| Rock-filling in Karst cave room which appear in tunnel excavation will produce a certain degree of post-construction settlement. It is proved that the large post-construction settlement of rock filling will have the changes of lining structure's stress and rock, or the destruction. While the regularity of influence by the post-construction settlement of the rock-filling in Karst to the lining structure and surrounding rock is still lack of research, the handle of the back filling is still given priority to experience. So carrying out the research of the law of post-construction settlement and the influence of the tunnel have a important value in theoretical and engineering practical. This Paper is based on the creep characteristics of rock-filled materials analyze the rules of different kinds of settlement and the influence to tunnel through the finite element numerical simulation.(1) we summarize the engineering properties of backfill material to analyze the mechanism and characteristics of rock-filling's instantaneous settlement and the post-construction settlement,then selecting the generalized kelvin model to simulate the creep characteristics of backfill materials based on the research, and transform it into Pony series to achieve the application of finite element analysis software.(2) Through numerical analysis, we get the rule of the rock-filled embankment' s settlement and concluded the influence of the difference backfill height and slope caused by uneven settlement distribution of rock-filled embankment. Then analyzing the characteristics of post-construction settlement by calculating the settlement with different backfill height and cavity size. we can conclude that rock-filling's transverse uneven settlement and the post-construction settlement is seriously affected by the scale of the Karst cave room,and we calculate the influence Coefficient with different cavern diameter.(3) By loading displacement on the top of the rock-filling to simulate the different types of post-construction settlement in the numerical analysis, analyzing the change of tunnel lining's stress under the influence of different kinds of settlement. And get the result that with the same maximum settlement, the degree of im Pact on the lining's stress with different types of settlement is the axial uneven settlement bigger thanhorizontal uneven settlement and bigger than Uniform settlement.(4) Through analyzing controlling value of different types of settlement by the numerical simulation,we can find that it should use the maximum settlements as control standard in analyzing control values of settlement. And then put forward the control measures of foundation settlement base on analyzing mechanism of rock-filling's settlements. |
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