Abstract: An ideal elasto-plastic solution of thick-walled cylinder is presented to acquire the ultimate bearing capacity of high-strength shaft lining based on the weighted double shear unified strength theory in consideration of different intermediate principal stress effects. In one case, under external pressure p₀,thick-walled cylinder is in full elastic state, but changes to elasto-plastic state when axial compression P is applied; in another case, only under external pressure p₀, thick-walled cylinder is in elasto-plastic state. Moreover, the formula of elasto-plastic stress solution, the formula of elasto-plastic ultimate bearing capacity, and the expression of the radius of plastic zone are obtained based on the weighted double shear unified strength theory, and the applicable conditions of different intermediate principal stresses are given. The aforementioned formula of ultimate bearing capacity is modified for C70 concrete shaft lining. Compared with the test value, the error of the ultimate bearing capacity calculated by the modified formula is about ±3%. In summary, the modified formula of ultimate bearing capacity is of guiding significance for the optimal design of shaft lining structure and model test results.

Key words: high-strength shaft lining, eighted double shear strength theory, thick-walled cylinder, elasto-plastic stress solution, ultimate bearing capacity