硬岩掘进装备支撑系统界面接触刚度非线性特性

Non-linear Behavior of Normal Contact Stiffness of Tunnel Surface and Supporting System of Tunnel Boring Machines

隧道岩石表面形貌和岩石力学特性对撑靴接触界面刚度特性关系密切。根据隧道岩石形貌特点,采用分形数学模型分析不同分形参数与表面粗糙度之间的关系,通过投影方法建立三维隧道岩石粗糙表面数值分析模型。考虑岩石隧道表面粗糙度,岩石力学特性、撑靴数量以及复合岩层等工况,分析不同参数下撑靴载荷与法向接触刚度之间的关系。结果表明:掘进装备的支撑系统界面法向接触刚度随着法向力、分形维数、弹性模量的增大而增大,随着特征尺度系数的增大而减小;撑靴数量的增加会带来界面法向刚度增加。在相同载荷下,双撑靴的接触刚度接近单撑靴接触刚度的两倍;岩石成分比例相同时,其法向刚度最小;当岩石成分比例不同时,较小弹性模量岩石成分越高,其法向刚度越大;岩石成分比例不同的情况下,其法向刚度相差不大。

The interfacial contact stiffness between the supporting system of tunnel boring machines （TBM） and the tunnel surfaces is closely related to the mechanical behavior of rocks and the morphology of tunnel surfaces. The mathematical model based on the fractal theory is employed to study the relation between the roughness and fractal parameters of three dimensional tunnel surfaces. The coarse surfaces are established by using the projecting method according to the characteristics of tunnel surfaces. Many parameters such as the roughness of the tunnel surfaces, the mechanical behavior of rocks, the number of the supporting boots and composite geologic structures are taken into consideration to obtain the correlation between the normal contact stiffness and the loads. The results show that the increases of the fractal dimension, the elastic modulus, the normal loads and the number of support boots cause the increase of the interfacial contact stiffness. The contact stiffness of the double supporting systems is twice of that of the single one subjected to the same load. The normal stiffness is minimal when the ratios of the soft and hard rocks in the composite geologic structures are approximately identical. The increasing of the ratio of soft rocks in the contacting area causes the increase of the contact stiffness. However, the variation of the contact stiffness is not obvious when the proportions of two kinds of rocks on the contacting area are changed.