Study On Pile-Soil-Structure Interaction Of Frame Structures In Mountainous Areas

Buildings in mountain towns always combined with slope and structure.It is often assumed that the structure is rigidly connected on the slope,and the pile,structure and retaining are designed independently,but in fact,there will be interaction among the slope,retaining wall and pile.How to consider these interactions for structural design and engineering safety is an urgent problem to be solved.At present,there is little research on this aspect and it is necessary to conduct study on pile-soil-structure interaction of these structures,which can provide reference for the design of pile,lateral earth pressure of retaining structure and the shear force of story-falling part in engineering practice.In this paper,the OpenSees finite element analysis software is used to simulate and analyze the whole model of the structure considering the interaction of superstructure,pile and soil.Considering the factors such as the height of the structure,the height of the slope,the distance between the pile and the slope,the soil parameters and so on,the gravity load and the earthquakes of 8 degree(0.2g)in the slope are analyzed.The influence of pile on lateral earth pressure of retaining,the influence of slope deformation on pile and the influence of interaction on the forces of these structures are discussed,and the design suggestions are given.The main conclusions of this paper are as follows:(1)Built structure on the mountain slope can increase the lateral earth pressure of retaining structure,the increase of soil pressure of retaining mainly above the retaining wall,and the maximum amplitude is in distance from the top one-third of the height.(2)The lateral earth pressure of the retaining wall under static action becomes larger with the stories increase.When the slope becomes higher,the lateral earth pressure is reduced because the retaining wall becomes higher and less rigid.As the distance between the pile and the slope increases,the influence between them gradually becomes smaller,and gradually approaches the unstructured condition.(3)The lateral earth pressure increases more in the upper 2/3 height of retaining wall,and the lateral earth pressure of structure will be slightly smaller in the lower 1/3 height range of retaining wall during earthquakes.The lateral earth pressure of retaining wall increases with the increase of stories and the slope height.With the increase of the distance between the pile and the slope,the influence of them becomes weaker.The better soil condition is,the smaller response in earthquakes.It is safe for the design of retaining wall to consider seismic angle and other measures in the code under small earthquakes,while it is unsafe under large earthquakes.The static earth pressure of retaining wall without considering the superstructure can not meet the design requirements during large earthquakes.The safety factor of 1.3 to 1.6 should be taken into account.The lateral earth pressure of slope can be further reduced by setting up the pull beams at the ground end.(4)The pile of the structure on the slope has the harmful effect of transferring the load of the superstructure to the retaining wall and the beneficial effect of anti-sliding of the slope.The maximum shear force of the pile is within the distance of 2 to 4 meters from the top,and the maximum bending moment is near the top when suffering earthquake.The number of stories has little effect on the internal force of piles.With the increase of the slope height,the shear force of piles increases.When the height of slope reaches 6 meters,the shear force will increase in the bottom range,and the anti-sliding effect will be stronger.With the different distance between the structure and the slope,the impact on the pile is small and can be ignored when the distance reaches about 10 times of the pile diameter.The better the soil is,the smaller the shear force will be.The pile in the lower grounding is most severely squeezed by the slope at the toe of the retaining wall,and the shear force is the largest.Comparing the shear force of the piles under different factors with the shear bearing capacity calculated by the code according to the size,when suffering large earthquakes,the high slope height(9m)can not meet the requirements.When the slope is high,the size or hoop of the pile the and the diameter of the reinforcement should be increased in design to ensures the safety of the pile.(5)It is beneficial to the supporting and the internal force of the column and pile on the slope to set pull beam when the depth is relatively shallow under earthquakes,which will increase the internal force of lower grounding column.The connection effect of the pull beam is the best at the ground end.(6)The whole model considering the interaction of pile-soil will change the shear distribution of each column in the upper grounding.The upper grounding column distributes less shear force and the lower distributes more.