基于格宾石笼的隧道支护构件静力加载模型试验设计

Static loading model test design for tunnel lining components based on gabion

尽管格宾石笼在边坡、护岸工程、路基加固等工程中已有了一定的应用,但鲜有研究提及格宾石笼在隧道支护中的应用。由于格宾石笼具有一定的承载力和良好的变形适应能力,在应对隧道围岩大变形和高地应力等方面具有一定应用前景,因此,对基于格宾石笼的隧道支护构件静力加载模型进行试验设计具有一定的实际意义。为了方便学生更好地了解格宾石笼作为隧道支护结构的力学作用机理,设计了一种简化的格宾石笼构件成形方法和与之配套的试验加载装置,并提出了基于离散元计算的格宾石笼隧道局部构件数值建模方法,进而对比和揭示了组成格宾石笼构件的两大主要参数(格宾网抗拉强度和填石有效模量)对格宾石笼建构的隧道支护构件静力力学特性差异的影响规律。通过该试验,为学生演示了基于格宾石笼建构的隧道支护局部构件的设计、拼装、试验加载以及数据采集的全过程,旨在为学生深入学习和掌握格宾石笼建构的隧道支护局部构件的试验静力力学行为及其建模方法提供一种新思路。

[Objective]Gabion is widely used in slope stabilization,revetment engineering,subgrade reinforcement,and other applications.However,its use in tunnel lining remains underexplored.Owing to its unique multiporosity,which provides excellent deformation capacity and notable bearing strength,gabion shows promising potential for managing the notable deformations and high ground stresses encountered in tunnel surrounding rock.Therefore,studying the static mechanical behavior of tunnel lining components made with gabion is of practical importance.[Methods]This paper presents a simplified molding technique for gabion components and a custom-designed test loading apparatus.Additionally,a numerical modeling methodology specifically tailored for gabion components in tunnel lining is introduced based on discrete element calculations.Next,a comparative analysis is conducted to examine the influence of two key parameters—the strength of the gabion mesh and the effective modulus of the stone filling—on the variation in static mechanical characteristics of tunnel lining components constructed with gabion.This study provides valuable insights into the performance of gabion-based tunnel linings.[Results]1)The failure of the gabion component in tunnel lining mainly occurs through instability,with only minor cases of wire breakage and stone-filling fracture.Throughout the loading process,the load-displacement curve of the component exhibits notable fluctuations driven by the ongoing interaction between the internal stone filling and the gabion mesh.The overall load-displacement curve increases and then decreases.Despite considerable deformation,the component maintains a high bearing capacity at the end of loading.2)The tensile strength of the gabion mesh has little effect on the deformation modulus during the initial deformation stage under static load but has more impact on the peak load.The higher the tensile strength of the gabion mesh,the greater the displacement and peak strength at peak load.Under varying tensile strength conditions,the differences in peak load displacement and peak strength reached 28.9%and 25.2%,respectively,because when the tensile strength of the gabion mesh is higher,the component is more resistant to failure,allowing a more effective interaction between the stone filling and the gabion mesh.3)Compared with the tensile strength of the gabion mesh,the effective modulus of stone filling has a pronounced impact on the component performance.As the effective modulus of the stone filling increases,the postpeak decline in the load-displacement curve becomes more prominent.During the loading process,the energy consumption of the component,peak loading strength,and effective modulus of the stone filling exhibit a distinct piecewise relationship,characterized by an initial increase followed by stabilization.[Conclusions]This experiment provides clear guidance for students conducting static loading mechanical model tests on gabion-constructed tunnel lining components,enhancing the effectiveness of experimental teaching.