| 延脆性变化对隧道掘进机刀具破岩过程及其破坏模式影响的颗粒元模拟分析 |
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| 引用本文： | 冀佩琦,张晓平,张 旗.延脆性变化对隧道掘进机刀具破岩过程及其破坏模式影响的颗粒元模拟分析[J].岩土力学,2016,37(Z2):724-734. |
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| 作者姓名： | 冀佩琦 张晓平 张 旗 |
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| 作者单位： | 1. 武汉大学 土木建筑工程学院，湖北 武汉 430072；2. 武汉大学 岩土与结构工程安全湖北省重点实验室，湖北 武汉 430072 |
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| 基金项目： | 国家重点基础研究发展计划（973）（No. 2015CB058102, No. 2014CB046904）；中央高校基本科研业务费专项资金（2016-2018年）。 |
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| 摘 要： | 在全断面岩石掘进机（TBM）刀具破岩的颗粒元模拟中颗粒参数的选取至关重要，其中颗粒间平行黏结切向、法向强度是关键控制性参数之一，它们之间的比值关系直接决定所模拟试样的延脆性质，影响刀具破岩过程及其破岩效果。为探讨延脆性对刀具破岩模式的影响，（1）建立9种采用不同平行黏结强度比值的数值模型，分别进行单轴压缩及巴西劈裂模拟，研究不同延脆性试样的力学行为及破坏模式的变化。（2）对9种模型进行双刀破岩，并监控其裂缝的发展情况及刀具的受力状况。（3）为减小随机性对模拟结果的影响，通过改变随机数，每种模型重复模拟5次，综合分析5次的计算结果。模拟分析发现，随着切向和法向黏结强度比值( )的增大，试样的脆性增加，破坏模式逐渐从剪切破坏转变为脆性张拉破坏，刀具破岩压碎区范围减小，张拉裂缝更容易在刀具间贯通延伸从而切割出块体更大的岩渣；随着试样脆性的增加，归一化比能减小，刀具破岩的效率增加；平行黏结强度比值相同的条件下采用不同随机数种子生成的模型中，试样的具体破坏情况有一定的差别，但总体破坏模式相似。
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| 关 键 词： | 隧道掘进机（TBM） 颗粒元 刀具破岩 延脆性 黏结强度 |
| 收稿时间： | 2016-06-18 |
Partide flow code analysis of effect of ductility-brittleness change on TBM cutters rock fragmentation process and its failure mode |
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| JI Pei-Qi,ZHANG Xiao-Ping,ZHANG Qi.Partide flow code analysis of effect of ductility-brittleness change on TBM cutters rock fragmentation process and its failure mode[J].Rock and Soil Mechanics,2016,37(Z2):724-734. |
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| Authors: | JI Pei-Qi ZHANG Xiao-Ping ZHANG Qi |
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| Institution: | 1. School of Civil Engineering and Architectural, Wuhan University, Wuhan, Hubei 430072, China; 2. Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province, Wuhan University, Wuhan, Hubei 430072, China |
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| Abstract: | The selection of particles’ parameters is of vital importance to simulate rock cutting by the tunnel boring machine(TBM）. The parallel bond shear/tensile strengths between particles, in particular, their ratio is one of the key controlling parameter, which directly determines the ductility or brittleness of the specimen and influences the process and the cutting result. In order to explore the effects of ductility brittleness on rock cutting, this paper conducts the following researches: (1) Creating 9 numerical models by applying different parallel bond strength ratios, and simulating uniaxial compression test and Brazilian tensile test respectively so as to examine the macromechanical behavior and failure mode of every model with different ductility-brittleness. (2) Making double-cutter rock cutting simulation on the nine models above, and monitoring every model’s crack propagation and cutter force condition. (3) To reduce the impact of randomness on the simulation results, making five repetitive simulations for every model by changing random seeds and analyzing the computation of five results comprehensively. Through these simulation researches above, it is discovered that as the ratio of shear bond strength to tensile bond strength( ) grows, brittleness increases and the failure mode of rock samples changes gradually from shear failure to brittle tension failure; and the crushed zone of cutter rock breakage reduces and the tension cracks are more likely to extend between cutters, thereby producing larger bulks of rock pieces. As the brittleness of the model increases, the normalized specific energy decreases and the efficiency of the rock cutting increases. With the same bond strength radio, by applying different random numbers, the specific failure condition of every model is somewhat different; but the overall failure mode is comparable. |
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| Keywords: | tunnel boring machine (TBM) particle flow code rock cutting ductility-brittleness parallel bond strength |
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