高速公路软土路基路桥过渡段差异沉降研究

Research on differential settlement of soft soil roadbed and bridge transition section in expressway

以山东省某高速公路软土路基路桥过渡段为研究对象,基于Midas有限元软件,分析软基路桥过渡段处治前后沉降量变化规律,并研究回填材料、高压旋喷桩对软基路桥过渡段沉降控制效果,探讨高压旋喷桩的位置参数、尺寸参数对沉降量的影响。不进行处治时,填料区的沉降变形曲线呈“V”形,沉降量先增大后减小,距桥台台背4.5 m时,沉降量达到最大值0.11 m;随距路基中心线距离的增大,路基表面沉降量在不断减小。换填法使得填料区的最大沉降量距桥台台背距离在逐渐变大,换填效果随刚度的增加在逐渐减弱,且当填料刚度增大5倍时,填料区的沉降量普遍小于软土区沉降量。喷射注浆法的沉降控制效果较稳定,沉降量随桩长的增大不断减小,当桩间距从1 m增加到1.5 m时,5 m桩长填料区最大沉降量增大了25%。

This paper takes the soft soil subgrade bridge transition section of a certain highway in Shandong province as the research object.Based on Midas finite element software,the variation law of settlement before and after the treatment of the soft soil subgrade bridge transition section is analyzed,and the effect of backfill materials and high-pressure rotary jet grouting piles on settlement control of the soft soil subgrade bridge transition section is studied.Finally,the influence of the position and size parameters of high-pressure rotary jet grouting piles on settlement is discussed.The research results show that without treatment,the settlement deformation curve of the filling area shows a"V"shape,and the settlement first increases and then decreases.When the distance from the back of the bridge abutment is 4.5 meters,the settlement reaches the maximum value of 0.11 meters.As the distance from the center line of the roadbed increases,the surface settlement of the roadbed decreases continuously.The replacement method gradually increases the distance between the maximum settlement of the filling area and the back of the bridge abutment,and the replacement effect gradually weakens with the increase of stiffness.Moreover,when the stiffness of the filling increases by 5 times,the settlement of the filling area is generally smaller than that of the soft soil area.The settlement control effect of the jet grouting method is relatively stable,and the settlement decreases continuously with the increase of pile length.When the pile spacing increases from 1 m to 1.5 m,the maximum settlement in the filling area of the 5 m pile length increases by 25%.