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CU test and CD test were performed to capture the stress-strain characteristics of the clay in Dongting Lake area, China. Since the classical constitutive model cannot ideally describe the strain hardening behavior of the clay, an improved constitutive model that involved three damage factors was proposed. The damage first factor D1, which represents elemental volume strength F, was fitted by the Weibull function. The second and third damage factors D2 and D3, which represent the porosity ratio e and the drainage rate Pε respectively, were fitted by Harris function. The CD test damage model is constructed by D1, D2, and D3. In the CU test, the porosity ratio e is a constant value, and the drainage volume is 0, so that D2 is constant value and D3 is 0. Therefore, the CU test damage model of the clay was constructed using the damage first factor D1. In the end, the accuracy of the proposed CU/CD damage constitutive models of the clay was validated with the experimental results. It is found that the results fitted by the proposed methodology are in good agreement with the experimental results.

Inflatable anchors have been applied to reinforce foundations because soft soil deposits have a low bearing capacity. However, previous research on the mechanical behaviors of inflatable anchors has focused on a single anchor. Since anchors are always used in a group, the uplift behavior of multiple inflatable anchors in soft soil should be investigated. A series of pull-out tests were conducted in this framework by changing the number, spacing, and layout of inflatable anchors. Additionally, the effect coefficient (ECO) of multiple inflatable anchors is discussed. It is found that the failure behavior of multiple inflatable anchors exhibits a three-stage curve: an initial linear stage, followed by nonlinear, and steady-state stages. In addition, the ultimate bearing capacity of multiple inflatable anchors is maximized if the ratio of the spacing of inflatable anchors to the equivalent expanding section diameter of an inflatable anchor is 6.84. It is recognized that the ECO of this new multiple inflatable anchor group is sometimes greater than 1, unlike that of conventional anchors, which have ECOs of less than 1. In addition, the layout of multiple inflatable anchors in the shape of a cinquefoil is recommended due to its high ECO.