| With the continuous advancement of modernization,the implementation of the strategy of developing the western region,and the emphasis on building an environm ent-friendly society,the problems of expansive soil encountered in the project are not uncommon.As a widely distributed rock and soil body in South China,Southwest China and Northwest China,expansive soil has become one of the major problems in infrastructure construction in China due to its complex mechanical properties and difficult management.For the treatment of expansive soil,the bolt support method is mainly used at present.However,in the practice of protecting the expansive soil,the conventional anchor rod gradually shows the disadvantages of insufficient anchoring force,limited elongation and easy damage of the anchorage section.Based on this paper,a new type of pressure-retaining bolt support structure for expansive rock and soil is developed,which is compared with the bolt system widely used in the engineering field.Finally,based on the action characteristics of the new type of pressure-locking bolt Its support performance is analyzed in depth.The following is the main research content of this article:Firstly,based on the current research on the basic engineering mechanical properties of expansive soil,the initial conditions are constructed by air humidity,ambient temperature and external load,and the characteristics of soil expansion and contraction are analyzed.The periodic correlation of dry-wet cycle to soil is systematically described.boundary characteristics,deformation characteristics,and the influence of internal mineral distribution characteristics.Secondly,through the analysis of the structure and action mechanism of the pressure anchor,the shear strength test of the bolts with different diameters of the pressure bolt is tested,the shear strength of the test bolt is measured,and the stress-strain curve obtained by laboratory test is analyzed.The amount of pressure generated by different bolts is obtained,and the mechanical characteristic curve of the pressure anchor is obtained.The construction method of the pressure bolt support structure is described.Thirdly,by selecting the expansion force attenuation curve and combining the mechanical characteristic curve of the pressure anchor,the support mechanism of the new pressure anchor is analyzed.Based on the anchoring force growth curve,thedeformation analysis of the new type of pressure anchors and ordinary bolts and ordinary pressure anchors is carried out.From the mathematical level,the energy constitutive analysis of the three anchors is carried out,and the mathematical expressions of the three anchors in different rod displacement stages are derived.According to the energy constitutive relationship of the three anchors,the limit energy values of the three anchors are compared and analyzed.Finally,based on the finite element software,the support effect of the pressure bolt support structure system in the slope of expansive rock soil is further studied,and the stability of the slope of the expansive rock mass supported by the pressure bolt is analyzed.The stability of the slope of the expansive rock and soil supported by the pressure bolt is evaluated,and the feasibility of allowing the pressure bolt to support the slope of the expansive rock and soil is verified. |
