine the safety of the structure. Through the question processing, provides a discussion for solving the similar problems.

Abstract: For the defects of simplified calculation method of vibration isolation efficiency to the spring vibration isolation foundation. In this paper a test method of vibration isolation efficiency was proposed.Through building a 1:8 model of spring vibration isolated turbine-generator foundation, this paper study the vibration isolation efficiency by measuring the acceleration.The test results and the simplified calculation’s results were slightly different as the latter ignoring the influence of high modes.The test results show that the test method is feasible.

Abstract: The performance of friction dampers to mitigate waves and earthquakes in tower-type offshore platform is investigated in this paper. Taking the offshore platform of TOWER-1 as an example, the equation of motion of offshore platform structure under earthquake and wave loads was established. The response reductions of offshore platform structure by different peak earthquakes were analyzed. The results show that the responses of the tower-type offshore platform structure under wave and earthquake could be effectively reduced by friction damper, and the energy dissipation ability of the friction damper differs in the different floors. The friction dampers give good response reductions in different peak earthquakes, and the response reductions of displacement are better than those of acceleration.

Abstract: In this paper, based on the finite element method, the K type common jacket structure connection in the form of positive connection and reverse connection conditions is being do comparative analysis. Research focus on dynamic characteristics, including of power spectrum analysis under the action of random vibration and fatigue properties of two kinds of connection type structure. The calculation results show: the inverted K type connection of jacket structure is about 10% increase in the stiffness and the dynamic performance, the inverted K type connection form is more worthy of popularization and application in engineering.

Abstract: Based on results of a deformation monitoring exercise, a numerical analysis was done to identify the causes of defects and assess the stability of a reinforced concrete bunker. Different scenarios were tested, among them the effects of coal lateral pressure on the wall, loading of different quadrants of the bunker, temperature differences and effect of differential settlement on crack formation. In calculating the coal pressure, classical theory presented by Rankine was used together with provisions of the design codes. Temperature differences are seen to have a significant effect on the stress distribution whereas differential settlement presents a major concern to the stability of the Bunker.

Abstract: Crack growth of concrete beam under dynamic tensile loading is a typical discontinuous problem. It is difficult to realize the process of crack propagation using the conventional finite element method, but the extended finite element method (XFEM) is an effective method to analyze the fracture developed in recent years. This paper introduces the basic principle of XFEM and the analysis method of simulating concrete cracking and crack propagation with XFEM. At the end the crack expansion process of the concrete specimen with initial crack and dynamic load is done. The influence of crack propagation on concrete beam stresses and displacements and the crack propagation laws under dynamic tension is studied. The case shows the unique advantage of XFEM in the crack propagation analysis field.

Abstract: The research status of anti-slide pile with prestressed anchor cable is summarized from the aspects of test, calculation and optimization design. The main problems in the design and application are elaborated, especially the interaction and deformation coordination among prestressed anchor cable, anti-slide pile and soil, as well as the existing shortcomings of soil arch effect, anti-slide pile internal force calculation, landslide thrust calculation and finite element numerical simulation. Anti-slide pile with prestressed anchor cable is analyzed on the research trends of development. Interaction mechanism, time effect, three-dimensional numerical simulation and further optimization design will be the key research direction.

Abstract: A semi-analytical method to calculate the degree of consolidation of the soilbag filled with mud soil with PVD built in is proposed. First a unit-body model is founded to obtain the low-dimensional solution. Through the successive iterations of the low-dimension solution, the solution considering the situation when the physical or geometry parameters of the model vary is finally obtained. The solution of the rectangular area is obtained by summing solutions of two square area with coefficients set. A lab experiment was done in Liubao test base of Zhejiang institute of hydraulics and estuary to research the consolidation performance of soilbag filled with mud soil buried with PVD. The semi-analytical method and FEM are applied to calculate the lab experiment case. From the comparison among the lab experiment, the semi-analytical method and FEM, it shows that the semi-analytical method calculates a good result of the degree of consolidation of the lab experiment.

Abstract: Abnormal high pressure exists in Lower Fars formation of Fauqi oil field in Iraq and lead to many complicated problems during drilling. There are salt, anhydrite and shale in Lower Fars formation through lithology analysis. Through the crossplot of sonic velocity vs. density data, it can be identified that the high pressure of Lower Fars is cause by the undercompaction of shale. Through composite analysis of different prediction methods of pore pressure, Eaton model is used to calculate the pore pressure of Lower Fars. The pore pressure begins to increase at the MB4 layer and declines to normal value at MB2 layer, and the peak is about 2.20 . The calculated results are in conformity with field situation, which can be applid to guide drilling practice in Fauqi oil field.

Abstract: Under cyclic load, the major shortcoming–ratcheting is produced in Wolffersdorff hypoplastic constitutive model. For eliminating ratcheting, Wolffersdorff hypoplastic model is ameliorated based on intergranular strain tensor. The added parameters in ameliorated model are determined by optimization method. Under cyclic load of triaxial consolidation undrained condition, the mechanics features of sand are described by the ameliorated Wolffersdorff hypoplastic constitutive model. Preliminary result shows that with increasing times of cyclic load excess pore water pressure is increased gradually and effective stress is reduced gradually. When effective is reduced to zero, the liquefaction happens. So in many projects, excess pore water pressure must dissipate by means of some measures. The sand liquefaction under the dynamic load is avoided.