湿陷性黄土地区公路桥梁病害形式及产生机理分析

Analysis for Disease Form and Mechanism of Highway Bridge in Collapsible Loess Area

甘肃地处黄土高原,因其大部分黄土具有湿陷性,加之公路建设速度加快、暴雨等极端天气频发,加剧了湿陷性黄土区域新旧桥梁病害的发生。目前对于病害形式及机理未作系统调查及分析,故选取湿陷性黄土覆盖的陇西及陇东地区公路桥梁为调查对象。通过调查表面其主要病害为锥、护坡破损及下陷;墩台基础冲刷致使桩基外露、下沉;桥头搭板破损。造成主要病害的原因为黄土浸水湿陷、水流冲刷导致桥梁下部结构病害的发生,进而引起上部结构及桥面系病害的出现。

Gansu province is located in the loess plateau,because most of the loess is collapsible,along with the speeding up highway construction and frequent rainstorm and other extreme weather,the occurrence of new and old bridge diseases in collapsible loess area is aggravated.At present,the form and mechanism of disease are not systematically investigated and analyzed.So,the collapsible loess covered highway bridge in Longxi and Longdong region is selected as the object of investigation.The investigation shows that the main diseases are cone slope and slope damage;pier foundation scour dew pile and slab breakage.The main causes of the disease are loess soaking,collapsibility and water erosion,which lead to the occurrence of structural diseases in the lower part of the bridge.Such reasons furtherly lead to the occurrence of superstructure and deck system diseases.