论文部分内容阅读
树脂锚固材料广泛应用于岩土工程加固,但其高温下具有的热解特性直接影响材料的锚固性能。通过高温拉拔、抗压实验与CT分析相结合的方法,研究高温下树脂锚固材料的锚固力学特性及其受热解细观结构变化的影响特征。研究结果表明:(1)高温拉拔实验中,20℃~250℃时,随着温度升高锚固力增大,250℃时达到峰值69.5 k N,较常温增大45.1%,这是由于树脂锚固材料内部充分固化的结果;250℃~350℃范围锚固力下降为47.2k N,较峰值减少32.1%;但在350℃~400℃范围,模拟管中的锚固材料发生爆裂与剧烈炭化,平均锚固力下降为15.2 k N,且500℃~600℃时完全失去锚固力。(2)高温抗压实验中,200℃时抗压强度达峰值65.8 MPa,较常温增加31.3%;350℃~400℃时强度较常温衰减95.2%,在600℃时强度衰减达99.3%。(3)CT扫描分析,350℃~500℃锚固材料平均灰度衰减22.6%,孔隙团大小增幅达199.6%。可见,350℃后树脂锚固材料快速热解炭化、内部孔隙剧增是造成其锚固力衰减的根本原因。
Resin anchoring materials are widely used in geotechnical engineering, but the pyrolysis characteristics at high temperature directly affect the anchoring performance of materials. Through the combination of high-temperature drawing, compressive test and CT analysis, the anchoring mechanical properties of high temperature resin anchoring material and the influence characteristics of pyrolysis mesostructure were studied. The results show that: (1) In the high-temperature drawing test, the anchoring force increases with the increase of temperature at 20 ℃ ~ 250 ℃, reaching 69.5 kN at 250 ℃, which is 45.1% The anchoring force in the range of 250 ℃ ~ 350 ℃ decreased to 47.2k N, which was 32.1% less than the peak value. However, in the range of 350 ℃ ~ 400 ℃, the anchoring material in the simulated tube burst and severe carbonization, and the average The anchoring force is reduced to 15.2 kN, and the anchoring force is completely lost at 500-600 ° C. (2) In the high-temperature compression test, the compressive strength reaches 65.8 MPa at 200 ℃, which is 31.3% higher than normal temperature. The strength decays 95.2% at room temperature from 350 ℃ to 400 ℃, and decreases to 99.3% at 600 ℃. (3) CT scanning analysis showed that the average grayscale attenuation of 22.6% and anchorage material of 350 ℃ ~ 500 ℃ increased by 199.6%. Visible, 350 ℃ after the resin anchoring material rapid pyrolysis charring, the internal porosity increase is the root cause of the attenuation of its anchoring force.