The Stability Of Tunnel Excavation On Adjacent Landslide Research

In the process of modern highway construction in our country, there are manytunnels built in the slope, the slope or landslide often has a variety of diseases.After agreat deal of investigation, the landslide is closely related to the tunnel excavation, thedeformation and destruction on slope or landslide prevention disease, this paper carriedout a tunnel near the stability of landslide and the tunnel deformation mechanism of theresearch work.In recent years, due to the strength subtraction, it is introduced the finiteelement method for landslide stability analysis, can directly evaluate safety factor(strength reduction factor), and the ability to visually depict the stress and straindistribution of the landslide, but also can reflect the gradual failure process of landslide,due to the strength subtraction of these features are unique, so the finite element limitanalysis method become the focus of research in recent years.In this paper, on the basis of theoretical analysis, combining with the chongqingmanley wanda project monkey rock tunnel project as an example, based on the theory offinite element strength subtraction, in view of the tunnel effect on adjacent landslidestability under different excavation method is studied.The main contents include:①the finite element strength subtraction slope or landslide stability safetycoefficient calculation, based on ANSYS program automatic calculation convergencefor landslide instability state judgement basis, the calculation results have goodconsistency with the engineering practice;②the landslide under gravity stress field, with the increase of strength reductionfactor, slope toe first should produce the plastic zone, plastic zone gradually to the slopeabove the development, the plastic strain zone area increases gradually, until thereduction calculation convergence to a certain value, the model reach ultimate state;③with tunnel buried depth increases, the stability of tunnel excavation on adjacentlandslide gradually reduce, stability of landslide is influenced by tunnel excavation way;④using whole section tunnel excavation, the excavation method of tunnelsurrounding rock perturbation is larger, near the landslide deformation also increases,calculation of safety factor is2.14, want to do a good job of landslide prevention andgovernance;⑤tunnel using left first hole to hole right up and down the steps excavation method, calculation of safety factor is2.196, compared with the whole sectionexcavation landslide stability safety coefficient increase some, but still need tostrengthen the monitoring in construction process;⑥tunnel use up and down hole on the right and then left hole excavation stepsmethod, calculation of safety factor is2.224, is a maximum of three excavation method,it also shows that the excavation method minimal impact on the stability of adjacentlandslide, while it also causes a landslide produce certain plastic strain, but is able tosatisfy the requirements of the actual construction;⑦tunnel excavation and the landslide deformation is interaction, the relationshipbetween the two are inseparable, therefore, the results of numerical analysis should befully combined with the engineering practice, so as to make finite element analysisresults as the theoretical support of actual construction measures.