客运专线铁路路基声屏障新型预应力立柱试验研究

Experimental study on structural performance of prestressed concrete column for passenger dedicate line railway subgrade noise barrier

我国客运专线列车设计时速将达到350km,路基轨道两侧声屏障受到的脉动力也随之增大,传统插板式声屏障采用螺栓连接的钢立柱易出现螺栓松动和钢材锈蚀等现象,为此,采用预应力混凝土立柱(PC)替代钢柱则不仅能有效解决这些问题,而且,PC柱比普通混凝土柱的抗裂、抗疲劳性更优越。此外,考虑声屏障施工工效,提出了预制PC立柱的两种快速装配连接形式,即插入式后浇连接和螺栓连接。通过4个立柱试件的模拟正负列车风压及台风风压的双向推覆荷载试验,表明了插入式连接PC立柱的插入深度达到1.5倍截面高度时,在台风的设计荷载作用下,立柱不会开裂,立柱顶部侧向位移小于L/250,结构近似保持弹性工作状态;螺栓连接PC立柱满足非台风地区时速350km客运专线路基声屏障的设计要求。

Train induced impulsive pressure on railway subgrade noise barrier is becoming larger due to train speed increase,reaching to 350km/h.Metal nuts of traditional noise barrier structure,connecting H type steel and foundation,are easy to loose and rust.Prestressed concrete(PC) column can solve above problems,and shows higher performance on crack resistance and fatigue resistance compared with concrete column.Considering convenience of noise barrier construction work,two new kinds of connecting methods between PC column and foundation are proposed,plug-in connecting and bolt connecting.Four PC column specimens were cast and tested under simulating load of positive and negative train wind pressure and super typhoon wind pressure.The test results show that PC column did not crack and the lateral displacement on the top of the column is less than H/250,and the structure maintains elasticity under typhoon wind load when the insertion depth is 1.5 times than PC column section height.PC column connected with bolts can meet the design requirements of railway subgrade noise barrier non-typhoon area with 350km/h train speed.