The Mechanism Of Grouting Pipe Roof In Fine Silt And Application In Shallow Buried Tunnelling

In this paper we combining Xidan-lingjing Hutong connecting tunnel project of Metro Line 4. focusing on difficulties in engineering of building large-span connecting tunnels, beneath roads, underground pipelines too many in the fine silt formation. Using theoretical analysis, numerical simulation, field tests and other research tools. In order to analyse the mechanism of pipe roof support in the fine silt formation, and simulation studies several pre-support program of what we have put. Research obtained the following results:(1)Use elastic foundation beam theory, introduction of two parameter model, building the mechanical model of pipe roof, analyse the mechanism of pipe roof, solving out the parameter equation of deflection,smoment,angle and subgrade reaction in the earth pressure. Combining practical project examples, what have proved the scientific of the model.(2)Make laboratory testing and field tests to grouting fine sands of the body. Study the mechanism of grouting, combining practical project, analysis and evaluation of the effects of grouting.(3)Combining practical project, making theoretical analysis and numerical simulation to the large span in shallow tunnels deep hole grouting program. Pipe shed timbering shelf management programs and grouting program in the fine silt formation which we have said before. From the soil surface subsidence caused by the digging of the tunnel shafts, surface differential settlement. Regional distribution of rock and plastic pipe roof deflections and moments were conducted comparative analysis, which was proved that grouting pipe roof drawn to the program works best suited to advance the protection program.In this paper, research has been successfully applied in the existing project, a similar project is also important for future reference.