单锚板桩结构的工作机理研究

Mechanism of sheet-pile structure with a single anchorage

板桩结构作为支挡建筑物广泛应用于基坑、码头等工程中,其涉及的主要问题是土压力作用下板桩的受力和变形,而土压力与变形又是相互关联的,属于典型的土与结构相互作用问题。以单锚板桩码头结构为例,基于有限元数值模拟,探讨了板桩结构的工作机理,研究了码头港池开挖过程中前墙两侧的土压力分布、结构的内力与变形、地基土的应力应变关系,以及地基不同位置处土单元的主应力旋转等问题。研究表明:正确地模拟土体的应力应变关系是分析此类问题的关键;港池开挖过程中,前墙陆侧土压力向主动方向发展,而海侧土压力则向被动方向发展;港池开挖造成了土体单元的主应力方向旋转,特别是港池海侧下方的土体主应力方向旋转剧烈。

The sheet-pile structure is extensively used in deep excavations and wharfs as the retaining structure. The key issue is the forces acting on the sheet piles as well as their deformations under the earth pressure. However, the deformations closely relate to the earth pressure. This issue becomes a typical problem of soil-structure interaction. Based on FEM numerical simulations, the working mechanism of the sheet-pile structure is investigated. The following aspects are studied with regard to a wharf case during its excavation: distribution of earth pressures at both sides of the front wall; internal forces and deformation of the structure, stress-strain relationship of foundation soils and rotation of the principal stresses. The results show that accurate modeling of stress-strain relationship of soils is the key to this kind of problem. During the excavation of the harbor basin, the seaward earth pressure of the front wall develops towards the active direction, while the landward one develops towards the passive direction. The excavation induces the rotation of the direction of the principal stress of soils, especially that of the soils under the harbor basin at the seaward side of the front wall.