膨胀土桥台台背填土开裂失稳原因分析及处治技术研究

Analysis of the Causes of the Cracking and Instability of the Backfill behind the Abutment of the Expansive Soil and Study of the Treatment Technology

为处治修建在膨胀土地基上的桥台台背填土及锥坡开裂病害,以广西钦崇路念文中桥为例,在考虑了膨胀土地基特有的工程特性后,分析了桥台台背填土及锥坡开裂失稳原因,并对桥台填料及锥坡进行处治改造,将台前锥坡挡墙扩大基础改为桩基础,台背填料置换5m深的无砂大孔混凝土,并加强其防排水处理。工后监测表明,经重新设计的锥坡加固效果显著,能有效提高坡体与桥台衔接处路堤的整体稳定。

In order to deal with the defects of abutment back filling and cone slope cracking,the Nianwenzhong Bridge on the Qinchong Road of Guangxi is taken as an background,the causes of cracking of abutment backfilling and cone slope are analyzed after considering the unique engineering characteristics of expansive soil foundation.In addition,the abutment filler and conical slope are treated and transformed,the expanded foundation of the conical slope retaining wall in front of the abutment is changed into pile foundation,and the filling at the abutment back is replaced by the 5-m deep large pore concrete without gravel,and the waterproof and drainage treatment are strengthened.The post construction monitoring shows that the re-designed cone slope can effectively improve the overall stability of embankment at the junction of slope and abutment.