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碳纤维相似材料模拟采动岩体损伤破裂表征方法及试验研究

Characterization methods and experimental study of mining-induced rock mass damage and fracture using carbon fiber similar materials

  • 摘要: 相似材料模拟试验是探究煤炭开采过程中覆岩破坏、岩层移动及岩层控制的重要手段,然而传统相似模拟材料难以对采动岩层内部损伤破裂及其动态发育过程进行有效监测。为此,将碳纤维引入矿山相似材料模拟实验领域,借助该复合材料优异的导电性能及电阻率变化对损伤的灵敏反馈,实现了相似模拟实验中采动岩层内部损伤与破裂规律的实时监测,并据此研发了一种具有损伤自感应功能的碳纤维相似模拟复合材料。研究发现随着碳纤维掺量的增加,相似材料电阻率变化与损伤系数演化规律趋于一致,且当相似模拟材料中碳纤维掺量≥2%,相似材料电阻率变化与损伤系数始终保持同步增长。基于此,探明了碳纤维相似模拟材料电阻率变化量与岩层损伤程度的关联效应,开展了近距离煤层过煤柱开采岩层结构动态演化与关键层破断时序物理模拟试验,分析了煤层开采全过程中的碳纤维相似材料电阻率变化特征,精准辨识了覆岩采动裂隙的发育程度、分布范围及各岩层损伤破裂时序,形成了适用于采矿工程相似模拟实验中的岩层损伤破裂动态过程新型量化与表征方法,为揭示采动岩层损伤破裂演化规律与优化岩层控制技术措施提供了科学依据。

     

    Abstract: Simulation experiments are a crucial method for investigating overburden failure, strata movement, and strata control during coal mining. However, traditional similar materials struggle to effectively monitor the internal damage, fracturing, and dynamic development processes within the strata during mining. To address this issue, carbon fibers were introduced into the field of similar material simulation experiments for mining. Leveraging the excellent conductivity and the sensitive feedback of resistivity changes in response to damage of this composite material, This enabled real-time monitoring of internal damage and fracture patterns within the mining strata during similar simulation experiments, leading to the development of a carbon fiber similar simulation composite material with damage self-sensing properties. The study found that as the carbon fiber content increased, the evolution patterns of the electrical resistance change rate and the damage coefficient of the similar material tended to coincide. When the carbon fiber content in the similar material exceeded 2%, the electrical resistance change rate and the damage coefficient consistently exhibited synchronized growth with essentially identical increments. Based on this, the correlation between the variation of resistivity in carbon fiber similar simulation materials and the degree of rock layer damage was investigated. Dynamic evolution experiments of the rock structure in close proximity to coal pillar extraction were conducted, focusing on the physical simulation of the timing of key layer fractures. The characteristics of resistivity changes in carbon fiber similar materials throughout the coal mining process were analyzed, enabling precise identification of the development extent, distribution range, and fracture timing of the overburden mining-induced cracks. This research established a novel quantitative and characterization method for the dynamic process of rock layer damage and fracturing applicable in mining engineering simulation experiments. It provides a scientific basis for revealing the evolution of damage and fracture in mining-induced strata and for optimizing rock layer control technologies.

     

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