高速公路低路堤路基服役状态风险评估

Risk assessment of expressway low-embankment-subgrade in service status

高速公路低路堤受到路基高度的限制,容易产生工后沉降过大或不均匀沉降等问题。路基设计和养护规范中均未针对低路堤设计进行统一规定,导致低路堤在建设期、运营期存在影响工程正常使用的问题。借鉴地质灾害风险评估理论,分析干湿循环、交通荷载等影响因素,考虑养护维修对各因素进行修正,提出了低路堤路基服役状态评估方法。该方法运用模糊综合评价法和物元分析方法分析建设期结构质量易损性、运营期路基危险性及养护维修修正值,得出低路堤路基综合风险度。将该方法运用于浙北低路堤段工程实例,得到的综合风险度为低度,服役状态风险程度与现场调查结果基本一致,说明了该评估方法的可行性。

The low embankment of the expressway is limited by the height of subgrade,and some special problems such as excessive settlement or uneven settlement are easily caused after construction.At present,the subgrade design and maintenance codes do not uniformly regulate the design of the low embankment,resulting in many problems that would affect the normal use of the structure during the construction and operation of the low embankment.Based on the risk assessment theory of geological disaster,this paper analyzed the effect of some factors such as drying and wetting cycle as well as traffic load on the low embankment of the expressway.In addition,considering the maintenance and repair,these factors were modified and the evaluation method of low-embankment-subgrade in service status was proposed.Combined with fuzzy comprehensive evaluation method and matter-element analysis method,the structural quality vulnerability in construction period,the risk of subgrade in operation period and the modified value of maintenance and repair were analyzed.And then the comprehensive risk of low-embankment-subgrade was obtained.The method was applied to a low embankment project in northern Zhejiang.The result shows that the comprehensive risk is low and the service state risk is basically consistent with the filed survey result,which illustrates the feasibility of the proposed evaluation method.