Stability And Mitigation Study Of Two Type's Typical Slopes Along Dujiang-Wenchuan Expressway

The Dujiang Yan _Wenchuan section of the No.317 State Expressway passes through the the front part of Long-Meng mountains, a main tectonics belt of the east margin of Qing-Tibet Plateau, which is composed of a series of active faults stretching in NE direction. Because of this, the geomorphology and geological conditions along the section is very complex. The geological hazards, such as landslides, rockfalls and debris flows occurs very frequently, which forms a great potential risk to the construction of the expressway. On the other hand, the construction will result in the formation of a lot of new high cut slopes. Their stability is very essential and strongly attended by the designer and owner. Moreover, some of this section extends in the world-wide famous sightseeing spot — the great ancient Dujiangyan water irrigation works, which has a over 2000 years long history, the recovery of entironment along this route is another key problem attended by the designer and owner.In order to have a better understanding to the slope stability and provide a solid foundation for the slope design, the author, following the research team of CDUT, had a comprehensive field investigation, and collected a great deal of data about these issues. On the basis of this, two types of slopes were chosen as typical examples, that is, the Dujiang Village slope and Shaowozi slope. The former stands for the kind of slope with better stability conditions, but slope surface protection and a high grade entironment recovery should be considered; the latter one is very hazardous, including partially instability and strongly relaxed. A series of Researches including slope failure model, limit equilibrium stability analysis and numerical simulation are conducted, which results in following conclusions:(1) The geological structures of Dujiang Village type slope is favourable for slope stability, that is, hard conglomerate rocks and rock blocky structure with no obvious large and weak discontinues. It whole stability is very well, no systematic supporting woks should be taken, There exists only some local small-scale wedge instability, which can be controlled by bolts easily. The main issue of this slope is slope surface protection and entironment recovery.(2) The entironment recovery on the steep rock slope such as Dujiang Village type is very challenged. Firstly, considering the reasonable combination of slope surface protection and entironment recovery the previous designed slope supporting scheme is checked and some modification is suggested. The key point of the...