Study Of Operation Management Technology On The Separated Subgrade In The Fengjie-Yunyang Section Of The G42 Shanghai-Chengdu Expressway

Fengjie-Yunyang section is a portion of the Shanghai-Chengdu Expressway(G42),which is an important part of the 7918 National Trunk Highway System of China.This section spans 71 km in length and passes through the Three Gorges Reservoir Region in northeast Chongqing.A large number of separated subgrades were constructed in view of local geology and terrain,with most of them connecting to bridges and tunnels.The separated subgrades total 14.47 km in length,about 20.37% of the entire length of the section.The portions with separated subgrades,together with bridges and tunnels(about 60% of the entire length of the section)linking to them,make up over 80% of the entire length of the Fengjie-Yunyang section.The special road conditions and separated subgrades in mountainous regions have caused difficulties for the operation management of the portions with separated subgrades,especially for the emergency rescue and safety management in case of major or extraordinary serious traffic accidents.According to the distributions of separated subgrades,bridges,and tunnels along the Fengjie-Yunyang section of G42,the operation and safety conditions of the portions with separated subgrades were analyzed.This study included the following steps:1.The section was divided into different administrative units in the light of the distributions of separated subgrades and the combinations of separated subgrades and bridges/tunnels;2.The types of emergencies that may occur on the portions with separated subgrades were analyzed and the severity classification for the potential emergencies was determined,for the purpose of exploring a coordinated control strategy in case of emergencies.3.An emergency rescue resource allocation scheme was made for the Fengjie-Yunyang section of G42 in the light of related requirements.4.After investigating the conditions of the road networks along the Fengjie-Yunyang section,an emergency road network system was established.Then a traffic management strategy and an induction scheme in case of emergencies were developed for the portions with separated subgrades.5.A comprehensive assessment was conducted of the influences of separated subgrades and the combinations of separated subgrades and bridges/tunnels on the operation management of the section,in order to explore an operation management technique specific to expressways with frequent and long separated subgrades.Objectives of this study,reduce the impacts of emergencies on traffic and improve the emergency security capabilities of the portions with separated subgrades,improve the management and service quality of the expressway.