Experimental study on EPB shield tunnel construction in soft ground

The very deep sedimentary deposits of soft clay are widely distributed over the underground of coastal areas and many interior cities of China.At present,in many cities of such regions,subways have been constructed or have beeing prepared for construction.In order to guarantee the practical use of the shield tunnel method in this kind of weak stratum,and to reduce environmental influence as well as the project construction cost,the interval tunnel of Shanghai subway line M8 was taken as research background,and model tests were carried out to simulate tunneling excavation with EPB shield machine.Therefore,according to the similarity theory and model test method,the similar system between the soil body-shield machine had been established.Afterwards,the artificial soil was configured to formulate the soft soil of Shanghai area and similarity model experiment procedures were designed for tunneling in such ground.In addition,the prototype shield machine with diameter of 6340 mm was simulated by a microtunneling machine with diameter of 400 mm.Finally,working parameters of various machines were combined for tunneling tests while the test results of machine and soil body were recorded simultaneously.Based on the analysis of test results,some useful conclusions were drawn for EPB shield machine tunneling in soft ground.