Hybrid Tests And Parametric Study Of Geosynthetic-Reinforced Pile-Supported Embankments

There is a complex coupling effect among soil arching effect of the embankments,tensile membrane effect of the geosynthetic reinforcement and load bearing effect of the soft ground in geosynthetic-reinforced pile-supported(GRPS)embankments.In model tests,the pile-soil ground is often simplified by differential settlement,which is difficult to reflect the real load bearing characteristics.Therefore,a geotechnical hybrid test method was used to simulate the GRPS embankments.Taking a field test as an example to perform the hybrid test.Compared with the measured results,the feasibility of the hybrid test method was analyzed.On this basis,hybrid tests with different embankment height and tensile stiffness of reinforcement were carried out to reveal the influence of embankment height and tensile stiffness of reinforcement.The main research results are as follows:(1)The soil arching effect of embankment and the tensile membrane effect of reinforced cushion were simulated by physical model.While,the rest parts,the interactions of pile and soil foundation were simulated by numerical model.The displacement and load data between the bottom surface of the embankment and the top surface of the pile foundation were timely exchanged through the developed geotechnical hybrid test platform.Experimental simulation of all components of GPRS embankment system was realized.(2)The test results had the same variation trend as the pile-soil load sharing and pile-soil settlement with the field test and the value were quite close to the field test,which proved that the geotechnical hybrid test could well simulate the complex coupling effects of the embankment,reinforced cushion and the pile foundation during the construction period of the GRPS embankment.The hybrid test method could well realize the simulation and evaluation of full component participation and full effect coupling working performance of GRPS embankment,and greatly save the test cost and time.(3)Based on the hybrid test technology,the experimental study on the influence of pile supported reinforced embankment parameters is carried out,and the effects of embankment height and tensile modulus on working characteristics are revealed.When the embankment height is low,the geosynthetic reinforcement with high tensile stiffness can improve the load efficacy of piles.The geosynthetic reinforcement with high tensile stiffness can significantly reduce the settlement and the differential settlement between piles and soil under different embankment height.