喷射混凝土是新奥法三大关键技术之一，对隧道围岩稳定起着重要的作用。速凝剂在喷射混凝土中为必不可少的外加剂，对喷射混凝土的质量有很大的影响。提出一种新型的高效液态速凝剂，具有掺量小、凝结时间短、后期强度损失少等特点。该液态速凝剂掺量为水泥质量的1%~3%，水泥净浆试验初凝时间为2 min左右，终凝时间为4 min左右，后期强度损失在10%以内，均满足国家一等品的要求。对速凝剂进行现场试验，在实际喷射过程中具有回弹小、无落浆等优点，是一种较为理想的喷射混凝土用液态速凝剂，具有良好的推广应用价值。

Shotcreting is one of the key technologies of NATM, and it plays an important role in tunnel rock stability. Accelerator is an essential admixture in sprayed concrete, and it has a significant influence on quality of sprayed concrete. The authors present a new highly efficient accelerator, which has characteristics of small dosages, short setting time and little loss of the later strength. Volume for the general quality of cement is 1%~3%. Initial setting time is about 2 min while the final setting time is about 4 min. The loss of the later strength of the concrete is within 10%. After the actual test in tunnel engineering, the accelerator has advantages of small rebound, less dust, which is an ideal liquid accelerator for sprayed concrete, and it is worth popularizing.