Bearing capacity of interfering strip footings on rock mass

ABSTRACT

The present study computes the ultimate bearing capacity of closely spaced strip footings resting on a rock mass. The investigation is executed numerically by using the lower bound finite element limit analysis in association with the semidefinite programming (SDP). Rock mass is assumed to be a perfectly plastic material and follows the modified Hoek-Brown failure criterion. The magnitude of efficiency factor (ξ_σ), which is the ratio of the ultimate bearing capacity of interfering footings to isolated footing, is assessed for different clear spacing distances between strip footings. The influence of various rock strength parameters, such as normalised uniaxial compressive strength (σ_ci/γB), geological strength index (GSI) and Hoek-Brown material parameter (m_i) on the footing interference, are also studied extensively. The results of the present study indicate that the interference effect increases continuously with an increase in m_i value; however, it reduces with an increase in GSI value. Detailed variations of the bearing capacity with mentioned parameters are shown and compared with the available literature. It is found that the present study generally provides a lower estimate of ξ_σ value.

KEYWORDS:

• Interference effect
• bearing capacity
• strip footing
• rock
• lower bound limit analysis
• semidefinite programming

Notations

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Disclosure statement

No potential conflict of interest is reported by the authors.