Influence of intermediate principal stress on correction formula of bearing capacity of rock foundation

摘要

Generally the bearing capacity of rock foundation is high, and practically it’s very hard to figurernout the exact value of the bearing capacity. As a result the researches related to the bearing capacity of rockrnfoundation are less likely to be taken. However with the increasingly growing load of buildings, the requirementsrnfor the bearing capacity of rock foundation are improving in response. The bearing capacity of rock foundationrninvolves the structure of the rock mass and strength of rock, thereby the solution of the bearing capacity ofrnrock foundation is far less perfect compared with the theory of the bearing capacity of soil foundation which isrndeveloped from the theory of plasticity. Presently the method of limit equilibrium and the slip line field theoryrnand the limit analysis are available to explore the ultimate bearing capacity of rock foundation, neverthelessrnthe results derived from these theories are most likely to be on the small side. The paper employs the TwinrnShear Theory to obtain the theoretical formula of the ultimate bearing capacity of strip-type rock foundation,rnconsidering the impacts of intermediate principle stress to the bearing capacity of rock foundation. With therncomparison of the project case, it indicates that the results are bigger than the ones applying the Mohr-Coulombrnstrength theory, and it will bring great economic benefits in the event it is put into the practical projects.