Stability Analysis Of Bolt Support Slope

A large number of road slopes have various diseases in the later period of use.The treatment of diseases often involves the anchoring of rock and soil and the stability of slopes.For the normal use after treatment,the characteristics and stability of bolt support and the various influencing factors in the problem should be deeply considered.In the aspect of rock and soil anchoring,the anchor mechanism of the expanded anchor is analyzed by the principle of small hole expansion.By considering the external stress,the stress expression of the plastic zone and the elastic zone is obtained.Based on the result,the expansion anchor can be directly calculated.The bearing capacity provided by the lateral friction of the anchoring section of the rod is analyzed by corresponding numerical simulation.In the stability problem,the determination of the slip surface in the finite element method is studied,and the equivalent plastic strain at the joint is used to make the sliding surface.Judgment of position;a large number of numerical studies on the mechanism of slope instability,the influence of soil mechanics on the safety factor and the position of the slip surface,and the numerical analysis of the slope under the bolt support.The specific research contents are as follows:(1)Based on the summary and analysis of the types of slope diseases,it is concluded that there is no fixed standard for the classification of slope diseases at present,but the slope instability failure is a common and harmful disease.The factors affecting the problem are analyzed and summarized.Several common and widely used methods for instability treatment are introduced,among which anchoring technology plays an important role in stability.(2)The influence that cohesion and internal friction angle had on the slope stability is calculated and analyzed.By adjusting the initial cohesion and internal friction angle,and using the finite element strength reduction method and limit equilibrium method,5 slopes at different falling gradient are calculated.The results show that: the influence that cohesive force had on the stability is greater than that of internal friction angle.With the increase of slope falling gradient,the conclusion is more and more obvious.When the falling gradient and the cohesion are small,the potential slip surface appears near the shallow layer of slope.With the increase of cohesion,the slip surface gradually develops to the deeper part of slope.When the slope is large,the influence that the cohesion had on the sliding surface is not obvious.For the internal friction angle,the smaller the slope is,the deeper the potential slip surface is.With the increase of the internal friction angle,the slip surface develops to the shallow layer of slope.(3)Aiming at the problem of determining the position of the slip surface in the finite element method,the equivalent plastic strain region of the joint is used to judge the instability point.Based on this idea,the discrete points of the slip surface are obtained,and the continuous slip surface position curve is obtained by fitting.(4)Most of the existing small hole expansion theories are convenient for the displacement.The boundary conditions often ignore the external stress.Only the additional stress values can be obtained.By setting the stress q at infinity,the soil of the Mohr-Coulomb criterion is bombed.Plasticity analysis;At the same time,numerical simulation calculations under different conditions were carried out for the influence of soil mechanics parameters on the expansion process.(5)The anchor has an obvious influence on slope stability.The finite element method and limit equilibrium method are used to calculate and analyze how to determine the optimal angle of incidence inclination of anchor under different slopes.The results show that,under the large slope,the safety factor will decrease with the increase of anchor angle,while under the small slope,the safety factor will increase with the increase of inclination angle.This change trend should be taken into account in practical engineering and reasonable anchor inclination should be selected.