京石高速公路拓宽沉降控制标准

Threshold of settlement control for widened Jing-Shi embankments

为确定京石高速公路拓宽沉降控制标准,以京石高速公路拓宽工程为依托,假设路面结构层底面沉降服从抛物线,建立了车辆荷载作用下的路面结构层数值分析模型,数值分析结果表明:旧路肩和新路肩之间的横坡改变率随着填高的增加先增大,在填高4～5m时达到最大,而后减小;为了保证路面结构在长期车辆荷载作用下路面结构层安全,旧路肩和新路肩之间的横坡改变率不宜超过0.45％.基于上述数值分析结果,结合已有工程经验,确定了京石高速公路拓宽沉降控制标准:旧路中心沉降不超过3 cm;拓宽后路基最大工后沉降不超过10 cm;旧路肩和新路肩之间的横坡改变率不超过0.45％.

To determine the threshold criterion for the settlement of widened Jing-Shi embankments,a numerical model for the widened embankment under vehicles loads has been developed in this study.The numerical analysis shows that:the variation of transverse gradient between old and new road shoulders increases early with the backfill increases,then decreases late.The maximum transverse gradient variation occurs when the backfill reaches 4～5 m;to warrant the safety of slab-on-grade structure,the maximum transverse gradient variation should be less than 0.45 %.Based on above analysis and experience,the threshold criterion for settlement control in the widened Jing-Shi embankment is presented as follows:the maximum settlement of the central part of old road should be less than 3 cm;the maximum settlement after construction for the widened embankment should be less than 10cm;the maximum transverse gradient variation should be less than 0.45 %.