| With the rapid development of expressway and high-speed railway, the soft rock tunnel project gradually increase, but more and more problems appear in the soft rock tunnel construction. The difficulty of determining the support parameters and the supporting opportunity of primary supporting are all along the problems of troubling the development and application of the supporting technology of the soft rock tunnel.Basing on summarizing the development of the supporting theory of the soft rock tunnel at home and abroad, analyze the engineering property of soft rock mass, the mechanical mechanism of destabilization and deformation of the soft rock mass, the action mechanism of the supporting of the soft rock tunnel, optimal theory of the supporting of soft rock tunnel. Then analyze the whole process of excavation and supporting of the vested soft rock tunnel and study on the opportunity of the supporting parameters and method by establishing the plane finite element model by MIDAS-GTS. The paper carries out the optimal research of the supporting construction time of the soft rock tunnel by taking the tunnel displacement which best reflects the situation of loosening deformation of rock mass for the parameter which mainly control the displacement of the tunnel and introducing the loads release factors to numerically simulate the time-space effect of the rock mass stress-releasing when the tunnel is excavating. Then obtain the optimum supporting construction time of the soft rock tunnel and analyze the rock mass displacement influences of soft rock tunnel caused by supporting method, strength grade of shotcrete, parameters of cables which are length, diameter and interpretable spacing. Finally base on the prophase analysis, an optimize design parameters to put forward for soft rock tunnel support.This research provides some scientific theory evidences and has significant meanings for design and construction of weak rock tunnels in similar geological conditions.
|
PDF Full Text Request