在高寒地区，常年地温仅７℃，若地下高压灌筑水泥净浆混凝土，如果所掺的外加剂达不到早强要求，强度不能在预期时间内达到设计要求，势必影响主体工程的进度。因此，选择外加剂时必须遵循以下原则：（１）在保证水泥净浆大流动度的条件下，选用有效减水剂；（２）要求在... In the high-cold area, the annual ground temperature is only 7°C. If the underground high-pressure cement concrete is poured, if the admixed additives do not meet the early strength requirements, the strength cannot meet the design requirements within the expected time, which will inevitably affect the progress of the main project. Therefore, the following principles must be followed when selecting the admixture: (1) Under the condition of ensuring large fluidity of the cement paste, an effective water-reducing agent should be selected; (2) Requirements in...