为解决单线铁路隧道由于断面小、通道狭窄而造成的施工机械与混凝土输送泵互通不顺畅的问题，设计一种窄体双缸S阀混凝土输送泵，该混凝土输送泵泵送机构采用液压油缸带动混凝土输送缸的结构模式和双缸往复式工作原理，双缸并列设置，在不减小输送量的前提下降低整机宽度(整机宽度为1.49 m)。采用Ansys软件对混凝土输送泵的关键部件力学性能进行分析，并计算S阀体的疲劳寿命。结果表明： 在静载荷作用下，活塞杆、主油缸和混凝土输送缸的最大等效应力均小于材料的屈服极限，满足结构强度要求； S阀体在动荷载作用下的最大等效应力小于材料的屈服极限，且疲劳寿命在疲劳敏感曲线的50%～90%内，满足结构强度和疲劳寿命设计要求。

A narrow body doublecylinder S valve concrete pump is designed so as to solve the disturbance problem between construction machinery and concrete pump used in singletrack railway tunnel with small crosssection and narrow gallery. The concrete pumping cylinder driven by hydraulic cylinder and the principle of reciprocating mode of double cylinder are adopted for the system; therefore, the width of the pumping system can be reduced to 1.49 m without lowering the pumping capacity. And then, the mechanical properties of major critical components and fatigue life of S valve of the concrete pump are analyzed by software Ansys. The study results show that: 1) The maximum equivalent stresses of piston rod, main cylinder and concrete pumping cylinder are less than yield limits of materials under the action of static load. 2) The maximum equivalent stress of S valve is less than yield limit of material under the action of dynamic load; and the fatigue life of S valve is 50% to 90% of the fatigue sensitive curve, which can meet the requirements of structural strength and fatigue life.