Undrained Cylindrical Cavity Expansion In Modified Cam-clay Soil: A Semi-analytical Solution Considering Biaxial In-situ Stresses


This paper presents a semi-analytical solution for undrained cylindrical cavity expansion in modified Cam-clay soils under biaxial in-situ stresses based on the small strain and large strain assumptions in the elastic and plastic regions, respectively. The cylindrical cavity expansion problem is treated as a boundary value problem and formulated by solving a system of first-order differential equations with four stress components as basic unknown variables. The validity of the proposed solution is examined by comparing with the existing solution, where the in-situ stress is uniform. Extensive parametric studies are conducted to investigate the effects of biaxial in-situ stresses on the stress distribution, the expansion process and the shape and size of elastic-plastic boundary. The results indicate that the elastic-plastic boundary is in the shape of an ellipse due to the shear stress induced by biaxial in-situ stresses. The major axis of the elliptical elastic-plastic boundary is in accordance with the direction of the larger in-situ stress. The present solution is free of the limitation that the cavity expands under the uniform in-situ stress, therefore it is expected to provide a more general method for practical geotechnical and petroleum problems.


Geosciences and Geological and Petroleum Engineering


National Natural Science Foundation of China, Grant 41772290

Keywords and Phrases

Biaxial in-situ stresses; Boundary value problem; Elastic-plastic boundary; Ellipse; Undrained

International Standard Serial Number (ISSN)

1873-7633; 0266-352X

Document Type

Article - Journal

Document Version


File Type





© 2023 Elsevier, All rights reserved.

Publication Date

01 Feb 2021