Research Of The Load Releasing Law During The Construction Process Of Large Section Tunnel

Tunnel was built underground which is quit different from the structures on the ground; the wall rock was the main origin of the load on the tunnel structures. The load which applied on the tunnel structures always are changing during the construction process. The research on the load releasing law of the tunnel construction process is helpful for the construction optimization. So the research on the load releasing law of the tunnel construction process is the focus of the research of construction process mechanics nowadays.The research object in this paper is Tianpingshan tunnel on Guiguang Railway, using the methods of theoretical analysis, numerical calculation and model test, the author do some job on the load releasing law during the construction process of large section tunnel.Firstly, on the base of lots of numerical calculation, the author summarized the law of load releasing during the construction process of different tunnel. On this basis, suggest the concept of section total load releasing rate and the difference coefficient of the load releasing.Secondly, research the engineering mechanical properties of the carbonaceous shale in the tunnel, including the routine mechanical parameters and the acoustic emission characteristic.At last, on the base of the laboratory experiment, by the methods of large scale 3-D geological mechanics model test, the author researched the the load releasing law during the construction process of large section tunnel. Including the load releasing law of the wall rock and the rock ahead the tunnel face. During the model test, we developed the similar material both of the carbonaceous shale and the lining of the tunnel. In order to solve the similar of the formation condition between the tunnel and the model developed the equipment of inclined planes filler in the model test.After the comparative analysis of the numerical calculation and model test, we know the load releasing law during the construction process of large section tunnel more clearly. It is meaningful for the construction optimization and the stability evaluation of the large section tunnel construction process.