Abstract：The method to calculate the ultimate bearing capacity of soft sandy gravel rock foundation is established based on Hoek-Brown strength criterion. In order to study its ultimate bearing capacity，the shear failure model is suggested；and the formulas for calculation normal stress levels on potential failure surface are ascertained. Combined with in-situ loading test of a certain hydraulic project，the bearing capacity of soft sandy gravel rock foundation and the effect of dead load stress on the bearing capacity are discussed. The calculation results show：(1) the method covers shortage which is difficult to obtain peak value of load at load-settlement curve due to the field test condition；(2) the calculation ultimate bearing capacity is greater than design intending load，which indicate that the strength of soft sandy gravel rock can satisfy the demand of the project；(3) the rational design footing load has a minor effect on ultimate bearing capacity，which is very important for obtaining normal stress on potential failure surface；(4) the dead load stress has apparent effect on ultimate bearing capacity；and (5) the difference between solutions of Hoek-Brown and Bell on ultimate bearing capacity is comparatively small. The analysis results provide new reference to the study of bearing capacity of this type in soft sandy gravel rock foundation.
