Study On Anchoring Section Shear Stress Nonlinear Characteristics And Application

Compared with other support pattern, anchor support has the advantages of easy construction, low construction cost, short construction period and other advantages. Moreover, pre-stressed anchor has the advantage of active support. Because of its advantages, the anchor supports are widely used in many fields of engineering construction and are gradually becoming the most important means of support in the areas of geotechnical engineering in our country. Mainly, Anchor is composed of two segments, including free section and anchor section. Compared with anchor section, the internal force of the free section is simple, only the axial force existed. Although the introduction of new technology and the monitoring technology of field will help people making a further judgment about anchorage, and the scientific theoretical calculation is still not mature, which can only be used as a reference design. The currently design method of anchor support is still at the experimental stage. Understanding the force of anchor segment is importantly significance for the correct use of anchor and expand the application. Based on the shear stress distribution of nonlinear characteristics of anchoring section, the design method of anchorage segment with nonlinear distributing shear stress was proposed. The main works of this paper was conducted as the following several aspects.(1)Based on the shear lag-debonding model, combining with load transfer method, the distribution property of shear stress along the anchor section, existing between the interface of anchorage body and surrounding soil was studied. The distribution function of the axial force was derived from the first-order derivate of the distribution function of the shear stress distributing along the anchor section. It was indicated that the shear stress was distributed nonlinearly.(2) Based on the derived distribution function of the axial force, the distribution function of axial force of the anchor support and shear stress of the anchor section was established at different stages, including the elastic phase, elastic-plastic phase, plastic phase and the plastic residual phase. In the examples, the results of the Mindlin’s model and the hyperbolic function model were compared.(3)Based on the Flac3D, the axial force of the anchor section of the anchor support in the soil slope was analyzed. Then, in order to verify the reliability of the model proposed in this paper, the simulated results of the axial force was transferred to shear stress of the anchor section.(4)Based on the shear lag-debonding model, considering that the distribution of shear stress along the anchor section was nonlinear, the method to calculate the anchoring depth was proposed. The results of the proposed method were compased to the method presented in the existing code, which considering the shear stress along the anchor section distributed linearly. Finally, in order to verify rationality of the proposed method, the numerical simulation was applied to the analysis of the safety of the strengthened slope.(5)The method proposed in this paper was applied to engineering example of slope central square of Huaihua Fortune. At the same times, the method to calculate the anchorage length and design parameters correctly use was introduced in detail.