Abstract: Common design methods of retaining structure cannot be suitable in the design of asymmetric foundation pit. In view of the increasingly common asymmetric excavation, a calculation method of earth pressure considering displacement is presented to modify the mode of earth pressure acting on retaining structures. Based on the obtained earth pressure mode, the force of the whole structure system is analyzed, and the analytical solution of rigid retaining structure with bracing under asymmetric excavation is derived. The influences of the internal friction angle of soil, bracing stiffness and asymmetric degree on the insert ratio of retaining structure are analyzed. The results show that the calculated insertion ratio of classical equivalent beam method is unsafe, for the reason that this method adopts the limit equilibrium earth pressure theory. And the unsafe degree of the calculation result is more serious when the friction angle of the soil is relatively small. The insertion ratio of the shallower side is more sensitive to the asymmetric excavation than that of the deeper side. Compared with the common design method which only considers the single side, the proposed method can effectively save the project cost. The verification of the test data shows that the presented solution can be used for the calculation and design of single-strut retaining structure under asymmetric excavation.

Key words: foundation pit, asymmetric excavation, earth pressure, analytical solution, insert ratio