Study On Earth Pressure Between Piles Under Seismic Action Considering Soil Arching

Pile-sheet retaining system has strong retaining capacity and low maintenance cost.It is widely used in construction projects,such as railway construction,highway construction,water conservancy projects and building construction.Owing to the soil arching between piles,the pile-sheet retaining built in excavation slope is quite different to that built in embankment slope.Soil arching effect is an important factor in the stability of soil between piles and the distribution of earth pressure on sheet.Rational utilization of soil arching effect can make full use of the strength of soil,and reduce the cost.Although the effect of soil arching between piles has been well known,the geometrical form of soil arching and the distribution of earth pressure on sheet have not yet reached a consensus.The calculation theory of earth pressure on sheet is still imperfect.The stability of soil arching and the calculation theory of earth pressure under seismic action are especially lack.Thus,there have blindness in the design of sheet in earthquake area.The paper is based on the National Natural Science Foundation of China,Seismic Failure Mechanism and Seismic Design Theory of Mountain Architecture(No.51638002).In view of practical projects,model test and theoretical analysis were combined to study on the stability of soil arching and the calculation of earth pressure on sheet under seismic action.The main achievements and conclusions are summarized as follows:(1)The model of pile-sheet retaining was designed,and model test of soil arching effect was carried out.By using non-contact full field strain measurement system(VIC-3D),the changes of displacement field on the top of slope,before and after the formation of soil arching,were studied.And the formation mechanism of the soil arching between piles was analyzed.(2)By simulating the slope excavation,the change of the earth pressure on the back of piles and sheets during the formation of soil arching were analyzed,and the distribution of earth pressure on the span of sheet was obtained.The three-dimensional shape of sliding body between piles is studied by removing the sheet between piles.(3)Basing the shaking table test of pile-sheet retaining,the effects of earthquake on earth pressure and soil arching were analyzed.The influences of different seismic wave and ground motion parameters on the earth pressure and the stability of soil arching are analyzed.And the effects of different seismic wave and seismic ground motion parameters on earth pressure and stability of soil arching were also studied.The test found that the slope under earthquake has obvious whiplash effect.The different response to earthquake action between pile and sheet was analyzed under the effect of soil arching.(4)By simplifying the soil arching problem as a plane strain problem,reasonable hypothesis and simplification were used to get the reasonable axis equation of soil arching and the position of the most disadvantageous section,and the results were verified with the results of model test.(5)The horizontal layer analysis method and pseudo static method were adopted to build the calculation model of seismic earth pressure on sheet.A calculation method of earth pressure on sheet was proposed,which has taken soil arching effect and earthquake into consideration.Compared with the unloading arch method,the silo method and the GB method,the validity of the proposed calculation method was verified.By using the proposed method,the effects of pile spacing,earthquake acceleration and soil friction angle on the earth pressure of sheet were analyzed.