板桩结构土压力理论的创新发展

对于板桩码头,其主要的荷载为作用于码头前墙上的土压力,该荷载一方面是由于港池开挖引起前墙两侧土压力的不平衡产生,另一方面是由于码头表面荷载作用于地基土,从而增加了前墙陆侧的土压力。板桩码头深水化的关键要求必须解决港池挖深导致的前墙土压力急剧增大问题,“遮帘”和“卸荷”是减少前墙土压力的有效途径,由于设置了遮帘桩和卸承台,使得板桩结构的受力情况更加复杂,涉及的关键科学技术问题是土和结构的相互作用。针对遮帘式和分离卸荷式板桩码头新结构开发过程中的土压力问题,先后研究了土体密度与粒径对静止土压力系数的影响、遮帘式板桩结构的土压力“桶仓压力效应”和“遮帘效应”,以及分离卸荷式板桩结构的土压力“卸荷效应”,为板桩码头新结构的发展奠定了理论基础。

Innovation and development of earth pressure theories for sheet-pile structures

The main loads on a sheet-pile wharf are the earth pressures acting on its front wall. On one hand, they are induced by the imbalance of earth pressures at both sides of the front wall owing to excavation of harbor basin; on the other hand, the surface loads of the wharf acting on the foundation soils further increase the landward earth pressures of the front wall. For the sharply increasing earth pressures on the front wall induced by the excavation depth of harbor basin which is required by deep-water sheet-pile wharves, the “barrier” and “unloading” measures are the effective ways to reduce the earth pressures on the front wall. The presence of barrier piles and relief platform leads to more complex forces acting on the sheet-pile structures, and the key scientific and technical problem concerned is the interaction between the soils and the structures. With regard to the earth pressure problems during the development of novel structures such as barrier and separated unloading sheet-pile wharves, a series of researches are performed to lay the theoretical foundation for the development of the novel structure of deep-water sheet-pile wharf, including influences of soil density and grain size on earth pressures at rest, silo effects and barrier effects of earth pressures on barrier sheet-pile structures, and unloading effects of earth pressures of separated unloading sheet-pile structures.