论文部分内容阅读
在隧道工程施工中,喷射混凝土作为一种必要的初期支护手段,对隧道围岩稳定性控制起着重要的作用,而速凝剂的品质及掺量又直接影响着喷射混凝土的强度与施工环境。基于铝酸盐速凝剂促凝机制,研制出一种高性能低掺量液态速凝剂。该液态速凝剂苛性比小于1.2,p H值为9~11,含固量为65%,溶液稳定不析出。通过XRD和SEM图谱分析及相关性能试验,该液态速凝剂能有效提高水泥水化程度,短时间内形成大量硅酸钙凝胶,相互搭接形成晶体结构,减少凝结时间;其适宜掺量为水泥质量的1.5%~3%,喷射混凝土后期强度损失在10%以内。在现场应用中,研制出一种高精度小流量液态速凝剂定量添加装置,确保精确控制液态速凝剂掺量;并完善相应的配套喷射工艺,有效提高喷射混凝土强度,降低施工中粉尘和回弹,具有良好的推广和应用价值。
In the construction of tunnel, shotcrete as an essential initial support means plays an important role in the stability control of surrounding rock of tunnel, and the quality and content of quick-setting admixture have a direct impact on the strength and construction of shotcrete surroundings. Based on the accelerating mechanism of aluminate quick-setting agent, a high-performance and low-dosage liquid quick-setting admixture was developed. The liquid quick-setting accelerator has a caustic ratio less than 1.2, a p H value of 9-11, and a solid content of 65%. The solution is stable and does not precipitate. Through XRD, SEM and related performance tests, the liquid quick-setting admixture can effectively improve the degree of hydration of cement, forming a large amount of calcium silicate gel in a short period of time and overlapping with each other to form a crystal structure and reduce the setting time. The suitable dosage 1.5% ~ 3% for the quality of cement, late strength loss of shotcrete within 10%. In the field application, we developed a high-precision small-flow liquid quick-setting agent quantitative adding device to ensure accurate control of the liquid quick-setting admixture dosage; and improve the corresponding injection process to effectively improve the strength of shotcrete and reduce the construction of dust and Rebound, has a good promotion and application value.