Soil Resistance Characteristics And Destruction Mode Of Rigid Anti-Slide Piles Under Deep Displacement In Deep Loess Area

Rigid anti-slide piles are widely used in natural landslides or artificial roads and roadbed construction induced landslides.A lot of analysis has been done on the distribution and calculation of the soil resistance of the anchorage section under the action of transverse landslide reasoning.However,due to the current standard of traditional building and bridge pile foundation,only a small amount of horizontal displacement(limit displacement 6~10mm)is allowed for the pile foundation,and the design concept of the anti-slide pile is considered to be anchored under the sliding surface,so the pile foundation is used for large displacement.There is still little research on the lateral ultimate soil resistance.However,in fact,for the anti-slide piles in the slope treatment,the pile-plate retaining walls in the roadbed filling,especially the anti-slide piles in the soil stratum(such as the deep loess area),the horizontal displacement of the pile foundation There is no strict limit.In these cases,the sliding resistance of the soil before the falling surface is easy to reach the limit or even destroy.However,the existing design calculation theory only uses the "allowable compressive stress" index to control,and the experimental and theoretical research on the limit of soil resistance has been rarely studied.In summary,this paper takes the landslide caused by the excavation of the actual highway high-slope slope in the deep loess area as the background,based on the case of the rigid anti-slide pile treatment project,using the elastoplastic theory analysis calculation,numerical simulation promotion,indoor geophysics The model(similarity 1:10)test verified that the soil resistance limit and failure mode of the rigid anti-slide pile with anchorage in deep loess under large displacement were studied,and the following main results were obtained:(1)Analytical solution of plastic soil pressure value and soil depth and strength parameters of rigid piles under lateral load by theoretical calculation,which is in good agreement with numerical calculation and model test results.The value of plastic soil pressure is used as the control index of soil pressure before the design of rigid anti-slide piles in loess area.(2)Under the large displacement load of the pile top,the failure of the rigid anti-slide pile under the soil condition is the layer-by-layer yield failure of the soil before the pile;the maximum soil resistance section in front of the pile rises rapidly(the displacement at the surface is 11mm)to the maximum.After the value(the displacement at the surface is 41mm),it begins to slowly decrease,and it is considered that the soil before the pile begins to enter plastic failure.(3)Under the condition of large displacement of the pile body(displacement >10mm at the surface),the lateral bearing capacity of the rigid anti-slide pile still shows a linear increase.When the maximum soil resistance section reaches the maximum value(the displacement at the surface is 41mm),the lateral thrust load is The ultimate load is 5 times and 3 times the ultimate bearing capacity of the traditional ultimate displacement limit(6,10mm).(4)The soil layer parameters have no obvious influence on the overall plastic displacement load value of the soil before the pile,but the impact on the breaking speed after the ultimate strength is obvious.The larger the value,the slower the plastic yield of the soil layer before the pile,the more the degree small.However,the displacement load value of the soil before the pile and the failure speed after exceeding the limit have a significant effect.The larger the value,the later the critical value is reached,but the sooner the yield failure occurs,the faster the destruction speed.(5)Using the concept of "extreme displacement" to solve the nonlinear ultimate soil resistance of the pile side based on the theory of elastic foundation beam.For the calculation of the bearing capacity of rigid piles under large displacement displacement,considering the yield of some soils instead of reducing the foundation coefficient,the calculation results are more theoretical and the distribution of soil resistance before piles is more reasonable.