为解决机制砂混凝土应用中存在级配不良、性能指标波动幅度较大、回弹率高及强度低等缺陷，以贵广高速铁路隧道施工为依托，采用室内试验和现场试验对机制砂加工系统的设备选型与在喷射混凝土及二次衬砌中的应用进行研究。研究结果表明: 1)粉煤灰掺量为40%、水胶质量比为0.37的大掺量粉煤灰机制砂喷射混凝土能够满足规范及设计要求; 2)选择喷射混凝土配合比时，可加大粉煤灰掺入量，降低单位用水量和水胶质量比，提高混凝土的工作性; 3)施工现场喷射工艺成熟时，还可适当降低坍落度值，以确保混凝土的喷射效果和实体质量; 4)水洗机制砂石粉含量并非越低越好，在8%～12%时混凝土的物理性能、力学性能以及耐久性能达到最佳。

The application of mechanicalcrushed sands concrete has some disadvantages, i.e. poor gradation, large fluctuation of performance indices, high rebound rate and low strength, etc. The equipment selection of processing system of mechanicalcrushed sands and its application to shotcrete and secondary lining of GuiyangGuangzhou Highspeed Railway Tunnel are studied by indoor and field experiments. The study results show that: 1) The mechanicalcrushed sand concrete with 40% of fly ash and 0.37 of waterbinder ratio can meet the requirements of relevant standards and design. 2) The working performance of concrete can be improved by increasing the amount of fly ash and reducing the water volume and waterbinder ratio when using shotcrete. 3) Appropriately reducing slump value to ensure shotcrete effect and solid quality can be chosen when the shotcrete process is mature at the construction site. 4) The mechanicalcrushed sand should not be too clean; and the physical, mechanical and durability properties of concrete can reach peak when the content of stone powder is 8%-12%.