Analysis For Influence Of Anchor Failure On Stability Reliability Of Slope Strengthened By Frame Anchors

In recent years,whether it is the development of underground space or is the construction of roads,slope engineering will be encountered.What's more,earthquakes in China are frequent,so the problem slope stability draws much attention.The frame prestressed anchor support structure,widely used in practical engineering,is not only convenient to construct,but also safe and reliable.A large number of scholars in China and abroad have carried out research and analysis on it,but at present,the stability analysis of the frame prestressed anchor support structure is often carried out using the fixed value method without considering the soil parameter variability and the uncertainty of the earthquake.The result of using the safety factor method in the project is safe,but in practice slope fails.If the reliability theory is introduced into the design of the frame prestressed anchor support structure,and the randomness of the parameters is taken into account,the calculation result will be more accurate and the occurrence of damage will be reduced.At present,the research on seismic stability of frame prestressed anchor support structure is still insufficient.Based on the existing research,the main research works were done as follows:(1)Based on the anchoring mechanism of frame prestressed anchors,the failure characteristics and main failure modes of anchors were studied.The random variables affecting the reliability of frame prestressed anchor retaining structures were analyzed.(2)Based on reliability theory,the performance function of a single anchor's failure and the internal stability performance function after the failure of a single anchor were established.With the specific engineering example,the reliability index of the reinforcement slope when a single anchor fails was calculated by using the verification point method,and a MATLAB program was made with Monte Carlo method.Finally,the engineering analysis was carried out,and the simulation results were compared with the theoretical calculation results.The results show that the two variation laws are consistent and the values' difference are small.(3)Based on the specific engineering examples,the finite element software GeoStudio 2012 is used to simulate the influence of single anchor failure on the slope stability and the influence of seismic acceleration on the reliability of slope stability.The increments of axial forces of other anchors and of slope displacements were analyzed when a single anchor fails under earthquake action.The results show that the anchor failure under earthquake action has a significant adverse effect on slope stability.In the design of slope support,not only the influence of uncertain factors should be considered,but also the anchors in key position should be designed specifically.(4)The influence of single variable and combined bivariate of soil physical parameters(severity ? ?cohesion c ?internal friction angle?)on slope reliability index was studied.The order of the influence extent of soil physical parameters on the slope reliability index is compared.The results show that the coefficient of variation of internal friction angle has the greatest influence on the slope reliability index when single variable varies.When the combination of bivariate varies,the coefficient of variation of internal friction angle and the coefficient of variation of gravity have the greatest influence on slope reliability.