Analysis of Bearing Capacity for Primary Support and Secondary Lining in Small-Section Expansive Soft Rock Tunnels
In the construction process of water diversion and irrigation projects in China,various types of soft rock tunnels have been frequently encountered.Due to the particularity of the engineering properties of expansive soft rock,tunnel construction often faces challenges such as support structure damage,instability,and large deformation.The soft rock tunnels are mainly subject to overall deformation failure.A numerical model for primary support has been established,and different support time and measures for surrounding rock have been proposed.The simulation calculations show that the convergence deformation of the surrounding rock is within the allowable range of the specifications,and the bearing capacity of the primary support measures meets the safety requirements during construction.This provides a theoretical basis for various rock support time and measures during the construction period.A numerical model for the secondary lining was also established.Considering the absorption and expansion of the surrounding rock due to water seepage during the tunnel operation period,the mechanical response characteristics of the secondary lining under different working conditions were analyzed.The results indicate that the tunnel invert in the secondary lining is the most unfavorable stress position,and the overall bearing capacity can be improved by increasing the thickness of the invert or amount of reinforcement.The study provides theoretical guidance for the design of support and lining structures in expansive soft rock tunnels and offers a reference for the design and construction of similar projects.
soft rock tunnelexpansivenessLDP curvebearing capacityfinite element analysis
万方数据
维普
