Abstract:Based on the problem of earth pressure concentration in soil pressure cells, a water bladder earth pressure gauge was invented. The thickness of pressure sensing water bladder can be controlled within 5-10mm.The pressure sensing water bladder is connected with the electronic pressure gauge through the transparent PU air pressure hose. The height position of the electronic pressure gauge needs to be fixed when the water bladder earth pressure gauge is used.In order to verify the testing performance of the water bladder earth pressure gauge, a comparison test was conducted between the water bladder earth pressure gauge and the vibrating string earth pressure cell buried in soils with different compression modulus.The analysis of the results shows that, because the pressure sensing water bladder is thinner than the earth pressure cell, although the problem of high measured earth pressure is unavoidable, the stress concentration problem is significantly improved when the earth pressure in the stratum is tested with the water bladder earth pressure gauge compared with the earth pressure cell.The water bladder earth pressure gauge is used in the model test of shield tunnel response. The test results show that the water bladder earth pressure gauge is obviously different from the earth pressure cell.From the analysis of the changing trend of the test results, the test results of the water bladder earth pressure gauge are reliable.The test principle of the water bladder earth pressure gauge is simple, and the cost is low, and the precision is high.Because of its flexible construction, the pressure sensing water bladder can be used to test the earth pressure of non-plane structure surface according to the test demand.