Influence Of The Fissures On The Stability And Supporting Of Foundation Ditch

The rapid development of city construction has greatly promoted the foundation ditch engineering inChina forward, design theory, calculation of foundation ditch engineering method has been improved, theconstruction technology has made great progress.But at the same time, the development of the city alsomakes the foundation ditch engineering problems become more and more complex, the periphery of thefoundation pit have been built or under construction building, adjacent to the surrounding variousunderground pipelines, the bottom or side tunnel, subway station, there are frequently occurring specialcase Fissures are widely distributed in places such as xian city, foundation pit engineering and faces theserious effect of fissures Fissure hazard to the engineering construction is very large, will produce buildingdehiscence, road collapse, pipeline rupture and other damage, similarly, the influence of the fissures infoundation ditch engineering is very great, serious impact on the design and construction of foundationditch engineering, but there is little research to fissures a specific effect on in foundation ditch engineering.This paper first analyzes the influence mechanism of fissures on the stability of foundation ditchengineering and the distribution of earth pressure, then by using the finite difference software FLAC3Danalyses have with and without fissures in two cases of foundation ditch horizontal displacement, verticaldisplacement, as well as the supporting pile stress conditions. In order to study the influence of fissures onfoundation ditch engineering more specifically, the distance from the foundation ditch of ground fissures,ground fissure angle changes and ground fissure parameters changes has carried on the detailed numericalsimulation, the specific work as follows:1. In view of the existence of fissures and without fissures in two cases, analysis the failure mode ofslope stability and the earth pressure on retaining structure distribution using the method and theory ofappropriate, introduced a specificformula.2. By using the finite difference software FLAC3D, building two model of the foundation ditcharound the existence of fissures and no fissures, excavating layer by layer, comparing the two kinds ofmodel results, analyzing the influence of fissures on the deformation and supporting of foundation ditchwhen existing fissures.3. Establishing the model of the distance between fissure and foundation ditch were0meters,3 meters,6meters,10meters, to excavate, comparing and analyzing the influence of fissure in the distancechange for foundation ditch engineering.4. Establishing the model of foundation ditch excavation in70°,75°,80°,85°and90°dip angle ofthe fissures, analyzing the influence of dip angle changing for foundation ditch engineering.5. Establishing the foundation ditch excavation model under the condition of the contact surfaceparameters changing of fissures respectively, analyzing the shear stiffness (1e6Pa~1e8Pa),normalstiffness (1e7Pa~1e9Pa),cohesive force (0~40KPa) and internal friction angle (5°~25°) change onthe impact of foundation ditch engineering.