红层泥岩路基上拱无砟轨道传力杆性能研究

Study on the performance of the dowel rod of slab track in the upper arch area of the red mudstone subgrade

在川中红层泥岩地区CRTS Ⅲ型板式无砟轨道会设置传力杆限制沿线路纵向路基上拱变形,但传力杆对上拱地区无砟轨道的影响规律尚不明确。为了探究传力杆的性能,建立无砟轨道-路基上拱-传力杆有限元模型,在路基底部施加余弦型上拱波形位移作为外部条件,同时在底座板接缝处设置传力杆。将传力杆布置方式、直径、间距作为影响因子,设置无传力杆对照组进行对比分析。针对红层泥岩路基上拱,研究结果表明:1)设置传力杆与不设置传力杆复合板与底座板最大离缝分别为1.14 mm和4.82 mm,底座板与路基最大离缝分别为3.16 mm和5.29 mm,表明传力杆的设置能较好降低最大层间离缝,尤其是复合板与底座板轨道结构之间的层间离缝。2)传力杆布置方式1(中性层均匀布置1排)下底座板板端应力为1.13 MPa,为传力杆布置方式2(上下2层、交错布置)下底座板板端应力2.98 MPa的37.9%,底座板板端应力较小,应力分布均匀。3)复合板与底座板最大离缝、底座板与路基最大离缝及底座板应力在传力杆直径为30 mm时分别为0.82 mm、1.66 mm、3.16 MPa,达到相对较小值。4)随着传力杆布置间距减小、传力杆数目增多,轨道结构应力几乎没有变化,轨道结构竖向位移明显减小,说明传力杆布置间距减小对轨道结构应力的影响可以忽略不计,但对轨道结构位移的限制效果越好。

In the red mudstone area of the central Sichuan Basin,dowel rods areadopted to limit the arch deformation of the CRTS Ⅲ-type slab track subgrade along longitudinal line direction,but the influence law of the dowel rods on the slab track in the upper arch area remains unclear.In order to explore the performance of the dowel rods,the finite element model of slab track-arch on subgrade-dowel rod was established.The cosine-shaped arch waveform displacement was applied at the bottom of subgrade as the external condition,and the dowel rods were set at the joint of the base plate.The layout,diameter and spacing of the dowel rods were considered as influencing factors,and a control group without using the dowel rods were set for comparative analysis.The results of the study show that:1)The maximum interlayer separation of composite plate and base plate with and without dowel rods are 1.14 mm and 4.82 mm,respectively,and the maximum interlayer separation of base plate and subgrade are 3.16 mm and 5.29 mm,respectively,thus indicating that the use of dowel rods can effectively reduce the maximum interlayer separation,especially between the track structure of composite plate and base plate.2)The stress at the end of the base plate is 1.13 MPa under the first arrangement plan of dowel rods(i.e.,the neutral layer is uniformly arranged in one row),which is 37.9%of the stress at the end of the base plate under the second arrangement of dowel rods(i.e.,the upper and lower layers are staggered),whereas the stress at the end of the base plate is small and evenly distributed.3)When the diameter of the dowel rod is 30 mm,the maximum interlayer separation between the composite plate and the base plate,the maximum interlayer separation between the base plate and the subgrade,and the stress in the base plate are 0.82 mm,1.66 mm,and 3.16 MPa,respectively,which are relatively small values.4)as the spacing distance between the dowel rods decreases and the number of the dowel rods increases,the stress of the track structure almost does not change,but the vertical displacement of the track structure decreases obviously.This indicates that the effect of the decreasing distance between the dowel rods on the stress of the track structure can be ignored,but the better the limiting effect on the displacement of the track structure is.