刃宽对硬岩掘进影响的仿真及试验研究

Research on disc cutter excavation characteristics for different blade width based on numerical simulations and experiments

滚刀在硬岩掘进中极易发生崩刃、偏磨等异常失效,研究硬岩掘进条件下刃型参数对滚刀破岩载荷和破岩效率的影响十分重要.本文采用滚刀破岩试验和仿真分析相结合的方法,从载荷曲线、破岩体积、破岩比能等方面分析了刃宽对滚刀破岩的影响.基于双线性本构模型及Benzeggagh–Kenane损伤断裂准则建立了岩石材料的内聚力本构模型,通过单轴抗压试验及巴西劈裂试验对内聚力本构模型的微观参数进行了校准,并进一步建立了滚刀破岩的内聚力仿真模型.结果表明:内聚力本构模型可以准确的模拟破岩过程中岩石裂纹的萌生和扩展过程.依据裂纹的萌生和扩展情况,滚刀破岩过程主要分为三个阶段:弹性阶段、裂纹萌生–扩展阶段及岩石破坏卸载阶段.滚刀破岩载荷和破岩体积随着贯入度、刀间距和刃宽的增加而增加;破岩比能随刃宽的增加呈先减小后增大的趋势.对于所选取的硬岩,采用13 mm刃宽滚刀破岩时比能最小,破岩效率最高;7 mm刃宽滚刀破岩时无法形成贯通岩片,相邻滚刀之间仍存在岩脊,破岩效率较低.

This study addresses the abnormal failures,such as blade fractures and wear,encountered by disc cutters when excavating hard rock with high uniaxial compressive strength.It is crucial to understand how disc cutter geometric parameters affect excavation efficiency and load,especially when performing disc cutter excavation on hard rock.We propose a rock modeling approach that combines a cohesive model with a solid model,leveraging the characteristics of a cohesive element.The model follows the double linear constituted evolution criterion and the Benzeggagh–Kenane damage failure criteria.Calibration of the cohesive model’s microscopic parameters was based on the uniaxial compressive strength test and Brazilian splitting tests,using stress reduction rate curves and crack morphology from these experiments.We developed a simulation model for rock breaking during disc cutter excavation and validated it through linear cutting tests.The study examines linear cutting test results and the simulation of rock breaking during disc cutter excavation results.This study examines how disc cutter width affects rock breaking by considering load curves,rock breaking volume,and specific energy.Results indicate that the cohesive constitutive model effectively simulates rock crack initiation and propagation.The rock breaking process comprises three stages:elastic,crack initiation-propagation,and rock unloading.The crack initiation-propagation stage is critical for rock breaking efficiency.Results show that disc cutter load and rock break volume increase with increasing penetration,blade width,and cutter spacing.Specific energy initially decreases with blade width increase and then increases.Optimal excavation efficiency occurs with a blade width of 13 mm and a spacing of 80 mm,whereas a 7-mm blade fails to achieve complete rock fragmentation,resulting in low efficiency.