The Reasearch On The Transfering Regulation On Anchoring Section Stress Of Pre-stress Anchorage Based On Finite Element Method

Geotechnical anchoring plays an important role in the field of geotechnicalengineering.Anchoring techniques include a variety of support in the form of the bolt, boltingand shotcrete, bolting and shotcrete net. Prestressed anchoring technique is to anchor throughthe rock and soil potential slip surface into the rock mass and stable part to be fixed andimposed in the head at a certain tensile force, so that the sliding soil and stability ingeotechnical the formation of a unified whole. This technology take full advantage of the rockmass strength and stability that it is economical, security, effective, constructed conveniently,and can be controlled easily, is widely used in engineering support areas.The study of the stress distribution in the anchoring position is the key to research prestressedanchor technology. The current specific project prestressed anchoring technology calculationis based on the stress that evenly distributed between the anchor segment as a precondition.The academic community generally believes that the distribution of stress along anchoringsection than the average, there will be a stress concentration zone exist; stress is close to zerowith the extension of the anchoring segment will appear on a certain position of the anchoringsegment; excessive extended the length of the anchoring section, is meaningless in practicalengineering.The study to prestressed anchor are mainly three types: the test method, the theoreticalderivation and numerical simulation. As test method can not accurately restore the actualproject conditions, and having a size effect, adjusting the parameters intricately, heavyworkload and some other reasons, there are certain shortcomings in the actual study.Numerical simulation method is the use of finite element principle, truss element simulation ofthe bolt, the analysis of the interaction of the bolt and the surrounding rock mass. In this thesis,the author uses finite element software-Midas, accoiding to the following respect to study the stress distribution in the prestressed anchor:1)stress distribution for different rock and soil anchoring;2)stress distribution for different anchorage length;3)stress distribution for different prestress conditions;4)stress distribution under different anchoring ways;5)stress distribution in the actual project the bond section of the prestressed anchor cable.We found that the stress concentrated at the starting site of the anchoring segment sufferedprestressed through the curve analysis; as the prestress increases, the stress distribution relativeto the average; when the anchoring segment length increased when the stress does notprestressed parts of the anchoring segment suffered from afar pass again; anchor and thesurrounding rock and soil modulus of elasticity greater the difference between the anchoringsection stress distribution on the more average when to a certain length of the anchoringsection, stress does not further anchoring segment suffered the prestressed parts of the distantpass; reasonable combination of tension and pressure-type anchor cable to the formation ofshear type anchor cable, we can effectively disperse the stress on the anchor body, serve toincrease the tensile strength of prestressed anchor cable effect; in the actual project, taking intoaccount the uneven grouting, groundwater, borehole collapse, can be properly anchoringsegment longer, but should be based on the actual situation.