Applied Mechanics and Materials Vols. 256-259

Abstract: Adding a new embankment adjacent to the existing highway embankment is a cost effective choice compared with building another new one and can mitigate the heavy traffic pressure. However, it may also cause some engineering problems including the change of slope of existing pavement or even local or global instability of embankments especially those on soft soils. How to prevent excessive change of the slope of the existing pavement induced by widening the existing embankments is of great importance in engineering practice. A numerical analysis by using a commercial FEM program was performed to explore the influence of the thickness of soft foundation soils, the widening width and the embankment height as well as the starting time of widening construction on the slope of the existing pavement. The results indicate that the bigger the thickness of the foundation soils as well as the bigger the widening width will result in bigger values of the slope of the existing pavement, especially at the early period of reconsolidation. Adverse slope will be induced by widening of the existing embankment.

Abstract: This paper introduces the composite waterproofing and drainage board, to solve issues such as the drainage problem and lack of sand gravel material in low filled embankment of plain area highway. Through the research of its application performance, design method and drainage effect. Studies show that the materials with perfect performance on tensile and compression strength are contribute to construction property of soil which under the board, it also can effective prevent water from seeping through the underground, and expel surplus water, to make sure the long-term stability of subgrade and subsoil. It is one perfect waterproofing and drainage materials used in low embankment highway.

Abstract: With the increasing of embankment culvert engineering applications, there has been due in part to the structural design is too conservative and not economic or select unreasonable structural form, leading to the phenomenon of cracking or even collapse of the culvert structure, and the phenomenon has seriously affected the normal use of the highway. In this paper, the numerical simulation of vertical earth pressure distribution on different structural forms of embankment on culverts, to discuss the impact of boundary conditions, fill height, the thickness of the culvert culverts vertical earth pressure. Combined with Heda highway a culvert covert field test results and numerical simulation results were compared and analyzed. The results show that the numerical simulation and field test results in good agreement with the culvert structure in the form of vertical earth pressure of the embankment culverts have a greater impact; the structure of different forms of the culvert in the upper soil pressure is significantly different. In addition, analysis of the impact of boundary conditions, filling height of culvert vertical earth pressure values. The results can reference for the study of the structural design of the embankment culverts security.

Abstract: Analysis and study high vacuum densification method in the application of soft soil foundation. According to the engineering characteristic and strength characteristics of Dalian coastal area soft soil, using the finite element analysis software ADINA to simulate the high vacuum densification method effect, obtain the changes of foundation displacement, pore water pressure and effective stress. Finally putting forward a reasonable and applicable design according to the processing method of the quality, time limit for a project, cost, environmental protection and so on.

Abstract: Ring-beam supporting technology is increasingly used in coastal soft soil area. Based on a foundation pit supporting case of general hospital in Tianjin, the 3-dim finite element construction was simulated with MIDAS/GTS. According to the calculation, the stress and deformation characteristics of deep foundation pit supporting structure under the ring-beam action in soft soil area, and the surrounding soil settlement is analyzed. The final foundation pit supporting solution is selected between two different schemes. The analysis method and conclusions are useful for design and construction of other similar projects.

Abstract: The detection index and evaluation for foundation engineering’s corrosion are performed in accordance with the “Code for Highway Engineering Geological Investigation” or “Code for Investigation of Geotechnical Engineering”. For both steel pipe piles and concrete pipe pile joints, the codes don’t consider the dissolved oxygen, Anaerobic organism and other corrosion factors. In order to improve the durability of the pipe pile foundation in coastal region, taking the typical coastal soft soil characteristics in eastern Zhejiang as example and by observing the steel corrosion electrochemical potential variation in the hypoxic environment, this paper analyses the corrosion risk of steel structures in marine deposit soft soil, and puts forward the microbial and electrochemical corrosion mechanism of the steel structures in foundation engineering in coastal environment. This paper argues that the Sulfate-Reducing Bacteria corrosion evaluation is indispensable in geotechnical investigation, and therefore should be included into the Code.

Abstract: Based on the engineering background of -350m level roadway in Beizao Coal Mine ,three schemes about the excavation and support of the roadway were simulated via the coupled fluid-solid theorem in the the finite difference software FLAC^3D. The stability of the soft rock roadway and the effect of bolt-grouting support were analysed according to the obtained numerical results of displacement,principal stress and plastic zone.It is concluded that the seepage has an influence on the stability of the soft rock roadway,besides,it is proved that the bolt-grouting support is rational and effective in the design of support concerning the soft rock roadway.The study has important guiding significance to other similar engineering.

Abstract: Flexible Berthing Pier is a port structure that absorbs, partly or totally depending on self- deformation, the ship berthing energy and the ship rolling energy caused by the wave. Flexible berthing pier mainly sustains the horizontal load. Present methods to calculate the horizontal bearing capacity of pile foundation consist of P-Y curve method, NL method and m method. P-y curves method is one kind of nonlinear subgrade-reaction methods; it considers the nonlinear character, layer character, different kinds, and load kinds of ground soil. Starting from the concept of spring joint in Newmark method, the contact non-linear finite element model is founded for the pile-soil system. By the formula of P-Y curves of compound foundation reaction method, the formulas of elastic coefficients of non-linear springs are deduced. The corresponding programs are organized based on Marc. By the numerical example, the rationality and the feasibility of the presented method is validated.

Abstract: Impulsive pressure induced by waves is an important factor to be considered in the design of offshore structures. This paper presents results from physical model tests on the impulsive pressure on deck of unsheltered jetties and similar structures exposed to directional waves in the presence of currents. The pressures were measured on a 1:50 scale model of a jetty head with down-standing beams and berthing members. Different incident wave angles, the current velocities and the angles between wave and current were considered to identify the effects of these factors on the impulsive pressures. Data collected from model tests were analyzed to gain insights on the mechanics of the impulsive pressure under different wave and current conditions. It is shown that the impulsive pressure is sensitive to the wave directionality and the current magnitude.

Abstract: The process of interaction of sea ice and a pier column structure was studied by using analogue simulation method in the paper, and the dynamic ice force acting on the pier column structure was achieved. Combining with theory analysis, it modified the dynamic ice force model suggested by Croteau. The results showed that the loading stiffness suggested by Croteau is too big to use in the dynamic ice force model and the Withalm formula and simulated results are more suitable. It suggested the calculation formulas of relative displacement in ice force unloading stage and the continuous ice force in ice force continuous stage.