基于纤维随机理论的隧道土工布渗透系数阻力理论模型OA

Aiming at the problem that the existing geotextile permeability coefficient models are difficult to accurately reflect the seeping-stress coupling conditions in actual engineering,a new permeability coefficient resistance model based on fiber random theory was proposed in the paper.The random distribution characteristics of fibers were characterized by introducing the normal distribution weight function,and the compressive stress effect was transformed into the adjustment parameters of the spatial orientation of fibers.Based on the analysis of performance parameters of geotextiles,the theoretical calculation formula of the total fiber length was established,and the theoretical framework of new permeability coefficient resistance model was derived in combination with the principles of fluid mechanics.To verify the reliability of model,15 sets of pressurized transverse permeation test data and 16 sets of pressurized vertical permeation test data for parameter calibration were used.The results show that the fiber random distribution parameter has a negative exponential relationship with the solid volume fraction(regression coefficient R2=0.95),and the compressive stress parameter has a significant linear positive correlation with the load value(regression coefficient R2=0.92).In addition,both the transverse and vertical permeability coefficients show a changing pattern of rapid attenuation first and then stabilization with the increase of external loads and the volume fraction of solids.The maximum deviation between the predicted results of the new model and the measured values does not exceed 0.16 cm/s,and thus the reliability and accuracy of the model are verified.The theoretical basis and technical support for the design of tunnel waterproofing and drainage systems can be provided.