Study On The Safety Performance Of Foundation Of Rock Mass Reinforced By Prestressed Anchor Rod About Wind Turbine

The new kind foundation of rock mass reinforced by prestressed anchor rod, which is a new type of foundation, is widely used in wind power industry and transmission line tower. Therefore, it is important to evaluate the safety of foundation in the form of the rock mass reinforced by prestrssed anchor rod, and it can make sure the safety performance and the normal operation during the life cycle of the foundation. Failure mode of the foundation has undergone tremendous changes with the use of light weight, high strength of the production of new materials. It is difficult to calculate exactly safety performance using the ultimate tensile stress and the ultimate compressive stress of the foundation. And fatigue is also one of the standard methods to assess the safety of the foundation. The ultimate pullout capacity and fatigue failure of the rock mass reinforced by prestressed anchor is analyzed according to fatigue model test and finite element numerical simulation, then the security of the rock mass reinforced by prestressed anchor is assessed. The main researches are as follows.(1)The finite element model of wind turbine is set up, and the load capacity of the foundation under the conditions of different geological conditions and different load cases is studied by the three dimendional finite element model. The results of analysis show that the higher the strength of the rock foundation, the greater the ultimate bearing capacity of anchor.(2)Simulation analysis is used to a reduced-scale experimental and concrete is used to simulate the rock mass. Pouring anchor mortar and concrete first, and then making rock- anchor the base model.The results show that increasing anchor hole diameter can improve the structural pullout capacity. The influence to the load capacity is researched with the change of bolt hole diameter and bolt diameter.(3)Fatigue loading on the bolt loading is controlled by pulsating fatigue testing machine, Using collection devices dhdas to collect the strain of bolt. Fatigue performance of prestressed rock- anchor foundation anchor, anchor, concrete anchor system is analyzed according to the test results. After four million times cyclic loading, fatigue failure phenomenon does not appear. It shows rock bolt foundation has better fatigue properties. Static fatigue tests carried out after drawing the final bolt pulled off, indicating that the interfaces between rock, mortar and anchor have a high load carrying capacity. Bolts are the weak parts of foundation of rock mass reinforced by prestressed anchor rod.