Analysis Methods For Soil Nailing Support System Under Limited Soil Pressure

Now, our country’s development speed of economic and city construction havemoved forward fast. As the land of the city use stress, high-rise building deepfoundation pits are often built in small space. In the process of Urban developmentand construction, the spacing between buildings usually is very small, interaction ofsoil and support structure becomes more and more complex, not only to ensure itsown stability, but also to ensure the safety of adjacent buildings and facilities.Traditional theories of Rankine’s earth pressure and the Coulomb earth pressureare derived in the condition of semi-infinite soil. Urban construction, which nowmeet the Rankine’s or Coulomb’s earth pressure theory’s conditions, become lessand less. In many cases, the distance of the excavated pit and the surroundingbuilding is not enough, can not meet the conditions of semi-infinite soil, therefore, ifwe directly apply the Rankine’s or Coulomb’s earth pressure theory of earth pressurein the foundation design will lead to error. The excavation of pit and the constructionof soil nailing, is not completed in one minute, but rather a process, and the project isconstructed, layer by layer. These conditions led directly to use the Rankine’s orCoulomb’s earth pressure theory in soil nailing project, unsuitably. The Rankine’sand Coulomb’s earth pressure theory directly applied to soil nailing support willproduce larger errors with these conditions.This article focuses on, analysis of the role of the limited soil pressuresupporting on the structure with Limit Equilibrium Method, combined with thefeature of soil nailing excavation and construction step by step, in the excavationengineering.After the study, the earth pressure strength of the non-cohesive soil increasesgradually as the distance between the foundation pit and neighbouring buildingsincreases, finally reaching the Rankine’s earth pressure; the earth pressure strengthof the clay soil increases gradually as the distance between the foundation pit andneighbouring buildings increases, finally reaching the Rankine’s earth pressure, but not always less than Rankine’s earth pressure. The inclination of failure surface isnot a constant, but varies with the depth of foundation pit and the distance betweenthe foundation pit and neighbouring buildings. The stability of the soil nail withdifferent distances is changed.