Study On The Anchoring Mechanism Of The Compression Anchors Based On Finite Difference Method In Loess Area

Compression(dispersed) anchor cables have been widely used in geotechnical engineering due to their anchoring sections being compressed and strong stability,high overall carrying capacity,convenient construction,and strong corrosion resistance etc.In recent years,a great progress has been made in the theoretical research,experimental research and numerical simulation of the anchorage mechanism and the load transfer mechanism of the anchorage section of compression(dispersed)anchor cables.However,most of the researching works currently done focused on the design of anchor cables in rock media,and relatively few studies have been conducted on anchor cables in soil media including loess.It is also unknown whether many of the existing design theories of compression(dispersed)anchor cables are equally applicable to soil media.The loess body has the characteristics of well-developed pores and high compressibility,which exactly fits the compression characteristics of the compression(dispersed)anchor cable to its anchoring medium.On the one hand,the soil body is compressed,which improves the properties of the soil body,On the other hand,anchor cables are provided greater anchoring force,which has also become an important prerequisite for compression(dispersed)anchor cables to be widely used in loess regions.Based on the above research background,this paper focused on the load transfer mechanism and the stress distribution of the anchoring section of compression(dispersed)anchor cables in soil media.Firstly,the concept and principle of the finite difference method and the numerical simulation software FLAC3 D based on this method,as well as the theoretical design and research methods of compression(dispersed)anchor cables and the relevant specifications for anchor cables design in China,were introduced.Secondly,the whole process of the stress distribution of the anchoring section was analyzed when the compression anchor cable was under the load,and the stress distribution law of the anchoring section of the anchor cable under multiple stages including elasticity,softening and debonding was obtained.In the establishment of the FLAC3 D model for the pull-out test of the compression anchor cables in weathered soil,the effect of soil grouting reinforcement was considered.The analysis results of the simplified model and the accurate model were compared with the test results,and the feasibility and the reliability of the two modeling methods was verified,it can also be known that the second modeling method is closer to the actual situation of the condition of the compression anchor cable,and the analysis results are more accurate.Based on the discussion of modeling method of the compression dispersed anchor cable,a FLAC3 D numerical model corresponding to the field failure test of the compression anchor cable in clay was established.The simulation values,test values were compared with the two theoretical design values to verify the applicability of the two theoretical design methods in soil medium and the accuracy of the modeling methods described in this paper.Finally,a numerical model of the engineering example of a compression dispersed anchor cable in the loess layer was established.Through variable parameter analysis,the law of influence of the anchor length of the anchor cable,the hole’s diameter of the anchor cable,and the number of the pressure-bearing plate on the stress distribution were obtained.By simulating the load bearing of compression dispersed anchor cables under different spacings of the pressure-bearing plates,the reasonable spacing of pressure-bearing plates for the compression dispersed anchor cable in the loess layer was obtained.