Research On Influence Of The Bedding Fault Zone On The Stability Of Surrounding Rock Of Underground Caverns

The stability of surrounding rock of underground caverns is extremely paid attention to in geotechnical engineering field at all times. And the reasonable evaluation of stability or not is directly related to the success of the underground engineering or not. Based on nonlinear FEM theory, the modified solid-element model is introduced to simulate the bedding fault zone in this paper. The proceeding of excavation is imitated by using dead-live elements in Marc. Considering the uncertain of initial stress field of the rockmass, the overloading method is used to evaluate the value of stability of surrounding rock.Firstly, the simulation method of initial stress field is expatiated and the corresponding formulas are deduced. By FEM, the initial stress field of surrounding rock of underground caverns of Baihetan hydroelectric station is deduced by actual measured data.Secondly, some numerical simulation methods of bedding fault zone in rockmass are analyzed and compared. The merits and shortcomings of these methods are discussed. By using the soft of Marc, the modified solid-element model is used to simulate the influence of the bedding fault zone. Combining the underground caverns of Baihetan Hydroelectric Station, the surrounding rock's displacements and the distributions of plastic area are studied by different place of the bedding fault zone in four conditions.Finally, a theory of wavelet strange point examination is used to check the displacement curve of surrounding rock's key point. The position of suddenly changed point of the corresponding displacement curve is gained by using overloading method and the fluctuated theory. The judged criterion of stability of surrounding rock of underground caverns is discussed. By analyzing the example of underground caverns of Baihetan Hydroelectric Station, a value of stability of the surrounding rock of underground caverns is given.