| Because of its low cost and convenient construction,frame prestressed anchors have been widely used in soil slope treatment in northwest China.At the same time,its excellent reinforcement effect and seismic performance have attracted a lot of scholars' attention.However,there are few studies on the earth pressure of the frame prestressed anchor support structure.Some literatures consider the pullout resistance of the anchor as a factor to reduce the earth pressure and ignore the effect of prestress on the earth pressure,which causes the calculation results to be different from some experimental observations.Based on the reinforcement mechanism of the frame prestressed anchor support structure,this paper studies the earth pressure of the slope reinforced by the frame anchor under static and dynamic effects as follows:(1)Based on the structural characteristics and working mechanism of the frame prestressed anchor supporting structure,the effects of prestress and anchor on earth pressure are analyzed.The results show that the prestress will affect the earth pressure and the anchor will not affect the earth pressure acting on the supporting structure.On this basis,the horizontal layer method is used to solve the active earth pressure of the frame prestressed anchor supporting structure under static action.The effect of prestress on earth pressure is analyzed through theoretical calculation and finite element software simulation.The results show that the prestress will increase the earth pressure on the supporting structure,and the horizontal layer analysis method can better reflect the nonlinear distribution of earth pressure.(2)Based on the analysis of the working mechanism of the frame prestressed anchor supporting structure,combined with the pseudo-dynamic method considering the prestress,the potential slip surface of the frame anchor reinforced slope when a harmonic earthquake occurs is determined.Combined with the horizontal layer analysis method,the active earth pressure of the frame anchor support structure considering prestress under simple harmonic earthquake was solved.Finally,combined with an engineering case,the theoretical analysis and numerical simulation methods are used to compare and analyze the law of earth pressure on the frame anchoring support structure under simple harmonic earthquakes of different intensities and different prestresses.The results show that higher prestress can restrain the amplitude of seismic earth pressure change.(3)In this paper,the effects of prestress,bond strength between anchor and soil,soil strength parameters,anchor spacing,and vertical earthquakes on the earth pressure acting on the frame anchor support structure were analyzed by Plaxis3 D finite element software.The results show that: regardless of earthquake or not,adjusting the anchor parameters does not change the size and distribution of earth pressure and prestressing is one of the important factors affecting earth pressure;increasing the soil strength parameters can effectively reduce the seismic earth pressure of the slope acting on the supporting structure;the effect of adjusting the spacing of the anchor and adjusting the prestress on the earth pressure is basically the same;vertical earthquake action will increase the earthquake earth pressure of the slope reinforced by frame anchors,but increasing the vertical earthquake acceleration coefficient has a limited effect on the increase of earthquake earth pressure. |
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