Laboratory study on face stability mechanism of slurry shields

With the increasing dimension of the slurry shields,more and more attention was paid to the face stability of slurry shields in recent years.A series of slurry shield model tests were carried out for the Yangtze River Tunnel of Shanghai.The results of the model tests were presented with particular emphasis on the balancing mechanism of slurry shields,the development of settlement at the excavating face and the limit slurry pressure.It was shown that settlements induced by the cutting face were mostly decided by the fluctuation of the slurry pressure in the chamber.The test results were compared with those of theoretical analysis of wedge model.The range of slurry pressure fluctuation was presented according to the test results.