考虑土拱效应的斜插式桩板墙合理板间距研究

结合高速公路边坡实际工程,采用ABAQUS有限元软件进行三维数值模拟分析; 从考虑板间土拱效应的角度出发,研究了0.2倍板宽、0.3倍板宽、0.4倍板宽、0.5倍板宽4组不同板间距下斜插式桩板墙的板后水平土压力、板后竖向土压力以及板间土拱强度沿横向的变化规律,并结合结构实用性和安全性,提出了斜插式桩板墙的合理板间距取值范围、板间土拱的拱脚位置以及拱顶参数关系。结果表明:斜插式桩板墙在悬臂段中下部相邻板间以板底作为拱脚形成板间竖向土拱,且板后土压力随深度表现为锯齿状分布,水平土压力小于经典库仑主动土压力,竖向应力大于土体自重应力; 板间土拱的拱脚位于斜插板板底,在设计施工时应进行局部加强以提高设计强度; 当板间距取0.3倍～0.4倍板宽时,板间土拱效应明显,板后土压力较小,建议斜插式桩板墙合理的板间距取值为0.3倍～0.4倍板宽; 所得结论有助于斜插式桩板墙结构的进一步优化设计,并产生显著的经济效益和社会效益。

Study on Reasonable Plate Spacing of Oblique Sheet-pile Wall Considering Soil Arching Effect

Combined with the practical engineering of a highway slope, the three-dimensional numerical simulation analysis was carried out by ABAQUS finite element software. From the angle of soil arch effect, the variation law of post-plate horizontal earth pressure, post-plate vertical earth pressure and inter-plate soil arch strength along the transverse direction of oblique wall with 0.2 times plate width, 0.3 times plate width, 0.4 times plate width and 0.5 times plate width were studied. Combining the practicability and safety of structure, the reasonable range of plate spacing, the position of the arch foot of the inter-plate soil arch and the relation of vault parameters were put forward. The results show that the oblique pile-sheet wall has a vertical soil arch between the adjacent plates in the middle and lower part of the cantilever section with the bottom of the plate as the arch, and the post-plate earth pressure is serrated with depth. The horizontal earth pressure is less than the classical Coulomb active earth pressure and the vertical stress is greater than the weight stress of the soil. The arch foot of the inter-plate soil arch is located at bottom of the oblique plate, and the local reinforcement should be carried out in the design and construction to improve the designed strength. When the plate spacing is 0.3 times-0.4 times of the plate width, the soil arch effect is obvious and the post-plate soil pressure is small, so the reasonable spacing of the slanted pile plate wall is 0.3 times to 0.4 times of the plate width. The conclusion is helpful for further optimization design of oblique sheet-pile wall structure, and will has significant economic and social benefits.