锚固层状岩体的复合加固理论与数值模拟试验分析

STUDY ON COMPOSITE ANCHORING THEORY AND NUMERICAL SIMULATION TEST ON LAYERED ROCKS

根据复合材料力学的理论和方法,将层状岩体-砂浆-锚杆支护系统看成一种由岩体(基体)、锚杆(增强材料)和砂浆(黏结材料)组成的加固复合材料,建立这种复合材料的细观力学等效模型。理论分析这种锚固复合材料的宏观力学性质与其各组分材料性能以及细观结构之间的定量关系;在大型商业有限元软件基础上进行二次程序开发编制,进行锚固复合材料的数值模拟试验研究,分析岩体强度、锚杆尺寸、砂浆强度以及锚杆几何布置间距等参数变化对层状岩体锚固复合材料的黏聚力和内摩擦角值的加强增长幅度,定量评估岩体锚固复合材料的等效强度特性。运用所建立的岩体锚固复合支护系统等效力学模型计算了锚固岩体相似模型试件的弹性常数和黏聚力和内摩擦角值,理论与数值模拟分析结果与岩体锚固的模型试验结果具有较好的吻合度,表明所建立的理论模型和数值分析方法是可靠的,可为岩土工程的设计与稳定性评价提供参数依据。

The equivalent meso-mechanical model of anchoring composite materials(ACM) consisting of layered rocks(matrix material),rockbolts(reinforcing material) and cement mortar(felting material) is established according to theory and method of mechanics of composite materials.The relations between macro-mechanical behavior of ACM and the characters,meso-structures of constituent materials in ACM are analyzed quantitatively by using the equivalent mechanical model.The reinforcing effects of rock of lower elastic module are more obvious than that of higher ones in the anchoring direction.And the reinforcing effects decrease as the space of rockbolts linearly increase.The elastic module of mortar has not much effect on that of ACM.In the numerical model test of ACM the reinforcing effects of mechanical properties of rocks,diameters of rockbolts,spaces between rockbolts,mechanical properties of cement mortar and geometrical arrangements of rockbolts on c,φ of anchoring composite materials are studied by numerical simulation tests with finite element commercial software and FEM subroutines.The equivalent strength characteristics of ACM are evaluated quantitatively.The elastic constants and c,φ for the similar model material of anchored rock mass are also computed by using the equivalent mechanical model of ACM.The results of theoretical analysis and numerical simulation tests with the equivalent mechanical model are consistent well with those of model tests by comparisons which indicates that the equivalent model and the numerical analysis method in this paper are of rationality and reliability.