The Stability Research At The Bottom Of Swelling Rock Tunnel

The Swelling rock possess a very significant water swelling, softening, disintegrating and drying shrinkage, cracking features, such tunnel project is often destroyed,On account of water the tunnel’s bearing capacity is insufficient,then Sink increase. Clearance within the deformation displacement is too large.And in The operating process of the tunnel because of The change of moisture content lead to surrounding rock stress change,lesd to bass drum and The secondary lining deformation. These diseases seriously endanger the safety of train operation. In this paper, Take swelling rock in Guojia town which is a part of Baolan tunnel on passenger line that transiting Qinan Country,Tianshui City,Gansu Province as an engineering background. In this thesis, analyzing swelling rock by swelling mechanism of the microscopic study and the conventional swelling testing to get their swelling characteristics, physical-mechanical parameters and the stress-strain curve. By analyzing the change in swelling parameters and mechanical parameters to get a more accurate constitutive relationship of swelling for this project. By using the finite element software ANSYS to simulate rock the status of the internal stress and strain.And then coming up with effective solutions. The main contents are as follows:(1)The main mineral composition of the region’s lime mudstone includes detrital minerals and clay minerals.The main expansive component of clay minerals is 8% of illite. This swelling rock belong to containmontmorilloniteno or less, illite and kaolinite are main. Through the study of subjective and external factors that affecting expansion rock characteristics, and then put forward a standard for dividing swelling rock. By improving the existing expansion instrument to realize that measuring expansive force of rock without the moisture content. And according to the statistical results of test, this expansion rock can be qualitative weak inflation.(2)By means of inflation mudstone under different moisture content and the triaxial compression test under different confining pressure is studied. Analysis of the stress strain curve of the rock. Get the rock under the different moisture content and confining pressure peak stress. To explore the influence of moisture content and confining pressure on rock strength. Using the least squares monadic linear regression analysis confining pressure and peak strength for linear analysis. Get rock under different moisture content of cohesive force and Angle of internal friction. Based on the typical mudstone triaxial stress-strain entire process get curve the strength analysis and the different stages of curve. Get a swelling rock stress-strain relationship.(3)Tunnel in the process of operating, The bottom of the tunnel wall rock change in moisture content changing,Do the numerical simulation. Then according to the safety factor and the displacement of inverted arch two discriminant criteria put forward Maximum moisture content and the maximum water penetration depth. And put forward engineering measures when the tunnel in construction process and operation conditions. In order to give the design and construction of the tunnel and maintenance to provide the necessary guidance. Provide technical support for tunnel in the process of operation safety.