Research On Bearing Performance Of Anti-sliding Key Support For Gently Inclined Bedding Rock Slope

Guizhou is located in the Yunnan-Guizhou Plateau,a typical karst landform area.The rocks in the geological environment are mainly layered sedimentary rocks.A large number of engineering constructions are often accompanied by mountain excavation,and then various types of bedding slopes are formed.When this type of slope contains a weak interlayer,it will often cause the slope with a gentle dip angle to slide.This type of landslide usually has the characteristics of larger scale and more difficult treatment.Anti-slide piles are the most commonly used support structure for the treatment of gently dipping and normal soft interlayer side(slide)slopes.They can be arranged on the excavated slope to form cantilever piles or anchor piles,or they can be arranged on the sliding body behind the slope In the formation of buried anti-slide piles.When the sliding of this type of landslide is only controlled by a single weak interlayer,the force of anti-slide piles is different from that of piles in the traditional understanding,especially the embedded anti-slide piles behind the slope,due to the rigidity and rigidity of the rock mass.Its restraining effect on the pile body should be mainly due to the shear near the weak interlayer,so the pile can be optimized,shortened and degenerated into an anti-sliding key,and only the weak interlayer needs to be controlled.Aiming at the problem of supporting the soft and weak interlayer rock slope with gentle dipping,anti-sliding key came into being as a new structure.The anti-sliding key masonry has a small amount of work and flexible setting,which can greatly increase the construction speed.The current research on anti-sliding keys is still in the exploratory stage.Engineering applications rely too much on experience and have not yet formed a mature theory to guide the design,resulting in stagnant use of anti-sliding keys.In this paper,the reinforcement of the anti-sliding key in gently inclined bedding rock slopes is studied based on numerical simulation methods,and the main conclusions obtained are as follows:(1)In a gently dipping bedding rock slope,the force of anti-slide piles is mainly concentrated near the weak interlayer,mainly under shear.After degenerating the pile into an anti-sliding key,its force is more reasonable.Generally speaking,the pile length is greater than 6m,which is called anti-slide pile,and the pile length is less than or equal to 6m,which is called anti-slide key.(2)Based on the summary analysis of the numerical simulation results,three simplified modes for the force of anti-sliding keys with different aspect ratios are proposed.(3)When other conditions remain unchanged,as the inclination angle of the weak interlayer increases,the internal force of the anti-skid key pile gradually increases,and the growth trend becomes more and more significant;as the shear strength of the weak interlayer increases,the resistance The internal force of the sliding key pile gradually decreases,and the downward trend becomes more and more significant.The sensitivity is: the internal friction angle is greater than the cohesive force.(4)Under the action of ultimate load,there are two failure modes of anti-skid key bearing failure,which are related to the aspect ratio of the anti-skid key.When the aspect ratio is greater than 2,the failure mode is shearing at the weak interlayer;when the aspect ratio is When it is less than 2,the failure form is that the anti-slip key is pushed down.(5)In view of the situation when the anti-slip key is sheared,increasing the reinforcement ratio cannot effectively improve the load-bearing capacity of the antislip key.On the contrary,after the concrete grade is raised to C40,under the same load,the stress of the steel bar is only 32.13% of that of C30 concrete,indicating that the bearing capacity of the anti-skid key mainly depends on the grade of concrete.(6)After the gently inclined bedding rock slope is reinforced with anti-slip keys,a pin key is formed at the weak interlayer,which prevents the potential slip surface from penetrating,which not only effectively inhibits the yield of the rock and soil medium,but also effectively suppresses the potential slip body Slide down.For the slope near the excavation face,spray anchor support is used to ensure the stability of the slope in front of the anti-slip key,and finally take into account the overall and local stability of the slope,which proves that the anti-slip key is used in this type of slope.Has a good support effect.