摘要
针对普通泡沫混凝土具有孔隙率高、收缩量大和强度偏低等缺点,提出一种微量碳纳米管(CNTs)增强粉煤灰泡沫混凝土(CNTAFC)材料的制备方法,采用模型试验与数值模拟方法探究其作为深埋软岩隧道缓冲层填充材料的适用性,并运用数字散斑技术对比有、无CNTAFC缓冲层支护结构作用下隧道围岩的变形规律。结果表明:微量CNTs可有效增强泡沫混凝土的抗压强度,且平均峰后抗压强度大于平均峰值抗压强度的60%,平均峰后曲线应变范围占平均极限应变的30%以上,满足隧道围岩缓冲层填充材料卸压减能性能的要求;CNTAFC试件具有强度显著提高、变形缓慢和能量逐渐外放的特点,且从能量释放的角度分析,质量比为0.05%CNTs掺量的CNTAFC试件更能满足深埋软岩隧道支护结构缓冲层填充材料卸压的要求;深埋软岩隧道CNTAFC缓冲层支护结构可有效改善隧道围岩的应力状况,显著提高隧道围岩的承载能力,保证隧道的长期安全运营。
In view of the shortcomings of ordinary foam concrete,such as high porosity,large shrinkage and low strength,a preparation method of micro carbon nanotubes(CNTs)-reinforced fly ash foam concrete(CNTAFC)was proposed in this paper.Digital speckle technique was used to compare the deformation law of tunnel surrounding rock with and without CNTAFC buffer layer support structure.The results show that trace CNTs can effectively enhance the compressive strength of foam concrete,and the average post peak compressive strength is greater than 60%of the average peak compressive strength.The average post peak curve strain range accounts for more than 30% of the average ultimate strain,which meets the re-quirements for the pressure relief deformation performance of the tunnel surrounding rock buffer layer fill-ing materials.The CNTAFC specimen has the characteristics of significantly improved strength,slow de-formation and gradual release of energy.From the perspective of energy release,the CNTAFC with a mass ratio of 0.05%CNTs can better meet the pressure relief requirements of the cushion layer filling material of the deep buried soft rock tunnel support structure.The CNTAFC buffer layer support structure of soft rock tunnel can effectively improve the stress condition and the bearing capacity of tunnel surrounding rock,and ensure the long-term safe operation of the tunnel.
作者
李永靖
王松
张淑坤
冯佃芝
LI Yongjing;WANG Song;ZHANG Shukun;FENG Dianzhi(College of Civil Engineering,Liaoning Technical University,Fuzin 123000,China;Liaoning Key Laboratory of Coal Gangue Resource Utilization and Energy Saving Building Materials,Liaoning Technical University,Fucin 123000,China;School of City and Architecture Engineering,Zaozhuang University,Zaozhuang 277160,China)
出处
《安全与环境工程》
CAS
CSCD
北大核心
2023年第5期54-65,75,共13页
Safety and Environmental Engineering
基金
国家自然科学基金项目(51974146、52174078)。
