隧道穿越既有支挡结构设计方案优化研究

Study on Optimization Design of Tunnel Through Existing Retaining Wall

山地城市交通工程建设过程中,出现了大量隧道穿越既有支挡结构的情况,隧道建设过程中可能会导致边坡的滑移破坏。本文以重庆曾家岩嘉陵江大桥工程为依托,边坡支挡结构拟采用抗滑钢架+锚索桩,依据勘察报告,采用荷载-结构法对隧道穿越既有支挡结构时采用的不同支挡结构加固方案和不同嵌固条件下支挡结构典型剖面的内力和变形进行研究。研究表明:随着新建支挡结构的左右桩嵌固深度的加大,支挡结构的水平和竖向最大位移在量值上均呈现出先减小后增大的趋势,最大弯矩量值呈现出减小的趋势,最大剪力量值呈现出先减小后增大的趋势,最大拉力量值呈现出减小的趋势,而最大压力量值亦呈现出减小的趋势。通过方案对比分析,采用抗滑钢架+锚索桩的加固方案有利于控制既有支挡结构的变形,确保地面变形在合理的范围内。

In the process of traffic engineering construction in mountainous cities,a large number of tunnels pass through existing retaining walls. Tunnel construction may contribute to slippage of slope. Based on Jialing River Bridge project,the paper proposes to use the anti-skid steel frame + anchor pile structure to support the block. According to the initial survey data,the internal force and deformation data of the B—B section of the retaining structure under different structure schemes and different embedding conditions were obtained by load-structure method. With the analysis of a finite element software,the maximal horizontal moment and the maximum vertical displacement show the trend of decreasing first and then increasing,the maximum bending moment value is decreasing and the maximum shear force value is decreasing first and then increasing. The value of the maximum pulling force showed a decreasing trend,and the maximum pressure value also showed a decreasing trend. The analysis shows that the reinforcement scheme of resistance slip steel frame + anchored pile is helpful to control the deformation of the existing retaining structure and ensure the ground deformation to be within the reasonable range