| Highway due to linear technology requirements and terrain conditions,inevitably excavation slope,and the high slope is often the first reinforcement after excavation,this leads to disturbance of retaining structures for the process of anti-slide pile excavation disturbance load-bearing characteristics influence the present situation of the study is less,this article USES the centrifugal model test,numerical simulation analysis,the theoretical calculation,for both the whole buried anti-slide pile in the process of the excavation disturbance load-bearing characteristics to carry out the system research,analysis of pile soil slope,before the excavation condition which focuses on anti-slide pile and horizontal load-bearing characteristics,main research results are as follows:(1)The influence of soil slope in front of the pile on the bearing characteristics of the existing full-buried anti-slide pile: the horizontal displacement of pile top gradually increases during the excavation process.The maximum shear force and bending moment of pile body are located at the boundary of stratum.The shear force of pile body is distributed in "Z" shape,and the bending moment of pile body is distributed in "parabola" shape.The soil resistance in front of the pile is close to zero from the top of the pile body to the total excavation height,and increases first and then decreases after entering the rock strata.The earth pressure behind the pile presents a trapezoidal distribution from the top of the pile to the total excavation height,and a triangular distribution after the pile enters the rock.When the slope of soil in front of the pile is large,the total amount of soil in front of the pile is small.In this case,the disturbance caused by the layered excavation of soil in front of the pile is small.In practical engineering,when the soil in front of the pile needs to be excavated deeply or completely,the slope of reserved soil in front of the pile should be 60°～75°.(2)The influence of excavation conditions on bearing characteristics of existing full-buried anti-slide piles: the slope safety factor decreases gradually with the excavation process,and the reduction of safety factor can be effectively controlled by increasing the number of excavation layers in front of the pile.The peak values of pile shear force and pile bending moment are both at the boundary of stratum.The pile shear force is in the shape of "Z" and the pile bending moment is in the shape of "parabola".When the number of excavation layers in front of piles is increased,the variation law and distribution form of earth pressure are basically the same as(1).Considering the variation of pile shear force,bending moment and earth pressure,it can be concluded that the excavation depth of the soil in front of the pile should be 1 / 2 of the non anchored section of the pile.When the excavation depth exceeds 2 / 3 of the non anchored section,the soil resistance in front of the pile will be greatly reduced.Considering the influence of economy and improving slope stability,the excavation height of each layer should be 3 ～ 4m,and the total excavation height should be less than 1 / 2of the non anchored section of the pile.(3)The load-bearing performance of the side pile and the central pile is basically the same,but the displacement and internal force of the side pile are slightly greater than that of the central pile due to the soil arching effect behind the pile and the difference of the load distribution of the single row pile.Therefore,the load-bearing performance of the side pile should be properly improved during the design.(4)The disturbance to anti-slide pile can be effectively reduced by cutting slope in advance and multi-layer shallow excavation in front of pile;In order to ensure the safety and stability of the whole structure of anti-sliding pile-slope,the slope behind the pile should be pre-reinforced before the excavation of the soil in front of the pile. |
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