Foundations may be constructed at close spacings. Prior investigations have presented insights into the interference effect of two nearby shallow foundations on homogenous soils. However, soils are often deposited in layers, such as a sand layer overlying clay. Hence, the interference effect of two adjacent foundations on their ultimate bearing capacity for sand overlying clay has been a relevant topic, which is complex because it is tied to a coupling effect of the geometric configurations and the soil properties. In this paper, the ultimate bearing capacity of two interfering strip footings on sand overlying clay is determined using an upper-bound limit state plasticity method known as discontinuity layout optimization (DLO). The solution is illustrated as design charts constructed through the use of dimensionless parameters. Parametric studies are performed to explore the influence of geometric and strength parameters on the bearing capacity and the failure mechanism. A simplified model is developed based on the data obtained from DLO. Validations are carried out to demonstrate the accuracy of the developed model using various statistical criteria, including coefficient of determination (R²), arithmetic mean and coefficient of variation.

地基的间距应很小。先前的研究已经提出了对附近两个浅层基础对均质土壤的干扰影响的见解。然而，土壤通常沉积在层中，例如覆盖在粘土上的沙层。因此，两个相邻地基对其覆砂粘土的极限承载力的干扰效应已成为一个相关主题，这很复杂，因为它与几何构型和土壤特性的耦合效应相关。在本文中，使用称为不连续性布局优化（DLO）的上限状态可塑性方法确定了两个干扰条形基础在覆砂粘土上的极限承载力。解决方案以通过使用无量纲参数构造的设计图来说明。进行参数研究以探讨几何和强度参数对承载力和破坏机理的影响。基于从DLO获得的数据，开发了一个简化的模型。使用各种统计标准（包括确定系数）进行验证以证明开发模型的准确性（R ²），算术平均值和变异系数。