School of Civil Engineering, Tongji University, Shanghai, 200092, China.
CCCC Second Harbor Engineering Company Co., Ltd., Wuhan, 430040, China.
Sci Rep. 2021 Aug 20;11(1):16962. doi: 10.1038/s41598-021-95678-0.
In engineering practice, the measured bearing capacity of a sand pile composite foundation in a mucky soil layer is much larger than the design value. Based on the sand pile construction and the load application process, a method of calculating the bearing capacity of the foundation based on the effective stress was proposed. Cavity diameter expansion in sand pile construction was simplified into a planar problem, and the cavity expansion theory was used to establish the expression of the rate of displacement and the horizontal stress increase. Based on the e-p curve and the calculation of the degree of consolidation, the relationships between the horizontal and vertical effective stress and the void ratio were obtained. According to the close relationship between the bearing capacity of the foundation in a mucky soil layer and the water content, an expression describing the relationships between the bearing capacity of the foundation, effective stress, void ratio, and water content was established. For the temporary engineering foundation treatment project, which needs a high bearing capacity but allows large foundation deformation, the design of sand pile composite foundations uses these relationships to take the consolidation effect of mucky soil into consideration, thereby reducing the replacement rate and lowering the construction cost.
在工程实践中，淤泥质土层中砂桩复合地基的实测承载力远大于设计值。基于砂桩施工和荷载施加过程，提出了一种基于有效应力的地基承载力计算方法。砂桩施工中的孔径扩张简化为平面问题，并利用空洞扩张理论建立了位移速率和水平应力增加的表达式。根据 e-p 曲线和固结度的计算，得到了水平和竖向有效应力与孔隙比的关系。根据淤泥质土层地基承载力与含水量的密切关系，建立了描述地基承载力、有效应力、孔隙比和含水量之间关系的表达式。对于需要高承载力但允许较大基础变形的临时工程基础处理项目，砂桩复合地基的设计考虑了淤泥质土的固结效应，从而降低了置换率，降低了施工成本。
