Research On Conditioned Soil Rheological Properties Experiment

Earth pressure balance (EPB) shield, a kind of tunnel boring machine (TBM), which is widely adopted in currently urban subway tunnel, municipal utility tunnel, railway and highway tunnel construction because of its wide application range and low pollution. Pressure balance control, one of the key technologies for EPB shield tunneling, is directly related to construction quality, safety and efficiency. The screw conveyer controls the flow of conditioned soil to make pressure balance. Therefore, to measure the flow properties of conditioned soil is the basis for screw conveyer working mechanism research and earth pressure control. So this paper research on conditioned soil rheological properties experiment, designed an experimental device, found out the flow properties of conditioned soil, provided a theoretical base for the EPB control.Conditioned tunnel soil is non-Newtonian fluid, and the flow properties are pressure related. Now there are several ways to research the flow properties of non-Newtonian fluid, such as field observation, experimental simulation, theoretical analysis, numerical calculation. This paper used experimental simulation to research the flow properties of conditioned soil by designing an experimental device and presenting experimental contents, process. Then using this device to carry out experiments and measure the flow properties of conditioned soil under different pressures and shearing speeds. Then analyze experimental results to find out the relationship between flow properties and pressure, provide a theoretical base for screw conveyer working mechanism research and EPB control. Main research work is as follows,(1) Based on non-Newtonian fluid mechanic theory to research the flow properties of condition soil, defined experimental device performance requirement and experiment requirement, defined experimental contents of different soil conditions, pressures and shearing speeds.(2) According to the performance requirement of experimental device, designed an experimental device to measure the flow properties of condition soil, including conceptual design, structure design, strength analysis, component selection, organization device manufacture, assembly, calibration and test.(3) Carry out experiments and get data, draw flow curve, analyze experiment result to confirm the flow properties of conditioned soil under different pressures and shearing speeds.This paper research achieved flow properties of conditioned soil have been used in subsequent 973 project simulation and experiment research application, and the result shows the flow properties are correct, can be used to tunnel screw conveyor performance and control mechanism research. The experimental device with compact structure and easily-operation is suit for engineering application.