Earth excavation method of deep and large foundation pit of adjacent building structures

The invention discloses an earth excavation method of a deep and large foundation pit of adjacent building structures. By the method, soil of a side with important building structures is reinforced by stirring piles, and a supporting effect of the soil on a ground wall is improved. In an earth excavation method, semi-basin type excavation is implemented on the basis of soil reinforced portions, excavation is implemented from a middle wall without the building structures on the periphery to a subway and a side with the building structures required to be protected, and soil remains on the subway and the side with the building structures required to be protected so as to protect walls; the middle wall side is excavated widely, and the construction schedule can be accelerated; and remaining soil which is close to the subway or remaining soil of the side with the important building structures is excavated in a subdividing and time-limited manner to achieve the supporting effect. By the construction mode, pit supporting completion time can be shortened to a maximum extent, supporting can be implemented as soon as possible, deformation of the foundation pit is reduced, and influences on the surrounding building structures are reduced.