Abstract:

The Problem of how to calculate the earth pressure for the earth-strip neighbouring excavations is run against frequently in excavation engineering practice; but there is no calculation method in the existing criterion of excavation for the moment. First, the retaining and protection forms between neighbouring excavations are classified and put together, the affirming principle of the width between two excavations is put forward; then, the superposition method on Coulomb’s earth pressure theory is presented; and the calculation formulas of the active earth pressure coefficient and earth pressure are derived and presented for clay and non-clay under differrent gradients and ground load, and the idea of the critical width and the calculation formula of reducing coefficient of the earth pressure of the earth-strip are also presented. The total and distributing earth pressure of earth-strip for different soils, different gradients and ground load can be calculated simply by the superposition method, the idea of the critical width and the calculation formula of reducing coefficient of the earth pressure of the earth-strip. Finally, two engineering examples are given to show that the retaining and protection structures generated by the method and the formulas are safe and rational; the method and the formulas can be for reference by similar excavation engineering.

Key words: neighbouring excavations, earth pressure of earth-strip, superposition method, critical width, reducing coefficient