Research On Stability Analysis Method Of Underground Cavern Based On Acceleration

China is a country with a large population and relatively poor resources.We have a large amount of land resources,but a small per capita occupancy that is only 0.777 hectares and less than 1/3 of the world per capita land area.Therefore,exploitation and utilization of huge and abundant underground space resources is the inevitable trend of national development.Engineering geology analogy method and numerical simulation method are the most commonly used methods for the stability analysis of underground cavern.And the existing methods of stability analysis usually have some disadvantages,such as too much experiential knowledge and inconsistent criterion.In order to evaluate the stability of underground cavern by using uniform model and standard,a stability analysis method based on acceleration is proposed.The concept of acceleration is introduced into the stability analysis of underground cavern.And the safety factor of underground cavern is calculated combining acceleration calculation and the concept of strength reduction.The stability of underground cavern is evaluated according to acceleration and safety factor.The main research work and achievements of the thesis are as follows:(1)The underground cavern is reduced to plane strain problem based on 4 basic hypotheses.On the basis of the limit equilibrium method,the calculation process of acceleration and safety factor of the potential failure surface of the underground cavern is deduced in detail.(2)Different potential failure surfaces have different accelerations and safety factors.Ant colony algorithm is used to calculate and search the potential failure surfaces with maximum acceleration or minimum safety factor.And Scilab software is used to program the process of calculating and searching.(3)Aiming at the typical circular underground cavern,the acceleration contour line and the safety factor contour line of the surrounding rock of the underground cavern are plotted.The calculation results are verified according to the point safety factor.It shows that the method is reasonable,and the calculation results are accurate.Moreover,the method takes into account the overall situation of surrounding rock and is more integrated compared with point safety factor.(4)The circular underground cavern with different strength surrounding rock and that with different supporting conditions are selected as examples.The characteristics and trends of changes of the acceleration contour line and the safety factor contour line are studied respectively.It is proved that the method is accurate and applicable to different strength surrounding rocks.For different thickness supporting structures,this method can quantitatively evaluate the support effect of supporting structures with acceleration and safety factor.