Abstract In the process of construction and operation of tunnels, the groundwater leakage, flood burst and harmful gas diffusion and other disasters pose a threat to the life and property safety of people. A temporary“isolating and blocking wall”can be created in a very short time by inflatable airbags to control the dangerous sources within a certain range, thus avoiding the expansion of the disaster. The inflatable airbag is of membrane structure, and its stress and deformation characteristics under external pressure have direct impact on the plugging failure mode of the airbag. Theoretical analysis on deformation and failure modes of the airbag under external pressure is conducted, and the accuracy of the theoretical formula is verified by a visualization model test. In this paper, based on the membrane theory and cavity theory in ABAQUS finite element, the inflating process of airbags under the model test condition and the deformation process under external pressure are simulated, and the comparison with the theoretical analysis results and the experimental data is conducted. Also, the effect of coefficient of the friction between the air? bag and the tunnel wall on the airbag deformation is studied. The result shows that the simulation result obtained using such method is highly identical to the model test data and values derived from the theoretical formula. Moreover,it can overcome the limitations of the theoretical formula in calculating the shape of the airbag, the material characteristics, the friction coefficient of the tunnel wall, etc., and reflect the various characteristics of the plugging of airbag more comprehensively, with a wider applicability.
Abstract：
In the process of construction and operation of tunnels, the groundwater leakage, flood burst and harmful gas diffusion and other disasters pose a threat to the life and property safety of people. A temporary“isolating and blocking wall”can be created in a very short time by inflatable airbags to control the dangerous sources within a certain range, thus avoiding the expansion of the disaster. The inflatable airbag is of membrane structure, and its stress and deformation characteristics under external pressure have direct impact on the plugging failure mode of the airbag. Theoretical analysis on deformation and failure modes of the airbag under external pressure is conducted, and the accuracy of the theoretical formula is verified by a visualization model test. In this paper, based on the membrane theory and cavity theory in ABAQUS finite element, the inflating process of airbags under the model test condition and the deformation process under external pressure are simulated, and the comparison with the theoretical analysis results and the experimental data is conducted. Also, the effect of coefficient of the friction between the air? bag and the tunnel wall on the airbag deformation is studied. The result shows that the simulation result obtained using such method is highly identical to the model test data and values derived from the theoretical formula. Moreover,it can overcome the limitations of the theoretical formula in calculating the shape of the airbag, the material characteristics, the friction coefficient of the tunnel wall, etc., and reflect the various characteristics of the plugging of airbag more comprehensively, with a wider applicability.
CHEN Jing1 YAN Shuwang2 ZHONG Xiaokai3
.Finite Element Study on Working Mechanism of Plugging Airbags in Tunnels under External Pressure[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(2): 135-144
2021, Vol. 58 