The Research On The Principle And Application Of The Spatial Soil Arching Effects

Numerous model tests show that the soil arching effect is universal existence,but now the research of the soil arching effect theory is mainly concentrated in the lateral earth pressure behind retaining wall in plane strain state and the vertical earth pressure of the pile in three-dimensional state. There are many inclined back retaining wall in actual project, but the research of the soil arching effect theory on the inclined back retaining wall are inperfection.The spatial effect impact on the action of the soil arching effect, but there is no reference associative study on the three-dimensional soil arching effect theory. Meanwhile the research and application of the soil arching effect theory in other actual project is just in the beginning phase, such as Mine Stopes, Excavation of the Underground Caverns, Excavation of the Shield, and others. It’s necessary to make a further study on the application of the soil arching effect principle in retaining wall and other related actual projects.In this dissertation, the application of the soil arching effect principle in retaining wall and the excavation of shield were researched further on basis of the studies available. The main original work were expressed as follows:1. Through introducing soil arching effect principle into the space earth pressure calculation model made by W. C. GU, we built the space earth pressure calculation model and the space earth pressure calculation model that adjacent to existing basements exterior wall that considering soil arching effects, then divided the model into Ⅰ、 Ⅱ、Ⅳ、Ⅳ four regions, and established horizontal and vertical static equilibrium differential equation of the level differential element that we taken from each region, and then deduced the calculation formula of space active earth pressure corresponding to each region, it can calculate active earth pressure anywhere behind retaining wall; also put forward the calculation method of resulting force and the position of it’s active point.2. Through drawing three-dimensional figure of the distribution of the space earth pressure of retaining wall and the retaining wall adjacent to existing basements exterior wall considering soil arching effect; we analyzed and summarized the rule of the distribution of the space active earth pressure and the height of its acting point.3. Using the theory of failure soil mass found by W. C. GU, we Put forward a new method that calculate angle a and β in trapezoidal wedge model; and through combining the theory of the soil arching effect deduced its corresponding active lateral earth pressure coefficient, then use it to modified Terzaghi loosing earth pressure theory, the calculated result of the modified Terzaghi loosing earth pressure is closer to model tests results and Flac simulation results; meanwhile put forward to the modified Terzaghi loosing earth pressure calculation method in three-dimensional, this method can calculate the average overburden earth pressure anywhere along with excavation surface width direction. The value of limited support pressure that calculated using the modified angle a and angle β and modified Terzaghi loosing earth pressure theory is closer to the model tests results.4. According to the characteristic of the inclined back retaining wall and considering the soil arching effect, we put forward a new calculation way of the active lateral earth pressure coefficient that made it possible to establish the lateral earth pressure theory of inclined back retaining wall backfill clayey soil; determined selection method of the soil unit at any location of the thin layer of soil, ensured that the continuity of the principle stress deflection angle; then Established horizontal and vertical static equilibrium differential equation based on the differential element method, and deduced calculation formula of active earth pressure, meanwhile got calculation formula of resulting force and it’s application point.