No abstract

Submarine pipelines located near harbour areas and in major shipping lanes are likely to be exposed to potential damage due to anchors and dropped object impact. To protect these pipelines, they are buried and protected with rock armour berms. The design of these rock berms has been traditionally based on model test results. In this paper, a simplified method is proposed to simulate the interaction between the anchor, seabed soil and rock armour, on the basis of the thrust earth pressure theory. The results agree well with the centrifuge test results.

The debarking location of a gas pipeline is at the area where typhoons take place frequently and the geotechnical condition of the slope is very complex. A sloping breakwater type structure is selected in this paper for the purpose of pipeline scour protection. Since part of the sloping foundation soil consists of silty clay whose strength is very low, the bearing capacity is checked with the base pressure induced by the breakwater. The stability of the foundation of the breakwater is analyzed with the method developed by Meyerhof. The scour protection structure is proved effective and stable.

The non-linear finite element program Ls-DYNA/ANSYS is applied to simulate numerically the capacity for the geo-materials to dissipate the energy induced by the falling objects. The calculation results for the crushed stone coincide well with those recommended by the current Code of《DNV-rp-f107_2010》, which is on the basis of experiment data, implying the feasibility of using this program to estimate the energy dissipating capacity of the geo-materials. Because little research has been performed with clay soil, the program Ls-DYNA/ANSYS is used to predict the energy dissipating capacity of clay layers.

The water system of an inner lake in a planned residential district is connected to the Tuanbo reservoir. To pass through the city road between this residential district and the Tuanbo reservoir and effectively control the water table level of the inner lake, two sluices with two box-culverts will be built under the city road. In the existing design, the cross-section and the base slab of the sluices are relatively greater than what is necessary, which is on the conservative safer side but not as economical. Considering the project requirements and load characteristics, this paper proposes different design solutions for the cross section of the sluices through comparison and analysis of the stresses and foundation deformations on the sluice walls, and base slab by means of FEM and computer simulation. As a result, an optimal cross-sectional structure of the sluices was selected, which significantly reduces the use of concrete, and is much more cost efficient than the existing design.