模拟岩石的平行粘结模型微观参数标定  

Calibration of micro-parameters of parallel bonded model for rocks

作　　者：蒋明镜[1,2,3] 方威[1] 司马军[1] 

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072 [2]土木工程防灾国家重点实验室(同济大学),上海200092 [3]岩土及地下工程教育部重点实验室(同济大学),上海200092

出　　处：《山东大学学报（工学版）》2015年第4期50-56,共7页Journal of Shandong University（Engineering Science）

基　　金：国家杰出青年科学基金资助项目(51025932);国家重点基础研究发展规划资助项目(2011CB013504;2014CB046901)

摘　　要：针对平行粘结模型不能同时满足岩石抗拉强度和抗压强度的问题,通过模拟岩石的单轴拉伸试验和单轴压缩试验,以已有的Lac du Bonnet花岗岩的室内试验结果为目标,标定了不同孔隙比和不同不均匀系数岩石离散元试样的微观参数。从微观破坏机制角度指出了平行粘结模型的不足之处,并提出了改进方法。研究结果表明:满足抗拉强度和抗压强度的微观胶结强度参数相差一个数量级;模型仅考虑了胶结的抗拉和抗剪特性,忽略了法向力对胶结强度的影响,导致模型不能正确反映岩石的拉压强度比值;建议采用可模拟颗粒破碎的团粒模型或者基于室内试验提出的胶接模型。The micro-parameters of parallel bond model could not satisfy the compressive strength and tensile strength simultaneously, this was a problem in the simulation of rocks. A set of uniaxial tension tests and uniaxial compression tests of rocks were simulated to investigate this problem. First, DEM specimens with different porosity ratio and differ- ent nonuniform coefficient were calibrated according to the laboratory test results of Lac du Bonnet granite. Second, the deficiency of the parallel bond model was pointed out and the improved methods were proposed from the perspective of microscopic failure mechanism. The simulation results showed that the microscopic parameters satisfied tension strength was one order of magnitude deviated from the microscopic parameters, which could also satisfy compression strength. Tensile characteristics and shear characteristics were considered in the parallel bond model, while the influence of normal stress on the bond was ignored. This was the reason that the tension-compression strength ratio of rock was different from the experimental result. It was advised to use clumped particle model which could simulate particle breakage or cementation model based on laboratory tests.

关 键 词：平行粘结模型 单轴拉伸 单轴压缩 微观力学参数 宏观特性 离散元 

分 类 号：TU45[建筑科学—岩土工程]