And the changes of the stress field and bias field of the surrounding rock of the tunnel under two kinds of conditions and with the staged excavation are obtained as well as the stability analysis of the surrounding r.

Studies on displacements and earth pressures of pit-retaining structure during excavation by steps;

At the same time,some calculating methods of earth pressures are discussed,such as estimating water and earth pressures together,estimating water and earth pressures separately,excavation by steps according to the construction process,earth pressures c.

Equation of ultimate state of active earth pressure loading increment on retaining wall in foundation pit during excavation by steps is set up;coefficient of sorting of earth pressure loading conforming to the requirement of reliability is given;problems in earth pressure calculation during excavation by steps are analyzed.

Based on unsteady seepage theory and doublelayered ground consolidation theory,analytical formulas for calculating the water head in active and passive zones of a foundation pit during stepped excavation were derived.

It studied the variation of the horizontal displacement and stress resulted from the step by step excavation of the circular work well for pipe-jacking,and the characteristics of the horizontal stress on the frame bracing structure.