硬化速率对喷射混凝土支护结构的影响分析  

Analysis of the effect of hardening rate on the shotcrete support structure

作　　者：梁海军 LIANG Haijun(Chengdu Yijuke Technology Co.,Ltd.,Chengdu 610095,China)

机构地区：[1]成都易居客科技有限公司,四川成都610095

出　　处：《水利建设与管理》2025年第3期39-42,48,共5页Water Conservancy Construction and Management

摘　　要：过高的速凝剂掺量可能导致混凝土硬化后产生气孔和裂纹,影响长期强度,且硬化速率对喷射混凝土的弹性模量有显著影响,硬化速率越小,初始弹性模量越大,但增长幅度越小。为研究速凝剂对喷射混凝土硬化速率及其对围岩支护结构的影响,本文通过配制C25纤维喷射混凝土并调整速凝剂掺入量,发现速凝剂能显著加速硬化过程,提高支护结构的强度和稳定性。研究中利用Midas有限元分析软件建立隧道喷射混凝土支护的三维数值分析模型,模拟了不同硬化速率下的支护效果。虽然速凝剂的使用能有效减小支护结构的沉降变形风险,但由于试验中速凝剂掺入量差别不大,导致模拟时不同硬化速率下的变形差异并不显著,最大沉降变形出现在拱顶部位。增加速凝剂掺入量会增大喷射混凝土的初期弹性模量。随着硬化速率的增加,支护结构两侧边墙的最大应力值逐渐减小,因此合理控制速凝剂用量对于优化支护结构受力分布和降低最大应力值具有重要意义。Excessive amounts of accelerator in shotcrete may cause the formation of pores and cracks after hardening,affecting the long-term strength.The hardening rate has a significant impact on the elastic modulus of shotcrete,where a lower hardening rate results in a larger initial elastic modulus,but with a smaller growth amplitude.To study the effects of accelerators on the hardening rate of shotcrete and its impact on surrounding rock support structures,C25 fiber-reinforced shotcrete was prepared,and the amount of accelerator was adjusted.The study found that accelerators significantly accelerate the hardening process,improving the strength and stability of the support structure.A 3D numerical model of tunnel shotcrete support was then established using Midas finite element analysis software to simulate the support effects under different hardening rates.Although the use of accelerators effectively reduces the risk of settlement deformation in the support structure,the differences in deformation under different hardening rates were not significant due to the small variation in accelerator dosage in the experiments.The maximum settlement deformation occurred at the crown.Increasing the accelerator dosage increases the initial elastic modulus of shotcrete.As the hardening rate increases,the maximum stress on both side walls of the support structure gradually decreases.Therefore,reasonable control of accelerator dosage is crucial for optimizing the stress distribution and reducing the maximum stress on the support structure.

关 键 词：公路工程 隧道支护 喷射混凝土 硬化速率 支护效果分析 

分 类 号：U454[建筑科学—桥梁与隧道工程]